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Nov. 19, 1946.
A. P. E. PLANIOL ETAL.
2,411,227
POWER PLANT FOR AIRPLANES
Filed Nov. 17, 1941
2 Sheets-Sheet 1
ATTORNEYS
‘
Nov. 19, 1946.
A. P. E. PLANIOL ETAL
2,411,227
POWER PLANT FUR AIRPLANES
Fi'led Nov. 1.7, 1941
2 Sheets-Sheet 2
52'
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ATTORNEYS
Patented Nov. 19, 1946
2,411,227
7
UNITED STATES PATENT OFFICE
2,411,227
POWER PLANT FOR AIRPLANES
Andi-é P. E. Planiol, Huntington, and Rene J. H.
Planiol, New York, N. Y.
Application November 17, 1941, Serial No. 419,483
1 Claim. (Cl. 170-1355)
1
2
The present invention comprises an improved
power plant for airplanes. The new power plant
the mixing chamber so that the gases after being
completely burned will be cooled by the air not
needed for this combustion. Preferably, however,
is characterized by a reduction of fuel consump
tion, and by increased power at take-oi! and at
rated altitude. The new power plant also insures
the turbine I2 is so constructed as to withstand
high temperatures. Such a turbine, in which
both the moving and stationary elements are
cooled, is disclosed in our copending United States
application Serial No. 419,464, ?led on even date
quick pick-up oi the airplane engine alter throt
tling and permits a plane equipped therewith to
?y at altitudes higher than those at which air
herewith, now Patent 2,369,795, issued February
planes equipped with the usual power plants can
now ?y.
10 20, 1945, and it is this construction which we
prefer to employ in the power plant of the present
Brie?y stated, the new power plant is designed
invention.
to insure complete combustion of the engine fuel,
In the particular embodiment of the invention
as distinguished from the substantially 50% com
the cooling medium for the ?xed blades of the
bustion now obtained with rich mixtures, to uti
lize the additional power thereby obtained to 15 turbine is air which is introduced through the
pipe 20 from the supercharger and delivered to
increase the power of the exhaust turbine and
the cooling jacket 2| of the turbine. Instead of
then to utilize the excess power thus given to
air, water or other liquid could as well be em
the turbine for assisting in the propulsion of the
airplane.
ployed for this purpose.
From the turbine Jacket 2| the air passes
For a better understanding‘of the invention,
through a pipe 22 to an annular chamber 23
reference may be had to the accompanying draw- ‘
formed between double walls of the mixing cham
ings, of which
ber Hi. The air thus preheated by the cooling
Fig. l is a view, partly diagrammatic, repre
of the turbine and of the mixing chamber is then
senting one embodiment of the invention; and
Figs. 2 and 3 are diagrammatic plan views of 25 sent inside the mixing chamber through a pipe
24 to take part in the combustion of exhaust
airplanes illustrating two possible locations of the
gases. The moving elements of the turbine are
new power plants therein.
liquid cooled as indicated in our patent applica
In Fig. 1 the airplane engine is indicated dia
grammatically at 2 as driving the propeller 4
tion Serial No. 419,464. The cooling liquid, after
passing through a radiator 30 and pipe 3|, enters
through the usual gear box 5. The engine 2,
a hollow rotating part of the turbine shalt
which may be of any usual construction, receives
through a bearing 83. The liquid leaves the ro
air for combustion through a pipe 8 from a super
tating element at a bearing 24 and returns
charger lll driven by an exhaust turbine l2.
through a pipe 35 and pump 38 back to the radi
Gases of combustion pass from the engine
through a pipe M to a mixing chamber IS.
ator 30. As this construction forms no part of
The gases in pipe [4 are only partly burned.
our present invention, the ?uid passages Within
the rotating elements of the turbine have not
Ordinarily not more than 50% of the chemical
been illustrated. For details of the turbine con
energy of the fuel is transformed into heat inside
struction, reference may be had to our above re
the engine if the mixture delivered by the car
buretors is rich and it is well known that if the 40 ferred to copending application. With such an
exhaust turbine but a slight excess of air beyond
power given by the engine has to be near the
that required for completing the combustion of
maximum a rich mixture is necessary to avoid
the exhaust gases need be delivered to the mixing
undue heating of the engine. In accordance with
chamber.
the invention, these exhaust gases, instead of
A throttle 26 is provided in the air line B for
being delivered either directly to the exhaust
control of the air to the engine. A two position
turbine I! or thereto after passing through a
valve 21 which allows the engine to receive air
cooling device, are ?rst completely burned in the
either from the supercharger through the pipe 8
mixing chamber It to which air for this combus
or directly from the outside atmosphere through
tion is delivered directly from the supercharger
a branch pipe ‘Ill is also provided in the air line 8.
