US2809793A - High lift airfoil system - Google Patents

Description

Oct. 15, 1957 D. K. vwmfemzpz HIGH LIFT AIRFOI'L SYSTEM Original Filed July 22, 1947 IN VEN TOR United States arent y O HIGH LIFT AIRFOIL SYSTEM Douglas K. Warner, Sarasota, Fla.

Original application July 22, 1947, Serial No. 762,631. Divided and this application December 3, 1951, Serial No. 259,623

1 Claim. (Cl. 244-42) This application is a division of application Serial No. 762,631, filed July 22, 1947, now Patent No. 2,631,794.

This invention relates to means for greatly increasing wing lift without increase in power, to means for permitting safe landings with such loads without landing runways, to means for extending laminar ow on the upper surface of a wing and to maintaining as high air velocity over the trailing portion of the wing as over the forward portion for equal vacuum lift, and to creating higher air pressure therebeneath, and to furnishing a new-type, eilicient, pressure propulsion.

This invention also permits stabilization in high flight of'a wing which at start of takeoff is almost entirely supported by air pressure beneath it.

One object is to permit diffusion of air entering the top surface of the wing where the maximum air velocity has normally started to diminish but in this case has been slightly increased by suction created by propulsion fans carried by the wing so that the air contacting the blades of the propulsion fans will have low enough velocity to prevent sonic speed over those blades and so extending laminar flow and avoiding the low efficiency of supersonic propeller blades.

Another object is to eject a thin layer of air over the trailing portion of the wing at abnormally high velocity to maintain the same high suction lift normallyonly found over the forward half of the wing.

Another object is to diffuse most of the air handled by the fans and discharge it under pressure below4 the rear'portion of the wing where it increases the pressure normally found at this lower location and further Vadds to the rearwardly located lifts to keep the center of pressure in high Vilight rearward of mid chord as it must be during the takeoff run close to a surface. This increased pressure on the upwardly sloping rear under surface provides anew type of pressure propulsion which is much more efficient than jet reaction propulsion or propeller propulsion, and it also doubles the wing lift without reduction in critical speed of the wing since it does not depend on increased maximum air velocities.

It improves on the plane shown in my Patent 2,444,318 in that a large number of fans are now used inside the rear portion of the wing across its full span which suck in air rearward of mid chord over the top surface and discharge most of the air under high pressure below the wing and a small amount at high velocity through a rearwardly directed slot above the wing, both discharge openings being far back to give the added lift on both surfaces a far rearward location, needed for stability.

In the accompanying drawings Fig. 1 is a cross-section view of the main wing of the plane showing its starboard runner in the background.

Fig. 2 is a top plan view of the whole plane and Fig.V 3 a rear view thereof.

The upper portion of Fig. 1 comprises a thick airfoil l such as NACA 644-621 designated by numeral 1. This airfoil is characterized by a large leading edge radius "ice and higher drag than the 66 series thinner airfoils but its large radius permits a lower'flap 11 to be hinged at 13 forward of the center of curvature 14 whereby when 11 has been forced down and forwardly by piston 31 in cylinder 32 which is fed as required with compressed air from transverse pipe 30 the normally forwardgedge of flap 11 is above the top surface/portion 28 of wing 1 which is hinged at 14 and whereby slots are formed over the top surface at 12a and at 29 which permit the high pressure air under 1 to leave at high velocity over Yits top surface and so give a forwardly located lift over the top surface while the plane is skimming close to a surface or slowing down at a 45 non-stall attack angle.

A slot 2 rearward of the normal terminus ofi laminar llow on the top surface provides with cowlings 15 an opening having the rearwardly increasing cross-sectional area of passage 16 leading to air straightening blades 1S and the fan blades, distinguished when down, by 3, Athrowing air (which is slowed and increased in pressure by diffusion) to beneath the wing and when up by 4 Where they throw air rearwardly over the top surface of'wingl in passage 19 having decreasing area rearwardly to give near sonic air velocity above the trailing portioniof the 'wing Depressions 17 are formed inthe top surface of the wing forwardly of fan blades 3 andV 4 and part thereof arebeneath cowlings 15 so forming the diffuser passage 16. Y

A rear lower flap 7 is depressed by compressed air in pipe 10 owing to cylinders 9 and acting onA pistons 8; and runners 6 extend down from the lateral tips of wing 1 closely adjacent the lateral edges of iiaps 7 and 11 whereby the compressed air under the wing may escape only from slots 12A and 29 over the leading edge of the wing and its fore part when close to a lower` sea orV land surface where a forwardly located lift is needed..-V

The pistons 31 act at spindles 35 thru connecting rods 33 on arms 34 the latter being pivoted at 62 on the plane, and at 43 on one end of arm 36,*the other end being pivoted at 37 in flap 11 where flap 12 is also pivoted to form a swinging extension of flap 11 to move-up and down over irregular surfaces such as Waves on the sea.

Air pressure under the wing would press flap 12andy roller 41 too hard against the surface werethis flap not restrained by air pressure in cylinders 38 acting on pistons 40. The wire 42 limits the travel of arm 34 downwardly so that arms 34 and 36 may not form a straight line and so resist the pressure on them if a high wave should hit the bottom of 11 which must move `back with wave contact. When retracted, flaps 11 and 12 form the under surface of the wings forward portion with pivot 37 now at 64 and. ,roller-41at 41A, The-latter is also shown over a wave trough at 41B in dottedV lines.

