July 5, 1966 T

Home , Port and starboard

July 5, 1966 T. W. SCHMIDT 3,259,338 AIRCRAFT FOR SHORT AND/0R VERTICAL TAKE-OFF AND LANDING Filed Feb. 17, 1964 5 Sheets-Sheet 1

INVENTOR. THEODORE W. SCHMIDT BY

ATTOR HEY July 5, 1966 T. W. SCHMIDT 3,259,338 AIRCRAFT FOR SHORT AND/OR VERTICAL TAKE-OFF AND LANDING Filed Feb. 17, 1964 5 Sheets-Sheet 2

‘MO?Mm

TNVENTOR. THEODORE W. SCHMIDT BY KM 77. QJM ATTORNEY July 5, 1966 T. W. SCHMIDT 3,259,338 AIRCRAFT FOR SHORT AND/OR VERTICAL TAKE-OFF AND LANDING

Filed Feb. 17, 1964 5 Sheets-Sheet 5

INVENTOR. THEODORE W. SCHMIDT

ATFORNEY 3,259,333 United States Patent O?ice Patented July 5, l9?6

1 2 Generally stated, the invention comprises an aircraft 3,259,338 having a fuselage wherein the center-.of-gravity is located, AIRCRAFT FOR SHORT AND/0R VERTICAL a wing, and lift engine nacelles pivotally mounted about TAKE-OFF AND LANDHNG a longitudinal axis vertically displaced above the aircraft Theodore W. Schmidt, Seattle, Wash, assignor to The Boeing Company, Seattle, Wash, a corporation of Dela \oentenof-gravity. ware As shown in FIGS. 1, 2 (and 3, the aircraft illustrated Filed Feb. 17, 1964, Ser- No. 345,448 is adapted for S/VTOL ?ight and consists of a fuselage 7 Claims. (Cl. 244-12) 2h, wing 21, an empennage including a vertical ?n 22, a rudder 23, a horizontal stabilizer 24 and an elevator 25. The win g 21 is provided with full span leading edge ?aps This invention relates to aircraft adapted for S/VTOL 10 (short and/or vertical take off and landing) and more 26, trailing edge ?aps 27, ?aperons 28 and carries star particularly to the attitude control system of such air board vand port jet propulsion cruise engines 29 and 30, craft including variation of the propulsion system moment respectively. Further outboard of the cruise engines are arms. located lift engine nacelles or pods 36 and 37 which pro Presently known attitude control systems for S/VTOL 15 vide the principal vertical thrust or lift required for verti aircraft, when the (aircraft is in vertical or hovering ?ight cal, hovering or transitional ?ight. The cruise engines so that aerodynamic control surf-aces do not function of 29 and 30, however, may be used to supplement the lift ?cientlly, are generally of the “reaction” or “throttling” through the ‘auxiliary rotatable nozzles 33 and 34 mounted types. Throttling control is accomplished by varying the on each cruise engine. thrust of the appropriatelylocated engine with respect In normal forward ?ight the aerodynamic control sur to the aircraft center of gravity. Reaction control gen faces are operated to function conventionally and forward erally consists of bleeding air from engines and ducting thrust is provided by cruise engines 29 and 30. In verti this air to the wing tips and the fuselage nose and tail cal, hovering or transitional ?ight, lift is provided through and then controllab'ly releasing this air to produce a thrust lift-devices comprising a plurality of lift-jet engines 35 reaction and thereby to control the aircraft attitude. The 25 located in pod-type nacelles 36 and 37. These nacelles disadvantage of these types of systems is that they sub are laterally spaced apart and symmetrically arranged stantially reduce the total lift thrust available for sus with respect to the aircraft longitudinal ‘axis and are taining the aircraft in ?ight and therefore when such sys pivotally mounted to the wing 21 above the center~of tems are employed it is generally necessary to incorporate gravity 38 of the aircraft. into the aircraft design a greater thrust/weight ratio. Transitional ?ight occurs when the aircraft is changing Since it is believed that a minimum thrust/weight ratio between hover ?ight wherein the {aircraft is supported by of 1.2 should be held for satisfactory control, the throt , the direct lift of the lift engine 35, and cruise ?ight where tling or reaction systems may result in a serious engine in the aircraft is supported by the lift of the wings 21. A weight penalty. Additionally, throttling systems ‘are gen very smooth transition is provided by this invention. As erally too slow in an emergency. 