July 5, 1955 w. H. AMSTER ET AI. 2,712,420 VERTICAL TAKE-OFF' AIRPLANE AND CONTROL SYSTEM THEREF‘OR Filed Dec. l, 1951 9 SheeJLs--Shee'tl l

“u1/J6 4 III-I1 a July 5, 1955 W. H, AMSTER ET AL 2,712,420 VERTICAL TAKE-OFF AIRPLANE AND CONTROL SYSTEM THEREFOR Filed Dec. l. 1951 9 Sheets-Sheet 2

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Filed Dec. l , 1951 9 Sheets-Sheet 4 July 5, 1955 w. H. AMsTER ET AL 2,712,420 VERTICAL TAKE-OFF AIRPLANE AND CONTROL SYSTEM THEREF‘OR Filed Dec. l, 1951 9 Sheets-Sheet 5

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[6fm/nd ¿me j 0 l July 5, 1955 w. H. AMSTER ET AL 2,712,429 VERTICAL TAKE-‘OFF ÁIRPLANE AND CONTROL SYSTEM THEREF'OR Filed Dec. l, 1951 9 Sheets-Sheet 9 @§17 2,712,426 United States Patent Oñâce Patented July 5, 1955 1 I. 2 Figure’ 5 is a perspective view illustrating the in normal horizontalz flight. 2,712,420 Figure V6 ís a perspective view showing the aircraft in VERTÍCAL 'rancore ALRPLANEAND CONTROL hovering- position ju'st above' the take-off and landing deck SYSTEM 'rHEREFoR of a vessel; _, Warren H. Amster, Montclair, N. I., and Clarence> H. Figure 7 is a phantom perspective view diagran1mati~ Holleman', Tarzana, and Eugene V. Browne, Los An cally showing the r'najor components of the surface con' gilles, Calif., assignors to Northrop Aircraft, Inc., Haw trol systern- and showing the control surfaces as stippled thorne, Calif., a corporation of California áreas. . Figure 8 is a plan view diagram of the control Application December 1, i951-,- seiiài No, 259,334 system'. z'z claims. (ci. 244-41) Figure 9 is a diagram showing thev rudder control sys tem viewed from the side as indicated by line 9-9 in Figure 8. _ _ This invention relates to airplanes, and inore particu Figure 10 is azpla'n view diagram showing the right larIy', to a new_vertically landing (tail down), horizon hand ele‘von control system'. ’ tally ñying' airplane, and a control system therefor. Figure il is a diagram showing the right-hand _Itis known thatpripr attempts have been made to pro connections viewed from the side as indicated by line vide' 'á'n‘air'cra'ft which cap'âble of flight as outlined in 11-11 in Figure' 10. the preceding paragraph. However, none as far as known Figure. 12 isa side view diagram showing the horizontal have been ~completely successful, for various' reasons. tail control- system and control stick connections to the Some disadvantages of the heretofore proposed airplanes elevon ­control system. _ of this type are unsuitable and impractical Figure 13 is a. diagram showing the control stick con ineans at _the tail section, inadequate control¿.­­systems, nections viewed from the rear as indicated by line i3-‘••13 poor stability, the lack of means for effecting a satis 2. in Figure l2, _ _ factory landingI operation at and on a desired spot', and Figure 14 is an enlarged perspective diagram showing impractical propeller designs requiring special, uncon~ the control stick mechanism of Figures l2 and 13 as ventional, and costly manufacture. _ _ viewed from the top left rear. _ _The tnain objects of the' present invention are" to pro .Figure l5 is a partial cut-away plan view of the air~ vide airplane capable of vertical take-orf and hover 30 plane, showing-_ landing _strut details with in the ing, transition from vertical to horizontal flight, static position on a ground line. _ _ _lii'gh speed, return to _vertical hovering attitude, and VFigure 1_6 is a horizontal side _view of a preferred pilot’s lowering to a good landing, wherein all the above listed seat installation in normal flight and ejection position. disadvantages and problems are overcome, and especially Figure 17 is a horizontal side view of the same pilot‘s having a simple yet _novel control system to provide and seat installation, showing the seat rotated as it wouid be maintain satisfactory control and all desired aspects of in the takeloff, hovering and landing position. maneuverability during and throughout all phases and _All directional references­ and locations specified in positions of night. _ this_description, and in the following claims, with respect Other _objects and features of advantage will be noted to `the airplane, i. e., downwardly, rearwardly, horizontal or specifically pointed out in the detailed description of «­ surfaces, et`c., are made relative to an assumed horizontal spccilic apparatus embodying this invention, which forms position 4ofthe airplane, as in conventional night. a major part of this specification. _ _Referring first to Figures l, 2 and 3 to begin the de In brief general terms, as to apparatus, our invention scription of detailed apparatus, the airplane of our inven comprises a relatively short , counter-rotating tion comprises a fuselage 1, two main wing panels 2 and dual propellcrs', a thin straight (únswept) high wing aft 3 intersecting the fuselage 1 near the top thereof, a ven of the fuselage center, a ventral tin, control system com tral fin 