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Патент USA US3077120

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Feb. 12, 1963
Filed June 29. 1959
MN
T. GOLD
SYSTEM FOR MONITORING
THE'. TAKE-'OFF
3,077,110
PERFORMANCE OF AN AIRCRAFT
2 Sheets-Sheet l
Feb. 12, 1963
T, GOLD
SYSTEM FOR MONITORING THE TAKE-OFF
Filed June 29, 1959
2 Sheets-Sheet 2
Oké
N
œmEHIn.
3,077,110
PERFORMANCE OF AN AIRCRAFT
Unite Staes
ffice
l
3,077,110
Patented Feb. 12, 1963`
2
3,077,110
olf can also be measured by remote external means such
as radar or the transmission of impulses as the aircraft
Theodore Gold, Ronkonkoma, N.Y., assigner to Sperry
munication link to the aircraft as well as a siutable air
SYSTEM FOR MONITORING THE TAKE-OFF
PERFORMANCE 0F AN AIRCRAFT
Rand Corporation, Great Neck, N.Y., a corporation of
Delaware
Filed June 29, 1959, Ser. No. 823,753
12 Claims. (Cl. 73-178)
passes ñxed positions.
However, this requires a com
craft display. Use of this type of equipment makes air
craft take-off monitoring contingent on the performance
of ground based equipment and requires additional air
field facilities.
It is therefore a primary object of the present in
'I'his invention relates to a system for monitoring the 10 vention to provide a take-olf monitoring system for air
take-olf performance of an aircraft. In particular it con
craft that continuously monitors the performance of the
cerns a system for accurately providing a continuous in
aircraft during the take-olf run and provides an in
dication of the actual performance of the aircraft during
stantaneous indication of changes in said performance.
the take-olf -run for purposes of determining whether the
lt is an additional object of the present. invention to
aircraft will become safely airborne within the runway 15 provide a take-olf monitoring system for aircraft that pro
distance available.
vides an indication of the relative magnitude of a signal
Several techniques are currently used to monitor the
representative of twice the forward -acceleration of the
performance of an airplane during take-oli. In one sys
craft multiplied by the remaining runway distance to be
tem, the pilot refers to performance charts to determine
traversed with that of a signal representative of the dif
the air speed which should be attained by the time the 20 ference between the square of the speed required for the
aircraft reaches a predetermined point on the runway.
craft to become airborne and the square of the actual
The pilot then compare-s the actual indicated air speed
speed of the craft.
with the desired air speed at the reference point. This
The above objects are achieved by the present invention
requires the pilot to refer to a visual check point outside
by a system which senses the forward »acceleration and
the cockpit at a `time when his attention is drawn to many 25 the air speed of the aircraft during the take-off. Means
other instruments within the cockpit. A further limita
responsive to the forward acceleration provides a lirst
tion of this system is that the pilot has no Way of monitor
signal representative of the product of twice the forward
ing performance of the craft during the take-off run until
acceleration and the distance -to be traversed under the
the check point is reached. Since the check point and the
prevailing conditions. Means responsive to the -air speed
point at which he must render a decision to continue or 30 provides a second signal representative of the difference
«abort are close together, it leaves him little time to ar
between the square of the speed required for the craft
rive at a decision in the event performance is marginal.
to become airborne and the square of the actual speed
Further, the actual air speed may exceed the required air
of the craft. The aforementioned signals are compared
speed at the check point although a failure has been ex
to provide a control signal representative of the difference
perienced which will prevent the aircraft from taking olf 35 therebetween. When the first signal is equal to or greater
safely.
than the second signal, the control signal is utilized to
Other take-off monitoring systems sense the actual
drive a pointer which provides an indication that a take
longitudinal acceleration of the aircraft as it proceeds
off may be executed safely. On the other hand when the
down the runway during the take-olf. One system of
ñrst signal is less than vthev second signal, the control sig
this type is disclosed in the National Advisory Committee 40 nal is utilized to drive the pointer to provide an indica
for Aeronautics Technical Note 3252, entitled, “Descrip
tion that the take-cfrr should be discontinued, or that addi
tion and Preliminary Flight Investigation of an Instru
tional distance along the runway will be required to be
ment for Detecting Subnormal Acceleration During Take
come airborne. An indication is provided of the distance
Off,” written by Garland J. Morris and Lindsay l. Lina,
traversed as well as the distance to‘be traversed.
