Source: http://www.google.com/patents/US2936969?dq=4316055
Timestamp: 2018-01-20 08:17:40
Document Index: 415162852

Matched Legal Cases: ['art 24', 'arts 220', 'art 220', 'arts 220', 'arts 220', 'arts 22011', 'arts 220', 'arts 220']

Patent US2936969 - Jet sustained and propelled aircraft - Google Patents
www.google.comhttp://www.google.com/patents/US2936969?utm_source=gb-gplus-sharePatent US2936969 - Jet sustained and propelled aircraft
Publication number US2936969 A
Filing date Jun 7, 1956
Publication number US 2936969 A, US 2936969A, US-A-2936969, US2936969 A, US2936969A
Inventors Arnold Griffith Alan, William Shaw
Jet sustained and propelled aircraft
US 2936969 A
May 17, 1960 A. A. GRIFFlTH ET AL 2,936,969
JET SUSTAINED AND PROPELLED AIRCRAFT Filed June '7, 1956 6 Sheets-Sheet l Inventors S19 Attorneys May 17, 1960 A. A. GRIFHTH E'rAL 2,936,969
JET sUsTAINED AND PROPELLED AIRCRAFT Filed June '7, 1956 6 Sheets-Sheet 2 FIGA.
Inven'zors www WM. Mn.. snm@v Attorneys May 17, 1960 A. A. GRIFFITH ET AL 2,936,969
JET SUSTAINED AND PROPELLED AIRCRAFT Filed June 7, 1956 6 SheetS-Sheet 3 FIG.
34 3o 37 2o l u) L 2e 42 1 'c/A 26 f y ,M
41 w y I '1 A 39 26 28 ESQ/E"- j -i n Khun-*nml 460 Inventors @M SW May 17, 1960 A. A. GRIFFITH ET AL 2,936,959
JET SUSTAINED AND PROPELLED AIRCRAFT Filed June 7, 1956 6 Sheets-Sheet 4 Inventors SQ-MM W Attorneys May 17, 1960 A. A. GRIFFITH ET AL 2,936,969
JET SUSTAINED AND PROPELLED AIRCRAFT Filed June 7, 1956 SSheets-Sheet 5 Inventors am. M J4 by MM Attorneys May 17, 1960 A. A. GRIFFITH ET AL 2,936,969
JET SUSTAINED AND PROPELLED AIRCRAFT 6 Sheets-Sheet 6 Filed June '7, 1956 l Inventors Attorney s ject from the surface of the aircraft.
2,936,969 JET sUsTAnsED AND PRoPELLEn- AIRCRAFT .man Amai-r Grimm Dern, amr william shaw, Amston,
England, assignorsto Rolls-Royce Limited; Derby, Eng landA Appunti@ June 1., 1956,. serial No. :19941 Claims priority, application Great June 8; 1955:' lvalailllse @21..244-12' This invention.l relates to aircraft., andji's particularly concerned with aircraft of the, type having propulsion "means, preferably including a pluraiity of engines, for use primarily in propelling the aircraft in a forward' di'- rection (such engineswillbe referred@ to hereinafter as propulsion engines)j and' also having a pluralitgofgas turbinejet-propulsion engines; for use primarily in pro t `ducing a vertical thrust. on the. aircraft (the latter engines will7 be referred to hereinafter as'lift engi'ues'). Such aircraft will be referred to as aircraft of the j'etflift type.
I't will beappreciated that the propulsion engines may he arranged so that their lines of thrust may be varied through an acute angle, for example for control' purposes, though in the preferred. arrangement the propulsion engines arev mounted in lixed alignment in the aircraft, and; Alikewise the lines, of thrust ofthe lift. engines may be varied` through an acute angie, for example to provide al forward orv rearward component; of thrust to accelerate or decelerate the aircraft, respectively;
ItJ will also be appreciated that the liftengines Awill normally be used during the talee-off andl atleast the initial phase `of the climb, and during the landing and at least the last phase off the descent of' the aircraft, but will be stopped` during cruising ght.