4_extending vertically downwardly from the aft ponents comprising full length elevon surfaces on the end of the fuselage, an all~movab1e horizontal tail surface of the wing, a rudder on the vcntraltin trail 5 (hereinafter called ) mounted at the lower end ing edge, and an all-movable horizontal tail control sur o_f the ventral lin 4,_and dual counter-rotating propellers face at the lower end of the ventral fin. A unique conti-ol 50 6. A pilot’s cockpit with removable enclosure 7 is pro~ arrangement permits elevator and movements of vided well forward of the wing paneis 2 and 3 where the the , as controlled by a conventional stick or con range of vision is exceptionaly large. Each wing panel trol wheel, while in the vertical and transition positions, has‘a dihedral angle of about l_5° from the horizontal, and and allows elimination of elevator movements of the a­ wing' tip _pod 9_is mounted on the tip of each wing elevons, as controlled by the stick, while in horizontal 55 panel _2 and 3. The tip pods 9 are long and slender, and ñíght. The wing has several degrees of dihedral, and each carries a landing s't'rut 10 projecting a short carries tip bodies having rearwardly extending shock distance fromthé rear. -These wing tip struts 10, in co means therein, and the venti-_al tin mounts a similar shock operation with`­ afin landing strut 11 extending aft from strut» means, thus forming three widely spaced points for the­­ ventral fin­ 4 and a collapsible tail> cone 12 on the the landing support, together witha main landing shock 80 a_f_t'_e_'i_1'dv of _fr_xs'eflage` L_fOrin the landing gear for this absor‘berin the tail~section of the fuselage. __ aircraft, and will be in more detail later. _The The present invention will be- more clearly understood normal _ñighopos'ition of the _trailcone 12 isv shown in byY reference to the following' detailed description- oi _a hrolr'en line’sin Figùifesl 3. The tip p'od's 9 maybe preferred embodiment, together'- with the­ accompanying as’î fuel a?nìaiñent housings, o'r' other desired 65 use. . .„ . drawings', wherein: _ _ áls'o shown in 1, 2 and 3, airplane attitude Figures l, 2i and 3 are plan, front end and left _side titiuittfol~ nieaús of a_ left­. and _a right-handY elevon views, respectively; of a preferredv aircraft configuration surface 1'4'_a`n"d 15 eritending' the full length of the wing embodying niepr'ese'?i invention; __ _ _ trailing edge, a rudder 16 _in the trailing edge of the Figure 4 is a perspective view illustrating' thesame 70 ventral tin 4, and the elevatori. The elevons 14 and aircraft-in its _vertical resting position on the ground or 1li _are operated by a conventional control stick, for ex a-landing platform. ample, a'r'id, by a­ mechanism to be subsequently described 2,712,420 3 in detail, will function as both and elevators or « Ru'dder operating valves 27 are each provided with hy~ as ailerons alone. draulic line connections 32 to the supply and return lines This airplane is designed to take-olf vertically from a of two separate airplane hydraulic power systems (not tail-down landing position as shown in Figure 4. After a shown), one complete system for each rudder valve and desired suñicient altitude has been attained, it is inclined actuating cylinder. Both hydraulic power systems nor toward the horizontal and starts to pick up speed in this mally are in operation, but in the case of failure of one, latter direction while still mostly “hanging” by >the pro the second alone can operate the rifdder. ' " pellers. Finally,.the airplane assumes a normal horizon lt is thus seen that a full-power rudder control system tal flight position as shown in Figure 5. _ is provided. When one of the pilot’s rudder pedals 17 is When ready to land, the pilot brings the airplane low li) depressed, for example, the `rudder cables 19 will rotate over the desired landing spot, which may be any .small the operating crank 20 and move the valve control rods platform (substantially level) on land or aboard a ship at 29 relative to the operating valves 27. sea. Then, as shown in Figure 6, the airplaneA is is thereby caused `to operate the actuating cylinders 21 and maneuvered into a vertical hovering position and lowered turn the rudder 16. With the valves 27 attached to the to the deck by`correctly adjusting 4the thrust of the pro movable cylinders 21, ‘and- correct connection of hydraulic pellers. It may be guided in any direction while .hover supply and return lines, the actuating cylinders will move ing, so that a good landing is readily accomplished, even in the same direction in which the valve control rods 29 with appreciable relative wind velocity and pitching of the were displaced,­ thus returning the valves to neutral and ship on the water. Stability is maintained at all times. stopping rudder movement at a position dictated by the The above briefly-described operation is made possible final rudder pedal position. All surface forces are re by the provisions of