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Патент USA US3089677

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May 14, 1963
F. GOSSLAU ETAL
3,089,667
JET AIRCRAFT FOR SHORT TAKE-OFF AND LANDING DISTANCES
Filed April 28, 1960
6 Sheets-Sheet 1
BY
May 14, 1963
F. GOSSLAU ETAL
3,089,667
JET AIRCRAFT FOR SHORT TAKE-OFF AND LANDING DISTANCES
Filed April 28, 1960
6 Sheets-Sheet 2
INVENTORS
Fri/z ?og/a,?
BY
Mar)? Pain/jar
MKS
May 14, 1963
F. GOSSLAU ETAL
3,089,667
JET AIRCRAFT FOR SHORT TAKE-OFF AND LANDING DISTANCES
Filed April 28. 1960
6 Sheets-Sheet 3
May 14, 1963
F. GOSSLAU ETAL
3,089,667
JET AIRCRAFT FOR SHORT TAKE-OFF AND LANDING DISTANCES
Filed April 28, 1960
6 Sheets-Sheet 4
F765
F766?
F/G..9
INVENTORS
Fr-ih- Gasrfaq.
BY
Hurl- 22in??
May 14, 1963
'
F. GOSSLAU ETAL
3,089,667
JET AIRCRAFT FOR SHORT TAKE-OFF AND LANDING DISTANCES
Filed April 28, 1960
6 Sheets-Sheet 5
May 14, 1963
F. GOSSLAU ETAL
3,089,667
JET AIRCRAFT FOR SHORT TAKE-OFF AND LANDING DISTANCES
Filed April 28, 1960
6 Sheets-Sheet 6
3,089,667
Unite States ?latent
Patented May 14, 1963
ll
2
3,�,6�_
engines into a position in which the jet thrust has a brak
.
ing component acting in the direction of the ?ight, and
this constructive solution is applied in aircraft for verti
JET AEREIRAFT FOR SHQRT TAKE-OFF
LANDING DISTANCES
cal take-off.
Fritz Gosslau, Grunwald, near Munich, and Kurt
Reiniger, StuttgartaZu?enhausen, Germany, assignors
to Junkers Flugzeng- and Motorenwerke A.G., Munich,
Germany
'It is also known to angularly displace the jet engine,
or to de?ect the jet by means of an adjustable exhaust
nozzle in order to obtain a vertical thrust component sup
Filed Apr. 28, 1960, Ser. No. 25,365
porting the aircraft and relieving the wing during vertical
Claims priority, application Germany May 2, 1959
take-off.
In accordance with the present invention, a jet engine
The present invention relates to a jet aircraft for short
having a very high thrust is provided, and such thrust is
take-off and landing distances, and more particularly to a
at least equal to the weight of the aircraft. However, in
jet aircraft capable of taking off and landing within a
accordance with the present invention, the jet engine is
fraction of the distance required by conventional jet air
not angularly displaced in the aircraft, nor is the jet de
planes capable of reaching extremely high, and supersonic 15 ?ected, since these known solutions of the problem of
speeds.
producing a high vertical component of the thrust, result
Modern jet propelled aircraft capable of ?ying at super
in extremely dif?cult constructive problems.
sonic speeds, require a very long runway for take-off and
In accordance ?with the present invention, the effective
28 Claims. (Cl. 244-12)
landing.
10
wing surface as well as the thrust of the engine are ap
It is the object of the present invention to provide a jet 20 proximately twice as great as in known supersonic air
aircraft capable of taking off from short runways, and of
craft. The wing load is not more than 350 kg/m.2 and
landing on short runways.
the thrust of the engine is at least equal to the take-off
A related object of the present invention is to provide
weight of the aircraft, which includes full fuel tanks.
a jet aircraft capable of take-off and landing on small
During take-off the aircraft is placed in extremely steep
25 position in which the wings have a maximum angle of
and unpaved air?elds within a short distance.
Another object of the present invention is to provide a
incidence in which the maximum lift is produced before
jet aircraft capable of take-oft" and landing at low speeds.
the stream lines break away from the wing surface.
The distance along which an aircraft rolls before tak
The jet engine has a downwardly inclined outlet noz
ing off and after landing, is mainly determined by two
zle producing a thrust whose line of force passes through
factors:
30 the center of gravity of the aircraft in the steeply inclined
take-01f position.
(a) A minimum take-off speed, and a minimum land
ing speed are necessary for taking off and landing within
An alighting means or landing gear including main
a minimum rolling distance so that the kinetic energy
wheels and tail wheel means is provided which is so ar
ranged that the wings of the aircraft have the desired
produced by the engine during take-off, or the kinetic en
ergy which has to be overcome by the brakes during 35 great angle of incidence when the aircraft rests on the
landing gear.
landing, is reduced to a minimum.
(21) The greatest possible acceleration corresponding
In the preferred embodiment of the present invention,
to great thrust is required for accelerating the aircraft to
take-off speed within the shortest possible time and the
the landing gear also includes an auxiliary wheel in the
nose of the plane corresponding to a conventional tricycle
shortest possible distance, while the greatest possible de 40 landing gear, so that the aircraft may ?rst rest on the
front wheel and main wheels in a substantially horizontal
celeration, corresponding to a braking force is required
position, and then turn to the take-off position resting
for reducing the landing speed of the aircraft until it stops
on the rear wheel means.
within the shortest possible time and shortest possible
distance.
'
The minimum landing and take-off speeds are deter
mined by the ?wing load and the lift coefficient of the wing,
and is determined by the equation
W 1
Auxiliary jet means are provided on the aircraft for
turning the aircraft between the two alighted positions,
and such auxiliary jets may also be used for propelling
the aircraft during ?ight, and for altering the position
of the aircraft during landing approach ?ight.
In accordance with the present invention, the landing
50 approach ?ight, and the rolling on the air?eld, takes place
in a landing position of the aircraft in which the angle
In this equation, W is the weight of the aircraft, S is
of incidence of the wings is again the maximum. During
the effective surface of the wing
the approach ?ight, extremely large parachute brakes are
opened, and the surface of the parachute brakes is di
W
mensioned in such a manner that the jet engines can
S
run at full power as is necessary in accordance with the
is the wing load, and CL is the lift coe?icient of the wing.
present invention for obtaining a very high vertical thrust
From the above equation follows that for a given weight
component permitting the landing of the aircraft in a
of the aircraft, the minimum speed can be lower if the
landing position in which the wings have the maximum
wing surface and lift coefficient are correspondingly 60 angle of incidence. The interaction of the parachute
greater. Use of large wing surface for low minimum
brake and the jet engine is such that an approach speed
speeds, and the use of lift-increasing means, such as ?aps,
is obtained which is considerably lower than the minimum
suction devices, and blower devices, is well-known, par
speed obtainable with the wings at the same angle of
ticularly for landing operations. However, a large wing
incidence, but with the jet engine thrust reduced, and no
surface results in a high drag at high speeds.
parachute brake applied. After the approach landing
For acceleration of the aircraft during take-off, the use
speed of the aircraft has been sufficiently reduced, the
of thrust-increasing means, such as rockets, catapults, etc.,
engine thrust is reduced, ?and the parachute brake detached
is well-known. In order to reduce the rolling distance
or otherwise rendered ineffective.
required for landing, it is known to produce an additional
A jet aircraft in accordance with the present invention
drag by brake ?aps and brake parachutes, or the ground 70 preferably comprises wing means having an effective sur
friction may be increased by Wheel brakes or other fric
face area selected so that the ratio between the weight of
tion producing means. It is also known to turn the jet
the aircraft and the surface is not greater than 350
3,089,667
3
tive during the landing approach flight in the position of
FIG. 10;
kg./m.2; jet engine means ?xed on the aircraft for pro
ducing a thrust at least as great as the weight of the air
FIG. 16 is a vector diagram illustrating the forces effec
tive when the parachute brake is open as shown in FIG.
craft; and alighting means for supporting the aircraft in
take-off and landing positions in which the angle of in
11; and
cidence of the wing means is a maximum for producing
FIG. 17 is a vector digram illustrating the forces acting
a maximum lift. The engine means is tilted with the air
in the condition of FIG. 12 in which the jet engines are
craft in the take-off position so that the vertical compo
stopped.
nent of the engine thrust is at least one-half of the total
Referring now to the drawings, and more particularly
engine thrust.
Normally closed parachute brake means are attached l0 to FIGS. 1 to 4, a fuselage 1 has alighting means includ
ing main wheel means 5, nose wheel means 6, and tail
to the aircraft and have in open condition an effective
wheel mains 7 connected by ?rst and second undercar
riages to the fuselage. Jet engines 3 and 4 are ?xed on
the fuselage and mainly extend in direction of the longi
su?icient to compensate the horizontal component of the
full engine thrust which is required during landing for 15 tudinal axis A of the airplane. The outlet nozzles 3a
and 4a of the jet engines 3 and 4 are downwardly in
producing a vertical component.
clined and have axes intersecting with a horizontal axis
The parachute brake is preferably attached to the tail
of the plane passing through the center of gravity 10.
?n of the aircraft at a point located in a horizontal plane
The axes 31 and 41 of the outlet nozzles 3a and 4a are
passing through the center of gravity of the aircraft when
20 located in a plane which de?nes an angle 6 with a plane
the aircraft is in the landing position.
passing through the chords 2a of the wings 2. The
Auxiliary jet means are provided for producing turn
plane of the wing chords de?nes an angle a with a hori
ing moments on the aircraft by which the aircraft is
zontal plane when the aircraft is in the take-off position
turned from the take-off position into a normal ?ight posi
shown in FIG. 7, or in the landing position shown in
tion, and from a normal ?ight position into the landing
25 FIG. 12. Consequently, the plane passing through axes
position.
31,, 41 of the nozzle outlet means de?nes with a hori
The take-off method of the present invention comprises
zontal plane the angle u-j-B.
the steps of placing the aircraft in a take-off position in
The fuselage supports a tail ?n 12 at the upper end
which the angle of incidence of the wings is a maximum;
surface selected for producing during landing approach
?ight and during movement of the alighted aircraft, a drag
of which a container for a parachute brake means is
and producing a jet thrust at least as great as the take-off
weight of the aircraft and having a vertical component at 30 mounted. The container 15 is preferably shiftable to
vary its distance from the longitudal axis of the plane
least one half of the total jet thrust.
The landing method of the present invention comprises
and from the center of gravity 10. The jet engines 3
the steps of placing during landing approach ?ight the
and 4 receive air through forwardly located inlets l1,
aircraft in a landing position in which the angle of in
and auxiliary ?ns 13 and 114 are provided which extend
cidence is a maximum; producing a jet thrust at least as 35 downwardly from the sides of the aircraft as best seen
great as the landing weight of the aircraft and having a
in FIGS. 3 and 4.
vertical component at least one half of the total jet thrust;
Auxiliary jet means 8 and 9 are mounted at opposite
and simultaneously braking the aircraft by parachute
sides of the vertical plane of symmetry of the aircraft,
as best seen in FIGS. 2 and 4, and each of the auxiliary
The novel features which are considered as character 40 jet means 8 and 9 is turnable about a horizontal axis,
istic for the present invention are set forth in particular
and may also be turnable about a vertical axis. Each
brakes.
in the appended claims. The invention itself, however,
of the wings ?2 has elevators 2b which may be connected
both as to its construction and its method of operation,
to the auxiliary jet means 8 or 9 on the same side for
turning movement about horizontal axes.
together with additional objects and advantages thereof,
will be best understood from the following description of 45
According to the present invention, the wheel means
speci?c embodiments when read in connection with the
5 and 7 are supported on an undercarriage in such a
accompanying drawings, in which:
manner that the wings 2 have the maximum angle of
FIG. 1 is a side view of a jet aircraft in accordance
incidence when the airplane rests on wheels 5 and 7 in
with one embodiment of the present invention;
the positions of FIGS. 7 and 12. The angle of inci
FIG. 1a is a side view on a larger scale illustrating aux 50 dence has a maximum value above which the air?ow
iliary jet means, FIG. 1b is a side view on a larger scale
breaks off from the wing surface during take-off, or at
illustrating parachute brake means;
which the airplane stalls during landing approach ?ight.
FIG. 2 is a plan view of the aircraft shown in FIG. 1;
FIG. 3 is a front view of the aircraft;
FIG. 4 is a rear view of the aircraft;
FIG. 5 is a side view of the aircraft in an alighted posi
tion;
FIG. 6 is a side view of the aircraft in an intermediate
55
The delta wing has very desirable characteristics for
the purposes of the present invention, inasmuch as the
lift increases to a very small extent as the angle of inci
dence is increased which may be mathematically ex
pressed as follows:
dcL
FIG. 7 is a side view of the aircraft in takeoff position; 60
do:
FIG. 8 is a side view of the airborne aircraft directly
Maximum lift is attained only when the angle of inci
after take-01f and still in take'off position;
dence is very large. On the other hand, in contrast to
FIG. 9 is a side view of the aircraft in ?ight position;
the straight and arrow-shaped wings, the delta wing is
FIG. 10 is a side view of the aircraft in landing ap
65 not subject to a'sudden breaking down of the lift, so
proach position;
that the loss of lift at the maximum angle of incidence
FIG. 11 is a side view of the aircraft in landing ap
occurs very slowly and therefore is not dangerous.
proach position with the parachute brake open;
An angle of incidence a of 25 degrees still produces
FIG. 12 is a side view of the alighted aircraft in landing
su?'icient lift if a delta wing is used. If the jet engines
position;
FIG. 13 is a side view of the aircraft in another alighted 70 are mounted on the aircraft in a position parallel to the
wings, a vertical thrust component of 40% is obtained
position with the parachute brake released;
which relieves the wing lift. When the outlet nozzles
FIG. 14 is a vector diagram illustrating the forces op
of the jet engines are inclined through an angle 5 of 5
erative during take-off of the aircraft in the positions of
degrees to the wing chords 2a, a vertical thrust compo
FIGS. .7 and 8;
FIG. 15 is a vector diagram illustrating the forceseffec 75 nent of 50% is obtained, as follows from the equation
alighted position;
3,089,667
5
6
Tv=T sin (wt-6). Since (n+6) is 30 degrees, sin
(oz-I-B) is 0.5, and the vertical thrust component
Tv=0.5T. Under these condition, the wing load is re
clined, a turning moment about the longitudinal axis of
the aircraft is obtained, which facilitates banking opera
tions. The two auxiliary jet means 8 and 9 are inde
duced to
pendently controlled ?for producing different thrusts
W=TSlJ1 ec+5
whereby -a turning moment about the vertical axis of the
aircraft is obtained. In a modi?ed construction, each of
the auxiliary jet means 8 and 9 is mounted on a support
including a universal joint, so that the directions of the
thrusts of the two auxiliary jet means can be adjusted to
S
wherein W is the take-off weight of the aircraft, T is the
thrust of the jet engine, and S is the effective surface of
the wing.