35 forward ?ight speed is beguniand increased by accelera It is the general object of this invention, therefore, to tion of the cruise engines, the pilot gradually throttles provide an instantaneous attitude control system operative back the lift engines as the wings develop lift until the during vertical or transition to or from horizontal cruise wings are carrying all of the load .of the aircraft and the flight by varying the distance or lever arm about the air lift engines are shut down completely. Likewise, as hover craft center~of-gravity at which the lift thrust acts. 4:0 ?ight is desired, the pilot gradually throttles back the Another object is to provide hover maneuverability and cruise engines, and lowers the ?aps and tilts the nose up attitude control for an ‘aircraft at ?ight speeds in the slightly, if desired, as he starts and gradually opens the V/STOL regime and during an emergency condition such throttle of the lift engines until all the load is carried by as failure of one of the lift producing engines without the lift engines, the cruise engines being cut down com appreciably decreasing the effectiveness of the available pletely and the plane now being in hover or vertical lift thrust produced by the remaining engines. ?ight. Still another object of the invention is to provide an In the illustrated embodiment of the lift engines within aircraft con?guration wherein the lift engines are partially each nacelle, the port and starboard nacelles are identical disposed in the aircraft wing and related to the aircraft and it will therefore be su?icient to describe one of them. centeraof-gravity so that an angular rotation of the lift Referring now to FIGS. 4 through 6, the nacelle 37 engine thrust vector changes the moment ‘arm length at 50 contains five lift engines 35 arranged in tandem with three which the thrust acts. forward of the wing torsion box and two aft. This ar ‘Other objects and advantages will become apparent rangement though structurally desirable is one of choice, when taken in connection with the accompanying draw as is the number of engines, and the engines may be ar ings in which: 55 ranged immediately adjacent to one another, if so de FIGURE 1 is a plan view of the aircraft according to sired. The engines are vertically mounted within the the present invention; nacelle so as to discharge in a downward direction there FIGURE 2 is a side view of the aircraft; by producing ‘a lifting force on the ‘aircraft. Each of the FIGURE 3 is a front view of the aircraft; ‘FIGURE 4 is a plan view of the port lift engine lift-engines is ?xed on its lateral axis and ?xed relative nacelle of the aircraft, showing ‘the lift engines in solid 60 to the aircraft’s lateral taxis relative to movement between lines; the engine and the fuselage. The lateral axis of the en FIGURE 5 is a side view of the nacelle shown in gine may be either congruent with or parallel to the FIGURE 4; lateral axis of the aircraft. The upper surface of the FIGURE 6 is a front view of the nacelle shown in nacelles 36, 37 have longitudinally extending engine air FIGURES 4 and 5, showing the intake doors in an open 65 intake doors 41 and the lower nacelle surfaces have a plu position; rality of vanes 42; both doors and vanes may be closed vFIGURE 7 is a diagrammatic section view of the when engines 35 are not operating so as to present a 'nacelle shown in FIGURE 6; and smooth aerodynamic surface. The vanes 42 pivot on 'FIGURE 8 is a front view of van iaircraft's‘howing the axes transverse (to the nacelle and may be selectively posi difference in moment arm variation dependent upon en 70 tioned so as to direct the exhaust gases discharging from gine location relative to ‘the aircraft center-of-gravity. the engines in either a vertical or near vertical direction. 