this invention, including the par sisted entirely by the hydraulic lcylinder components, and ticular aerodynamic configuration, control system, and the pilot, therefore, feels no pedal forces as a result of landing means, all of which cooperate together, and each aerodynamic reactions. To provide the desired feed­back will now be taken up individually. ­ v forces tothe pilot, a two-way rudder >centering spring as It has been found that a swept back wing becomes sembly 34 is connected between the rudder operating highly unstable at’low speed and high engine power. crank 20and airplane structure 26. With this connection Since these two conditions occur when the present airplane placed in the system, the centering spring assembly 34 is in the vertical hovering attitude and in the transition will center the rudder if any component of the control sys~ range between vertical and horizontal night, a thin straight tem ~from the operating crank 20 to the rudder pedals 17 wing was selected in preference to a swept-backV or delta is severed. ’ ' ' ' planform. Another problem arose when it was found that Referring nowto the elevon controls (Figures 7, l0, i a conventionally located horizontal tail would­ cause and l1), the right-hand el'evon 15 is provided‘witli dual erratic stability and large trim shifts. I In addition, the elevon actuating cylinders 35 and elevon horns ~3_6 sirn strong propeller slip stream would greatly increase buffet- , ilarly to the rudder system._­ Elevon'p'iston rods',?a7_ ar'e ing and shaking, if the usual tail were incorporated. pivotally connected to the airplane structure, 26, and Therefore, We have provided the present all-movable ele elevon operating valves 39 have jointed outboard and in vator 5 at the lower end of the ventral iin 4, where it is board valve control rods 40 and 41, respectively. An out away from both wing wake and propeller slip stream. board bell crank 42 is rotatably mounted in a structural The ventral tin itself provides directional stability and bracket 44’and has two long arms 45 and one short arm also serves as a necessary landing support. Since the ele- ‘ 46. The short arm 46 is pivotally connected to the out# _vator 5 does not afford longitudinal control during hover board valve control rod 4G. An inboard bell crank 47 is ing flight, the elevons 14 and~15 are movable as elevators similarly provided, to be freely rotatable about a'lixed in as well as ailerons during this flight stage, and an ade~ board bell crank axis 49. The :short arm of the inboard quate elevon control area is provided by making the ele bell crank 47 is' pivotally connected to ­the inboard valve 45 control rod 41. Interconnection cables 50 between the vonsThe essentially over-al1 control as long system as the iswing shown panels in Figure 2 and 7.3; Full respective long arms of the bell cranks 42 and 47 provide ‘power controls are used throughout, since such a system simultaneous and parallel operation of the elevon actuat offers reliable operation and independence from reactions ing cylinders 35 connected to the right-hand elevon 15. due to wide variations of control surface forces especially ­­ Two sets of elevon bell crank pulleys 51 are rotatably prevalent in a high speed airplane of this type. mounted on the long arms of the inboard bell crank 47. Beginning with the rudder system, and referring also A cable drum 52 is also freely rotatable on the inboard to Figures 8 and 9, this system comprises conventional f' bell crank axis 49. ' An elevon servo actuator 54 pilot’s rudder` pedals 17, connected by a pedal linkage 18 has one end pivotally attached to structure 26 and the Vother end pivotally connected at 90° to a drum `lever arm to move rudder cables 19 and a rudder operating crank 55 secured integrally with the cable drum 52. A dual 20. Two hydraulic rudder actuating cylinders 21, operat~­ elevon cable system comprising elevon “up" cables 56 and ing in a parallel linkage, have their closed ends con~ elevon “down” cables 57 is connected at the inboard end Vnected to a dual rudder horn 22 attached to the rudder 16. ' of the elevon 15, these cables passing around the bell Each cylinder assembly includes a rudder piston rod 24 crank pulleys 51 and being fastened to opposite sides of connected to the customary piston 25 operating in'its re 60 the cable drum 52 in grooves therein. spective cylinder, and both4 piston rods 24 are pivotally Thus, when the elevon cables 56 and 57 are operated by anchored to the 'airplane structure 26. Each cylinder is the pilot’s manual controls, both bell cranks 42 and 47 also 'provided with a rudder operating valve 27 attached will be rotated, sincethe cable ends at the cable drum 52 'directly to its respective cylinder housing, and two rudder are being held stationary, and the elevon >actuating'cylin valve control rods 29 operate in and'. out of the valves 65, ders 35 are controlled exactly likethexrudder.