Au
dated November 1954. The aforementioned Technical 45 indication of the check line position is also provided.
Note 3252 described an instrument utilizing a linear ac
When the acceleration characteristic of the aircraft de
celerometer and a pressure diaphragm coupled together
creases appreciably during the take-off run, additional
so that the normal decrease in acceleration with increasing
means are provided for obtaining a signal representative
velocity during take-olf is compensated by the increase
of the average acceleration which is utilized «for moni
in dynamic pressure in order to give -a constant predictable
toring purposes.
indicator reading as long as the thrust and resistance are
The forward acceleration required for an aircraft to
normal. It will be appreciated that this instrument mere
increase its ground speed from V1 to V2 within a distance
ly provides an indication of the instantaneous longitudinal
Sis
acceleration being experienced by the craft during the
take-olf. One limitation of the aforementioned instru
ment is that the actual acceleration during take-off may
fluctuate above and below the require acceleration. With
instantaneous .acceleration being compared with a stand
ard, the pilot has the burden of mentally evaluating
The required acceleration from »time t to reach the
take-olf velocity Vto when the actual air speed of the
aircraft is V, and the distance actually traversed from
whether or not the average acceleration to some point 60 initiation of the take-off run is St is
down the runway is satisfactory. If the average accelera
tion is subnormal, but at the time the pilot takes a read
ing the instantaneous acceleration is norm-al, there is an
indication given to the pilot that he can safely take olf
where the runway component of wind is Vw, the take-off
when in reality the air speed of the craft will be in 65 distance is Sg and «r is the air density ratio for the pre
adequate for safe take-olf.
vailing pressure and temperature conditions at the runway.
Another system which senses the actual longitudinal
By monitoring the sensed forward acceleration of the
acceleration of the craft as it proceeds down the runway
craft, the success of the take-olf perform-ance may be
but overcomes the above limitations is disclosed in co
predicted in accordance with the following equation:
pending application S.N. 613,104, filed October 1, 1956, 70
now Patent No. 3,034,09 6.
Aircraft performance on the runway during the take
3,077,110
3
4
ing knob 35 of the potentiometer 33 provides a signal
from the potentiometer 33 having a magnitude representa
tive of the air speed required »for the aircraft take-off
within the allocated take-off distance with the prevailing
the following drawings in which:
atmospheric density. The potentiometer 30 is also con
FIG. 1 is a schematic block diagram of a preferred
nected -to provide a signal in opposition to the signal pro
embodiment of a take-off monitoring system, and
vided by the potentiometer 33 to the squaring circuit
FIG. 2 is an alternative embodiment of the system of
34. The signal into the squaring circuit 34 is therefore
FIG. 1.
representative of the take-0E ground speed, i.e., the dif
Referring now to FlG. l, a linear accelerometer lil
is mounted in the craft with its sensitive axis disposed 10 ference between the required air speed and the component
of the prevailing head wind parallel to the runway. The
parallel with respect to the horizon in order that it is
take-off ground speed signal is squared in the squaring
responsive only to the forward acceleration experienced
circuit 34. The squaring circuit 34 is connected to an
by the craft and provides a signal having a magnitude
other input terminal of the summing network 32. The
proportional to the magnitude of the forward accelera
a successful take-off may be performed within the al
located take-olf distance.
The invention will now be described with reference to
tion.
The accelerometer 10 is connected to a filter 11 15 signal provided by the summing network 32 is repre
where the acceleration signal is ñltered before it is ap
plied to an input terminal of a multiplying network 12.
The accelerometer 10 is also connected to an integrator
sentative of the required take-off ground speed squared
minus the actual ground speed squared. The summing
network 32 is connected to the summing network 23 to
provide a signal in opposition to that supplied by the
signal representative of the forward velocity of the craft. 20 multiplying network 12.