To enhance pressure under the wing in high flight plates 60 and 44 are suspended under the wing by struts 45 and end plates 6 to form diffusers, increasing air pressure adjacent the wing skin. Similar plates S9 are spaced from wall 5 of fan diffusers to add propulsive thrust against that wall 5.

Since landing at a 45 attack angle involves a steep and rapid descent path, the trailing edge of runners 6 would hit the ground very hard if the shock were not cushioned by wheels 20 supported by arms 23 pivoted at 24 within said runners and by piston 21 within air cylinder 22. On contact the plane swivels down on its air cushion.

' Further aids to stability and control are front stabilizer floats 47 having at their forwardly located tips aileron elevators 46 pivoted at their 1A chord point. Stabilizers l47 have a higher attack angle than wing 1 while-rear troughs over which propellers 51 and 52, 25 and 26 turn. These are operated by engines 55 in pods supported beneath the tips of upper stub wings 49 and by airfoil struts.53. Propeller blades turn upwardly in front of struts53 and stub wings 49 giving increased lift from blades which may now be close to the wing since there is no damaging effect from down currents behind the blades moving down where there is no wing. This permits lighter frame and pods and adds a Katzmaier elect of alternate ilow direction to the highly eicient lift behind upward moving blades.

These propellers, mounted over the rear stabilizer wings, also form a high velocity air stream vover the in- Side surface of tail tins 4S so that even at zero plane velocity this plane has complete directional stability and that with tail tins of less than normal size because the air velocityover their inside surfaces is always extremely high being adjacent the path of the propeller tips and since they are assisted by the side walls of housings 54 subject to similar high air velocity at slow plane speed.

The rear flaps 7 like the trailing edge 12 of front flap 11 are divided so that some may rise higher than others to conform with variation in surface below.

The slot 29 is gradually increased in opening as starting speed increases to prevent the center of pressure moving rearwardly. This and the new added rear lift permits stability with the same center of gravity in ight as at takeol with much greater aspect ratio than is possible with my designs in Patents 2,444,318 and 2,559,036.

Control of this plane diiers from that of conventional planes where depression of a port aileron to bank for a right turn, turns the craft to the left so requiring a larger rudder and more drag. Here the swiveling front elevators have nothing ahead of them to disturb airflow and are normally set at zero lift instead of the usual negative lift of rear elevators. To bank for right turn the leading edge of the right elevator is tipped down increasing its drag and causing the .plane to turn nght without need of any rudder.

Runways are not required for takeoif and landing because instead of concentrating the plane load at small spots at the base of wheels it is spread over the whole surface beneath the wing. The long takeol run required should have most of its length over shallow water where the drag is much less than that due to tires on foot thick concrete pavement and where the runway cannot be destroyed by sneak attacks before war declarations. A very quick stop can be made in the water if the rear flap is raised and it may then be lowered together with the front ilap to hop up onto the beach. After unloading, the plane can hop up, again swiveling about face with the aid of its rear wing propellers, and then reload and skim out over the water again, rising after attaining 300 M. P. H.

Numeral 56 indicates the location of the engines driving fan blades 3 and 4 and 57, a diffuser, taking air from said blades for its first stage of supercharge and S8 is a slot from which the engine exhaust ejects rearwardly above the rear surface assisting the jet from fan blades in creating rear lift and reaction propulsion.

Gun turrets 52A are, shown above stub wings 49 in line with the propellers 25 and 26 so permitting firing in all directions except straight to the side.

Having thus described my invention I claim:

An aircraft including an airfoil member having depressions formed in the trailing portion of its upper surface rearwardly of the chord midpoint and conduits extending downwardly and rearwardly through said member from said depressions to the lower surface of said member, the cross sectional area of said conduits increasing gradually from said depressions to said lower surface, and said depressions and conduits extending across the full span of said airfoil member, and fan means including rotary blades mounted within said member, said blades during operation of said fan means describing rotor discs extending across the upper ends of said conduits and above said upper surface, said fan means being arranged to irnpel streams of air downwardly and rearwardly through said conduits and also rearwardly over the trailing edge portion of said upper surface, whereby high air velocity and suction is maintained over all the trailing upper surface where normally downward air pressure exists and whereby the normally high air pressure condition below the trailing portion is increased by diffusion of high velocity air in said passages having gradually increasing area.

References Cited in the iile of this patent UNITED STATES PATENTS 1,755,342 Tissot Apr. 22, 1930 1,801,356 Loveland Apr. 21, 1931 1,879,618 Icre Sept. 27, 1932 1,957,896 Marguglio May 8, 1934 2,077,471 Fink Apr. 20, 1937 2,142,123 Fahrney lan. 3, 1939 2,147,360 Zaparka Feb. 14, 1939 2,241,521 Richard May 13, 1941 2,272,661 Finley Feb. 10, 1942 2,364,677 Warner Dec. 12, 1944 2,444,318 Warner June 29, 1948 2,469,619 Warner May 10, 1949 2,559,036 Warner July 3, 1951 FOREIGN PATENTS 22,286 France Dec. 30, 1920 488,942 Great Britain July 18, 1938 586,496 Germany Oct. 2l, 1933 652,942 Great Britain May 2, 1951 719,406 Germany Apr. 7, 1942

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