According to thisinvention, therefore, an aircraft of the jet-lift type includesmeans for starting the lift engines of the aircraft in flight comprising means tocon- 'duet ramair pressurisedhy the forward Hight of the. air,- craft to thecorripressorA intakes of the lift engines to cause theengines to windmillf at such avrotational speed that,
on injectionk and ignition of fuel in their combustion ehmnber's, theL rotation of' the engines becomesfself-sustaining. v
i Preferably the starting means comprises an air intake in the aircraft having closure means to open and close the intake, and which when the intake is closed lie liush with the surface of the body ofthe aircraft, andmeans 3 vwhen theintalre is opened to cause" the airflowing over the aircraft, due to its forward flight to be deected towards the compressor intakes of the lift engi-nes;
i The closure meansv and the deiiector means mayv be i aoi'ded` by varies which are adjustable between a position ini which they lie flush with the surface ofthe body of the aircraft, and aposition in which they form passages between them through which the a-ir flowover the aircraft is"deflected towards the compressor intakes of the liftengincs. In the second position the varies preferably pro- Iri one arrangement iin accordance with this featureof invention, thev vaines are adjustablev from the liush position, through the deilecting position, toa position they form passages: which are. substantially at i right angles to the surface of the aircraft.
The closuremeansmaycomprise a doori ordoors,` which Awhen closed: lie hush with thesurface of the, aircraft, and the deflector means is afforded by vanes which liewithin the, doors when, these arev closed.. Y
"Tn one arrangement in accordance with the invention p 2,936,969 d Patented. kMay LZ, 1960 theV *doorsr move substantially parallel' to the. surface. of
the`aircraft and lie within the skin of the aircraftwheh the intake is opera VIn another arrangement. the. doors may be .hinged adjacent one or both longitudinally-extending. edges :of the intake.v opening, The vnes may het pivoted" to, project through the intakeV opening when the doors arel opened. t
The, vanes may he formed effectively in one, piece,l or
may he formed. with a main portion,Y including the leading edge, which is adjustable between the position in which is lies, liush with the surface, or liesJ within the doorsand' theA position in which it, detl'ects the air towards .the compressor intakes,y and with a trailing portion which is either independently adjustable ork is free to trail in accordance with thegforces exerted, on it by the;v airflow.
Where the .lift engines are angularly adjustable, for example to havetheir upper ends inclined' towards the front ofthe aircraft'to provide a' forward component of thrust rear of the door with anges at the side of the doorclosing thespaces' between the door' and the sides of the airintake opening so that the front ofthe said door forms a forwardly-projecting scoop to takev inaii` owing over theaircra'ft and deflect it dow-n into the compressor intakes of the lift engines arranged under the door.
V"I-he'top of the d'oor'may be formed i-'n part by a series of vanesA preferably on axes lying in the fore-and-aftl; di-
rection whichcan be movedfrom a position inwhich they-lieflush with the surface of' the door to one in which they leave.V openings through the door above the compressor intakesl of thelift engines arranged under the door.
Four* embodiments of' this invention-'willi now be described with;l referenceV to. the accompanying drawings. in
which:v
Figure l is= aplanview of au` aircraft of the iet-lift type, showing one arrangement: oli the invention,
- 'Figure/ is an elevation. of the aircraft of 'Figure l,
Figure 3 is a1section on the'line III-IHA of Figure 1f, Figure/r is a detailf View corresponding to.- Fig-ure; 3, showing the first arrangemennf Figure. 5 is` a ttuef view of the. partsv illust-rated Figure 4, seen from above with thevanes partially c ut away. Figure 61 i's a sectiono n the l'ine. Vit-,VI of Figure. 4, showing parts in one position,
Eigrme 7 isa section on the line-VH--VII of Figure, 4,
' Showing parts in another position.
Figure. 8f is a perspective View of a second arrangement of the invention,l
Figures' 9 to 12.y are diagrammatic views, being vertical longitudinal sections, of. a, third, arrangement of the invention,` w-ithpartsin various: positions, v
' Figure', lf3;y isa perspective View Qfan aircraft of' the j et-V lift type showing yet a dih'crent arrangement of the invention, and;`
' Figure/,SL14 andY 15,-are detail views: on an enlarged scale showing one of the doors illustrated in Figure 13.