The summing network 23 provides a control signal
This integrator 13 is connected to an integrator 14 which
representative of twice the forward acceleration times the
integrates the velocity signal to provide a signal repre
remaining runway distance before take-off times the
sentative of the distance actually traversed by the craft
density ratio minus the difference between the square of
from the beginning of the take-ofi run St. The integra
the required ground speed and the actual ground speed.
tors 13 and 1-4 may be, for example, electromechanical
13 which integrates the acceleration signal to provide a
integrating devices. The integrator .14 is connected to
an input terminal of a summing network 15.
A potentiometer 20 is connected to another input ter?
The summing network 23 is connected to energize a
meter mechanism 39 in accordance with the control signal.
The meter mechanism 39 is mechanically connected by
a shaft 40 to a pointer 41.
minal of the summing network 15. The potentiometer
The pointer 41 forms a portion of the display, gen
20 provides a signal representative of the distance to be 30
erally indicated at 42, of the takeaotf monitor instrument
traversed by the aircraft from the beginning of the take
of the present invention. The display 42 is viewable
off run until the aircraft becomes airborne, which is
through an opening in the instrument housing 43 which
known as the take-olf distance Sg. Manual adjustment
is mounted preferably on the cockpit instrument panel.
having a magnitude representative of the take-off distance. 35 The display also includes a disc 44, a rotatable distance
card 45, and a rotatable check line index 46.
The summing network 15 is connected to another input
The pointer 41 is rotatable on the face of the instru
terminal of the multiplying network 12. The distance
ment by means of the shaft 40 which protrudes through
traversed signal St is applied to the summing network
an aperture in the center of the disc 44. The pointer
15 in opposition to the take-olf distance signal Sg. The
output of the summing network 15 is a signal representa 40 41 is cooperative with indicia Sil and 51 which are paint
ed on the disc 44. The indicium 50, for example, may
tive of the take-off distance S8 minus the distance tra~
be painted red or cross-hatched while the indicium“ 51
versed St.
is painted a contrasting color such as green or a solid
An air density ratio transducer 22 which is responsive
color, respectively, to provide a prominent line of de
to the prevailing static pressure and temperature condi
tions is connected to a third input terminal of the multi 45 marcation 52 therebetween. The extremity of the point
er 41 is so disposed and rotatable as to lie adjacent one
plying network 12. The transducer 22 provides a signal
of the indicium 50 or 51 during the operation of the in
representative of the prevailing air density. The multi
strument as will be described.
plying network 12 is connected to an input -terminal of a
of a knob 21 of the potentiometer 20 provides a signal
To provide an indication of the distance traversed as
summing network 23. The signal provided by the multi
plying network 12 is representative of twice the multiple 50 well as the distance remaining to be traversed before
take-off, the integrator 14 is connected to a servo system
of the forward acceleration multiplied by the distance
remaining to be traversed as corrected by the prevailing
air density.
-
53 which in turn is connected to drive the distance card
45 through a slip clutch 54 and gearing 55. The servo
system 53 rotates the distance card 45 in a clockwise di
A pitot tube 24 is mounted on the exterior of the air
rection proportional to the distance actually traversed by
craft to provide pressures representative of the total pres
sure and the static pressure experienced by the aircraft
the aircraft from the beginning of the take-off run. The
to an air speed transducer 25. The air speed transducer
distance card 45 has graduations thereon representative
25 provides a Signal having a magnitude representative
of distance in thousands of feet which are cooperative
of the actual air speed of the craft. The air speed trans
with a fixed lubber line 60.
ducer 25 is connected to a squaring circuit 26. A potenti 60
As the aircraft proceeds down the runway during the
ometer 30 is connected to the squaring circuit 26 to pro
take-off run, a point is reached at which the pilot must
vide a signal in opposition to the signal provided by the
decide whether to continue the take-off in a normal man
air speed transducer 25. 'I'he potentiometer 30 is manual
ner to become airborne, or to discontinue the take-off.