Ill by means of a branch pipe It. The burning
A two position valve 28 is provided also in the
of these gases in the mixing chamber substantially
raises the temperature of the gases for delivery
exhaust line ll. Valve 28 in one position connects
line It to the mixing chamber l6 and in its other
to the turbine l2. Unless the turbine I2 is de
position cuts oil? the mixing chamber and ex
signed to withstand these very high temperatures,
hausts the engine gases directly to atmosphere
a substantial excess of air must be delivered to
2,411,227
3
4
through a branch pipe 52 and a nomle 51 giving
pellers, as the weight of either hydraulic or elec
tric coupling means would be excessive. and ?ex
iblity of the system with mechanical coupling
a jet propulsion effect for a purpose hereinafter
to be described.
The mixing chamber Ill is built to withstand the
high temperatures generated therein. It has an
inner wall 53 of metal able to resist very high
temperatures, as for example, stainless steel or
other heat-resisting material. Upon the inside of
the wall 53 is a relatively thick coating 54 of ce
ramic material, and upon the outside of wall 53
would be impaired.
.
Before describing the method of operation at
take-off and the improvements effected in the
take-oil’ by the new power plant, the advantages
inherent in the new system during ?ying will ?rst
be discussed.
As is well known, the higher the altitude the
greater must be the size of the propeller for the
same motive effect upon the airplane, because of
are vanes 55 for dissemination of heat. This in
her wall, together with an outer wall 56, de?nes
the lower atmospheric pressure. There is a limit
the annular passage 23 through which the air
to the tip speed at which propellers may be ef
from pipe 22 is ?rst passed before introduction
with the exhaust gases into the mixing chamber.
fectively driven at very high altitudes, which
speed is that of the velocity of sound which is
This arrangement serves the double purpose of
progressively lower as the air becomes less dense
cooling the walls of the mixing chamber so that
and as temperature becomes lower and lower. To
the tensile strength thereof will be maintained
overcome this di?lculty, either the propellers
and of preheating the air for the combustion with
in the chamber. By a, proper adjustment of the 20 would need to be larger to increase their power
for a given tip speed, or more propellers would
thickness of wall 53, size of ?ns 55, thickness of
coating 54, and speed of air ?ow through annular
need to be provided. No substantial increase in
space 23, it is possible to adjust the temperature
propeller size is practicable because requiring un
due length in landing gear to permit clearance of
of the walls of the mixing chamber at the best
value. This value has to be as high as possible 25 the ground by the propeller when the plane lands.
in order to avoid losses of heat of the burning
Additional propellers have heretofore required ad
gases. The cooling of these gases corresponds to
ditional engines, each engine being of a smaller
a loss in the power given by the turbine. This loss
size for a given total power on board the plane.
is minimized :by the transfer of heat from the
With the power plant of the present invention ad
walls not to a separate cooling ?uid but to the air 30 ditional propellers are provided and these ad
which brings the heat back to the general cycle '
ditional propellers are operated by the excess
of the machine. The losses of heat are also re
power delivered by the turbine obtained by com
duced by using an external insulating envelope 12
pleting the combustion of the engine gases. Any
of asbestos or the like for the combustion cham
type of variable pitch propeller for the turbine
her and a similar envelope 13 for the turbine,
may be used. For very high altitude ?ying, we
In Fig. 1 both the mixing chamber and the sta
prefer to use two counter rotating propellers on
tionary parts of the turbine are indicated as suc
each turbine shaft. The arrangement has many
cessively cooled by the same air steam whereas
advantages: For a given size of the propellers it
additional air for combustion in the chamber I6
is possible to increase the total power. When
is indicated as being delivered directly through 40 the pitch is very high, which is necessary to de
the pipe iii. If desired, however, the cooling of
crease the tip speed when the plane is ?ying very
the chamber l6 and ?xed parts of the turbine
fast, the efficiency is slightly increased. There
could be effected by parallel air streams instead
is also an increase in the total surface of the
of by the series arrangement illustrated. For ex
blades'bringing also a possibility of slight de
ample, the pipes 22 and 24 could be connected di
crease of the size for a given power.