Referring nowl to Figures l-ff, there is shown an, aircraft of substantial-ly delta plan form having a small apex angle at the nose, and Athus forming substantially an isosceles triangle. The crew; fuel and equipment are disposed within the bodyl 10,` which also forms a sustaining surface, of lrelatively small area as comparedwit-h presentpractice. There are provided two Ybarrilcsolf propulsionenginesylh one bank adjacent each of the. base angles of they isosceles triangle, and each bank consists of a number of gas-turbine jet-propulsion engines mounted vertically one above the other. 'The banks extend above and below the adjacent part of the aircraft body, as will be seen from IFigure 3,V and have their intakes 12 facing forwards and their exhausts 13 directed rearwardly.
Also mounted within the body of the aircraft are four banks of lift engines 14, the thrust from which sustains the aircraft during take-olf and landingrthe lift engines are gas turbine jet-propulsion engines, and the two forward banks, one on either side of the longitudinal centreline, each contain eight engines in pairs, while the two correspondingly-disposed rear banks each contain ten engines in pairs.
Doors 15 are provided in the underside of the body of the aircraft, which are opened before starting the lift engines, `a pair of doors being shownfor each bank of engines, and an air intake 16 is also provided for each bank of engines -on the top of the body.
One arrangement of air intake in accordance with the invention is shown in greater detail in Figures 4-7, and comprises a series of pivoted vanes 20 which in one position (shown in Figure 6) close olf the intakeV 16 and afford a smooth external surface to the body of the aircraft, and which in another position (shown in Figure 7) afford intake openings 21 which deflect the airstream flowing over the exterior of the aircraft, due to its forward flight, towards the compressor intakes 22 of the lift engines 14.
The pivoted vanes 20 may be moveable to a third position, in which the passages 21 between them extend substantially vertically, for use during the vertical takeoff or landing of the aircraft.
Each of the pivoted vanes 20 is mounted atl its ends by means of pivot pins 23 secured to a thickenedV part 24 of the aircraft structure surrounding the intake opening, and is also supported between its ends by means providing the drive for pivoting the vanes. The aircraft structure is lformed with a number of ribs 25 which extend transversely across the intake opening, and with a beam 26 integral with the ribs and extending fore-andaft of the opening and approximately across its centre. The beam is thicker than the ribs and is hollow to contain the main drive-shaft 27 for pivoting the vanes 2t). This drive shaft is driven, for example, by an electric motor, and rotates each of the vanes 20 about their pivotal axes 28 by means of a worm 29 and worm-wheel 30. The worm 29 (see Figure 6) is keyed to the shaft 27 and is normally held in xed axial relation to the shaft by a spring 31 which has its other abutment 32 also keyed to the shaft and prevented from axial movement by abutting a radial face of a bush 33 in which the shaft is mounted. The worm-wheel 3l) is in splined engagement with the central portion of a bolt 34 which is supported in bushes 35, 36 in a swelling 37 rising from the hollow beam 26 the head 38 of the bolt projecting outside one wall of the swelling 37 and being formed with ears 39 which engage with corresponding slots 40 in a flange 41 on the vane 20, and the threaded end projecting outside the opposite wall of the swelling and passing through another tlange 42 on the vane to engage with a nut 43 which is tightened against the ange and suitably locked. The flanges 41, 42 lie against the walls of the swelling 37 to locate the vane against endwise movement, and the vane is supported by the bolt 34, which is secured to it, resting in the bushes 35, 36 in the swelling 57 on the beam. On rotation of the worm 29, the worm-wheel is rotated to drive the bolt 34 to which it is splined, and thus to rotate the vane 20 about its pivotal axis 28 by means of the ears 39.
The vanes 2i) are so designed that they are capable of being opened to a substantial extent independently of one another, and the arrangement described above provides that, should one of the vanes jam inthe closed position, due for example to being damaged in flight, the drive shaft 27 is not prevented from rotating, but the worm 29 associated with the damaged vane advances along the shaft 27 compressing the spring 31, and the other vanes are opened in substantially the normal way. Thus if there are, say, thirty-two vanes in the intake, its effective area is only reduced by aboutone thirty-second should one vane jam.