ly adjusted by a knob 31 to provide a signal from the
The point along the runway at which this decision is made
potentiometer 30 having a magnitude representative of 65 must allow sufficient remaining runway distance to bring
the component of the prevailing head wind parallel with
the aircraft to a safe stop on the runway. This point
the runway. The signal applied to the squaring circuit
along the runway is known as the check line. The dis
26 is therefore representative of the actual ground speed
tance from the beginning of the takeoff run to the check
of the aircraft, i.e., the difference between the actual air
line is the check line distance. The check line index 46
speed and the component of the prevailing wind. The 70 in cooperation with the card 45 provides an indication of
signal representative of the aircraft ground speed is
the check line distance. A check line select knob 61 is
squared in the squaring circuit 26.
connected through a differential G2 to a pinion gear 63
The squaring circuit 26 is connected -to an input ter
which drives a ring gear 64. The check line index 46
minal of a summing network 32. A potentiometer 33
is mounted upon and rotates with the gear 64.
is connected to a squaring circuit 34. Manually adjust 75
The check line index 46 is cooperative with the dis
5
3,077,110
tance indications on the distance card 45. Manually
adjusting the knob 61 rotates the index 46 until it is
aligned with the correct distance on the card 45. There
after, the card 45 and the index 46 are synchronously
driven in a clockwise direction by the servo system 53;
the latter through the slip clutch 54, diiîerential 62,
pinion gear 63 and ring gear 64. The check line index
46 is also cooperative with the lubber line 60.
A reset knob 65 is connected to the card 45 by means
6
borne speed of the craft within the take-off distance in
View of its present speed. Under these circumstances, the
pointer 41 is driven in a clockwise direction beyond the
line 52 and will be adjacent the indicium 51 indicating
a take-off may be safely executed.
When the signal from the network 12 has a magni
tude less than the signal from the network 32, the accel
eration of the craft is inadequate to achieve the necessary
take-off speed within the predetermined take-off distance
of the gearing 55 and to the index 46 through the dif
in view of the present speed of the craft. The pointer
10
ferential 62; pinion gear 63 and ring gear 64. Manual
41 will therefore be driven to lie adjacent the indicium
adjustment of the reset knob 65 rotates the card 45 and
50 indicating that performance is submarginal. The
the index 46 for resetting at the beginning of a take-olf
pilot then has the option of discontinuing the take-Gif
run. The slip clutch 54 prevents any damage to the
early in the take-olf run or continuing the take-off to see
servo system 53 during the reset adjustment.
15 if performance will improve by the time 'the check line
In the operation of the system of the present inven
is reached. At the check line or shortly thereafter, a
tion, at the beginning of the take-off run, the reset knob
ñnal decision must vbe made.
65 is manually adjusted to rotate the card 45 until its
The position of pointer 41 with respect to the indicia
vzero graduation lies beneath the lubber line 60. The
50 and 51 and the demarcation line 52 provides an indi
check line select knob 61 is then manually adjusted to 20 cation of the relative performance of the aircraft. For
rotate the check line index 46 until it lies adjacent the
example, indicium 51 may be so designed that with
distance on the card 45 representative of the check line
pointer 41 adjacent the center thereof, the aircraft per
distance. The knob 31 of the potentiometer 30 is ad
formance is 10% above nonnal. Correspondingly, with
justed in accordance with the runway component of the
pointer 41 adjacent the center of the indicium 50, the
prevailing wind. The knob 35 of the potentiometer 33 25 aircraft performance is 10% below normal. The rela
is adjusted in accordance with the air speed required for
tive performance of the aircraft is related to the distance
the aircraft to become airborne under the prevailing con
required for take-off. For example, in certain aircraft,
ditions. The knob 21 of the potentiometer 20 is adjust
a. 7% decrease in performance requires a 10% increase
ed in accordance with the take-off distance.
in take-od distance for the craft to become airborne. By
As the aircraft proceeds along the runway at the be 30 this means, the pilot may assess the subnormal perform
ginning of the take-olf run, the accelerometer 10 senses
ance of the craft in terms of the additional runway dis
the forward acceleration experienced by the craft and
tance required to become airborne and reach a decision
provides a signal representative thereof. The accelera
accordingly.