In accordance with the present invention, the thrust
10 any desired position.
In accordance with the present invention, the aircraft
of the engine is selected to be at least as great as the
is in a steeply inclined position during landing approach
flight, and while decelerating after landing. In this man
weight W of the aircraft, so that the required aerodynamic
lift can be determined by the following equation:
ner, a sufficiently high vertical thrust component of the
?xedly mounted jet engines is obtained. The maximum
angle of incidence is again the angle of attack of the
wing at which the ?airflow breaks off and the lift termin
the moment of take-off of an aircraft is
ates. While the aircraft is tilted to obtain the greatest
possible angle of incidence, the engine is run at full power,
if necessary at full power with after-burning.
Since the landing position of the aircraft is the Same as
the effective aerodynamic wing load of
the take-off position, the vertical component of the thrust
L
is again 50% of the total thrust, and of the weight of the
I?
aircraft. The landing weight of the aircraft is smaller
is 100 kg./rn.2 or less due to the action of the vertical 25 than the take-off weight of the aircraft, since fuel has
been consumed during ?ight and the fuel tanks are
thrust component of 0.5T or 05W. Due to the effect
empty. Therefore, the Wing load
of the vertical thrust component, the take-off speed is
reduced to 70% as compared with known jet aircraft,
an =150 kg./m.z
and the required kinetic energy is reduced by 50% irre
S
spective of the improvement obtained by the reduction
Since the vertical component of the thrust is at least one
of the wing load as compared with the corresponding
half of the total thrust, which corresponds to one half
values for known jet aircraft.
of the weight of the aircraft, the aerodynamic wing load
The horizontal thrust component depends on the cos
is reduced to 75 kg./m.2. This wing load determines the
u-j-b?, and assuming an angle of 30 degrees, the hori 35 landing speed which may, for example, be 130 kin/h.
zontal ?thrust component is 87% of the total thrust. Con
However, in order to maintain the stationary equilibrium,
sequently, the horizontal thrust component remains with
the horizontal thrust component must be destroyed to such
in reasonable limits, and permits sufficiently rapid acceler
an extent that no more of the horizontal thrust com
ation during the take-off. The greater aerodynamic drag
ponent remains effective as is necessary for overcoming
of the aircraft during the last part of the take-off run 40 the aerodynamic resistance of an aerodynamic braking
15
Assuming, from the example, that the wing load in
Kg=200 kgjmz
in steeply tilted position is only approximately 10% of
the take-off thrust and is therefore negligible.
In a preferred embodiment of the invention, the en
gine inlets 11 are constructed as two-dimensional super
sonic planar diifusors with variable angle of displace
device.
7
In accordance with the present invention, a parachute
15a, which normally is carried in closed condition in the
container 15, is opened during ?landing approach ?ight.
The parachute brake means ?15a is oversized and com
ment for producing an oblique compression shock and
provided with a pivoted inlet ?ap. The inlet ?ap may
be tilted down to hold the intake losses low while the air
craft moves at low ?ying speeds after take-off or before
pensates at least a major part of the horizontal component
iliary jet means 8 and 9 are mounted for pivotal move
ment about horizontal axes between a position upwardly
inclined with respect to the longitudinal axis of the air
craft, as shown in FIGS. 6, 7, 8, 10 and 11, and ?a position
attaching the parachute, since an aircraft having delta
of the full engine thrust. Parachute brakes used in known
landing methods have a much smaller size designed to�
compensate the inertia of the landing aircraft with the
landing, or taxies on the ground.
50 jet thrust substantially reduced or no longer applied.
Since in the positions shown in FIGS. 8 and 10, the
As shown in FIGS. 11 and L2, the parachute brake 15a
aircraft is steeply tilted and moves at low speed, the
is attached to the tail ?n 12 at a point which is located
conventional controls are not fully effective and aux
in a horizontal plane passing through the center of gravity
iliary small jet means 8 and h are provided. The aux
10 of the ?aircraft when the aircraft is in the steeply in
iliary jet means 8 and 9 may be coupled to the respective 55 clined position in which the angle of incidence of the
elevators 2b, or are operable independently of the ele
wings 2 is a maximum. This requires attachment of the
vators. The auxiliary jets 8 and 9 may be controlled
parachute to the upper side of the aircraft, for example to
by a gyroscopic automatic control apparatus for the pur
the top surfage of the fuselage, or to bracket means se
pose of stabilization.
cured to the fuselage and upwardly projecting from the
in the preferred embodiment of the invention, the aux 60 same. However, it is preferred to use the tail ?n :12 for
wings is provided with a tail ?n of a shape suitable for
attaching the parachute brake in accordance with the
present invention, so that the brake force of the para
downwardly inclined to the longitudinal axis of the air 65 chute brakes passes through the center of gravity when
craft in which the tail end of the aircraft is raised by
the aircraft is in landing approach position.
turning the aircraft about its horizontal axis which may
The parachute brake is attached to the ?aircraft not
be desired for turning the aircraft from the position of
at the center of gravity, but a certain distance behind the.
FIG. 8 to the position of FIG. 9. In the intermediate
center of gravity. In this manner, a remarkable stabiliza
position of the auxiliary jet means, the thrust of the auxi 70 tion of the aircraft during the landing approach ?ight and
lary jet means extends in direction of the longitudnial
during the rolling in alighted condition is obtained, and
axis of the aircraft, and adds to the propulsion thrust.
such stabilization is highly desirable, since the aircraft
When the two auxiliary jet means 8 and 9 are turned
lands ?at very low speed and at a great angle of incidence
in opposite directions so that, ?for example, jet means 8
whereby the e?iciency of the aerodynamic controls is
is downwardly inclined and jet means 9 is upwardly in 75 impaired.
3,089,667
8
the take-off weight W. The aerodynamic drag D5 is over
The combination of the parachute brake with an over?
sized wing, for example a delta wing, permits a safe land-
come by the horizontal thrust Th which is 0.87T and en
ables the aircraft to accelerate.
ing operation at a low approach speed of, for example.
In the position of ?FIG. 8, the aircraft is already air
borne but still in the take-off position. The auxiliary
jets 8 and 9, and the elevators 217 may now be turned into
130 km./h.
It is evident that a low landing approach speed is a.
prerequisite for a short rolling distance on the air?eld.
a position extending substantially in direction of the longi
During the rolling of the aircraft on the air?eld, all acre-
tudinal axis of the aircraft, so that the aircraft climbs in
dynamic braking devices are e?icient only during the ?rst.
normal ?ight position with the thrust of the jet engines
part of the rolling when the speed is still su?iciently high.
As the aircraft decelerates and slowly rolls to a stop, the� 10 being etfective in a plane passing through the center of
gravity 10 of the aircraft.
parachute brake is no longer effective and wheel brakes.
For illustrative purposes, the data of an aircraft con
or landing skis are provided for bringing the aircraft to
structed in accordance with the present invention are given
a stop.
as an example:
The effective surface of the parachute brake according:
to the present invention is approximately 20% greater? 15
than the effective surface of the wing, which may be ex-<
pressed as 1.28.
The horizontal component of the thrust is 0.87 of the
total thrust, since it depends on cos 30�. The braking
force of the parachute brake substantially corresponds to 20
the horizontal thrust component.
As previously ex
plained, the landing weight WE is smaller than the take
off weight W, which is substantially equal to the total
thrust of the engine. From this follows that the surface
load of the parachute is approximately
IKE =125 kg./m.2
SP
Wing load at take-off weight ___________ __ 200 kg./m.2
Rolling distance _____________________ __ 110 m.
Rolling time ________________________ __ 6 sec.
Take-off speed ______________________ __ 150 km./h.
Average acceleration on the runway _____ __ 0.75 g.
Effective aerodynamic wing load ________ __ 100? kg./m.
In this table, the character g represents the acceleration
of gravity expressed in rn./sec.2.
The above table shows that an aircraft in accordance
25 with the present invention requires a rolling distance for
take-off of 110 m., whereas known aircraft of the same
type requires 800 in. rolling distance for take-off. A
.greater increase of the ratio between thrust and weight is
within the scope of the present invention, and will result
ent invention will now be described with reference to 30 in a further reduction of the take-off distance.
FIGS. 5 to 9, and to the diagram of FIG. 14.
The take-off operation has been described with reference
As shown in FIG. 5, the aircraft is in an alighted sub
to the preferred embodiment of the present invention in
The take-off of an aircraft in accordance with the pres
stantially horizontal position resting on the main wheels
which in addition to the rear undercarriage, a nose wheel
5 and on the nose wheel 6. ?In this position, boarding of
6 is provided. However, the nose wheel 6 is not an essen
the plane is facilitated. The aircraft is moored or an 35 tial element of the present invention, and the aircraft may
chored to the ground so that the engines can be brought
be started in the position of FIG. 7, and roll the entire
up to full power with after-burning. The aircraft is then
take-off distance in the position of FIG. 7. The position
released, and taxies in the position of FIG. 5 on the for
of FIG. 5 provides a greater stability during the ?rst part
ward landing gear. The direction of thrust of the auxil
of the take-off run at slower speed, and moreover is desir
iary jet means 8 and 9 extends substantially through the 40 able for boarding and loading, and for taxiing the air
center of gravity 10 of the aircraft.
craft.
When the aircraft has moved through substantially
A landing operation in accordance with the present in
half the available rolling distance, the aircraft is gradu~
vention is illustrated in FIGS. 10 to 13, and diagram
ally tilted by operation of the elevators 2b and by tilting
matically illustrated in FIGS. 15 to 17 .
the auxiliary jet means 8 and 9 in upward direction. The 45
Before the aircraft approaches the landing ?eld, the
auxiliary jet means 8 and 9 are provided with compressed
auxiliary jets 8 and 9 are tilted upwardly to turn the air
air from the compressors of the main engines 3 and 4, and
craft into the landing approach position shown in FIG.
include a combustion chamber and a nozzle. However,
10 in which the wings have a great angle of incidence.
the auxiliary jet means may also be constructed as simple
The elevator means 212 may also be used for this purpose.
expansion nozzles ?for cold operation with compressed air,
While the aircraft approaches the air?eld in the position
or for operation with combustion gas supplied from the
of FIG. 10, the thrust of the engines 3 and 4 is reduced,
main jet engines 3 and 4. The auxiliary jet means may
and the speed is approximately 190 km./h.
also be small independent jet engines. In any event, the
The diagram of vFIG. 15 illustrates the directions of the
auxiliary jet means 8 and 9 are capable of providing a.
forces in the condition of the aircraft during ?ight in the
thrust which is almost 10% of the thrust of the main
position of FIG. 10. The landing weight WE is effective,
engines 3 and 4. In this manner, they can provide a turn
since the fuel tanks are empty. The thrust T of the jet
ing moment suf?cient to overcome an opposite moment
engines is small, and the horizontal and vertical compo�
produced by the weight of the aircraft acting at the center
of gravity 10 and by the friction resistance during the
nents of the thrust are correspondingly small.
The aero
dynamic drag Ds is effective. The required lift L corre
rolling of the aircraft. The auxiliary jet means 8 and 9? 60 sponds to the landing weight.
gradually turn the rolling aircraft into the position of
The parachute brake 15a is now opened, as shown in
FIG. 7 in which the aircraft is supported on the rear
FIG. 11 and simultaneously the jet engines 3 and 4 are
undercarriage, and rests on wheels 5 and 7. In this posi
driven at full power, preferably without after-burning.
tion, the direction of the thrust of the jet engines 3 and
The brake action of the parachute brake 15a reduces the
4 extends at an angle of 30� to a horizontal plane, and the 65 ?ying speed to a landing speed of 130 km./h. while the
wings have the maximum angle on incidence.
aircraft ?ies stationarily without loss of height. The
The jet engines 3 and 4 operate at full power with
forces acting on the aircraft during this landing approach
after-burning, and the aircraft continues to roll at increas
?ight, are illustrated in the diagram of FIG. 16. Since
ing speed. The diagram of FIG. 14 illustrates the forces
the jet engines 3 and 4 operate at high power, the vertical
acting on the aircraft during the take-off in position of
thrust component Tv compensates substantially one half
FIG. 7.
of the landing weight WE. The required lift L is also sub
The vertical component TV of the thrust T is 0.5T, and
stantially one half of the landing weight. The horizontal
since the thrust T is substantially equal to or greater than
thrust Th is compensated by the drag Dpar of the parachute
the weight W of the aircraft, an aerodynamic lift L is re
brake, and by the aerodynamic drag DS. Since the drag
quired, which is consequently substantially one half of
3,089,667
id
is greater than the horizontal thrust, the aircraft slows
down.