.Between the vanes 20 and the compressor intakes 22 there is provided a set of fixed vanes in the form of a grid having thin longitudinal and lateral vertical slats 45, 46 extending across the intake. The grid is supported from the ribs 25, and may be made in sections with the end lateral slats of each section bent over to form flanges 46a (best seen in Figure 7) to locate the sections in position. The xed vanes 45, 46 serve to straighten the ow of air due to the forward motion of the aircraft, which is deilected into the intake by the vanes 20, when these are for example in the position shown in Figure 7, before the air reaches the compressor intakes 22 of the lift engines. v
Another arrangement in accordance with the invention is shown in the perspective view of Figure 8.
In this arrangement a pair of doors 150 are provided which when closed have their external surface ilush with the surface of the body 10 Vof the aircraft, and enclose the vanes 120. l
The doors may be supported by any convenient linkage arrangement, or may be mounted on rollers 151 which run on the ilanges of channel-section members 152 extending peripherally of the body of the aircraft. Further rollers 153 may be provided to co-operate with the webs of members 152 to prevent endwise movement of the doors 150. The doors mayr be actuated by, for example, hydraulic rams 154 anchored to structural members of the aircraft. Two movable vanes are shown, which are pivoted about axes which lie below the doors 150. These vanes may be operated by a ram 155, anchored to aircraft structure, through radius arms 156 and links 157, and may be dimensioned so that they may be pivoted to project through the intake opening when the doors are open. The vanes 120 are shown as each being formed in one piece, that is, each vane pivots as a whole.
In addition a fixed vane 117 is provided, and the vanes 117, 120 together serve to deflect air into the compressor l intakes 22 of the jet lift engines 14 four of which are shown.
The jet lift engines 14 may be mounted, for example on trunnions 118, to pivot about a transverse axis, for example to provide a forward component of thrust during the initial climb of the aircraft. The engines may be rocked about their pivotal axes by a rod 119. In a case such as the above it may be desirable to provide an arrangement such as is shown diagrammatically in Fgures 9-12.
In this arrangement, which is similar to that shown in Figure 8, the aircraft is provided with doors 250 (Figure 10) and the vanes 220 are each formed in two parts 220s, 220b which 'are separately pivotable about a common axis 228. The major part 220a of each vane, which includes the leading edge, is connected to a mechanism such as for example that shown in Figures 4-7 or in Figure 8, to be adjusted about the axis 228. When the doors 250 are open the parts 220a may be pivoted to the position shown in Figure 9 to afford passages 221 between them through which the air is deflected towards the compressor intakes 22 of the lift engines 14, and when the doors are to be closed the parts 220a Will be pivoted to the position shown in Figure 10 in which they lie within,
and clear of the doors in their closed position. A xed vane 217 is also provided at the forward end of the intake opening. y
The jet lift engines are mounted on trunnions 218 adjaagresse cent their. centres of gravity to, pivot. about axes running transversely of the aircraft, and may' be pivoted' so that forward ends are inclined towards, the, front of the aircraft, to give a forward. component of 4thrust to assist, for example, in the climb ofthe aircraft' ('as shown in Figure 1l) or towards the rear of the aircraft, to give a rearward orbraking component of .thrust tov assist, for example, in decelerating the aircraft during its descent (as shown in'- Figure 12). Ifn the former case the trailing parts 22011 of the vanes may be pivoted rearwards,.to be substantially aligned with the axes of the engines, and inthe latter case the trailing parts may be pivcited forwards, so` tha-t the vane has a largevcamber and. the-trailing parts are again aligned with, the axes of ther engines. The trailing parts 220B ofthe vanes may be operated by a. mechanism such as that shownv in Figures 4 7?, or that inFigure 8. i
In a modification, the trailing parts 220b of the vanes may be free to swing, and they will thus take up a position determined by the pressure loads acting on them due to the airow.
In the arrangements shown in Figures 13 to 15 the aircraft 10 is similar to that shown in Figures 1-3 but is provided with doors 311 which cover the openings 312 of intakes 16 in the body above each group of vertical lift engines 14 which discharge downwards through doors 15 on the underside of the body.