rectly together and pipe l8 could be so connected
The most important feature of the new inven
as to cause the air therein to traverse the annular
tion is that the excess of power given by the tur
chamber 23 before entering the combustion cham
bine does not require any fuel consumption, as
ber I6.
the energy of the turbine comes from the un
After combustion in the mixing chamber ii the 50 burned exhaust gases of the engine. In other
gases and any air in excess of that required for
words for a given power the fuel consumption is
the combustion passes to the turbine l2 through
materially reduced, or for a given fuel consump
the line 40 and after expansion therein is de
tion substantially more power is obtained. At
livered through a line 42 terminating in a jet 44
50,000 feet, for example, the atmospheric pres
directed rearwardly of the plane.
55 sure is about one-tenth of the pressure at sea
The turbine i2 thus receives a large volume of
level, while the pressure of the exhaust gases de
gases at relatively high temperatures, with the
livered to the turbine is about that of the atmos
result that more power can be obtained there
phere at sea level. The turbine thus operates
from than is required for driving the supercharg
with an expansion coefficient of about 10 to 1 and
er Ill. In accordance with the invention this ex_ 60 will deliver about the same power as the engine.
cess power is utilized toaid in the propulsion of
The thermal ei?ciency oi.’ the turbine, for this ex
the airplane and also to give stability to the sys
pansion coefficient of 10 to 1 is about the same
tem. In the particular embodiment of the in
as that of the engine. Calculations we have made
vention illustrated, which is that preferred, the
show that for normal ?ying conditions the new
turbine is arranged through suitable gear reduc 65 power plant can reduce the fuel consumption
tion 46 to drive the supercharger Ill and through
by as much as 30 to 40%.
another gear reduction 41 to drive propellers 48
Another, and important, advantage of the new
preferably 01’ the counter-rotating type as indi
power plant is the increase in engine pick-up
cated in the drawings. Instead of driving sepa
which is obtained thereby. This will be apparent
rate propellers, the excess power of the turbine 70 if one considers the case of a military plane, for
could be coupled back to the engine shaft through
example, after the engine has been throttled for
mechanical, ?uid or electric means, but the em
a dive and the pilot then wishes to start his en
ciency of such an arrangement would not be as
gine again quickly. In the usual case, where the
high as when the turbine is connected for di
exhaust turbine merely drives the supercharger,
rect driving of one or more independent pro 76 the throttling of the engine reduces the turbine
2,411,227
speed to such an extent that the supercharger
cannot deliver sufficient air to the engine when
the throttle is again opened. Consequently the
pilot must dive again to speed up the turbine.
fuel thereto and the‘plane is ready to take off.
The pilot therefore adjusts all the propellers for
short pitch and increases the speed of the engines
with the engine throttled, the propeller 48 will
drive the turbine with the result that when the
engine throttle is again opened the supercharger
is effective to supply air for quick speed-up or the
engine.
10
bines by the direct injection of fuel into the mix
ing chambers, the turbines will develop substan
tial power equal to or in excess of that developed
by the engines. Consequently the plane will take
off easily. After the plane leaves the ground the
amount of fuel injected into the mixing chambers
is gradually decreased. This decreases the pres
and turbines simultaneously. Because of the in
With the new power plant, during the ?rst dive $1 crease in density of the ?uid supplied to the tur
Contrary to what is now happening with nor
mal turbo driven superchargers, it is even pos
sure therein and when such pressure falls below
sible to increase the speed of the turbo machine
the normal intake manifold pressure for which
during the time in which it is not used to feed
the throttled engine. This is very easily done 15 the engine is designed, valves 28 are operated to
cause the engine exhaust gases to be delivered di
by slightly decreasing the pitch of the turbine's
re'ctly to the mixing chambers. As the plane con
propeller. Thus when the pilot will again open
tinues to gain altitude, the amount of fuel de
the throttle the pressure in the inlet manifold
livered through nozzles 5|) is further reduced and
will be above its normal value and the pick-up
will be made with a greater power. The turbo 20 ?nally stopped completely, at which time normal
?ying conditions prevail.
