US2478793A - Variable camber airfoil - Google Patents

Description

S. TREY VARIABLE CAMBER AIRFOIL Aug. 9, 19.49.`

3 Sheets-Sheet l Filed Aug. 5, 1 .946

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INVENTOR S-P65 7km# 6%4@ ATTORNEY S. TREY VARIABLE CAMBER'AIRFOIL Aug. 9, 1949.

3 Sheets-Sheet 2 Filed vAug. 5, 1946 All.

INVENTOR 55H65 7kg Y ATTORNEY Aug. 9, 1949. s. TREY VARIABLE CAMBER AIRFOIL Filed Aug. '5, 1946 5 Sheets-'Sheet 3 INVENTOR 551,65 7km ATTORNEY Patented Aug. 9, 1949 UNITED STATES ATENT OFFICE 10 Claims.

rI'he invention is concerned with aeroplane wings and, more particularly, with wings of variable camber.

In a copending application, Ser. No. 681,084, I have disclosed how the camber of an aerofoilv can be raised without structural changes by producing an articially created mass ow of air overl the surface of the aerofoil. It is the main object of the present invention to produce such an articially created camber, but not a xed camber, as in the aforesaid application, the camber in the present invention being variable. It is also an object of the present invention to create this articial camber by the flow over the surface of the wing of a high velocity stream of air in part emanating from a vane forming the upper portion of the nose ofthe aerofol. A iurther'object of the invention is to combine the air stream emanating from said Vane with a iet of air of still higher velocity emanating from the leading edge of the aeroioil, the two streams, superimposed on one another, forming a single, moving air skin flowing towards the trail-ing edge of the aerofoil'. It is also an object of the present invention to control the mass iiow'oifv the air over the surface of the aerofoil by manipulation oi said Vane. A further object is to compensate for whatever reduction in air pressure and resulting suction may occur behind the aforesaid superimposed stream When said vane is moved outward, by causing a supplementary stream of air to be produced behind said vane. Itis also an objectoi the invention to supply the air for said supplementary stream from lobes; at the tip ends. oi the aerofoil, thereby accomplishing thedoublepurpose of admitting air from. outside anddestroying. tip vortices. Another object is to coordinate the velocities of the air stream emanating from the vane and of thejet emanating from. thelead- I ing edge so that the velocityof the latter is in ex:- cess of the former. Still another object is to provide the aerofoil with a tail flap and tocoordinate the. operation. of this'gtail flap with the movement of said vane. Qther objects, not

specifically mentioned. above,.wi1l. become appar- 2 Figure 3. Figure 6 is a longitudinal cross section of an aerofoil embodying the present invention,

`corresponding to Figure 2. Figure '7 is a top plan View of an aerofoil provided with air :absorbing wing tips. Figure 8 -is a similar View of an aerofoil wherein the air absorbing wing tips are omitted, the outside air in this case being admitted at the leading edge. Figure 9 is a cross section taken along the line 9 9 of Figure '7. Figure 10 is a cross section taken along the line lil-IU' of Figure 8.

Referring to the gures in detail, the same letter being applied to the same or corresponding element in all of the iigures, i is the main body of the aerofoil; 2, 2 are the lobes at the tip ends of the wing; 3 is the slot at the leading edge from which the high velocity jet is discharged; 4 is the vane forming the upper portion of the nose of the vaerofoil'; 5 is the tail ap; 6 is the inner tubing for admitting air into the aerofoil from outside; l is the outer tubing, coaxial with the tubing S, also for admitting outside air, the air admitted through the tubing 6 being led to the blower where the air is changed to a highivelocity stream, and the air admitted throughfthe tubing 7 supplying the supplementary stream, as will be explained later. The nacelle is denoted by the numeral the blower, by the numeral 9, and the engine for running the blower by the numeral lil. Behind the vane flt isa chamber il with its guide vane 2S, the function of which will also be explained later. A duct I3 leads from the tubing?? to the chamber Il. The lobes 2 are screened from the air jets emanating from the leading edge and from the vane i-Y by plates I4. The vane is turnableabout an axis I5 which is parallel to the leading edge. The axis is not shown in Figure 6. The vane thas an opening IE for the admission of air and another opening I1 for the discharge of the air. The high velocity air stream follows the path i? from the centrifugal blower 9- (not shown in Figure 5 and only indicated in Figure 6) into the duct i8y which leads to the vane 4 and to the slot 3 at the leading edge, a connecting duct 20- leading from Vthe duct i8 into the vane 4. From the passage i9, a duct 22 leads the same high velocity air stream into the passageway 2| between the tail flap 5 and the main body of the aerofoil. The flap 51s turnable at 2i! about a line parallel to thev trai-l1'- ing' edge and when the i'lap is. turned down, the passageway 2l is open on top.. 'as well as at the bottom. A valve 2S having a passageway 2T is operated jointlyv with the tail flap 5 by a linkage 23 one arm 25 of which is connected with the applications.

tail flap and another arm 24 with the valve 26. In Figure 6, another type of valve is shown operated by a linkage 28. The air jet emanating from the slot 3 is indicated by the arrows A when the vane 4 is down. When the vane 4 is moved outward, as shown in Figure 5 by the dotted lines, the air jet from the slot 3 is discharged along the arrows A'. The air emanating from the vane 4 when it is moved outward is indicated by the arrows B. The two streams A and B are merged into the single stream C and flow towards the trailing edge of the aerofoil over the surface of it.