­ _actuating '27 as simultaneously controlled by a valve rod yoke 3,0. system. When theelevon servo actuator 54,;is operated vThe rod yoke 30 is pivotally connected to each of said by powerapplied thereto,'the cable drum__­5_2 is rotated, rudder valve control rods 29 substantially in line there and, when the elevon cables 56 and 57 are beingheld with and forms an adaptor for one end of an electrical .- stationary at the pilot’s end, the _bell cranks „42 and~ 47 autopilot rudder servo actuator 31 which is pivotallyv con 70 are thereby rotated to govern elevon movement.v There nected at its other end to one side of the rubber operating fore, the elevon 15 may be _operated by two _independent crank 20. When the rudder servo actuator 31 is in input control systems, eitherseparately or simultaneously, active, it serves as an ordinary solid control red and r'noves'y `but bythe same full-power hydraulic'actu'ating means. as a whole when the operating vcrank 20 rotates. Opera The dual input connections­ disclosed hereinfor the elevon tion of the rudder servo actuator will be referred toflater. use a method and means similar to that shown, described

2,712,420 7 f8 producer is shown herein as comprising an aerodynamic position, the plunger 122 may be conveniently locked force bellows 117 (Figures 10 and 12) having a bellows in a retracted position above’the ground level, for ease of force shaft 119 connected to the elevator control crank moving the airplane on three dollies under the wing tip 105. When in neutral, the force connection line from struts 10 and fin strut 11. the bellows 117 to the control crank 105 passes through UL Thus, three wide-spread landing support points are the crank center of rotation, so that centering forces are provided, without the necessity for separate installations obtained. These synthetic force producers form no part usable for landing purposes only. Aiœlatively large wing of the present invention and are well known in the art. dihedral angle makes the possibility of tip-over more re From the foregoing control system description, it will mote. As mentioned before, the airplane is capable of be noted that the elevator 5 is always connected for move li) successful landings on a small deck of a vessel, for ex ment whenever the control stick 60 is moved in fore-and ample, even under fairly rough weather conditions. _It aft directions. During vertical and hovering flight, the can be hovered over the landing spot and set down during elevator 5 is not etîective for longitudinal control how a 35 knot relative wind. This is made possible by control ever, as mentioned previously. Therefore, during air movements of the rudder 16 to move the airplane side plane take-off, and transition to horizontal flight, the ways while hovering, and of the elevons 14 'and 15 to stick yoke 71 will be maintained in the “full elevator” po gether in the same direction to move the airplane along sition so that the elevons 14 and 15 can move in the same at 90° to sideways motion while hovering. To then com direction simultaneously for elevator action aud control. plete a landing under relative Wind conditions, the tail is Upon reaching normal horizontal flight, the hand crank “tucked under” and the engines simultaneously shut down. 92 will be turned by the pilot to the “zero elevator” posi- ‘ As shown in Figures 16 and 17, the pilot is provided tion, where the elevator 5 is the sole longitudinal control with an ejection type seat 125 having two positionsof surface. `>Then, before going into the vertical hovering rotation about a lateral axis. Figure 16 shows the seat position for a landing, the hand crank 92 and stick yoke in the position used for normal horizontal flight and ejec 71 will be returned to “full elevator.” tion, if necessary. Figure 17 shows the seat rotated 45° It is important to note that normal conventional con to the other position used during take-off and hovering. trol stick operation by the pilot is adhered to at allftimes, A line representing an instrument panel 126 shows its regardless of system control changes by the hand crank preferred location and angles of pilot sight line in viewing '92. It will also be understood that the hand crank 92 .a certain point on the panel. may be replaced by automatic power means under control The positions of the control stick in Figures l6 and 17 of the pilot. are both neutral positions. Normal position 60a shows The rudder servo actuator 31, elevon servo actuators the stick position when the adjustable linkage 62 (Fig ‘54 and elevator servo actuator 114, each acting inde ures l2 and 14) is in its shortest position, and “vertical” pendently in series with the pilot’s manual controls for position 60h shows the stick position when the adjustable Yits respective surface, may functionas autopilot servos, linkage 62 is in its longest position. This stick adjust trim actuators, and any other control purposes which are ' ment provision gives the pilot a natural stick neutral posi desired. The full-span elevons 14 and 