In the position of FIG. 12, the aircraft has landed,
horizontal axis until the position of FIG. 11 is obtained.
In this manner, the angle of incidence can be varied.
The jet engines 3 and 4 are operated during take-off
and rolls on wheels 5 and 7 in a landing position in which
with after-burning, resulting in a thrust which is 35%
the ?wings have an angle of incidence of approximately 5 higher than the rated thrust of the engine. Since dur
25�. The Wheel brakes are operated by an automatic
ing take-off considerable intake losses occur due to the
brake device at a friction coefficient of 0.45. The brake
low speed of the aircraft, the remaining effective thrust
of the jet engines is substantially equal to the take-off
action of the parachute brake is high during the ?rst part
of the rolling as long as the speed is still great. When
weight of the aircraft.
the speed of the aircraft is reduced, the drag of the para 10
?FIGURES la and 1b are intended to furnish additional
chute is rapidly reduced, while the braking effect of the
illustration.
wheel brakes increases due to the reduction of the lift
The pivotal movement of the auxiliary jets 8 and 9
at lower speed of the aircraft, and reduction of the verti
about axis 18 is brought about by means of booster '16
cal thrust component obtained by first reducing the
and lever 17, whereby the aircraft becomes controlable
power of the engines, and then by stopping the engines. 15 about its lateral axis.
The weight of the aircraft is no longer compensated, and
As shown in 1FIG. lb, the parachute-container 15 is
acts on the wheels during the second part of the rolling
mounted on the tail ?n, and conical container-cap 15b
movement of the aircraft, so that the wheel brakes be
is ejected and separates from container 115 when the para
come more effective.
chute brake is released. The conical container-cap pulls
The distribution of forces is illustrated in the diagram 20 out the auxiliary parachute 20 and the latter pulls out
of FIG. 17, which shows the landing weight WE counter
from container 15 the main parachute 15a in closed con
acted only by the smaller lift L, since the engines produce
dition. When the rope 25 is pulled out, parachute 15a
no thrust. The parachute brake produces a smaller drag
opens.
Dpar, since the speed is reduced, and in addition to the
The main parachute is attached to a slide 22 displace~
drag DzhLr is effective, which includes the brake force of 25 able on rail 21. The displacement is effected by means
the wheel brakes and the aerodynamic drag.
of a booster 23.
?
The wheel brakes produce a turning moment on the
The direction of reaction of the parachute brake can
aircraft which tends to turn the aircraft from the posi
tion shown in FIG. 12 to the position shown in FIG. 13
in which the aircraft rolls on the wheels 5 and 6. The
drag of the parachute brake produces an opposite mo
ment, but when the drag of the parachute becomes so
small that the aircraft tends to tilt into the position of
FIG. 13, the parachute is released and thrown off. The
thereby be changed from ?24a to 241) with respect to the
center of gravity of the aircraft. Through such a dis
placement either a moment can be created about the cen
ter of gravity of the aircraft, or a displacement of the
center of gravity may be taken into account, or the angle
of landing approach can be in?uenced by the stabilizing
effect as produced by the force of reaction of the para
aircraft now rolls to a stop and is slowed down by the 35 chute, While the aircraft is alighting.
wheel brakes.
It will be understood that each of the elements de
For illustrative purposes, the data during landing of
scribed above, or two or more together, may also ?nd
an aircraft according to the present invention are given
a useful application in other types of jet aircraft differ
as an example:
40
ing from the types described above.
Wingload at landing weight ____________ __ 150 kg/.m.
While the invention has been illustrated and described
as embodied in a jet aircraft for short take-off and land
Speed of approach ____________________ __ 190 km./h.
ing distances employing a parachute brake for landing,
Landing speed _______________________ __ 130 km./h.
it is not intended to be limited to the details shown,
since various modi?cations and structural changes may
be made without departing in any way from the spirit
Rolling distance ______________________ __ 110 m.
Rolling time _________________________ __ 6 sec.
Average deceleration on runway _________ __ 0.6 g.
Effective aerodynamic wing load _________ __ 75 kg./m.2
Surface load on the parachute brake ______ __ 125 kg./m.2
The above example shows that an aircraft in accord
ance with the present invention can come to a stop within
a distance of 110 m., whereas known aircraft of the same
type requires 500? rn. rolling distance for landing. The
rolling distance of the aircraft according to the present
invention could be further reduced by increasing the
thrust of the jet engines by after-burning during the land
ing operation, and by providing parachute brakes of cor
of the present invention.
Without further analysis, the foregoing will so fully re
veal the gist of the present invention that others can, by
applying current knowledge, readily adapt it for various
applications without omitting features that, from the
standpoint of prior art, fairly constitute essential charac
teristics of the generic or speci?c aspects of this invention
and, therefore, such adaptations should and are intended
to be comprehended within the meaning and range of
equivalence of the following claims.
What is claimed as new and desired to be secured by
Letters Patent is:
respondingly greater effective surface. However, a para
l. A jet aircraft for short take-off and landing distances,
chute brake may be required Whose size become impracti
comprising, in combination, wing means having a maxi-'
cal. Evidently, conventional brake ?aps can also be 60 mum lift at a given great angle of incidence; jet engine
used during landing operations, particularly since brake
means rigidly ?xed on the aircraft for producing a longi
?aps are provided on the aircraft of the present inven
tudinal jet thrust; and means on the aircraft for supports
tion for operation during flight.
ing the aircraft on the ground including ?rst undercara
As clearly shown in FIGS. 11 and 12, the parachute
riage means supporting the aircraft in take-01f and land
brake is attached to the aircraft in such a manner that 65 ing positions in which the angle of incidence of said wing
the plane of the drag forces passes through the center of
means is substantially said given angle of incidence and
gravity of the aircraft. Several parachute brakes can be
in which said engine means is tilted with respect to hori
attached to the upper side of the aircraft, and in this
zontal and vertical planes so that the vertical component
event it is necessary to distribute the points of attachment
of the jet thrust is substantially half of the weight of the
along a plane passing through the center of gravity so 70 aircraft whereby the aircraft is lifted during the take-off
that the drag produced by the parachute brakes tends to
and landing partly by the lift of said wing means produced
hold the aircraft in the position of FIG. 11,
by the forward movement of the aircraft driven by the
Preferably, the holders 15 of the parachute, or a
horizontal component of the jet thrust and partly by the
plurality of holders are displaceable so that turning move
vertical component of the jet thrust whereby short take
ments can be produced for turning the aircraft about its
off and landing distances are obtained, and second under
3,089,667
11
carriage means for supporting the aircraft on the ground in
another alighted position in which the longitudinal axis
of the aircraft is substantially horizontal.
2. A jet aircraft as set forth in claim 1 wherein said
12
aircraft on the ground including ?rst under-carriage means
supporting the aircraft in take-off and landing positions in
which the angle of incidence of said wing means is sub
stantially said given angle of incidence and in which said
wing means have an effective area selected so that the
engine means is tilted with respect to horizontal and ver
ratio between the weight of the aircraft and said effective
tical planes so that the vertical component of the jet thrust
is substantially half of the weight of the aircraft whereby
the aircraft is lifted during the take-off and landing partly
by the lift of said wing means produced by the forward
area is not greater than 350 kg./m.2.
3. A jet aircraft as set forth in claim 1 wherein said
engine means is tilted to a horizontal plane an angle of
10 movement of the aircraft driven by the horizontal com
ponent of the jet thrust and partly by the vertical compo
4. A jet aircraft as set forth in claim 1 wherein said
nent of the jet thrust whereby short take-off and landing
longitudinal thrust is at least as great as the weight of the
distances are obtained, and second undercarriage means
aircraft.
for supporting the aircraft on the ground in another
5. A jet aircraft as set forth in claim 1 wherein said
wing means have such a shape that the lift increases to a 15 alighted position in which the longitudinal axis of the air
craft is substantially horizontal; and auxiliary jet means
very small extent as the angle of incidence is increased.
for producing turning moments on the aircraft for turn
6. A jet aircraft as set forth in claim 1 wherein said
substantially 30�.
wing means have an effective area selected so that the
ratio between the weight of the aircraft and said effective
area is not greater than 350 kg./m.2, wherein said longi
tudinal thrust is as least as great as said weight of said
aircraft and wherein said wing means have such a shape
ing the aircraft between a position in which said wing
means is substantially horizontal, and said take-off and
landing positions.
10. A jet aircraft for short take-off and landing dis
tanoes, comprising, in combination, wing means having
a maximum lift at a given great angle of incidence; jet
engine means rigidly ?xed on the aircraft for producing
of incidence is increased.
7. A jet aircraft for short take-off and landing dis 25 a longitudinal jet thrust; means on the aircraft for sup
porting the aircraft on the ground in take-off and landing
tances, comprising, in combination, wing means having a
positions in which the angle of incidence of said wing
maximum lift at a given great angle of incidence; jet
means is substantially said given angle of incidence and
engine means rigidly ?xed on the aircraft for producing
in which said engine means is tilted with respect to hori
a longitudinal jet thrust; means on the aircraft for sup
porting the aircraft on the ground in take-off and landing 30 zontal and vertical planes so that the vertical component
that the lift increases to a very small extent as the angle
of the jet thrust is substantially half of the weight of the
aircraft whereby the aircraft is lifted during the take-off
and landing partly by the lift of said wing means pro
in which said engine means is tilted with respect to hori
duced by the forward movement of the aircraft driven
zontal and vertical planes so that the vertical component
of the jet thrust is substantially half of the weight of the 35 by the horizontal component of the jet thrust and partly
by the vertical component of the jet thrust whereby short
aircraft whereby the aircraft is lifted during the take-off
take-off and landing distances are obtained; and nor
and landing partly by the lift of said wing means pro
mally closed parachute brake means attached to the air
duced by the forward movement of the aircraft driven by
craft movable between a plurality of positions displaced
the horizontal component of the jet thrust and partly by
the vertical component of the jet thrust whereby short 40 relative to the center of gravity of the aircraft, said
parachute brake means having in open condition an ef
take-off and landing distances are obtained; and auxiliary
jet means for producing turning moments on the aircraft
fective surface selected for producing during landing ap
for turning the aircraft between a position in which said
proach ?ight ?and during movement of the alighted air
wing means is substantially horizontal, and said take-01f
craft a drag suf?cient to compensate at least a major part
of the horizontal component of the full jet thrust, and
and landing positions.
8. A jet aircraft for short take-off and landing distances,
for exerting in said displaced positions a turning moment
comprising, in combination, wing means having a maxi
on the aircraft.
mum lift at a given great angle of incidence; jet engine
11. Jet aircraft for short take-off and landing distances,
means rigidly ?xed on the aircraft for producing a longi
comprising, in combination, wing means having an ef
positions in which the angle of incidence of said wing
means is substantially said given angle of incidence and
tudinal jet thrust; means on the aircraft for supporting the
aircraft on the ground in take-off and landing positions in
which the angle of incidence of said wing means is sub
stantially said given angle of incidence and in which said
fective surface area selected so that the ratio between the
weight of the aircraft and said surface area is not greater
than 350 kg./m.2; jet engine means ?xed on the aircraft
for producing a thrust at least as great as the weight of
engine means is tilted with respect to horizontal and ver
the aircraft; valighting means for supporting the aircraft
tical planes so that the vertical component of the jet thrust 55 in take-off and landing positions in which the angle of
is substantially half of the weight of the aircraft whereby
incidence of said wing means is a maximum for produc
the aircraft is lifted during the take-0E and landing partly
ing a maximum lift; and normally closed parachute brake
by the lift of said wing means produced by the forward
means attached to the aircraft at a point of the aircraft
movement of the aircraft driven by the horizontal com
located in a horizontal plane passing through the center
ponent of the jet thrust and partly by the vertical compo 60 of gravity of the aircraft when the aircraft is in said
nent of the jet thrust whereby short take-off and landing
distances are obtained; and auxiliary jet means for produc
ing turning moments on the aircraft for turning the air
craft between a position in which said Wing means is sub
landing position, said parachute brake means having in
open condition an effective surface selected for producing
during landing approach ?ight and during movement of
the alighted aircraft a drag sufficient to compensate a
stantially horizontal, and said take-off and landing posi 65 major part of the horizontal component of the full engine
tions, said auxiliary jet means being mounted on the air
thrust.
craft for turning movement about a horizontal axis be
12. Jet aircraft for short take-off and landing distances,
tween positions upwardly or downwardly tilted to the
comprising, in combination, a fuselage having a tail ?n;
longitudinal axis of the aircraft, and an intermediate posi
wing means secured to said fuselage having an effective
tion for propelling the aircraft in a normal ?ight position. 70 surface area selected so that the ratio between the weight
9. A jet aircraft for short take-off and landing distances,
of the aircraft and said surface area is not greater than
comprising, in combination, wing means having a maxi
350 kg./m.2; jet engine means ?xed on the aircraft for
mum lift at a given great angle of incidence; jet engine
producing a thrust at least as great as the weight of the
means rigidly ?xed on the aircraft for producing a longi
tudinal jet thrust; means on the aircraft for supporting the 75 aircraft; alighting means for supporting the aircraft in
13
3,089,667
'14
take-off and landing positions in which the angle of in
means having in open condition an effective surface se
cidence of said Wing means is a maximum for producing
a maximum lift; and normally closed parachute brake
lected for producing during landing approach ?ight and
means attached to the aircraft at a point of said tail ?n
located in a horizontal plane passing through the center
of gravity of the aircraft when the aircraft is in said
landing position, said parachute brake means having in
open condition an effective surface selected for produc
ing during landing approach ?ight and during movement
of the alighted aircraft a drag su??icient to compensate
a major part of the horizontal component of the full
engine thrust.