machine, fed with exhaust gases at pressures
The above described operations involving the
higher than the normal will also give a greater
control of throttles 28, valves 21 and 28 and the
power and its propeller’s pitch, being below the
delivery of fuel to the injectors 50 could be man
normal, the traction of all the power plant will be
ually performed by the pilot or could of course be
substantially increased above its normal value.
performed automatically in response to the pres
The provisions of a propeller driven by the ex
sure in the mixing chambers and inlet manifolds
haust turbine also makes possible a continuously
of the engines, and to other variables if desired.
changing speed ratio between engine and turbo
The general features of the new power plant
machine, as the relative pitches of the two pro
pellers may be changed at will. Thus the best 30 have now been described in connection with Fig.
l. The various parts thereof may be located at
speed and power adjustments of the machines
any convenient point on the plane, and the num
may be made to suit every ?ying condition.
ber of plants employed will depend, of course,
At take-oil‘, due to the low or zero pressure dif
upon the size of airplane and power desired.
ferential across the turbine, the conditions are
There may be the same number of engines and
different and hence the invention includes means
turbines, or there may be additional engines on
for varying the system at this time, which means
the plant. Such additional engines could be in
effectively increase the power at take-off. Refer
dependent of the turbines, or, if suf?ciently large
ring again to Fig. 1, there will be noted an in
turbines are employed, one turbine could receive
jector 50 for introducing liquid fuel directly into
the exhaust gases from two engines.
the mixing chamber. This injector is used only
Due to the relatively high mass of the rotating
at take-off or for ?ying at very low levels. As
parts of turbine and supercharger and due also
sume the power plant of the airplane to be com
to the high angular velocities of these two ma
posed of two units, each such as shown in Fig. 1,
chines, the gyroscopic torques appearing during
that is the plant has two engines and two tur
bines each operatively connected with propellers. 45 the quick evolutions of the plane may be unduly
high. It is possible to decrease or even suppress
When the airplane is on the ground the valve
completely these torques by rotating the turbine
21 is turned and the engine takes the air directly
and the supercharger in opposite directions and
from the atmosphere through 10 and 8 and the
by increasing, if necessary, the inertia of one or
engines are started in the normal way to run
idling. The exhaust gases from the engines start 50 the other of these machines. As the super
charger is smaller than the turbine it is generally
the turbines which begin to run slowly. The
useful to rotate it faster than the turbine, to ob
pitch of the turbine propellers is set for zero so
tain the best efficiencies for both the machines.
that the resisting torque is negligible, permitting
By using this counter-rotating disposition the
the turbo machines to increase slightly in speed.
common framework of the two machines trans
65
When the speed of the turbine is sufficiently high
mits to the plane only the difference of the two
the valves 28 in the exhaust lines 14 are turned
gyroscopic torques.
to exhaust the engine gases to atmosphere
It is well known that for a body having a
through the pipes 52 which, as shown, terminates
moment of inertia I, rotating with an angular
in a jet 51, and to shut off the gases from the
velocity w, the gyroscopic torque is proportional
mixing chamber. Simultaneously liquid fuel is 60 to I X w. If I1w1 applies to the turbine and
injected into the mixing chambers through the
laws to the supercharger, then the resulting gyro
injectors 50 with the result that the turbines l2
scopic torque, if the machines are rotating in
now operate as gas turbines instead of operating
opposite directions, will be proportional to
as exhaust turbines. Gradually increasing the
delivery of fuel to the chambers increases the 65
speed of the turbines and as a result the outlet
pressure of the superchargers.
As this outlet
pressure increases, valves 21 are turned to con
The resulting torque may be eliminated by
suitably adding to the inertia of the supercharger,
or to the inertia of the turbine, if it is found that
meet the supercharger with the engine and throt
tles 25 are operated to out down the air supply to 70 the natural compensation obtained from the
counter rotation of the two machines is not accu
the engines and thereby avoid excessive pressure
rate enough.
in the inlet manifolds thereof. The pilot now
Thus, in our new power plant, gear box 46 pref
has complete control of both of the engines in the
erably includes reversing gears so that the super
normal way, as when the turbo machines are not
in use, and of the turbines by the control of the 75 charger and turbine rotate in opposite directions.