The tip ends of the aerofoil shown in Figure 'l form lobes 3D different from the lobes 2 shown in Figure l. The lobes 30 are designed to absorb air vortices forming underneath through the openings 3| whence the absorbed air is conducted by suction into the chamber II behind the vane 4 and, when the latter is turned outward, the so conducted air forms a supplementary stream beneath the stream B emerging from the vane 4. The purpose of the guide vane 29 is to better direct the supplementary stream.

The main purpose of the invention, as stated in the preamble, is to raise the camber of the aerofoil. This is accomplished when the vane is Vturned outward until the opening I6 registers with the duct 20, as is clear from the drawing, Figure 5. When the aerofoil has no camber, as in Figure 6, a camber is created in the same manner as the manner used for raising the camber in Fig. 5. The location of the blower may be within the aerofoil, as in Figure 6, or in other parts of an airplane. The velocities of the air streams depend on the dimensions of the openings through which the air is admitted and discharged. By properly proportioning the width of the slot 3 and the dimensions of the openings i6 and I'I of the vane 4, it is a simple matter to arrange that the velocity of the air discharged from the vane be less than the velocity of the air jet at the leading edge. This relationship is necessary in order to secure the curving of the stream C, as shown, to follow the surface of the aerofoil towards the trailing edge in a mass skin ow. AS to the supplementary stream emerging from the chamber II, the purpose is to counteract any suction which may occur under the stream B, and to avoid the formation of vortices Vwhich would materially interfere with the smooth operation of the device.

The method of coordination between the mo- Vtion of the vane 4 and the motion of the tail ilap 5 comes within well known standard operations Land need not be discussed. Suice to say that this cooperation is dictated by demands for lift and regulation of the downwash and upwash at any period of flight, including, of course, the conditions during the take-off and landing. In this specification, no attempt is made to go into discussion of matters not directly concerned with the present invention. Some of the features have already been disclosed in earlier or copending Thus, for instance, the reason for the pear shaped form of the cross section of the lobes 2, Figure 4, is fully explained in my copending application, Ser. No. 672,245, now forfeited. The purpose of the shield I4 is also explained in the same application, although the plates I4 in the present case do not extend as far as they do in that application. While the size of the plates I4 is deemed suflicient in the present case, they could, of course, be further extended,

`as in the former case. In general, it is to be understood that the illustrations in the present case are not to be considered as limiting the invention, the scope of which is only to be measured by the claims which follow.

I claim:

1. In a wing of airfoil shape a first airfoil portion and a second airfoil portion, means mounting said second airfoil portion for rotation about an axis parallel to the leading edge of the wing, a source of air under pressure, means forming a nozzle adjacent the leading edge of said wing for directing a stream of air from said source over the upper surface of said second airfoil portion, means forming a second nozzle adjacent the leading edge of said rst airfoil for emitting a stream underneath the upper surface of said second airfoil portion when said second portion is rotated outwardly from said iirst airfoil portion, and means connecting said second nozzle with said source when said second airioil portion is rotated outwardly, the rst one of said air streams having a Velocity higher than said second stream.

2. In a wing of airfoil shape a nrst airioil portion and a hollow vane-shaped airioil portion, means mounting said second portion for rotation about an axis parallel to the leading edge of said rst portion, a source of air under pressure, means forming a nozzle adjacent the leading edge of said wing for directing a stream of air from said source over the upper surface of said hollow vane-shaped airfoil portion, means forming a second nozzle at the trailing edge of said hollow vane-shaped airfoil portion, and means connecting said second nozzle with said source and opening said second nozzle when said hollow vane-shaped airfoil portion is rotated outwardly of said nrst airfoil portion.

3. A structure according to claim 2, including means forming a third nozzle at the leading edge of said rst airfoil portion and under said hollow vane-shaped airfoil portion and connected to a second pressure source, whereby to counteract suction back of said hollow vane-shaped airioil portion in its outwardly rotated position.

4. A structure according to claim 3 wherein said second pressure source is independent of said :Irst mentioned pressure source.

5. An aerofoil having a hollow vane forming the upper section of its forward portion, said vane being turnable about a line parallel to the leading edge of said aerofoil, means for producing a high velocity air stream, an ejection slot at said leading edge, ducts for said air stream opening into said slot and into said vane when the latter is turned outward, an exit for the discharge of the air from said vane, the width oi said slot and the dimensions of said openings into and out of said vane being proportioned to cause the velocity of the air emanating from said slot to be higher than the velocity of the air discharged from said Vane.

6. A structure according to claim 3, including air supplying means for said nozzles at the leading edge of the wing.

'7. A structure according to claim 3, including lobar extensions formed on the tips oi the wing and means in said extensions for supplying air to said nozzles.

8. A structure according to claim 3 including, lobar extensions at the tips of said wing and means supplying air to said second source located in said lobar extensions.

9. A structure according to claim 1 including, lobar extensions at the tips of said wing and side plates intermediate said wing and said extensions.

10. In a wing of airfoil shape a rst airfoil portion, a second airfoil portion, means mounting said second airfoil portion for rotation about an axis parallel to the leading edge of the wing, a. source of air under pressure, means forming a nozzle adjacent the leading edge of said wing for directing a stream of air from said source over the upper surface of said second airfoil portion, means forming a second nozzle adjacent the leading edge of said rst airfoil for emitting a stream underneath the upper surface of said second airfoil portion when said second portion is rotated outwardly from said rst airfoil portion and means connecting said second nozzle with said source when said second airfoil portion is rotated outwardly @by predetermined amounts to regulate the flow through said connecting means whereby 6 the relative velocities -from the nozzles is controlled.

SERGE TREY.

REFERENCES CITED The following referencesv are of record in the le of this patent:

UNITED STATES PATENTS

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