13. let aircraft for short take-off and landing distances,
comprising, in combination, wing means having an ef
during movement of the alighted aircraft a drag sufficient
to compensate a major part of the horizontal component
of the full engine thrust.
16. Jet aircraft for short take-off and landing distances,
comprising, in combination, wing means having an effec
tive surface area selected so that the ratio between the
weight of the aircraft and said surface area is not greater
than 350 kg./m.2; jet engine means ?xed on the aircraft
for producing a thrust at least as great as the weight of
the aircraft, said jet engine means including a jet outlet
means having an axis extending downwardly inclined to
the longitudinal axis of the aircraft and passing through
fective surface area selected so that the ratio between 15 the center of gravity of the aircraft; alighting means for
the weight of the aircraft and said surface area is not
supporting the aircraft in take-off and landing positions in
greater than 350 kg./m,2; jet engine means ?xed on the
which the angle of incidence of said wing means is a
aircraft for producing a thrust at least as great as the
maximum for producing a maximum lift and in which
said engine means is tilted with the aircraft so that the
weight of the aircraft; alighting means for supporting the
aircraft in take-off and landing positions in which the 20 vertical component of the engine thrust is of about one
half of the total engine thrust; normally closed parachute
angle of incidence of said wing means is :a maximum for
brake means attached to the aircraft and having in open
producing a maximum lift; normally closed parachute
condition an effective surface selected for producing dur~
brake means attached to the aircraft and having in open
ing landing approach ?ight and during movement of the
condition an effective surface selected for producing dur
ing landing approach ?ight and during movement of the 25 alighted aircraft a drag suf?cient to compensate a major
part of the horizontal component of the full engine thrust;
alighted aircraft a drag suf?cient to compensate a major
part of the horizontal component of the full engine thrust;
and movable auxiliary jet means producing turning mo
and movable auxiliary jet means producing turning mo
ments on the aircraft for turning the aircraft from nose
wheel alighted position into steep take-off position and
wheel alighted position into steep take-off position and 30 from said take-off position into a normal ?ight position
in which said wing means have a smaller angle of inci
from said. take-elf position into a normal ?ight position in
dence, and for turning said aircraft during landing ap
which said wing means have a smaller angle of incidence,
proach ?ight from said normal ?ight position into said
for turning said aircraft during landing approach
landing position.
?ight from said normal ?ight position into said landing
17. Jet aircraft for short take-off and landing distances,
position.
comprising, in combination, a fuselage having a tail ?n;
14. let aircraft for short take-off and landing distances,
wing means secured to said fuselage having an effective
comprising, in combination, wing means; jet engine means
ments on the aircraft for turning the aircraft from nose
?xed on the aircraft for producing a thrust, said jet en
gine means including a jet outlet means having an axis
surface area selected so that the ratio ?between the weight
of the aircraft and said surface area is not greater than
extending downwardly inclined to the longitudinal axis
of the aircraft ?and passing through the center of gravity
of the aircraft; alighting means for supporting the air
craft in take-off and landing positions in which the angle
350 kg/m?; jet engine means ?xed on the aircraft for
producing a thrust at least as great as the weight of the
aircraft, said jet engine means including a jet outlet means
having an axis extending downwardly inclined to the
landing approach ?ight and during movement of the
half of the total engine thrust; normally closed parachute
longitudinal axis of the aircraft and passing through the
of incidence of said Wing means is a maximum for pro
ducing a maximum lift and in which said engine means 45 center of gravity of the aircraft; alighting means for sup
porting the aircraft in take-off and landing positions in
is tilted with the aircraft so that the vertical component
which the angle of incidence of said wing means is a
of the engine thrust is of about one half of the weight
maximum for producing a maximum lift and in which
of the aircraft; and normally closed parachute brake
said engine means is tilted with the aircraft so that the
means attached to the aircraft and having in open condi
vertical component of the engine thrust is of about one
tion an effective surface selected for producing during
alighted aircraft a drag su?icient to compensate a major
part of the horizontal component of the full engine
thrust.
brake means attached to the aircraft rearwardly of the
center of gravity of the aircraft at a point of said tail ?n
located in a horizontal plane passing through the center
15. Jet aircraft for short take-off and landing distances, 55 of gravity of the aircraft when the aircraft is in said land
ing position, said parachute brake means having in open
comprising, in combination, a fuselage having a tail ?n;
condition an effective surface selected for producing dur
wing means secured to said fuselage having an effective
ing landing approach ?ight and during movement of the
surface area selected so that the ratio between the weight
alighted aircraft a drag sufficient to compensate a major
of the aircraft and said surface area is not greater than
350 kg./m.2; jet engine means ?xed on the aircraft for 60 part of the horizontal component of the full engine
thrust, said drag producing a resultant force passing
producing a thrust at least as great as the Weight of the
through the center of gravity of the aircraft; and mov
aircraft, said jet engine means including a jet outlet means
able auxiliary jet means producing turning moments on
the aircraft for turning the aircraft from nose-wheel
alighted
position into steep take-off position and from
center of gravity of the aircraft; alighting means for 65
said take-off position into a normal ?ight position in
supporting the aircraft in take-off and landing positions
which said wing means have a smaller angle of incidence,
in which the angle of incidence of said wing means is a
having an axis extending downwardly inclined to the
longitudinal axis of the aircraft and passing through the
and for turning said aircraft during landing approach
maximum for producing a maximum lift and in which
?ight from said normal ?ight position into said landing
said engine means is tilted with the aircraft so that the
vertical component of the engine thrust is of about one 70 position.
chute brake means attached to the aircraft at a point
18. Jet aircraft for short take-off and landing distances,
comprising, in combination, wing means having an effec
of said tail ?n located in a horizontal plane passing
through the center of gravity of the aircraft when the
tive surface area selected so that the ratio between the
weight of the aircraft and said surface area is not greater
half of the total engine thrust; and normally closed para
aircraft is in said landing position, said parachute brake 75 than 350 kg./m.2; jet engine means ?xed on the aircraft
3,089,667
? 15
16
wing means is a maximum for producing a maximum lift
and in which said engine means is tilted with the aircraft
so that the vertical component of the engine thrust is of
about one half of the weight of the aircraft; and nor
mally closed parachute brake means attached to the air
for producing a thrust, said jet engine means including a
jet outlet means having an axis extending downwardly
inclined to the longitudinal axis of the aircraft and pass
ing through the center of gravity of the aircraft; alight
ing means for supporting the aircraft in take-off and land
ing positions in which the angle of incidence of said wing
craft at a point of the aircraft located in a horizontal
plane passing through the center of ?gravity of the air
craft when the aircraft is in said landing position, said
means is a maximum for producing a maximum lift and
in which said engine means is tilted with the aircraft so
parachute brake means having in open condition an ef
that the vertical component of the engine thrust is of
about one half of the weight of the aircraft; and normally 10 fective surface selected for producing during landing ap
proach ?ight and during movement of the alighted air
closed parachute brake means attached to the aircraft and
craft a drag sufficient to compensate a major part of the
having in open condition an effective surface selected for
horizontal component of the full engine thrust.
producing during landing approach ?ight and during
22. Jet aircraft for short take-off and landing distances,
compensate a major part of the horizontal component 15 comprising, in combination, wing means; jet engine means
?xed on the aircraft for producing a thrust; alighting
of the full engine thrust.
means for supporting the aircraft in take-elf and land
19. Jet aircraft for short take-off and landing dis
ing positions in which the angle of the incidence of said
tances, comprising, in combination, wing means having
movement of the alighted aircraft a drag su?icient to
wing means is a maximum for producing a maximum lift
an effective surface area selected so that the ratio be
tween the weight of the aircraft and said surface area 20 and in which said engine means is tilted with the air
craft so that the vertical component of the engine thrust
is not greater than 350 kg./m.z; jet engine means ?xed
is of about one half of the weight of the aircraft; nor
on the aircraft for producing a thrust; alighting means
mally closed parachute brake means attached to the air
for supporting the aircraft in take-o?f and landing posi
craft at a point of the aircraft located in a horizontal
tions in which the angle of incidence of said wing means
is a maximum for producing a maximum lift and in 25 plane passing through the center of ?gravity of the air
craft when the aircraft is in said landing position, said
which said engine means is tilted with the aircraft so
parachute brake means having in open condition an ef
that the vertical component of the engine thrust is of
about one half of the weight of the aircraft; normally
closed parachute brake means attached to the aircraft
and having in open condition an effective surface se
fective surface selected for producing during landing ap
proach ?ight and during movement of the alighted air
30 craft a drag su?icient to compensate a major part of the
lected for producing during landing approach ?ight and
during movement of the alighted aircraft a drag sufficient
to compensate a major part of the horizontal compo
nent of the full engine thrust; and movable auxiliary
jet means producing turning moments on the aircraft 35
for turning the aircraft from nose-wheel alighted posi
alighted position into steep take-off position and from
said take-off position into a normal ?ight position in
which said wing means have a smaller angle of incidence,
and for turning said aircraft during landing approach
?ight from said normal ?ight position into said landing
tion into steep take-off position and from said take-off
position into a normal ?ight position in which said wing
position.
means have a smaller angle of incidence, and for turn
ing said aircraft during landing approach ?ight from said
normal ?ight position into said landing position.
horizontal component of the full engine thrust; and mov
able auxiliary jet means producing turning moments on
the aircraft for turning the aircraft from nose-wheel
40
23. Jet aircraft for short take-off and landing distances,
comprising, in combination, wing means having an effec
tive surface area selected so that the ratio between the
20. Jet aircraft for short take-off and landing dis
tances, comprising, in combination, wing means having
weight of the ?aircraft and said surface area is not greater
than 350 kg./m.2; jet engine means ?xed on the aircraft
an effective surface area selected so that the ratio be
tween the weight of the aircraft and said surface area 45 for producing a thrust at least as great as the weight of the
aircraft; alighting means for supporting the aircraft in
is not ?greater than 350 kg./m.2; jet engine means ?xed
take-off and landing positions in which the angle of
on the aircraft for producing a thrust at least as great
as the weight of the aircraft; alighting means for sup
incidence of said wing means is a maximum for pro
porting the aircraft in take-off and landing position in
ducing a maximum lift; normally closed parachute brake
half of the total engine thrust; normally closed parachute
part of the horizontal component of the full engine thrust;
aircraft located in a horizontal plane passing through
the center of gravity of the aircraft when the aircraft is
in said landing position, said parachute brake means hav
nose-wheel alighted position into steep take-01f position
which the angle of incidence of said wing means is a 50 means attached to the aircraft and having in open condi
tion an effective surface selected for producing during
maximum for producing a maximum lift and in which
landing approach ?ight and during movement of the
said engine means is tilted with the aircraft so that the
alighted aircraft a drag su?icicnt to compensate a major
vertical component of the engine thrust is of about one
and movable auxiliary jet means producing turning
brake means attached to the aircraft at a point of the 55
moments on the aircraft for turning the aircraft from
and from said take-off position into a normal ?ight posi
tion in which said wing means have a smaller angle of
ing in open condition an effective surface selected ?for
producing during landing approach ?ight and during
movement of the alighted aircraft a drag sufficient to
compensate a major part of the horizontal component
of the full engine thrust; and movable auxiliary jet means
producing turning moments on the aircraft for turning
60
incidence, and for turning said aircraft during landing
approach ?ight from said normal ?ight position into said
landing position, said auxiliary jet means being mounted
on the aircraft for turning movement about a horizontal
axis between positions upwardly and downwardly tilted
to the longitudinal axis of the aircraft, and an intermediate
the aircraft from nose-wheel alighted position into steep 65 position for propelling the aircraft in normal ?ight posi
take-off position and from said take-off position into a
normal ?ight position in which said wing means have a
smaller angle of incidence, and for turning said aircraft
during landing approach ?ight from said normal ?ight
position into said landing position.
21. Jet aircraft for short take-off and landing distances,
comprising, in combination, wing means; jet engine means
?xed on the aircraft for producing a thrust; alighting
?means for supporting the aircraft in take-off and land
tion.
,
.
.
24. Jet aircraft as set forth in claim 23 wherein said
auxiliary jet means include jets ?located on opposite sides
of the longitudinal vertical plane of symmetry of the air?
craft.
,
t
25. Jet aircraft for short take-off and landing distances,
comprising, in combination, wing means having an effec
tive surface area selected so that the ratio between the
ing positions in which the angle of incidence of said 75 weight of the aircraft and said surface area is not greater
3,089,667
17
18
than 350 -kg./m.2; jet engine means ?xed on the aircraft
for producing a thrust at least as great as the weight of the
means having brake means and supporting the aircraft in
aircraft; alighting means including ?rst undercarriage
cidence of said wing means is a maximum for producing a
maximum lift and second undercarriage means for sup?
take-off and landing positions in which the angle of in
means supporting the aircraft in take-off and landing
positions in which the angle of incidence of said wing UK porting the aircraft in another alighted position in which
means is a maximum for producing a maximum lift
the longitudinal axis of the plane is substantially horizon
and second undercarriage means for supporting the air
tal; normally closed parachute brake means attached to the
craft in another alighted position in which the longitudinal
aircraft and having in open condition an effective surface
axis of the plane is substantially horizontal, said alighting
selected for producing during landing approach ?ight and
means include main wheel means, nose wheel means, and 10 during movement of the alighted aircraft a vdrag su?icient
tail wheel mean-s, and friction brakes at least for said
main wheels, the center of gravity of the aircraft being
located forwardly of said main wheel means in said other
to compensate a major part of the horizontal component
of the full engine thrust, said parachute brake means be
ing detachable from the aircraft so that the aircraft turns
alighted position, and rearwardly of said main wheel
from said landing position to said other alighted posi
means in said take-off and landing positions; and movable 15 tion when said parachute brake means is detached and
auxiliary jet means producing turning moments on the
said brake means are applied; and movable auxiliary jet
aircraft for turning the aircraft from said other alighted
means producing turning moments on the aircraft for
position into said take-off position, and from said take
off position into ?a normal ?ight position in which said
wing means have a smaller angle of incidence.