15 can be used as tion in both seat positions without any change the Ahigh lift wing flaps, in horizontal ñight, preferably by en actual control mechanisms. Of course, the adjustable ergizing the elevon servo actuators 54 to deflect both ele linkage 62 may comprise any kind of extensible means vons downwardly simultaneously, as desired. They can lockable in at least two different positions, such as in thus be used to increase the lift during climbs, and to de 40 cluding a power-driven actuator, for example. crease the lift and drag during high speed horizontal As also illustrated in Figures 16 and 17, the rudder llight, the amount of these several factors depending upon pedals 17 remain connected in the same position for both 'the aerodynamic characteristics of the particular airplane positions of the pilot’s seat 125. Adequate control by involved. « the pilot’s legs is obtained without adjusting the rudder The spring-loaded elevon push-pull rods 80 and 81 are pedals 17 to new neutral positions. . preloaded to act as rigid connecting rods up to a prede With regard to power plant, the airplane of the presen termined value beyond the normal system operating loads invention preferably inco-rporates a turbo-prop gas tur Iimposed upon them. Above the preload force, they will bine engine having two power units 127 installed near stretch or compress, to prevent damage to system com the lower side of the fuselage 1, one on each side of the ponents. This precaution is highly desirable since the fin airplane center line, to the rear »of engine air intakes mechanical advantage of any stick forces in the fore 129. A two-speed reduction gear in a gear box 130 is ‘and-aft direction is exceptionally high (approaching in provided between the 'power units and propellers, along finity) when the stick yoke 71 is near the “zero elevator" with clutching means in the gear reduction unit for ope-r position. When the hydraulic power is off, such as when ating one or both power units to drive the propellers. the airplane is parked, carless or inadvertent handling of The propellers 6 are not blades but conven the control stick could therefore result in easily overload tional aircraft type propellers, utilizing a blade angle con ing any part of the elevon control system between the con trol system to render them known as “constant speed" trol stick 60 and the elevon actuating cylinders 35. propellers. The landing strut arrangement is shown in Figure l5. While in order to comply with the statute, the inven The wing tip struts 10 and the fin landing strut 11 each tion has been described in language more or less specific comprisea piston and cylinder assembly 120 of any suit as to structural features, it is to be understood that the able type, preferably small combination compressed air invention is not limited to the lspecific features shown, but that the means and construction herein disclosed com and hydraulic shock struts with an enlarged bumper 121 prise the preferred form of putting the invention into on, the external end of the strut. The stroke of these three' effect, vand the invention is therefore claimed in any of its struts is about 6 inches. ' ' ._ forms or modifications within the legitimate and valid The collapsible tail cone 12 covers the major landing scope of the appended claims. shock absorber, which normally extends ‘substantially What is claimed is: 7 farther to the rear than the other landing struts. It is 1. A vertically rising airplane comprising a fuselage, a made of a ñexible material which completes the smooth 70 high main wing attached to said fuselage and having a contour ofthe fuselage tip when extended, and folds up relatively high dihedral angle, a ventral ñn extending when the airplane lands, as shown in Figure 4. The tail perpendicularly downwardly` under the rear of said fuse cone strut installation comprises a plunger 122 and a cas lage, a horizontal tail plane at the lower end of said ventral ing 124 attached to the airplane structure 26, similar in fin, and landing strut means on said airplane extending type to the other three struts, but having a total stroke 75 to the rear for landing support in a tail-down position. of about 48 inches. When the airplane is in the parked 2. An airplane in accordance with claim 1 wherein said attracco 10 wing is essentially straight in pla'níorm, and including an pivotal about two axes, aileron control means connected elongated fore-.and-aft pod member at each wing tip, and between said control member and said elevons for mov wherein said landing strut means comprises a wing tip ing said elevons in opposite directions simultaneously for strut in the aft end of each of said pod members,­ a fm roll control, when said control member is moved in a strut near the lower end of said ventral lin, and a tail lateral controlling direction about one of said axes, ele cone strut in the aft section of said fuselage. vator control means connected between said control mem 3. An