3,259,338 3 4 The center-of-thrust-lift 39 is located in the same body the wing, therefore, is within proper design limits. The station ‘or transverse vertical plane as aircraft C.G. 38 wing leading edge is straight, rather than swept back, and this coincides with a position of approximately 25 since wing sweep has the effect of increasing the “effective to 30 percent of the means aerodynamic chord of wing 21. dihedral angle”; though leading edge sweep may be pro The vanes 42 control the direction of thrust of the engines vided by increasing the aspect ratio or the span of the in the longitudinal plane and since the axis of the vanes outboard portion of the wing. is vertically displaced above the aircraft C.G. 38 the The positioning of the lift engine nacelles 36 and 37 pitch attitude of the aircraft may be easily controlled by is also structurally advantageous. ‘The nacelles are lo selectively positioning the vanes. cated from the fuselage longitudinal axis at a distance of When cruise engines 29 and 30 by means of rotatable 10 approximately 70 percent of the wing semi-span and nozzles 33 and 34 are used to provide auxiliary thrust for presents a wing bending moment requirement for sustain lift, the center-of-thrust-lift 40 of these engines is in the ing the aircraft in vertical ?ight by the lift engines 35 body station or transverse vertical plane of the normal alone which is no greater than the design maneuver aircraft C.G. 38 and center-of-thrust-lift 39. requirements during normal horizontal ?ight at the same The vanes 42 are also selectively operable to control 15 aircraft gross weight. aircraft yaw. Differential positioning e.g. port nacelle Referring now to FIG. 8, the advantages of the new vanes de?ected forward and starboard nacelle vanes de aircraft con?guration described above as a roll control ?ected rearward to obtain a yaw to the left, is controllable system in normal ?ight can be shown by comparison with by pilot moved members (not shown). a prior aircraft con?guration in which the rotation axis The greatest advantage provided by this invention is of the pods is on the same horizontal plane as the aircraft the highly effective roll control system, in combination C.G. The aircraft shown has a fuselage 60, wing 61 with the aforementioned pitch and yaw control, resulting‘ and lift-devices 62, 63 in the “single-plane” or prior con from the rotation of lift engines at a location which is ?guration. Lift-devices 64, 65 are shown vertically dis vertically above and laterally spaced from. the aircraft placed above the aircraft center-of-gravity 66 and will be center~of-gravity. One embodiment of an aircraft which 25 referred to as a “dual-plane” or new con?guration. To shows the location of the rotatable lift engine nacelles produce a roll moment about the aircraft C.G. 66 the lift spaced apart and above the aircraft C.G. is shown in or thrust vector is multiplied by the lever arm distance FIGURES 1 through 3 and mounting of the nacelle may from the C.G. 66 to the thrust vector as measured by a be seen in FIG. 7. The nacelle 37 is rotatably mounted line perpendicular to each thrust vector and passing on wing 21, about its longitudinal axis on a shaft 43 30 through the aircraft C.G. In the “single-plane” or prior resting in bearings secured to the wing. An actuating con?guration rotation in the same direction of the lift means, such as hydraulic actuator 44, is secured to the devices 62, 63 through an angle or changes the moment tiltable engine mounting nacelle structure 47 on one end arms a and b to a’ and b’. However, these moment arms and to the wing 21 structure on the other end. remain equal in length so that no roll moment is produced Actuating forces for the nacelle rotation are minimal 35 (since the lift force of both lift-devices is equal) and only since the resultant thrust vector of the engines passes a side force develops. In the “dual~plane” or new con through the nacelle hinge point and produces bearing ?guration, the vertical displacement of the rotation axes friction rather than a resisting moment. Controls (not of the lift-devices causes a difference in moment arms shown) for actuator 44 are integrated with the aircraft between the thrust vectors from lift-devices 64 and 65 aerodynamic control system (not shown) so that pilot 40 when both are rotated to the same angle a. The differ control system operation regardless of the mode of ?ight ence in moment arms a" and b" produces a roll moment remains the same. Rotation of the lift-devices, i.e. nacelle equal to the difference in lever arm lengths multiplied by and the ?ve lift engines 35 therein, changes the direction the thrust. The same lateral force is produced as in the of thrust of the engines relative to the aircraft C.G. 38. ?rst considered con?guration. To produce a roll moment The nacelle 36 rotation is limited so that the