26. Jet aircraft for short take-off and landing distances,
comprising, in combination, wing means having an effec
turning the aircraft ?from said other alighted position
into said take-off position, and from said take-off posi
20 tion into a normal ?ight position in which said wing means
have a smaller angle of incidence, and for turning said
aircraft during landing approach ?ight from� said normal
tive surface area selected so that the ratio between the
?ight position into said landing position.
weight of the aircraft and said surface area is not greater
28. Jet aircraft as set forth in claim 27 wherein said
than 350 kg./m.2; jet engine means ?xed on the aircraft 25 alighting means includes main wheel means, nose wheel
for producing a thrust at least as great as the Weight of the
means, and tail wheel means, and friction brakes at least
aircraft; alighting means including ?rst undercarriage
for said main wheels; and wherein the center of gravity
of the aircraft is located forwardly of said main wheel
take-off and landing positions in which the angle of in~
means in said other alighted position, and rearwardly of
cidence ?of said wing means is a maximum for producing 30 said main Wheel means in said take-off and landing posi
a maximum lift and second undercarriage means for sup
tions.
means having brake means and supporting the aircraft in
porting the ?aircraft in another alighted position in which
the longitudinal axis of the plane is substantially horizon
tal; and normally closed parachute brake means attached
to the aircraft and having in open condition an effective
References Cited in the ?le of this patent
UNITED STATES PATENTS
1,499,472
1,875,267
Pratt ________________ __ July 1, 1924
Savoja ______________ __ Aug. 30, 1932
component of the full engine thrust, said parachute brake
2,145,459
2,246,716
Rhines ______________ ___ Jan. 31, 1939?
Bottrill ______________ _.._ June 24, 1941
means being detachable from the aircraft so that the 40
aircraft turns from said landing position to said other
alighted position when said parachute brake means is
2,481,379
2,513,867
2,678,783
Zimmerman __________ __ Sept. 6, 1949
Heffernan ____________ __ July 4, 1950
Meyers ______________ __ May 18, 1954
detached and said ?brake means are applied.
2,734,702
Northrop ,_ ___________ .___ Feb. 14, 1956
27. Jet aircraft for short take-off and landing distances,
comprising, in combination, wing means having an effec 45
2,761,634
Velaquez ____________ __ Sept. 4, 1956
2,929,580
2,958,480
2,971,725
Ciolkosz ____________ __ Mar. 22, 1960
Saulnier ______________ __ Nov. 1, 1960
Jakimiuk ____________ __ Feb. 14, 1961
surface selected for producing during landing approach
?ight and during movement of the alighted aircraft a drag
su?icient to compensate a major part of the horizontal
tive surface area ?selected so that the ratio between the
weight of the aircraft and said surface area is not greater
than 350 kg./m.2; jet engine means ?xed on the aircraft
for producing a thrust at least as ?great as the weight of
the aircraft; alightin-g means including ?rst undercarriage
FOREIGN PATENTS
787,102
Great Britain __________ __ Dec. 4, 1957
l fuel tanks.
a jet aircraft capable of take-off and landing on small
During take-off the aircraft is placed in extremely steep
25 position in which the wings have a maximum angle of
and unpaved air?elds within a short distance.
Another object of the present invention is to provide a
incidence in which the maximum lift is produced before
jet aircraft capable of take-oft" and landing at low speeds.
the stream lines break away from the wing surface.
The distance along which an aircraft rolls before tak
The jet engine has a downwardly inclined outlet noz
ing off and after landing, is mainly determined by two
zle producing a thrust whose line of force passes through
factors:
30 the center of gravity of the aircraft in the steeply inclined
take-01f position.
(a) A minimum take-off speed, and a minimum land
ing speed are necessary for taking off and landing within
An alighting means or landing gear including main
a minimum rolling distance so that the kinetic energy
wheels and tail wheel means is provided which is so ar
ranged that the wings of the aircraft have the desired
produced by the engine during take-off, or the kinetic en
ergy which has to be overcome by the brakes during 35 great angle of incidence when the aircraft rests on the
landing gear.
landing, is reduced to a minimum.
(21) The greatest possible acceleration corresponding
In the preferred embodiment of the present invention,
to great thrust is required for accelerating the aircraft to
take-off speed within the shortest possible time and the
the landing gear also includes an auxiliary wheel in the
nose of the plane corresponding to a conventional tricycle
shortest possible distance, while the greatest possible de 40 landing gear, so that the aircraft may ?rst rest on the
front wheel and main wheels in a substantially horizontal
celeration, corresponding to a braking force is required
position, and then turn to the take-off position resting
for reducing the landing speed of the aircraft until it stops
on the rear wheel means.
within the shortest possible time and shortest possible
distance.
'
The minimum landing and take-off speeds are deter
mined by the ?wing load and the lift coefficient of the wing,
and is determined by the equation
W 1
Auxiliary jet means are provided on the aircraft for
turning the aircraft between the two alighted positions,
and such auxiliary jets may also be used for propelling
the aircraft during ?ight, and for altering the position
of the aircraft during landing approach ?ight.
In accordance with the present invention, the landing
50 approach ?ight, and the rolling on the air?eld, takes place
in a landing position of the aircraft in which the angle
In this equation, W is the weight of the aircraft, S is
of incidence of the wings is again the maximum. During
the effective surface of the wing
the approach ?ight, extremely large parachute brakes are
opened, and the surface of the parachute brakes is di
W
mensioned in such a manner that the jet engines can
S
run at full power as is necessary in accordance with the
is the wing load, and CL is the lift coe?icient of the wing.
present invention for obtaining a very high vertical thrust
From the above equation follows that for a given weight
component permitting the landing of the aircraft in a
of the aircraft, the minimum speed can be lower if the
landing position in which the wings have the maximum
wing surface and lift coefficient are correspondingly 60 angle of incidence. The interaction of the parachute
greater. Use of large wing surface for low minimum
brake and the jet engine is such that an approach speed
speeds, and the use of lift-increasing means, such as ?aps,
is obtained which is considerably lower than the minimum
suction devices, and blower devices, is well-known, par
speed obtainable with the wings at the same angle of
ticularly for landing operations. However, a large wing
incidence, but with the jet engine thrust reduced, and no
surface results in a high drag at high speeds.
parachute brake applied. After the approach landing
For acceleration of the aircraft during take-off, the use
speed of the aircraft has been sufficiently reduced, the
of thrust-increasing means, such as rockets, catapults, etc.,
engine thrust is reduced, ?and the parachute brake detached
is well-known. In order to reduce the rolling distance
or otherwise rendered ineffective.
required for landing, it is known to produce an additional
A jet aircraft in accordance with the present invention
drag by brake ?aps and brake parachutes, or the ground 70 preferably comprises wing means having an effective sur
friction may be increased by Wheel brakes or other fric
face area selected so that the ratio between the weight of
tion producing means. It is also known to turn the jet
the aircraft and the surface is not greater than 350
3,089,667
3
tive during the landing approach flight in the position of
FIG. 10;
kg./m.2; jet engine means ?xed on the aircraft for pro
ducing a thrust at least as great as the weight of the air
FIG. 16 is a vector diagram illustrating the forces effec
tive when the parachute brake is open as shown in FIG.
craft; and alighting means for supporting the aircraft in
take-off and landing positions in which the angle of in
11; and
cidence of the wing means is a maximum for producing
FIG. 17 is a vector digram illustrating the forces acting
a maximum lift. The engine means is tilted with the air
in the condition of FIG. 12 in which the jet engines are
craft in the take-off position so that the vertical compo
stopped.
nent of the engine thrust is at least one-half of the total
Referring now to the drawings, and more particularly
engine thrust.
Normally closed parachute brake means are attached l0 to FIGS. 1 to 4, a fuselage 1 has alighting means includ
ing main wheel means 5, nose wheel means 6, and tail
to the aircraft and have in open condition an effective
wheel mains 7 connected by ?rst and second undercar
riages to the fuselage. Jet engines 3 and 4 are ?xed on
the fuselage and mainly extend in direction of the longi
su?icient to compensate the horizontal component of the
full engine thrust which is required during landing for 15 tudinal axis A of the airplane. The outlet nozzles 3a
and 4a of the jet engines 3 and 4 are downwardly in
producing a vertical component.
clined and have axes intersecting with a horizontal axis
The parachute brake is preferably attached to the tail
of the plane passing through the center of gravity 10.
?n of the aircraft at a point located in a horizontal plane
The axes 31 and 41 of the outlet nozzles 3a and 4a are
passing through the center of gravity of the aircraft when
20 located in a plane which de?nes an angle 6 with a plane
the aircraft is in the landing position.
passing through the chords 2a of the wings 2. The
Auxiliary jet means are provided for producing turn
plane of the wing chords de?nes an angle a with a hori
ing moments on the aircraft by which the aircraft is
zontal plane when the aircraft is in the take-off position
turned from the take-off position into a normal ?ight posi
shown in FIG. 7, or in the landing position shown in
tion, and from a normal ?ight position into the landing
25 FIG. 12. Consequently, the plane passing through axes
position.
31,, 41 of the nozzle outlet means de?nes with a hori
The take-off method of the present invention comprises
zontal plane the angle u-j-B.
the steps of placing the aircraft in a take-off position in
The fuselage supports a tail ?n 12 at the upper end
which the angle of incidence of the wings is a maximum;
surface selected for producing during landing approach
?ight and during movement of the alighted aircraft, a drag
of which a container for a parachute brake means is
and producing a jet thrust at least as great as the take-off
weight of the aircraft and having a vertical component at 30 mounted. The container 15 is preferably shiftable to
vary its distance from the longitudal axis of the plane
least one half of the total jet thrust.
The landing method of the present invention comprises
and from the center of gravity 10. The jet engines 3
the steps of placing during landing approach ?ight the
and 4 receive air through forwardly located inlets l1,
aircraft in a landing position in which the angle of in
and auxiliary ?ns 13 and 114 are provided which extend
cidence is a maximum; producing a jet thrust at least as 35 downwardly from the sides of the aircraft as best seen
great as the landing weight of the aircraft and having a
in FIGS. 3 and 4.
vertical component at least one half of the total jet thrust;
Auxiliary jet means 8 and 9 are mounted at opposite
and simultaneously braking the aircraft by parachute
sides of the vertical plane of symmetry of the aircraft,
as best seen in FIGS. 2 and 4, and each of the auxiliary
The novel features which are considered as character 40 jet means 8 and 9 is turnable about a horizontal axis,
istic for the present invention are set forth in particular
and may also be turnable about a vertical axis. Each
brakes.
in the appended claims. The invention itself, however,
of the wings ?2 has elevators 2b which may be connected
both as to its construction and its method of operation,
to the auxiliary jet means 8 or 9 on the same side for
turning movement about horizontal axes.
together with additional objects and advantages thereof,
will be best understood from the following description of 45
According to the present invention, the wheel means
speci?c embodiments when read in connection with the
5 and 7 are supported on an undercarriage in such a
accompanying drawings, in which:
manner that the wings 2 have the maximum angle of
FIG. 1 is a side view of a jet aircraft in accordance
incidence when the airplane rests on wheels 5 and 7 in
with one embodiment of the present invention;
the positions of FIGS. 7 and 12. The angle of inci
FIG. 1a is a side view on a larger scale illustrating aux 50 dence has a maximum value above which the air?ow
iliary jet means, FIG. 1b is a side view on a larger scale
breaks off from the wing surface during take-off, or at
illustrating parachute brake means;
which the airplane stalls during landing approach ?ight.
FIG. 2 is a plan view of the aircraft shown in FIG. 1;
FIG. 3 is a front view of the aircraft;
FIG. 4 is a rear view of the aircraft;
FIG. 5 is a side view of the aircraft in an alighted posi
tion;
FIG. 6 is a side view of the aircraft in an intermediate
55
The delta wing has very desirable characteristics for
the purposes of the present invention, inasmuch as the
lift increases to a very small extent as the angle of inci
dence is increased which may be mathematically ex
pressed as follows:
dcL
FIG. 7 is a side view of the aircraft in takeoff position; 60
do:
FIG. 8 is a side view of the airborne aircraft directly
Maximum lift is attained only when the angle of inci
after take-01f and still in take'off position;
dence is very large. On the other hand, in contrast to
FIG. 9 is a side view of the aircraft in ?ight position;
the straight and arrow-shaped wings, the delta wing is
FIG. 10 is a side view of the aircraft in landing ap
65 not subject to a'sudden breaking down of the lift, so
proach position;
that the loss of lift at the maximum angle of incidence
FIG. 11 is a side view of the aircraft in landing ap
occurs very slowly and therefore is not dangerous.
proach position with the parachute brake open;
An angle of incidence a of 25 degrees still produces
FIG. 12 is a side view of the alighted aircraft in landing
su?'icient lift if a delta wing is used. If the jet engines
position;
FIG. 13 is a side view of the aircraft in another alighted 70 are mounted on the aircraft in a position parallel to the
wings, a vertical thrust component of 40% is obtained
position with the parachute brake released;
which relieves the wing lift. When the outlet nozzles
FIG. 14 is a vector diagram illustrating the forces op
of the jet engines are inclined through an angle 5 of 5
erative during take-off of the aircraft in the positions of
degrees to the wing chords 2a, a vertical thrust compo
FIGS. .7 and 8;
FIG. 15 is a vector diagram illustrating the forceseffec 75 nent of 50% is obtained, as follows from the equation
alighted position;
3,089,667
5
6
Tv=T sin (wt-6). Since (n+6) is 30 degrees, sin
(oz-I-B) is 0.5, and the vertical thrust component
Tv=0.5T. Under these condition, the wing load is re
clined, a turning moment about the longitudinal axis of
the aircraft is obtained, which facilitates banking opera
tions. The two auxiliary jet means 8 and 9 are inde
duced to
pendently controlled ?for producing different thrusts
W=TSlJ1 ec+5
whereby -a turning moment about the vertical axis of the
aircraft is obtained. In a modi?ed construction, each of
the auxiliary jet means 8 and 9 is mounted on a support
including a universal joint, so that the directions of the
thrusts of the two auxiliary jet means can be adjusted to
S
wherein W is the take-off weight of the aircraft, T is the
thrust of the jet engine, and S is the effective surface of
the wing.