tion is iiltered in the iilter 11 to eliminate the effect of
As the aircraft proceeds along the runway during the
high frequency components thereof before it is applied 35 take-off run, the distance traversed signal from the in
to the multiplying network 12. The acceleration signal
tegrator 14 energizes the servo system 53 which rotates
«is also integrated in the integrator 13 and again in the
the card 45 in a clockwise direction by means of Vthe
integrator 14 to provide a signal representative of the
gearing 55. The card 45 continuously provides an indi
distance traversed by the aircraft from the beginning of
cation of the distance traversed and the distance to be
the take-off run to the summing network 15. The output 40 traversed by cooperation of the graduations thereon with
signal of the summing network 15 is representative of the
the lubber line 60. The servo system 53 also drives the
distance remaining to be traversed and is applied to the
check line index 46 synchronously with the card 45
multiplying network 12. The signal representative of
through the differential 62 and gearing 63 and `64».
the air density ratio from the transducer 22 is also applied
When the check line index 46 becomes aligned with
to the multiplying network 12.
45 the lubber line 60, the pilot must render a final decision
The total and static pressure experienced by the air
regarding continuance or discontinuance of the take-off
craft is sensed by the pitot tube 24 and converted to an
based on the aforementioned considerations.
electrical signal representative of the actual air speed of
It will be obvious to those skilled in the art that the
the craft by the transducer 25. The actual air speed sig
specific design of the indicia 50 and 51 and the position
nal is applied to the squaring circuit 26 along with a 50 of the demarcation line 52 will be dependent upon the
corrective signal representative of the prevailing wind
type of aircraft in which the take-où” monitor system is
condition. The dilference therebetween is squared in the
utilized and the considerations governing the check line
point.
circuit 26 and applied to the summing network 32. The
signal representative of the required take-off speed cor
The acceleration characteristics of many aircraft re
rected for the prevailing wind conditions is squared in 55 main substantially constant during the take-off run in
the squaring circuit 34 and also applied to the summing
which event the above-described take-off monitoring sys
network 32. The output of the summing network 32 is
tem provides a continuous accurate indication of aircraft
representative of the difference between the square of
performance. In certain aircraft however, as the air
plane proceeds down the runway, the acceleration char
the required take-off speed and the square of the actual
speed of the craft and is applied to the summing network 60 acertistic decreases appreciably due to changes in the
aerodynamic drag and engine thrust with increasing air
23 in opposition to the output signal from the network
speed. With aircraft of the latter type, it is preferable
12. The summing network 23 provides a control signal
to utilize the average acceleration in lieu »of the actual
representative of the difference between its input signals
acceleration. The average acceleration may be calcu
to energize the meter mechanism 39. The meter mecha
nism 39 drives the pointer 41 accordingly to provide a 65 lated by subtracting from the instantaneous acceleration
one-half the anticipated decrease of acceleration meas
continuous measure of the aircraft performance.
ured as a function of the difference in dynamic pressure
When the signal from the network 12 is equal to the
`from the value at the present position of the aircraft to
signal from the network 32, the pointer 41 is aligned with
the value at take-off. For a linear variation of accelera
the demarcation line 52 indicating performance is ade
quate and a take-off may be executed safely within the 70 tion
allocated runway distance. When the signal from the
network 12 has a magnitude greater than the magnitude
of the signal from the network 32, the forward accelera
where
tion of the aircraft over the remaining runway distance
ax=forward horizontal acceleration
will rbe more than adequate to achieve the required air 75 aar-.initial acceleration at q equals zero
3,077,110
8
>'i'
lation resistor S4 and the summing resistor 86 to ground
potential while the -qa signal is connected through the
isolation resistor $5 and the summing resistor 86 to ground
q=dynamic pressure (l/zpo Vez)
po=atmospheric density for standard sea level conditions
JVe=equivalent air speed
ifi/:gross weight of the aircraft
K=dynamic pressure compensating factor
potential. The signal representative of qm--qa is applied
across the resistive winding of the potentiometer -83 as
modified by the position of the slider of the potentiome
where
ter 81.