airplane in accordance with claim l including ber and. said horizontal tail surface for longitudinal con. a pair of hinged elevon surfaces in the trailing edge of -trol, elevon control means connected between said con said wing, one of said pair on each side of said fuselage, trol member and said elevons for moving said elevons in a rudder in the trailing edge of said ventral fin, and where 10 the same direction simultaneously for longitudinal con in said horizontal tail plane is movable as an'elßvator trol, said elevon control means and said elevator control surface. means being simultaneously and additively responsive to 4. An airplane in accordance with claim l including elevation controlling movements of said control member counter-rotating propellers at the front of said fuselage, about thel second control axis, and pilot-operated means a pair of hinged elevons. in the trailing edge of.> said wing, 15 connected to said elevon control means tol eliminate the one` of said pair on each side of said fuselage andextend longitudinal control movements of said elevons `­with ing substantially­ the full length of said trailing' edge, a movement of said control member. ' rudder` in the trailing edge of said ventral tin, wherein l0. Apparatus in accordance with claim 9 wherein said lsaid horizontalA tail­ plane is. movable as a longitudinal elevon control means includes a yoke member pivotally control surface and' is outside of’ the slip stream. of said 20 connected to said pilot’s control member about a. yoke propellers, and saidîwing being situated so that said elevons axis. parallel to one of said control member axes, said function as longitudinal control surfaces when moved in yoke member having two corner connection points. lo the same direction­ simultaneously. . ' , cated so that a line through said points is parallel, to said t 5‘. AnA airplane in accordance with'` claim l including yoke, axis and so that said line and said parallel4 control an» elongatedl fore-and-att pod member at, cach _wìng- tip, member. axis are equ-idistant from said yoke axis, a- left and whereinl said landing strut means includes a: wing hand elevon link pivotally connected to one of said con _tip shock strut` assemblyv tixedi in> the aft endl of’ each: of nection points,A a right-hand elevon link pivotally connect said pod members, a tin shock' strut­ assembly fixed near ed> to the other connection point, and elevon actuating the l‘ower att edge of- said ventral fin, a tail shock strut means connected between each of said linksA and its re in- the aft sect-ion o? said fuselage, and a- flexible: coll'ap 30 spective elevon, and wherein said pilot-operated means sible. cover member connected at- the forward­ side- to- a comprises an adjustable linkage between said control rigid section of said fuselage and conneetedî at the- aft member and said yoke member for rotating said connec side to said taii' shock strut near the extremity thereof, tion points. into and. out of coincidence with said parallel said ñ'exible- cover member completing the' smooth elc-v control> member axis. 'tjerion contour of: said' fuselagey aft:l section when saidïi tail 35 ll., Apparatus in accordance with claim l0 wherein shock strut is i'n- the normal‘ extended position, said~ tail said yoke member and said adjustable linkage have4 a shock strut- havi‘ng- a stroke several times­ the strokes of first operating position relative to said control- member said wing tip struts and said' iin struts, and normally- ex where said connection points are coincident with said tending» farther to the rear than the latter three struts. parallel control member axis„ and a second operating 6. I-n- an airplane of the type described; a~ wing; a pair 40 position where said connection points are at a given ‘of elevon surfaces hinged to said wing, one ofsaici pair maximum. distance from said parallel axis, said elevon on eachsideof said airplane, a- ventral tinîextending-down links` are. push-pull members which are positioned at sub wardly under­ the rear of‘ said airplane, a: rudder hinged stantiallyy 90° to the plane containing said' parallel­ con to said‘ventral-À lin, a horizontal tailv4 control' surface at the trolA member axis and said connection point line when lower end'y of said ventral fin movable' in­ longitudinal 45 Vsaid yoke is in said second position and said pilotf’s con control directions, means for movingV said rudd‘er‘> for trol member is in a neutral position where said elevon `directional control?, means for movingy said elevons in surfaces and said horizontal tail surface normally are not oppositedirections simultaneously-for roll control, means deflectedA from straight and level ñight position; ,for simultaneously moving-,saidv elevons and said' horizon l2. Apparatus irl-accordance with claim 9 wherein-said tal‘ tail surface inthe same direction for' longitudinal con 50 elevon. control means comprises an elevon control ele trol, and control means for