In accordance with the present invention, the thrust
10 any desired position.
In accordance with the present invention, the aircraft
of the engine is selected to be at least as great as the
is in a steeply inclined position during landing approach
flight, and while decelerating after landing. In this man
weight W of the aircraft, so that the required aerodynamic
lift can be determined by the following equation:
ner, a sufficiently high vertical thrust component of the
?xedly mounted jet engines is obtained. The maximum
angle of incidence is again the angle of attack of the
wing at which the ?airflow breaks off and the lift termin
the moment of take-off of an aircraft is
ates. While the aircraft is tilted to obtain the greatest
possible angle of incidence, the engine is run at full power,
if necessary at full power with after-burning.
Since the landing position of the aircraft is the Same as
the effective aerodynamic wing load of
the take-off position, the vertical component of the thrust
L
is again 50% of the total thrust, and of the weight of the
I?
aircraft. The landing weight of the aircraft is smaller
is 100 kg./rn.2 or less due to the action of the vertical 25 than the take-off weight of the aircraft, since fuel has
been consumed during ?ight and the fuel tanks are
thrust component of 0.5T or 05W. Due to the effect
empty. Therefore, the Wing load
of the vertical thrust component, the take-off speed is
reduced to 70% as compared with known jet aircraft,
an =150 kg./m.z
and the required kinetic energy is reduced by 50% irre
S
spective of the improvement obtained by the reduction
Since the vertical component of the thrust is at least one
of the wing load as compared with the corresponding
half of the total thrust, which corresponds to one half
values for known jet aircraft.
of the weight of the aircraft, the aerodynamic wing load
The horizontal thrust component depends on the cos
is reduced to 75 kg./m.2. This wing load determines the
u-j-b?, and assuming an angle of 30 degrees, the hori 35 landing speed which may, for example, be 130 kin/h.
zontal ?thrust component is 87% of the total thrust. Con
However, in order to maintain the stationary equilibrium,
sequently, the horizontal thrust component remains with
the horizontal thrust component must be destroyed to such
in reasonable limits, and permits sufficiently rapid acceler
an extent that no more of the horizontal thrust com
ation during the take-off. The greater aerodynamic drag
ponent remains effective as is necessary for overcoming
of the aircraft during the last part of the take-off run 40 the aerodynamic resistance of an aerodynamic braking
15
Assuming, from the example, that the wing load in
Kg=200 kgjmz
in steeply tilted position is only approximately 10% of
the take-off thrust and is therefore negligible.
In a preferred embodiment of the invention, the en
gine inlets 11 are constructed as two-dimensional super
sonic planar diifusors with variable angle of displace
device.
7
In accordance with the present invention, a parachute
15a, which normally is carried in closed condition in the
container 15, is opened during ?landing approach ?ight.
The parachute brake means ?15a is oversized and com
ment for producing an oblique compression shock and
provided with a pivoted inlet ?ap. The inlet ?ap may
be tilted down to hold the intake losses low while the air
craft moves at low ?ying speeds after take-off or before
pensates at least a major part of the horizontal component
iliary jet means 8 and 9 are mounted for pivotal move
ment about horizontal axes between a position upwardly
inclined with respect to the longitudinal axis of the air
craft, as shown in FIGS. 6, 7, 8, 10 and 11, and ?a position
attaching the parachute, since an aircraft having delta
of the full engine thrust. Parachute brakes used in known
landing methods have a much smaller size designed to�
compensate the inertia of the landing aircraft with the
landing, or taxies on the ground.
50 jet thrust substantially reduced or no longer applied.
Since in the positions shown in FIGS. 8 and 10, the
As shown in FIGS. 11 and L2, the parachute brake 15a
aircraft is steeply tilted and moves at low speed, the
is attached to the tail ?n 12 at a point which is located
conventional controls are not fully effective and aux
in a horizontal plane passing through the center of gravity
iliary small jet means 8 and h are provided. The aux
10 of the ?aircraft when the aircraft is in the steeply in
iliary jet means 8 and 9 may be coupled to the respective 55 clined position in which the angle of incidence of the
elevators 2b, or are operable independently of the ele
wings 2 is a maximum. This requires attachment of the
vators. The auxiliary jets 8 and 9 may be controlled
parachute to the upper side of the aircraft, for example to
by a gyroscopic automatic control apparatus for the pur
the top surfage of the fuselage, or to bracket means se
pose of stabilization.
cured to the fuselage and upwardly projecting from the
in the preferred embodiment of the invention, the aux 60 same. However, it is preferred to use the tail ?n :12 for
wings is provided with a tail ?n of a shape suitable for
attaching the parachute brake in accordance with the
present invention, so that the brake force of the para
downwardly inclined to the longitudinal axis of the air 65 chute brakes passes through the center of gravity when
craft in which the tail end of the aircraft is raised by
the aircraft is in landing approach position.
turning the aircraft about its horizontal axis which may
The parachute brake is attached to the ?aircraft not
be desired for turning the aircraft from the position of
at the center of gravity, but a certain distance behind the.
FIG. 8 to the position of FIG. 9. In the intermediate
center of gravity. In this manner, a remarkable stabiliza
position of the auxiliary jet means, the thrust of the auxi 70 tion of the aircraft during the landing approach ?ight and
lary jet means extends in direction of the longitudnial
during the rolling in alighted condition is obtained, and
axis of the aircraft, and adds to the propulsion thrust.
such stabilization is highly desirable, since the aircraft
When the two auxiliary jet means 8 and 9 are turned
lands ?at very low speed and at a great angle of incidence
in opposite directions so that, ?for example, jet means 8
whereby the e?iciency of the aerodynamic controls is
is downwardly inclined and jet means 9 is upwardly in 75 impaired.
3,089,667
8
the take-off weight W. The aerodynamic drag D5 is over
The combination of the parachute brake with an over?
sized wing, for example a delta wing, permits a safe land-
come by the horizontal thrust Th which is 0.87T and en
ables the aircraft to accelerate.
ing operation at a low approach speed of, for example.
In the position of ?FIG. 8, the aircraft is already air
borne but still in the take-off position. The auxiliary
jets 8 and 9, and the elevators 217 may now be turned into
130 km./h.
It is evident that a low landing approach speed is a.
prerequisite for a short rolling distance on the air?eld.
a position extending substantially in direction of the longi
During the rolling of the aircraft on the air?eld, all acre-
tudinal axis of the aircraft, so that the aircraft climbs in
dynamic braking devices are e?icient only during the ?rst.
normal ?ight position with the thrust of the jet engines
part of the rolling when the speed is still su?iciently high.
As the aircraft decelerates and slowly rolls to a stop, the� 10 being etfective in a plane passing through the center of
gravity 10 of the aircraft.
parachute brake is no longer effective and wheel brakes.
For illustrative purposes, the data of an aircraft con
or landing skis are provided for bringing the aircraft to
structed in accordance with the present invention are given
a stop.
as an example:
The effective surface of the parachute brake according:
to the present invention is approximately 20% greater? 15
than the effective surface of the wing, which may be ex-<
pressed as 1.28.
The horizontal component of the thrust is 0.87 of the
total thrust, since it depends on cos 30�. The braking
force of the parachute brake substantially corresponds to 20
the horizontal thrust component.
As previously ex
plained, the landing weight WE is smaller than the take
off weight W, which is substantially equal to the total
thrust of the engine. From this follows that the surface
load of the parachute is approximately
IKE =125 kg./m.2
SP
Wing load at take-off weight ___________ __ 200 kg./m.2
Rolling distance _____________________ __ 110 m.
Rolling time ________________________ __ 6 sec.
Take-off speed ______________________ __ 150 km./h.
Average acceleration on the runway _____ __ 0.75 g.
Effective aerodynamic wing load ________ __ 100? kg./m.
In this table, the character g represents the acceleration
of gravity expressed in rn./sec.2.
The above table shows that an aircraft in accordance
25 with the present invention requires a rolling distance for
take-off of 110 m., whereas known aircraft of the same
type requires 800 in. rolling distance for take-off. A
.greater increase of the ratio between thrust and weight is
within the scope of the present invention, and will result
ent invention will now be described with reference to 30 in a further reduction of the take-off distance.
FIGS. 5 to 9, and to the diagram of FIG. 14.
The take-off operation has been described with reference
As shown in FIG. 5, the aircraft is in an alighted sub
to the preferred embodiment of the present invention in
The take-off of an aircraft in accordance with the pres
stantially horizontal position resting on the main wheels
which in addition to the rear undercarriage, a nose wheel
5 and on the nose wheel 6. ?In this position, boarding of
6 is provided. However, the nose wheel 6 is not an essen
the plane is facilitated. The aircraft is moored or an 35 tial element of the present invention, and the aircraft may
chored to the ground so that the engines can be brought
be started in the position of FIG. 7, and roll the entire
up to full power with after-burning. The aircraft is then
take-off distance in the position of FIG. 7. The position
released, and taxies in the position of FIG. 5 on the for
of FIG. 5 provides a greater stability during the ?rst part
ward landing gear. The direction of thrust of the auxil
of the take-off run at slower speed, and moreover is desir
iary jet means 8 and 9 extends substantially through the 40 able for boarding and loading, and for taxiing the air
center of gravity 10 of the aircraft.
craft.
When the aircraft has moved through substantially
A landing operation in accordance with the present in
half the available rolling distance, the aircraft is gradu~
vention is illustrated in FIGS. 10 to 13, and diagram
ally tilted by operation of the elevators 2b and by tilting
matically illustrated in FIGS. 15 to 17 .
the auxiliary jet means 8 and 9 in upward direction. The 45
Before the aircraft approaches the landing ?eld, the
auxiliary jet means 8 and 9 are provided with compressed
auxiliary jets 8 and 9 are tilted upwardly to turn the air
air from the compressors of the main engines 3 and 4, and
craft into the landing approach position shown in FIG.
include a combustion chamber and a nozzle. However,
10 in which the wings have a great angle of incidence.
the auxiliary jet means may also be constructed as simple
The elevator means 212 may also be used for this purpose.
expansion nozzles ?for cold operation with compressed air,
While the aircraft approaches the air?eld in the position
or for operation with combustion gas supplied from the
of FIG. 10, the thrust of the engines 3 and 4 is reduced,
main jet engines 3 and 4. The auxiliary jet means may
and the speed is approximately 190 km./h.
also be small independent jet engines. In any event, the
The diagram of vFIG. 15 illustrates the directions of the
auxiliary jet means 8 and 9 are capable of providing a.
forces in the condition of the aircraft during ?ight in the
thrust which is almost 10% of the thrust of the main
position of FIG. 10. The landing weight WE is effective,
engines 3 and 4. In this manner, they can provide a turn
since the fuel tanks are empty. The thrust T of the jet
ing moment suf?cient to overcome an opposite moment
engines is small, and the horizontal and vertical compo�
produced by the weight of the aircraft acting at the center
of gravity 10 and by the friction resistance during the
nents of the thrust are correspondingly small.
The aero
dynamic drag Ds is effective. The required lift L corre
rolling of the aircraft. The auxiliary jet means 8 and 9? 60 sponds to the landing weight.
gradually turn the rolling aircraft into the position of
The parachute brake 15a is now opened, as shown in
FIG. 7 in which the aircraft is supported on the rear
FIG. 11 and simultaneously the jet engines 3 and 4 are
undercarriage, and rests on wheels 5 and 7. In this posi
driven at full power, preferably without after-burning.
tion, the direction of the thrust of the jet engines 3 and
The brake action of the parachute brake 15a reduces the
4 extends at an angle of 30� to a horizontal plane, and the 65 ?ying speed to a landing speed of 130 km./h. while the
wings have the maximum angle on incidence.
aircraft ?ies stationarily without loss of height. The
The jet engines 3 and 4 operate at full power with
forces acting on the aircraft during this landing approach
after-burning, and the aircraft continues to roll at increas
?ight, are illustrated in the diagram of FIG. 16. Since
ing speed. The diagram of FIG. 14 illustrates the forces
the jet engines 3 and 4 operate at high power, the vertical
acting on the aircraft during the take-off in position of
thrust component Tv compensates substantially one half
FIG. 7.
of the landing weight WE. The required lift L is also sub
The vertical component TV of the thrust T is 0.5T, and
stantially one half of the landing weight. The horizontal
since the thrust T is substantially equal to or greater than
thrust Th is compensated by the drag Dpar of the parachute
the weight W of the aircraft, an aerodynamic lift L is re
brake, and by the aerodynamic drag DS. Since the drag
quired, which is consequently substantially one half of
3,089,667
id
is greater than the horizontal thrust, the aircraft slows
down.
In the position of FIG. 12, the aircraft has landed,
horizontal axis until the position of FIG. 11 is obtained.
In this manner, the angle of incidence can be varied.