2 dT
* HOLA +3; W?
where
10
G = gravitational constant
A=wing area of the aircraft
CD=drag coeiiicient of the aircraft
¿L_-:coefficient of rolling resistance between the tires and
the runway
15
CLzlift coeñicient of the aircraft
T=thrust
The decrease in acceleration between qa and qto is then
20
The average acceleration is then the present accelera
tion less
25
The output terminal of the computer network 70 is
connected to an input terminal of a summing network
87. The other input terminal of the summing network
87 is connected to receive the filtered acceleration signal
from `the linear accelerorneter if? via the filter 11. The
signal from the network 70 is connected to the sum
ming network -87 in opposition to the acceleration signal
from the accelerorneter 19). The output terminal of the
summing network 87 is connected to an input terminal
of the multiplier l2.
As described previously with respect to FIG. l, the
other yinput terminals of the multiplier 12 are connected
to the output terminals of the air density ratio transducer
22 and the summing network 15 respectively. The multi
plier network 12 is connected to an input terminal of
the summing network 23 to provide a signal representa
tive of twice the average forward acceleration multiplied
by the distance remaining to be traversed as corrected
by the prevailing atmospheric conditions, i.e.
where
qto=dynamic pressure at take-off
qa=actual dynamic pressure
The monitoring function for the take-off monitor sys
tem then becomes
30
The other input terminal of the summing network 23
is connected to the output terminal from the network
32. The summing network 23 provides a control signal
to the meter mechanism 39 ¿representative of twice the
Referring now to FIG. 2 an embodiment of the in 35 average acceleration times the remaining runway dis
vention will be described which utilizes a signal repre
tance before take-off times the density ratio minus the
sentative of the average acceleration to monitor take-off
difference between the square of the required ground
performance. The system of FIG. 2 is the same as that
speed and the actual ground speed. The meter mecha
of FIG. 1 with the exception that a signal representative
nism 39 drives the pointer 41 by means of the shaft 40
of
40 in accordance with this control signal in a manner similar
to that described with respect to the embodiment shown
is applied to the system of FIG. 1.
in FIG. 1.
The operation of the system of FIG. 2 is the same
as that described above with respect to FIG. l except the
This signal is ob
tained from a computer network generally indicated at
45 display `42 now provides a comparison of the Vaircraft
70.
performance in terms of the average acceleration which
A signal representative of the qw term is provided
compensates »for the decreasing acceleration characteristic
by manually adjusting a knob 71 to position the slider
of the craft.
of a potentiometer 72. A positive D.-C. voltage source
While the invention has been described in it-s preferred
73 is applied across the resistive winding of the po
tentiometer 72. A signal representative of the actual dy 50 embodiments, it is to be understood that the words which
have been used are words of description rather than of
namic pressure qa is obtained vfrom a dynamic pressure
transducer 74. The dynamic pressure transducer 74 is
responsive to the actual static and total pressure as ob
limitation and that changes within the purview -of the
appended claims may be made without departing from
the true scope and spirit of the invention in its broader
tained from a Pitot tube 75 mounted on the exterior
aspects.
of the craft. The transducer 74 positions the slider of
a potentiometer 76 in accordance with dynamic pressure
by means of a bellows 77. A negative D.-C. voltage
source 78 is applied across the resistive winding of the
potentiometer 76.
A signal representative of twice the gross weight 2W
is obtained by manually adjusting a yknob St) which po
sitions the slider of a potentiometer 8'1. A signal repre
sentative of the K term is provided by manually adjusting
a knob y82 to position the slider of a potentiometer `83.