resultant lift 45 in the “single-plane” or prior con?guration, one of the two thrust vector may be varied from vertical by 15 degrees lift-devices must be rotated at a greater angle than the outboard (maximum moment angle) to 30 degrees in other. The disadvantageous result of this requirement for board (practical structural limitation). It may be seen greater rotation of one lift-device is two-fold: (l) the total that the advantage of tilting the entire pod lies in the lift available for the aircraft is reduced, since the vertical synchronous movement of all ?ve of the engines together. component of thrust of the lift-device which has been Furthermore, a less complicated installation results since rotated further is reduced; and (2) the lateral force pro a single swivel-type attachment point to the common duced is greater since the horizontal component of thrust engine mounting nacelle structure 47 for fuel, electrical, of the further rotated lift-device increases and thereby the and other systems is required rather than separate attach bank angle into which the plane must be maneuvered to ment points to each engine. ‘ 55 prevent lateral dislocation becomes larger. The aircraft embodiment shown in FIGS. 1 through 3 Considering now the operation of the control system. in also shows a wing arrangement which results in the de— the novel “dual-plane” con?guration during vertical or sired lateral spacing and vertical displacement of the lift hovering ?ight, the advantages are also readily apparent. engine nacelle axes of rotation while the nacelles remain Rolling moments required to control the aircraft while partially disposed in the wing. The vertical displacement hovering are similar to those just discussed. Additional of the lift engines 35 and therefore the resultant thrust problems in hovering ?ight may be created, however, if vector rotation axis was accomplished by using a severe one of the lift engines of the aircraft ceases to operate or positive dihedral wing angle. However, a high wing air a gust causes the aircraft to bank. The success of elim craft requires that the “effective dihedral angle” be limited ination of the roll angle depends on the available roll to approximately 3 degrees to maintain good control and moment which can be produced. The “dual-plane” con stability characteristics in normal ?ight. To satisfy this 65 ?guration satis?es this requirement while providing maxi requirement, the inboard portion of the wing out to the mum total lift which is critical during hovering ?ight and lift engine nacelles has a 10 degree positive dihedral angle produces lateral forces which cause the aircraft to move while the outboard portion of the wing has a 2 degree in a direction relative to the ground opposite to the negative dihedral angle. Since the outboard portion of 70 direction from which the gust emanated or the loss of the wing is further from the aircraft C.G. than the inner thrust produced. panel, it has a much greater lever arm and though smaller While there has been shown and described the funda in area the moment produced by aerodynamic lift of this mental novel features of this invention as applied to the portion of the wing is essentially equivalent to the inboard preferred embodiment, it will be understood that various portion moment. The total “effective dihedral angle” of 75 omissions and substitutions and changes in the form and 3,259,338 5 6 details of the device illustrated may be made by those 5. The aircraft of claim 4 wherein the thrust producing skilled in the art without departing from the spirit of lift-devices comprise: the invention. .It is the intention therefore to be limited (a) lift engine nacelles partially disposed in said wing, only by the scope of the following claims and reasonable each nacelle including equivalents thereof. (1) engine mounting nacelle structure rotatably I claim: journaled in said wing, 1. An aircraft having a center-of-grav‘ity comprising: (2) a plurality of vertically oriented lift engines (a) a fuselage, mounted on said structure, (b) a wing ?xedly attached to said fuselage and pro (3) an aerodynamically smooth cowl enclosing jecting laterally from both sides thereof; 10 said engines and said mounting structure and (0) a plurality of lift-devices