The jet engines 3 and 4 are operated during take-off
and rolls on wheels 5 and 7 in a landing position in which
with after-burning, resulting in a thrust which is 35%
the ?wings have an angle of incidence of approximately 5 higher than the rated thrust of the engine. Since dur
25�. The Wheel brakes are operated by an automatic
ing take-off considerable intake losses occur due to the
brake device at a friction coefficient of 0.45. The brake
low speed of the aircraft, the remaining effective thrust
of the jet engines is substantially equal to the take-off
action of the parachute brake is high during the ?rst part
of the rolling as long as the speed is still great. When
weight of the aircraft.
the speed of the aircraft is reduced, the drag of the para 10
?FIGURES la and 1b are intended to furnish additional
chute is rapidly reduced, while the braking effect of the
illustration.
wheel brakes increases due to the reduction of the lift
The pivotal movement of the auxiliary jets 8 and 9
at lower speed of the aircraft, and reduction of the verti
about axis 18 is brought about by means of booster '16
cal thrust component obtained by first reducing the
and lever 17, whereby the aircraft becomes controlable
power of the engines, and then by stopping the engines. 15 about its lateral axis.
The weight of the aircraft is no longer compensated, and
As shown in 1FIG. lb, the parachute-container 15 is
acts on the wheels during the second part of the rolling
mounted on the tail ?n, and conical container-cap 15b
movement of the aircraft, so that the wheel brakes be
is ejected and separates from container 115 when the para
come more effective.
chute brake is released. The conical container-cap pulls
The distribution of forces is illustrated in the diagram 20 out the auxiliary parachute 20 and the latter pulls out
of FIG. 17, which shows the landing weight WE counter
from container 15 the main parachute 15a in closed con
acted only by the smaller lift L, since the engines produce
dition. When the rope 25 is pulled out, parachute 15a
no thrust. The parachute brake produces a smaller drag
opens.
Dpar, since the speed is reduced, and in addition to the
The main parachute is attached to a slide 22 displace~
drag DzhLr is effective, which includes the brake force of 25 able on rail 21. The displacement is effected by means
the wheel brakes and the aerodynamic drag.
of a booster 23.
?
The wheel brakes produce a turning moment on the
The direction of reaction of the parachute brake can
aircraft which tends to turn the aircraft from the posi
tion shown in FIG. 12 to the position shown in FIG. 13
in which the aircraft rolls on the wheels 5 and 6. The
drag of the parachute brake produces an opposite mo
ment, but when the drag of the parachute becomes so
small that the aircraft tends to tilt into the position of
FIG. 13, the parachute is released and thrown off. The
thereby be changed from ?24a to 241) with respect to the
center of gravity of the aircraft. Through such a dis
placement either a moment can be created about the cen
ter of gravity of the aircraft, or a displacement of the
center of gravity may be taken into account, or the angle
of landing approach can be in?uenced by the stabilizing
effect as produced by the force of reaction of the para
aircraft now rolls to a stop and is slowed down by the 35 chute, While the aircraft is alighting.
wheel brakes.
It will be understood that each of the elements de
For illustrative purposes, the data during landing of
scribed above, or two or more together, may also ?nd
an aircraft according to the present invention are given
a useful application in other types of jet aircraft differ
as an example:
40
ing from the types described above.
Wingload at landing weight ____________ __ 150 kg/.m.
While the invention has been illustrated and described
as embodied in a jet aircraft for short take-off and land
Speed of approach ____________________ __ 190 km./h.
ing distances employing a parachute brake for landing,
Landing speed _______________________ __ 130 km./h.
it is not intended to be limited to the details shown,
since various modi?cations and structural changes may
be made without departing in any way from the spirit
Rolling distance ______________________ __ 110 m.
Rolling time _________________________ __ 6 sec.
Average deceleration on runway _________ __ 0.6 g.
Effective aerodynamic wing load _________ __ 75 kg./m.2
Surface load on the parachute brake ______ __ 125 kg./m.2
The above example shows that an aircraft in accord
ance with the present invention can come to a stop within
a distance of 110 m., whereas known aircraft of the same
type requires 500? rn. rolling distance for landing. The
rolling distance of the aircraft according to the present
invention could be further reduced by increasing the
thrust of the jet engines by after-burning during the land
ing operation, and by providing parachute brakes of cor
of the present invention.
Without further analysis, the foregoing will so fully re
veal the gist of the present invention that others can, by
applying current knowledge, readily adapt it for various
applications without omitting features that, from the
standpoint of prior art, fairly constitute essential charac
teristics of the generic or speci?c aspects of this invention
and, therefore, such adaptations should and are intended
to be comprehended within the meaning and range of
equivalence of the following claims.
What is claimed as new and desired to be secured by
Letters Patent is:
respondingly greater effective surface. However, a para
l. A jet aircraft for short take-off and landing distances,
chute brake may be required Whose size become impracti
comprising, in combination, wing means having a maxi-'
cal. Evidently, conventional brake ?aps can also be 60 mum lift at a given great angle of incidence; jet engine
used during landing operations, particularly since brake
means rigidly ?xed on the aircraft for producing a longi
?aps are provided on the aircraft of the present inven
tudinal jet thrust; and means on the aircraft for supports
tion for operation during flight.
ing the aircraft on the ground including ?rst undercara
As clearly shown in FIGS. 11 and 12, the parachute
riage means supporting the aircraft in take-01f and land
brake is attached to the aircraft in such a manner that 65 ing positions in which the angle of incidence of said wing
the plane of the drag forces passes through the center of
means is substantially said given angle of incidence and
gravity of the aircraft. Several parachute brakes can be
in which said engine means is tilted with respect to hori
attached to the upper side of the aircraft, and in this
zontal and vertical planes so that the vertical component
event it is necessary to distribute the points of attachment
of the jet thrust is substantially half of the weight of the
along a plane passing through the center of gravity so 70 aircraft whereby the aircraft is lifted during the take-off
that the drag produced by the parachute brakes tends to
and landing partly by the lift of said wing means produced
hold the aircraft in the position of FIG. 11,
by the forward movement of the aircraft driven by the
Preferably, the holders 15 of the parachute, or a
horizontal component of the jet thrust and partly by the
plurality of holders are displaceable so that turning move
vertical component of the jet thrust whereby short take
ments can be produced for turning the aircraft about its
off and landing distances are obtained, and second under
3,089,667
11
carriage means for supporting the aircraft on the ground in
another alighted position in which the longitudinal axis
of the aircraft is substantially horizontal.
2. A jet aircraft as set forth in claim 1 wherein said
12
aircraft on the ground including ?rst under-carriage means
supporting the aircraft in take-off and landing positions in
which the angle of incidence of said wing means is sub
stantially said given angle of incidence and in which said
wing means have an effective area selected so that the
engine means is tilted with respect to horizontal and ver
ratio between the weight of the aircraft and said effective
tical planes so that the vertical component of the jet thrust
is substantially half of the weight of the aircraft whereby
the aircraft is lifted during the take-off and landing partly
by the lift of said wing means produced by the forward
area is not greater than 350 kg./m.2.
3. A jet aircraft as set forth in claim 1 wherein said
engine means is tilted to a horizontal plane an angle of
10 movement of the aircraft driven by the horizontal com
ponent of the jet thrust and partly by the vertical compo
4. A jet aircraft as set forth in claim 1 wherein said
nent of the jet thrust whereby short take-off and landing
longitudinal thrust is at least as great as the weight of the
distances are obtained, and second undercarriage means
aircraft.
for supporting the aircraft on the ground in another
5. A jet aircraft as set forth in claim 1 wherein said
wing means have such a shape that the lift increases to a 15 alighted position in which the longitudinal axis of the air
craft is substantially horizontal; and auxiliary jet means
very small extent as the angle of incidence is increased.
for producing turning moments on the aircraft for turn
6. A jet aircraft as set forth in claim 1 wherein said
substantially 30�.
wing means have an effective area selected so that the
ratio between the weight of the aircraft and said effective
area is not greater than 350 kg./m.2, wherein said longi
tudinal thrust is as least as great as said weight of said
aircraft and wherein said wing means have such a shape
ing the aircraft between a position in which said wing
means is substantially horizontal, and said take-off and
landing positions.
10. A jet aircraft for short take-off and landing dis
tanoes, comprising, in combination, wing means having
a maximum lift at a given great angle of incidence; jet
engine means rigidly ?xed on the aircraft for producing
of incidence is increased.
7. A jet aircraft for short take-off and landing dis 25 a longitudinal jet thrust; means on the aircraft for sup
porting the aircraft on the ground in take-off and landing
tances, comprising, in combination, wing means having a
positions in which the angle of incidence of said wing
maximum lift at a given great angle of incidence; jet
means is substantially said given angle of incidence and
engine means rigidly ?xed on the aircraft for producing
in which said engine means is tilted with respect to hori
a longitudinal jet thrust; means on the aircraft for sup
porting the aircraft on the ground in take-off and landing 30 zontal and vertical planes so that the vertical component
that the lift increases to a very small extent as the angle
of the jet thrust is substantially half of the weight of the
aircraft whereby the aircraft is lifted during the take-off
and landing partly by the lift of said wing means pro
in which said engine means is tilted with respect to hori
duced by the forward movement of the aircraft driven
zontal and vertical planes so that the vertical component
of the jet thrust is substantially half of the weight of the 35 by the horizontal component of the jet thrust and partly
by the vertical component of the jet thrust whereby short
aircraft whereby the aircraft is lifted during the take-off
take-off and landing distances are obtained; and nor
and landing partly by the lift of said wing means pro
mally closed parachute brake means attached to the air
duced by the forward movement of the aircraft driven by
craft movable between a plurality of positions displaced
the horizontal component of the jet thrust and partly by
the vertical component of the jet thrust whereby short 40 relative to the center of gravity of the aircraft, said
parachute brake means having in open condition an ef
take-off and landing distances are obtained; and auxiliary
jet means for producing turning moments on the aircraft
fective surface selected for producing during landing ap
for turning the aircraft between a position in which said
proach ?ight ?and during movement of the alighted air
wing means is substantially horizontal, and said take-01f
craft a drag suf?cient to compensate at least a major part
of the horizontal component of the full jet thrust, and
and landing positions.
8. A jet aircraft for short take-off and landing distances,
for exerting in said displaced positions a turning moment
comprising, in combination, wing means having a maxi
on the aircraft.
mum lift at a given great angle of incidence; jet engine
11. Jet aircraft for short take-off and landing distances,
means rigidly ?xed on the aircraft for producing a longi
comprising, in combination, wing means having an ef
positions in which the angle of incidence of said wing
means is substantially said given angle of incidence and
tudinal jet thrust; means on the aircraft for supporting the
aircraft on the ground in take-off and landing positions in
which the angle of incidence of said wing means is sub
stantially said given angle of incidence and in which said
fective surface area selected so that the ratio between the
weight of the aircraft and said surface area is not greater
than 350 kg./m.2; jet engine means ?xed on the aircraft
for producing a thrust at least as great as the weight of
engine means is tilted with respect to horizontal and ver
the aircraft; valighting means for supporting the aircraft
tical planes so that the vertical component of the jet thrust 55 in take-off and landing positions in which the angle of
is substantially half of the weight of the aircraft whereby
incidence of said wing means is a maximum for produc
the aircraft is lifted during the take-0E and landing partly
ing a maximum lift; and normally closed parachute brake
by the lift of said wing means produced by the forward
means attached to the aircraft at a point of the aircraft
movement of the aircraft driven by the horizontal com
located in a horizontal plane passing through the center
ponent of the jet thrust and partly by the vertical compo 60 of gravity of the aircraft when the aircraft is in said
nent of the jet thrust whereby short take-off and landing
distances are obtained; and auxiliary jet means for produc
ing turning moments on the aircraft for turning the air
craft between a position in which said Wing means is sub
landing position, said parachute brake means having in
open condition an effective surface selected for producing
during landing approach ?ight and during movement of
the alighted aircraft a drag sufficient to compensate a
stantially horizontal, and said take-off and landing posi 65 major part of the horizontal component of the full engine
tions, said auxiliary jet means being mounted on the air
thrust.
craft for turning movement about a horizontal axis be
12. Jet aircraft for short take-off and landing distances,
tween positions upwardly or downwardly tilted to the
comprising, in combination, a fuselage having a tail ?n;
longitudinal axis of the aircraft, and an intermediate posi
wing means secured to said fuselage having an effective
tion for propelling the aircraft in a normal ?ight position. 70 surface area selected so that the ratio between the weight
9. A jet aircraft for short take-off and landing distances,
of the aircraft and said surface area is not greater than
comprising, in combination, wing means having a maxi
350 kg./m.2; jet engine means ?xed on the aircraft for
mum lift at a given great angle of incidence; jet engine
producing a thrust at least as great as the weight of the
means rigidly ?xed on the aircraft for producing a longi
tudinal jet thrust; means on the aircraft for supporting the 75 aircraft; alighting means for supporting the aircraft in
13
3,089,667
'14
take-off and landing positions in which the angle of in
means having in open condition an effective surface se
cidence of said Wing means is a maximum for producing
a maximum lift; and normally closed parachute brake
lected for producing during landing approach ?ight and
means attached to the aircraft at a point of said tail ?n
located in a horizontal plane passing through the center
of gravity of the aircraft when the aircraft is in said
landing position, said parachute brake means having in
open condition an effective surface selected for produc
ing during landing approach ?ight and during movement
of the alighted aircraft a drag su??icient to compensate
a major part of the horizontal component of the full
engine thrust.
13. let aircraft for short take-off and landing distances,
comprising, in combination, wing means having an ef
during movement of the alighted aircraft a drag sufficient
to compensate a major part of the horizontal component
of the full engine thrust.