7
2,411,927
8
In Fig. 2 is illustrated diagrammatically a con
velocity of sound at the temperature of the gases,
venient arrangement of the new power plant in
an airplane. 1 In Fig. 2 the various piping con
nections have been omitted for simplicity. In
this arrangement the propellers "a driven by
the turbines are indicated as oi’ the puller type,
being located on the leading edge of the wings
52 while the propellers la of the engines are of
the pusher type, being located on the trailing
edge oi’ the wing.
For very high altitude ?ying, it might be pref
erable to have all the propellers on the trailing
edge and this disposition will be described in
Fig. 3.
In Fig. 2 only two engines and two turbines are 15
indicated but for very high altitudes, as ex
plained above, a greater number of propellers
would be employed. Four engines and four tur
bines would be a good arrangement.
In Fig. 2 the turbo machine is located in a 20
cowling 80. smaller than the cowling 6| housing
the engines due to the fact that for the same
power the turbo machine is smaller than the
engine.
At “a is the exhaust oi’ expanded gases com
ing from the turbine and giving the jet propul
sion.
In Fig. 3 the exhaust turbines and the super
chargers operated thereby, indicated diagram
convergent nozzles are preferred. but where
speeds higher than that of the velocity of sound
are expected, then the nozzles should have the
deLaval convergent-divergent form.
From the above description it will be apparent
that the invention provides a practical and em
cient power plant having all the important
features and advantages heretofore specified, and
that these advantages are primarily due to the
provision of means for causing complete com
bustion oi’ the engine exhaust gases together with
the means for utilizing the additional power ob
tained by such complete combustion.
We claim:
In a power plant for airplanes, the combina—
tion comprising an internal combustion engine,
a propeller driven thereby, a turbine having ele
ments ?uid cooled to withstand high tempera
tures, a propeller driven by said turbine, a gas
mixing and combustion chamber having an inlet
and an outlet, a supercharger driven by said tur
bine, means for injecting liquid fuel into said
chamber, said supercharger being connected to
25 the inlet of said chamber and said turbine being
connected with the outlet of said chamber, a con
nection between said supercharger and said en
gine. valve means in said connection adapted in
one position to permit ?ow of air from said super
matically at I21; and illb, respectively, are posi 30 charger to said engine and in another position
tioned for rotation about axes at right angles to
to cut oil’ said supercharger from the engine and
the direction of ?ight. and the shafts thereof are
connect the engine to atmosphere, 0. connection
coupled by spur gearing 10 to the shafts of pro
between said engine and the inlet oi‘ said cham
pellers 48b. By providing channels ‘H leading
ber and valve means in said last mentioned con
to the forward ede, air can be delivered directly 35 nection adapted in one position to permit ?ow of
to the superchargers, and by providing the out
exhaust gases from said engine to said chamber
let ducts 42b terminating at the trailing edge of
and in another position to cut oil’ said chamber
the wing in nomles 44b, Jet propulsion following
from said engine and deliver the engine exhaust
a first stage expansion of the exhaust gases in the
gases to the atmosphere, whereby said turbine
turbines, is added to the already high power of 40 may be operated either as an exhaust turbine or
the unit.
as a combustion turbine, depending upon the
The particular shape to be given to nozzles 44,
position of said valve means and upon the delivery
“a or “b will depend upon the expected speed
of fuel to said chamber.
of the exhaust gases issuing therethrough.
ANDRE P. E. PLANIOL.
Where the intended speed is below that oi’ the
RENE J. H. PLANIOL.
Certi?cate of Correction
Patent N 0. 2,411,227.
November 19, 1946.
ANDRE P. E. PLANIOL ET AL.
It is hereby certi?ed that errors appear in the printed speci?cation of the above
numbered patent requiring correction as follows: Colunm 3, line 38, for the word
“steam” read stream; column 7, line 35, for “ede” read edge; and that the said Letters
Patent should be read with these corrections therein that the same may conform to
the record of the case in the Patent Office.
Signed and sealed this 4th day of February, A. D. 1947.