eliminating, at’ will, longi ment driven by said pilot’s control member and rotatable tudinal, control; movements of said el‘evonsV only/«L said in. longitudinal controlling directions about an element Control' means being arrangedv to reinstate, at will,_ lon axis,.two­position crank~ means pivotally connected to said gitudinal control movements of said elevons along with element andY having connection points thereon rotatable said’ horizontalv tail` surface. ^ ~55 insan arc about said element axis with said element when 7. Apparatus in accordance> withV claim 6’wherei'1r said said-.crank means is in one of its two positions, said-"con airplane has counter-rotating propell‘ers` to move said- air nection. points being rotatable exactly on said element pla-ne forwardly; and wherein said horizontal: tail' surface axisjwlien. said crank means' is in the second ofsaid­ two lies outside the circumference of the rotating‘path's o?said positions', and'el'evon actuating means connected between propellers projected in a fore-and-aft direction.. said connection points on4 said crank means andA said 8. Apparatus in accordance with claim 6 wherein said elevons; andv wherein` said pilot-operated means com wing is essentially straight in planform- and has a rela prises adjustable. means connected. between said» element tively' high; dihedral angle, and including air elongated andïsa'id' crank means for moving said­ crank means.. be fore-and-aft; pod member at each~ wing-­ tip, and. landing tween, said' two4 positionsl relative toy said element. strut‘means on said. airplane extending to the rear forf 65: I3”. airplane. in accordance with claim. L includ landing support in a tail-down position, said landing . ing afpilot’s control member connected to a control sys means including a wing4 tip shoe@ strut in, the aft tem for'controlling-movements of- said` airplane,A a pil'ot’s end of? each' of said. podtmembers; and» a fin siuoclltv strut near the lower aft edge of said ventral iin. Seatlpivoted' to have; two: operating positions relative'> to said airplane, one for horizontal flight and one for ver 9. In an airplane of the type described, a wing, a pair 70 of elevon surfaces hinged to said wing, one of said pair tical and hovering flight, and adjustable connecting means on each side of said airplane, a ventral tin extending down between said control member and said control system wardly under the rear of said airplane, a horizontal tail arranged to provide two positions of said control mem surface at the lower end of said ventral lin movable in ber relative to said control system, one of said member longitudinal control directions, a pilot’s control member 75 positions being convenient to the pilot in one of said seat 2,712,420 1 l 12 positions, and the other member position being convenient tudinal control, a pilot’s control member, first control to the pilot in the other seat position. means connected between said control member and said 14. A control system for an airplane adapted to take~ horizontal tail surface for 'longitudinal control, second off and land vertically along a line of thrust therein and control means connected between said control member and ily horizontally along said thrust line, said control system said wing control surfaces for moving said wing sur comprising a first control surface movable in a given faces in the same direction simultaneously for said direction relative to said airplane, a second control sur longitudinal control, said ñrst and second control means face movable in the same relative direction, means for being simultaneously and additively ifesponsive to move simultaneously moving said first and second control sur ments of said control member in a given direction, and faces in the same direction, and controllable means for pilot-operated means connected to said second control eliminating, at will, movements of said second control sur means to eliminate said longitudinal control movements 'face with movements of said first control surface, said of said wing control surfaces with movement of said controllable means being arranged to reinstate, at will, pilot’s control member in said given direction. said second control surface movement with said first con 19. Apparatus in accordance with claim 18 wherein trol surface movement. said second control means comprises a rotatable element 15. A control system for an airplane adapted to take driven by said pilot’s control member in said same atti off and land vertically along a line of thrust therein and tude controlling directions about an element axis, a yoke ~ily horizontally along said thrust line, said control system member pivotally connected to said pilot’s control mem comprising a ñrst control surface movable in a given ber about a yoke axis parallel to said element axis, said direction relative to said airplane, a second control sur 20 yoke member having two corner «connection points lo» face movable in the same relative direction, means