As indicated above, the K factor depends upon the aero
dynamic characteristics of the particular aircraft which
What is claimed is:
1. A system for monitoring the performance of an air
craft during the take-off run comprising acceleration re
sponsive means mounted on said craft for providing a
60
signal representative of the forward acceleration experi
enced by said craft, means for providing a signal repre
sentative of the remaining distance to be traversed be
fore take-‘off at the prevailing air density conditions,
means responsive to said acceleration and distance sig
nals for providing a first signal representative of a func
tion of the product thereof, speed responsive means
mounted on said craft for providing a signal representa
tive
of the actual speed of the craft, means 4for providing
The potentiometers 72, 76, 811 and 83 are intercon
a signal representative of the speed required for said craft
nected by means of resistors '84, -85 and 86 to form the
D.-C. computer network '70 which provides a signal repre 70 to become airborne, means responsive to said required
speed signal and said actual speed signal for providing
sentative of
a second signal representative of the diiference between
a function of the required speed signal and a function
of the actual speed signal, and means responsive to said
In operation, the qw signal is connected through the iso
first and second signals for providing a measure repre
can be obtained by reference to manufacturer’s data.
3,077,110
sentative of the difference therebetween whereby the per
formance of the aircraft may be monitored.
2. A system for monitoring the performance of an air
craft during the take-off run comprising means including
acceleration responsive means mounted on said craft for
10
of the required speed signal and a function of the actual
speed signal, means responsive to said first and second
signals for providing a measure representative of the dif
ference therebetween, and display means including means
responsive to said measure for monitoring the perform
providing a signal representative of the average forward
acceleration experienced by said craft, means for pro
viding a signal -representative of the remaining distance
7. A system for monitoring the performance of an air
craft during the take-off run comprising acceleration re
to be traversed before take-off at the prevailing air den
sponsive means mounted on said craft for providing a
ance of the aircraft.
sity conditions, means responsive to said acceleration 10 signal representative of the forward acceleration experi
and distance signals for providing a first signal representa
enced by the craft, means for providing a. signal repre
tive of a function of the product thereof, speed respon
sentative of the distance along the runway to be traversed
sive means mounted on said craft for providing a signal
during the take-off run, means responsive to said accelera
representative of the actual speed of the craft, means for
tion signal for providing a signal representative of the
providing a signal representative of the speed required 15 distance actually traversed, means responsive to the dis
for said craft to become airborne, means responsive to
tance to be traversed and the distance actually traversed
said required speed signal and said actual speed signal
signals for providing a signal representative of the dif
for providing a second signal representative of the dif
ference therebetween, means responsive to the prevailing
ference between a function of the required speed signal
air density conditions for providing a signal in accordance
and a function of the actual speed signal, and means re 20 therewith, multiplying means responsive to said accelera
sponsive -to said `first and second signals for providing
tion, difference in distance and air density signals for pro
viding a signal representative of twice the product there
a measure representative of the diiference therebetween
whereby the performance of the aircraft may be moni
of, air speed responsive means mounted on said craft
tored.
for providing a signal representative thereof, means for
3. A system for monitoring the performance of an 25 providing a signal representative of the required take-off
aircraft during the take-off run comprising acceleration
speed of the craft, means connected to said air speed
responsive means and said required take-off speed signal
responsive means mounted on said craft for providing a
producing means for providing a correction signal rep
signal representative of the forward acceleration experi
resentative of the component of the prevailing wind, ñrst
enced by said craft, means for providing a signal repre
sentative of the remaining distance to be traversed before 30 squaring means responsive to said corrected air speed sig
n-al for providing a ñrst signal representative of the square
take-off at the prevailing air density conditions, means
thereof, second squaring means responsive to the cor
responsive to said acceleration and distance signals for
rected required take-off speed signal for providing a sec
providing a first signal representative of a function of the
ond signal representative of the square thereof, means
product thereof, speed responsive means mounted on said
craft for providing a signal representative of the actual 35 responsive to said first and second squared signals for
providing a signal representative of the difference there
speed of the craft, means for providing a signal repre
between, means responsive to said product signal and said
sentative of the speed required for said craft to become
square difference signal for providing a control signal
airborne, means responsive to said required speed signal
and said actual speed signal for providing a second signal
representative of the difference therebetween, and means
representative of the difference between a function of the 40 responsive to said control signal for providing a measure
required speed signal and a function of the actual speed
signal, means responsive to said first and second signals
thereof whereby the performance of the aircraft may be
monitored.
8. A system of the character described in claim 7 in
for providing a measure representative of the difference
cluding means responsive to the distance traversed signal
therebetween, and display means including means re
sponsive to said measure for monitoring the performance 45 for providing an indication representative thereof.
of the aircraft.