[ml-l
LESLIE FRAZER,
First Assistant Uommz'ss'ioner of Patents.
7
2,411,927
8
In Fig. 2 is illustrated diagrammatically a con
velocity of sound at the temperature of the gases,
venient arrangement of the new power plant in
an airplane. 1 In Fig. 2 the various piping con
nections have been omitted for simplicity. In
this arrangement the propellers "a driven by
the turbines are indicated as oi’ the puller type,
being located on the leading edge of the wings
52 while the propellers la of the engines are of
the pusher type, being located on the trailing
edge oi’ the wing.
For very high altitude ?ying, it might be pref
erable to have all the propellers on the trailing
edge and this disposition will be described in
Fig. 3.
In Fig. 2 only two engines and two turbines are 15
indicated but for very high altitudes, as ex
plained above, a greater number of propellers
would be employed. Four engines and four tur
bines would be a good arrangement.
In Fig. 2 the turbo machine is located in a 20
cowling 80. smaller than the cowling 6| housing
the engines due to the fact that for the same
power the turbo machine is smaller than the
engine.
At “a is the exhaust oi’ expanded gases com
ing from the turbine and giving the jet propul
sion.
In Fig. 3 the exhaust turbines and the super
chargers operated thereby, indicated diagram
convergent nozzles are preferred. but where
speeds higher than that of the velocity of sound
are expected, then the nozzles should have the
deLaval convergent-divergent form.
From the above description it will be apparent
that the invention provides a practical and em
cient power plant having all the important
features and advantages heretofore specified, and
that these advantages are primarily due to the
provision of means for causing complete com
bustion oi’ the engine exhaust gases together with
the means for utilizing the additional power ob
tained by such complete combustion.
We claim:
In a power plant for airplanes, the combina—
tion comprising an internal combustion engine,
a propeller driven thereby, a turbine having ele
ments ?uid cooled to withstand high tempera
tures, a propeller driven by said turbine, a gas
mixing and combustion chamber having an inlet
and an outlet, a supercharger driven by said tur
bine, means for injecting liquid fuel into said
chamber, said supercharger being connected to
25 the inlet of said chamber and said turbine being
connected with the outlet of said chamber, a con
nection between said supercharger and said en
gine. valve means in said connection adapted in
one position to permit ?ow of air from said super
matically at I21; and illb, respectively, are posi 30 charger to said engine and in another position
tioned for rotation about axes at right angles to
to cut oil’ said supercharger from the engine and
the direction of ?ight. and the shafts thereof are
connect the engine to atmosphere, 0. connection
coupled by spur gearing 10 to the shafts of pro
between said engine and the inlet oi‘ said cham
pellers 48b. By providing channels ‘H leading
ber and valve means in said last mentioned con
to the forward ede, air can be delivered directly 35 nection adapted in one position to permit ?ow of
to the superchargers, and by providing the out
exhaust gases from said engine to said chamber
let ducts 42b terminating at the trailing edge of
and in another position to cut oil’ said chamber
the wing in nomles 44b, Jet propulsion following
from said engine and deliver the engine exhaust
a first stage expansion of the exhaust gases in the
gases to the atmosphere, whereby said turbine
turbines, is added to the already high power of 40 may be operated either as an exhaust turbine or
the unit.
as a combustion turbine, depending upon the
The particular shape to be given to nozzles 44,
position of said valve means and upon the delivery
“a or “b will depend upon the expected speed
of fuel to said chamber.
of the exhaust gases issuing therethrough.
ANDRE P. E. PLANIOL.
Where the intended speed is below that oi’ the
RENE J. H. PLANIOL.
Certi?cate of Correction
Patent N 0. 2,411,227.
November 19, 1946.
ANDRE P. E. PLANIOL ET AL.
It is hereby certi?ed that errors appear in the printed speci?cation of the above
numbered patent requiring correction as follows: Colunm 3, line 38, for the word
“steam” read stream; column 7, line 35, for “ede” read edge; and that the said Letters
Patent should be read with these corrections therein that the same may conform to
the record of the case in the Patent Office.
Signed and sealed this 4th day of February, A. D. 1947.
[ml-l
LESLIE FRAZER,
First Assistant Uommz'ss'ioner of Patents.
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