for cated so that a line through said points is parallel to said simultaneously moving said first and second control sur yoke axis and so that said line and said element axis are faces in the same direction, and controllable means for equidistant from said yoke axis, a left-hand wing con maintaining, at will said second control surface in a neu trol surface link pivotally connected to one of said con tral position with respect to movements of said first conV nection points, a right-hand wing surface link pivotally trol surface. connected to the other connection point, and -wing sur 16. A control system for an airplane adapted to„,take« face actuating means connected between each of said olf and land vertically along a line of thrust therein and links and its corresponding wing control surface, and «ily horizontally along said thrust line, said control system wherein said pilot-operated means comprises an adjust »comprising a first control surface movable for attitude ' able linkage between said rotatable element and said yoke control about a lateral axis perpendicular to said line of member for rotating said connection points-into and out thrust, a second control surface also movable for the of coincidence with said element axis. same attitude control, a pilot’s control member, first con 20. A .vertically rising airplane comprising a fuselage, trol means connected between said control member and a wing attached to said fuselage, a tail tin attached to said first" control surface, second control means con said fuselage, and landing strut means on the rear tips nected between said control member and said second of said wing and tail iin for landing support in a tail control surface, said first and second control means and down position, said wing having a substantial elevation hsurfaces being simultaneously and additively respon« .angle between the two halves thereof at their intersec sive to movements of said control member in a given tion with the fuselage, and said tail ñn extending from direction, and pilot-operated means connected to said 40 said fuselage in the direction to bisect the reflex angle second control means to eliminate said attitude control formed by said wing as viewed along the longitudinal movements of said second control surface with movement axis of said airplane, whereby three substantially evenly of said pilot’s control member in said given direction. spaced landing strut points are provided for stability. 17. Apparatus in accordance with claim 16 wherein 21. A vertically rising airplane comprising a fuselage, said second control means comprises a rotatable ele a wing attached to said fuselage and having a relatively ment driven by said pilot’s control member and rotatable high dihedral angle, said wing being essentially straight in said same attitude controlling directions about an in planform, an elongated fore-and-aft pod member at element axis, two-position crank means pivotally con each wing tip, a ventral tin extending downwardly under’ vnested to said clement and having connection points the rear of said fuselage, and landing strut means in thereon rotatable in an are about said element axis with 50 cluding a wing tip strut in the aft end of each of said said element when said crank means is in one of its two pod members and rearwardly extending fin strut means positions, said connection points being rotatable exactly attached near the lower extremity of said ventral ñn. on said element axis when said crank means is in the 22. A vertically rising airplane comprising a fuselage, second of said two positions, and second~surface actuat a wing attached to said fuselage and having a relatively ing means connected between said connection points 55 high dihedral angle, a ventral fin extending­ downwardly on said crank means and said second surface, and where~ under the rear of said fuselage, a horizontal tail plane in said pilot-operated means comprises adjustable means attached to said ventral fin, and landing strut means connected between said element and said crank means on said airplane extending to the rear for landing support for moving said crank means between said two positions in a tail-down position. relative to said element. 60 18. A control system for an airplane adapted to take References Cited in the file of this patent off and land vertically along a line of thrust therein and UNITED STATES PATENTS to ily horizontally along said thrust line, and said air plane ha’ving a wing and a tail section, wherein said con 2,308,802 Barling ______.. Ian. 19, 1943 trol system comprises a horizontal control surface at 2,382,460 Young _‘______Aug. 14, 1945 said tail section movable for longitudinal control of said­ FOREIGN PATENTS t ' airplane, a pair of wing control surfaces hinged to said 568,548 Great Britain ______Apr.,1o,.1945 wing, one of said pair on each side of said airplane, said 728,256 wing control surfaces being also movable for said longi Germany ______- Nov. 24, 1942