4. A system of the character described in claim 3 in
which said display means includes means responsive to the
actual distance traversed for providing an indication
9. A system of the character described in claim 7
wherein said last-mentioned means includes a meter move
ment responsive to said control signal which actuates a
pointer in accordance therewith, and display means coop
50 erative with said pointer whereby an indication of the rela
thereof.
tive performance of the aircraft is provided.
5. A system of the character described in claim 4
10. A system of the character described in claim 9
including means for selectively positioning an index in
wherein said display includes distance traversed indicating
accordance with the check line distance, said index being
means driven in accordance with said distance traversed
cooperative with said distance traversed indication means
signal.
and movable therewith after being initially set.
11. A system of the character described in claim 10
6. A system for monitoring the performance of an
including means for positioning an index in accordance
aircraft during the take-off run comprising acceleration
with the check line distance, said index being cooperative
responsive means mounted on said craft for providing a
with said distance traversed indicating means.
signal representative of the forward aceleration experi
12. A system for monitoring the performance of an
enced by said craft, computer means for providing a sig 60
aircraft during the take-off run comprising acceleration
nal representative of the average decrease in forward ac
responsive means mounted on said craft for providing a
celeration to be expected during the remaining portion of
signal representative of the forward acceleration experi
the take-off, means for providing a signal representative
enced by the craft, means including means responsive to
of the remaining distance to be traversed before take-off
at the prevailing air density conditions, means responsive 65 the actual dynamic pressure for providing a signal repre
sentative of the average decrease in forward acceleration
to said acceleration, decrease in acceleration, and dis
to be expected during the remaining portion of the take
tance signals for providing a first signal representative of
oiî as a function of the diñerence between the dynamic
a function of said acceleration, decrease in acceleration,
and `distance signals, speed responsive means mounted on
pressure at take-off and the actual dynamic pressure,
said craft for providing a signal representative of the 70 means for providing a signal representative of the dis
actual speed of the craft, means for providing a signal
tance along the runway to be traversed during the take-off
representative of the speed required for said craft to
run, means responsive to said acceleration signal for pro
become airborne, means responsive to said required speed
viding a signal representative of the distance actually tra
signal and `said actual speed signal for providing a second
versed, means responsive to the distance to be traversed
signal representative of the difference between a function 75 and the distance actually traversed signals for providing a
3,077,110
12
11
second squared signals for providing a signal representa
tive of the difference therebetween, means responsive to
said product signal and said squared difference signal for
providing a control signal representative of the difference
therebetween, and means responsive to said control signal
for providing a measure thereof whereby the performance
signal representative of the diiference therebetween,
means responsive to the prevailing air density conditions
for providing a signal in accordance therewith, multiply
ing means responsive to said acceleration, decrease in
acceleration, diiference in distance and air density signals Ur
for providing a signal representative of a function of said
of the aircraft may be monitored.
acceleration, decrease in acceleration, difference in dis
tance and air density signals, air speed responsive means
mounted on said craft for providing a signal representa
References Cited in the ñle of this patent
tive thereof, means for providing a signal representative 10
UNITED STATES PATENTS
of the required take-off speed of the craft, means con~
Hansel ________________ __ Oct. 7,
nected to said air speed responsive means and said re
2,613,071
quired take-oit speed signal producing means for pro
viding a correction signal representative of the component
of the prevailing Wind, first squaring means responsive
to said corrected air speed signal for providing a first
signal representative of the square thereof, second squar
ing means responsive to the corrected required take-off
2,922,982
15
1952
Hoekstra _____________ __ Jan. 26, 1960
OTHER REFERENCES
NACA Technical Note 3252, November 1954. (Copy
in Scientific Library TL 521 U58.)
Klass: Monitor Designed to Aid Jet Talreolfs,” Avia
speed signal for providing a second signal representative
tion Week magazine, June 23, 1958, pages 65, 67, 69 and
of the square thereof, means responsive to said ñrst and 20 7o. (Copyin 73-178.)
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