The doors 311 have side cheeks 316 in contact with the sides of the openings 312 so that when the doors are raised into the position shown in Figures 13 and 14 there is presented a vertical rectangular forward-pointing opening 317. The doors 311 are preferably hinged adjacent their rear edge.
In addition the doors 311 each have vanes 318 in three series of four, and the vanes 318 are hinged about fore-` and-aft axes to cross members 319 and 320, the members` 320 being formed in the shape of the leading edge of an aerofoil and forming the front of the door.
Any convenient means may be provided for raising the doors from the position which they occupy in Figure 15 to that which they occupy in Figures 13 and 14 and for pivoting the vanes through a right angle vfrom the ush position which they occupy in Figure 13 to that which they occupy in Figures 14 and 15 In normal ight the doors 311 lie flush with the external surface of the aircraft, as shown in Figure 15, but with the vanes 318 flush with the doors as shown in Figure 13.
When it is desired to start the vertical lift engines 14 by ram effect, the doors 311 are raised until they occupy the position shown in Figure 13 (with the vanes 318 in the closed position) and air will be forced under the doors and will enter the compressors of the vertical lift engines.
When the engines have started, the vanes are pivoted to the position shown in Figure 14, which may be considered the normal running position with the aircraft moving forward and the vertical lift engines in operation.
When the aircraft has reduced speed so that the ram eect is no longer important, the doors 311 may be closed to the position shown in Figure 15 which is the position which they occupy for vertical descent and for ground running.
Each of the four arrangements described allows the intakes 16 to be opened and closed, and provides means for deflecting air flowing over the surface of the aircraft, due to its forward speed, towards the compressor intakes 22 of the lift engines 14 without undue loss of ram pressure, so as to cause windmilling of the engines at such a rotational speed that, on injection and ignition of fuel in their combustion chambers, the rotation of the engines becomes self-sustaining. The fuel and ignition systems of the lift engines may be of any known or convenient sort. Thus the lift engines may be stopped and have their intakes 16 and exhaust doors 15 closed during the major part of"A a andi the n'la'yilest'artedi irr this manner before. landing; The inventibn provides arrangements which avoid theK necessity for'eiectr'c starter-motors for the lift engines, or compressed air tappings from the propulsion engines to the lift engines for'sta'rting).
1. aircraft of the jet-lift type having; ar body of aerodynamic sustaining' form carryingr propulsion) engines.
for said; tunnels having means to open and close the int-akte which lie` flush/withsaid surface when the intake closed and means to cause some of the air owing over the aircraft due to its forward ight to be deected toward the lift engine air compressor intakes when the tunnel intake is open to cause the lift engines to windmill at such a rotational speed that, on injection and ignition of fuel the rotation of the engines becomes self-sustaining.
2. An aircraft as claimed in claim 1 in which the closure and deector means are vanes, means mounting said vanes to be adjustable between a position in which they lie ush with the surface of the body of the aircraft, and
, a position in which they form passages between them and direct the airflow over the aircraft towards the compressor intakes of the lift engines.
3. An aircraft as claimed in claim 2 in which the vanes, when ythey act to deect the air towards the compressor intakes of the lift engines have portions which project beyond the surface of the aircraft.
4. An aircraft as claimed in claim 2 in which means is provided to adjust the vanes from the ush position through the deecting position to a position in which they form passages which are substantially at right angles to the surface of the aircraft.
5. An aircraft as claimed in claim 1 in which the clo sure means for the tunnel air intake comprises a door which when closed lies ush with the surface of the aircraft, andthe deector means comprises vanes, and means mounting said vanes to lie within the doors whenthese are closed. n
6. An aircraft according to claim 5 in which means mounts said door to move substantially parallel to the surface of the aircraft and lie within the skin of the aircraft when the intake is open.
7. An aircraft as claimed in claim 5 in which means mounts the vanes to pivot so as to project through the intake opening when the door -is opened. A
8. An aircraft as claimed in claim 2 in which the vanesjare each formed with a main portion, including the leading edge, means to adjust said portion between the position in which it lies within the doors, and the position in which it deects the air towards the compressor intakes, and with a trailing portion, and means to position said trailing portion independently in accordance with the forces exerted on it by the airflow.