pivotally mounted on ?xedly attached to the latter; and, said wing for discharging a propulsive gas stream (b) actuating means interconnecting each of said en in a substantially downward direction so as to pr0~ gine mounting nacelle structures to said wing for vide an upward thrust on the aircraft, each of said selective rotation of said nacelle. lift-devices having a lateral axis, each of said lift 15 ‘6. The aircraft of claim 5 wherein each of said nacelles devices being ?xed on its lateral axis relative to move include: rnent between the device and said fuselage, at least (a) air inlet means mounted in the upper surf-ace of one of said lift devices being on each side of said said cowl; fuselage and laterally spaced therefrom, each of said (b) exhaust vanes pivotally mounted about axes trans lift-devices having a pivotal axis, each of said pivotal 20 verse to the aircraft longitudinal axis; and axes being substantially parallel to the aircraft l0ngi< (c) means for selective control of the thrust axes in a tudinal axis and vertically displaced above said air longitudinal plane. craft center-of-gravity; and '7. In combination with an S/VTOL aircraft with a cen (d) means to simultaneously rotate said lift-devices in ter-of-gra-vity, a longitudinal axis, a lateral axis, and hav the same direction so as to change the distance from 25 ing a wing on each side of the aircraft, said aircraft center-of-gravity to the thrust axes of (a) vertical lift means for each of ‘said wings, said lift-devices as measured by a line perpendicular (b) each of said vertical lift means being positioned to each thrust axis and passing through the aircraft above said center-of-gravity and rotatable about an center-of-gravity. ‘axis parallel to the aircraft’s longitudinal axis and 2. The aircraft of claim 1 wherein the wing comprises: 30 each of said vertical lift means being ?xed about the (a) "an inboard portion having a positive dihedral; aircraft’s lateral axis, and and (0) means for rotating ‘both of said vertical lift means (b) an outboard portion having a negative dihedral; simultaneously in the same direction for varying the said pivotally mounted lift-devices being positioned at relative effective lift thereof. the intersection of said inboard and outboard wing 35 portions. References Cited by the Examiner 3. The aircraft of claim 2 wherein the Wing has an ef UNITED STATES PATENTS fective dihedral angle of not more than three degrees. 4. An aircraft having a center-of-gravity comprising: 1,851,764 3/1932 Hahn .; ______244-7 (a) a fuselage, 40 2,930,544 3/1960 Howell ______244—~12 (b) a wing ?xedly attached to said fuselage and pro 3,031,157 4/1962 Varden ______244-—-12 X jecting laterally from both sides thereof; and 3,066,889 12/1962 Kelly ______244—12 (c) means for providing attitude control of said air FOREIGN PATENTS craft comprising, 283,980 1/1928 Great ‘Britain. 1(1) thrust producing lift-devices pivotally mount 45 ed on axes substantially parallel to said aircraft OTHER REFERENCES longitudinal axis and vertically displaced above Buchstaller: German application No. 1,151,178, pub said aircraft center-of-gravity for providing an lished July 4, 1963. upward thrust, at least one of said lift-devices being on each side of said fuselage and laterally References Cited by the Applicant displaced therefrom, UNITED STATES PATENTS (2) means to simultaneously rotate said lift-de vices in the same direction so as to differentially 2,363,129 11/ 1944 Heitmann. change the distance from said aircraft center~of 2,552,359 5/1951 Winslow. gravity to each lift-device thrust vector between 55 2,562,905 8/ 1951 Gadeberg. the lift»devices mounted on opposite sides of 2,650,050 8/1953 Chandler. said fuselage as measured by a line perpendicu 2,736,515 2/195‘6 tDolan et al. "lar to each thrust vector and passing through the 2,926,868 3/ 1960 Taylor. aircraft center-of-gravity, and 2,939,654 6/ 1960 Coanda. (3) thrust axis directional means mounted on 60 2,981,501 4/ 1961 Schaefer. each of said lift-devices for angularly rotating 3,077,321 2/1963 Dunham. the thrust vector of said lift~devices in a longitu dinal plane to provide aircraft pitch and yaw MILTON BUCHL-ER, Primary Examiner. moments. G. P. EDGELL, L. C. HALL, Assistant Examiners.