16. Jet aircraft for short take-off and landing distances,
comprising, in combination, wing means having an effec
tive surface area selected so that the ratio between the
weight of the aircraft and said surface area is not greater
than 350 kg./m.2; jet engine means ?xed on the aircraft
for producing a thrust at least as great as the weight of
the aircraft, said jet engine means including a jet outlet
means having an axis extending downwardly inclined to
the longitudinal axis of the aircraft and passing through
fective surface area selected so that the ratio between 15 the center of gravity of the aircraft; alighting means for
the weight of the aircraft and said surface area is not
supporting the aircraft in take-off and landing positions in
greater than 350 kg./m,2; jet engine means ?xed on the
which the angle of incidence of said wing means is a
aircraft for producing a thrust at least as great as the
maximum for producing a maximum lift and in which
said engine means is tilted with the aircraft so that the
weight of the aircraft; alighting means for supporting the
aircraft in take-off and landing positions in which the 20 vertical component of the engine thrust is of about one
half of the total engine thrust; normally closed parachute
angle of incidence of said wing means is :a maximum for
brake means attached to the aircraft and having in open
producing a maximum lift; normally closed parachute
condition an effective surface selected for producing dur~
brake means attached to the aircraft and having in open
ing landing approach ?ight and during movement of the
condition an effective surface selected for producing dur
ing landing approach ?ight and during movement of the 25 alighted aircraft a drag suf?cient to compensate a major
part of the horizontal component of the full engine thrust;
alighted aircraft a drag suf?cient to compensate a major
part of the horizontal component of the full engine thrust;
and movable auxiliary jet means producing turning mo
and movable auxiliary jet means producing turning mo
ments on the aircraft for turning the aircraft from nose
wheel alighted position into steep take-off position and
wheel alighted position into steep take-off position and 30 from said take-off position into a normal ?ight position
in which said wing means have a smaller angle of inci
from said. take-elf position into a normal ?ight position in
dence, and for turning said aircraft during landing ap
which said wing means have a smaller angle of incidence,
proach ?ight from said normal ?ight position into said
for turning said aircraft during landing approach
landing position.
?ight from said normal ?ight position into said landing
17. Jet aircraft for short take-off and landing distances,
position.
comprising, in combination, a fuselage having a tail ?n;
14. let aircraft for short take-off and landing distances,
wing means secured to said fuselage having an effective
comprising, in combination, wing means; jet engine means
ments on the aircraft for turning the aircraft from nose
?xed on the aircraft for producing a thrust, said jet en
gine means including a jet outlet means having an axis
surface area selected so that the ratio ?between the weight
of the aircraft and said surface area is not greater than
extending downwardly inclined to the longitudinal axis
of the aircraft ?and passing through the center of gravity
of the aircraft; alighting means for supporting the air
craft in take-off and landing positions in which the angle
350 kg/m?; jet engine means ?xed on the aircraft for
producing a thrust at least as great as the weight of the
aircraft, said jet engine means including a jet outlet means
having an axis extending downwardly inclined to the
landing approach ?ight and during movement of the
half of the total engine thrust; normally closed parachute
longitudinal axis of the aircraft and passing through the
of incidence of said Wing means is a maximum for pro
ducing a maximum lift and in which said engine means 45 center of gravity of the aircraft; alighting means for sup
porting the aircraft in take-off and landing positions in
is tilted with the aircraft so that the vertical component
which the angle of incidence of said wing means is a
of the engine thrust is of about one half of the weight
maximum for producing a maximum lift and in which
of the aircraft; and normally closed parachute brake
said engine means is tilted with the aircraft so that the
means attached to the aircraft and having in open condi
vertical component of the engine thrust is of about one
tion an effective surface selected for producing during
alighted aircraft a drag su?icient to compensate a major
part of the horizontal component of the full engine
thrust.
brake means attached to the aircraft rearwardly of the
center of gravity of the aircraft at a point of said tail ?n
located in a horizontal plane passing through the center
15. Jet aircraft for short take-off and landing distances, 55 of gravity of the aircraft when the aircraft is in said land
ing position, said parachute brake means having in open
comprising, in combination, a fuselage having a tail ?n;
condition an effective surface selected for producing dur
wing means secured to said fuselage having an effective
ing landing approach ?ight and during movement of the
surface area selected so that the ratio between the weight
alighted aircraft a drag sufficient to compensate a major
of the aircraft and said surface area is not greater than
350 kg./m.2; jet engine means ?xed on the aircraft for 60 part of the horizontal component of the full engine
thrust, said drag producing a resultant force passing
producing a thrust at least as great as the Weight of the
through the center of gravity of the aircraft; and mov
aircraft, said jet engine means including a jet outlet means
able auxiliary jet means producing turning moments on
the aircraft for turning the aircraft from nose-wheel
alighted
position into steep take-off position and from
center of gravity of the aircraft; alighting means for 65
said take-off position into a normal ?ight position in
supporting the aircraft in take-off and landing positions
which said wing means have a smaller angle of incidence,
in which the angle of incidence of said wing means is a
having an axis extending downwardly inclined to the
longitudinal axis of the aircraft and passing through the
and for turning said aircraft during landing approach
maximum for producing a maximum lift and in which
?ight from said normal ?ight position into said landing
said engine means is tilted with the aircraft so that the
vertical component of the engine thrust is of about one 70 position.
chute brake means attached to the aircraft at a point
18. Jet aircraft for short take-off and landing distances,
comprising, in combination, wing means having an effec
of said tail ?n located in a horizontal plane passing
through the center of gravity of the aircraft when the
tive surface area selected so that the ratio between the
weight of the aircraft and said surface area is not greater
half of the total engine thrust; and normally closed para
aircraft is in said landing position, said parachute brake 75 than 350 kg./m.2; jet engine means ?xed on the aircraft
3,089,667
? 15
16
wing means is a maximum for producing a maximum lift
and in which said engine means is tilted with the aircraft
so that the vertical component of the engine thrust is of
about one half of the weight of the aircraft; and nor
mally closed parachute brake means attached to the air
for producing a thrust, said jet engine means including a
jet outlet means having an axis extending downwardly
inclined to the longitudinal axis of the aircraft and pass
ing through the center of gravity of the aircraft; alight
ing means for supporting the aircraft in take-off and land
ing positions in which the angle of incidence of said wing
craft at a point of the aircraft located in a horizontal
plane passing through the center of ?gravity of the air
craft when the aircraft is in said landing position, said
means is a maximum for producing a maximum lift and
in which said engine means is tilted with the aircraft so
parachute brake means having in open condition an ef
that the vertical component of the engine thrust is of
about one half of the weight of the aircraft; and normally 10 fective surface selected for producing during landing ap
proach ?ight and during movement of the alighted air
closed parachute brake means attached to the aircraft and
craft a drag sufficient to compensate a major part of the
having in open condition an effective surface selected for
horizontal component of the full engine thrust.
producing during landing approach ?ight and during
22. Jet aircraft for short take-off and landing distances,
compensate a major part of the horizontal component 15 comprising, in combination, wing means; jet engine means
?xed on the aircraft for producing a thrust; alighting
of the full engine thrust.
means for supporting the aircraft in take-elf and land
19. Jet aircraft for short take-off and landing dis
ing positions in which the angle of the incidence of said
tances, comprising, in combination, wing means having
movement of the alighted aircraft a drag su?icient to
wing means is a maximum for producing a maximum lift
an effective surface area selected so that the ratio be
tween the weight of the aircraft and said surface area 20 and in which said engine means is tilted with the air
craft so that the vertical component of the engine thrust
is not greater than 350 kg./m.z; jet engine means ?xed
is of about one half of the weight of the aircraft; nor
on the aircraft for producing a thrust; alighting means
mally closed parachute brake means attached to the air
for supporting the aircraft in take-o?f and landing posi
craft at a point of the aircraft located in a horizontal
tions in which the angle of incidence of said wing means
is a maximum for producing a maximum lift and in 25 plane passing through the center of ?gravity of the air
craft when the aircraft is in said landing position, said
which said engine means is tilted with the aircraft so
parachute brake means having in open condition an ef
that the vertical component of the engine thrust is of
about one half of the weight of the aircraft; normally
closed parachute brake means attached to the aircraft
and having in open condition an effective surface se
fective surface selected for producing during landing ap
proach ?ight and during movement of the alighted air
30 craft a drag su?icient to compensate a major part of the
lected for producing during landing approach ?ight and
during movement of the alighted aircraft a drag sufficient
to compensate a major part of the horizontal compo
nent of the full engine thrust; and movable auxiliary
jet means producing turning moments on the aircraft 35
for turning the aircraft from nose-wheel alighted posi
alighted position into steep take-off position and from
said take-off position into a normal ?ight position in
which said wing means have a smaller angle of incidence,
and for turning said aircraft during landing approach
?ight from said normal ?ight position into said landing
tion into steep take-off position and from said take-off
position into a normal ?ight position in which said wing
position.
means have a smaller angle of incidence, and for turn
ing said aircraft during landing approach ?ight from said
normal ?ight position into said landing position.
horizontal component of the full engine thrust; and mov
able auxiliary jet means producing turning moments on
the aircraft for turning the aircraft from nose-wheel
40
23. Jet aircraft for short take-off and landing distances,
comprising, in combination, wing means having an effec
tive surface area selected so that the ratio between the
20. Jet aircraft for short take-off and landing dis
tances, comprising, in combination, wing means having
weight of the ?aircraft and said surface area is not greater
than 350 kg./m.2; jet engine means ?xed on the aircraft
an effective surface area selected so that the ratio be
tween the weight of the aircraft and said surface area 45 for producing a thrust at least as great as the weight of the
aircraft; alighting means for supporting the aircraft in
is not ?greater than 350 kg./m.2; jet engine means ?xed
take-off and landing positions in which the angle of
on the aircraft for producing a thrust at least as great
as the weight of the aircraft; alighting means for sup
incidence of said wing means is a maximum for pro
porting the aircraft in take-off and landing position in
ducing a maximum lift; normally closed parachute brake
half of the total engine thrust; normally closed parachute
part of the horizontal component of the full engine thrust;
aircraft located in a horizontal plane passing through
the center of gravity of the aircraft when the aircraft is
in said landing position, said parachute brake means hav
nose-wheel alighted position into steep take-01f position
which the angle of incidence of said wing means is a 50 means attached to the aircraft and having in open condi
tion an effective surface selected for producing during
maximum for producing a maximum lift and in which
landing approach ?ight and during movement of the
said engine means is tilted with the aircraft so that the
alighted aircraft a drag su?icicnt to compensate a major
vertical component of the engine thrust is of about one
and movable auxiliary jet means producing turning
brake means attached to the aircraft at a point of the 55
moments on the aircraft for turning the aircraft from
and from said take-off position into a normal ?ight posi
tion in which said wing means have a smaller angle of
ing in open condition an effective surface selected ?for
producing during landing approach ?ight and during
movement of the alighted aircraft a drag sufficient to
compensate a major part of the horizontal component
of the full engine thrust; and movable auxiliary jet means
producing turning moments on the aircraft for turning
60
incidence, and for turning said aircraft during landing
approach ?ight from said normal ?ight position into said
landing position, said auxiliary jet means being mounted
on the aircraft for turning movement about a horizontal
axis between positions upwardly and downwardly tilted
to the longitudinal axis of the aircraft, and an intermediate
the aircraft from nose-wheel alighted position into steep 65 position for propelling the aircraft in normal ?ight posi
take-off position and from said take-off position into a
normal ?ight position in which said wing means have a
smaller angle of incidence, and for turning said aircraft
during landing approach ?ight from said normal ?ight
position into said landing position.
21. Jet aircraft for short take-off and landing distances,
comprising, in combination, wing means; jet engine means
?xed on the aircraft for producing a thrust; alighting
?means for supporting the aircraft in take-off and land
tion.
,
.
.
24. Jet aircraft as set forth in claim 23 wherein said
auxiliary jet means include jets ?located on opposite sides
of the longitudinal vertical plane of symmetry of the air?
craft.
,
t
25. Jet aircraft for short take-off and landing distances,
comprising, in combination, wing means having an effec
tive surface area selected so that the ratio between the
ing positions in which the angle of incidence of said 75 weight of the aircraft and said surface area is not greater
3,089,667
17
18
than 350 -kg./m.2; jet engine means ?xed on the aircraft
for producing a thrust at least as great as the weight of the
means having brake means and supporting the aircraft in
aircraft; alighting means including ?rst undercarriage
cidence of said wing means is a maximum for producing a
maximum lift and second undercarriage means for sup?
take-off and landing positions in which the angle of in
means supporting the aircraft in take-off and landing
positions in which the angle of incidence of said wing UK porting the aircraft in another alighted position in which
means is a maximum for producing a maximum lift
the longitudinal axis of the plane is substantially horizon
and second undercarriage means for supporting the air
tal; normally closed parachute brake means attached to the
craft in another alighted position in which the longitudinal
aircraft and having in open condition an effective surface
axis of the plane is substantially horizontal, said alighting
selected for producing during landing approach ?ight and
means include main wheel means, nose wheel means, and 10 during movement of the alighted aircraft a vdrag su?icient
tail wheel mean-s, and friction brakes at least for said
main wheels, the center of gravity of the aircraft being
located forwardly of said main wheel means in said other
to compensate a major part of the horizontal component
of the full engine thrust, said parachute brake means be
ing detachable from the aircraft so that the aircraft turns
alighted position, and rearwardly of said main wheel
from said landing position to said other alighted posi
means in said take-off and landing positions; and movable 15 tion when said parachute brake means is detached and
auxiliary jet means producing turning moments on the
said brake means are applied; and movable auxiliary jet
aircraft for turning the aircraft from said other alighted
means producing turning moments on the aircraft for
position into said take-off position, and from said take
off position into ?a normal ?ight position in which said
wing means have a smaller angle of incidence.
26. Jet aircraft
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