9. In an aircraft as claimed in claim 8, transverse pivots for engines, means to angularly adjust said engines about said pivots, and means-insuring the trailing portions of the vanes to be substantially aligned with the longitudinal axis of the engines.
10. An aircraft as claimed in claim 1, a door normally closing said air intake and lying ush with the surface of the aircraft, a hinge at the rear of the door wit-h flanges atv the sides of the door closing the spaces between the door and the sides of the air intake, a hinge for the rear edge of said door, means to raise the front of said door so that the said door forms a forwardly-projecting scoop to take in air flowing over the aircraft and deflect it down into the compressor intakes of the lift engines arranged under the door.
11. An aircraft as claimed inV claim 10, a series of vanes forming in part the top of the door, means to move said vanes from a position in which they lie flush with the surface of the door to one in which they leave openings through the door above the compressor intakes of the lift engines arranged under the door.
12. An aircraft as claimed in `claim 11 in which the vanes are hinged about axes extending in the fore-andaft direction of the aircraft.
13. In an aircraft as claimed in claim 2, a worm and wormwheel device adapted to raise and lower said varies and having a common operating shaft carrying a number of worms each engaging a wormwheel, means connecting Aeach wormwheel to a vane whereby it is raised or lowered,
each worm being axially displaceable on its shaft, a spring biasing said worm against a stop so that in the event of any one or more vanes sticking in the closed S position the reaction between the wormwheel and its worm will cause displacement of the Worm along its shaft against the reaction of its spring, which movement permits the continued turning of the shaft carrying the worms and the operation accordingly of the non-sticking varies.
References Cited in the file of this patent f UNITED STATES PATENTS 2,381,705l Vokes Aug. 7, 1945 2,389,313 Hunter Nov. 20, y1945 2,502,045 Johnson Mar. 28, 1950 '2,567,392 Naught Sept. 11, 1951 2,712,217 Sargent et al. July 5, 1955 2,736,514 Ross Feb. 28, 1956 Pinkos et al. July 17, 1956
US2389313 * Sep 11, 1943 Nov 20, 1945 Goodrich Co B F Shield assembly for air scoops or the like
US2502045 * Apr 10, 1946 Mar 28, 1950 John Johnson Fluid-sustained and fluid-propelled airplane
US2567392 * Jun 28, 1948 Sep 11, 1951 Harold Naught Fluid sustained aircraft
US2712217 * Apr 28, 1950 Jul 5, 1955 Mcdonnell Aircraft Corp Mechanism for reducing the drag of ram jet engines
US2736514 * Mar 9, 1953 Feb 28, 1956 Goodyear Aircraft Corp Convertible aircraft
US2755040 * Oct 10, 1951 Jul 17, 1956 Glenn L Martin Co Air intake system for an aircraft
US2997257 * Jan 5, 1960 Aug 22, 1961 Rolls Royce Aircraft with vertical lift engines and deflecting intakes therefor
US3022026 * Apr 17, 1959 Feb 20, 1962 Power Jets Res & Dev Ltd Air intake for jet sustained aircraft
US3032295 * Sep 18, 1958 May 1, 1962 Bristol Aircraft Ltd Aircraft arranged for vertical take-off and landing
US3037723 * Aug 11, 1960 Jun 5, 1962 Rolls Royce Housings for jet propulsion gas turbine engines
US3043538 * Apr 3, 1961 Jul 10, 1962 Rolls Royce Power plant for use in jet sustained aircraft
US3058691 * Feb 3, 1958 Oct 16, 1962 Snecma Vertical take off composite aircraft
US3074668 * Dec 8, 1959 Jan 22, 1963 Snecma Burner for hot fuel
US3099423 * Oct 2, 1961 Jul 30, 1963 Rolls Royce Vtol aircraft engine inlet structure
US3136500 * Oct 2, 1961 Jun 9, 1964 Rolls Royce Housings for jet propulsion gas turbine engines
US3161374 * Oct 22, 1962 Dec 15, 1964 Boeing Co Vertical lift aircraft
US3177654 * Sep 26, 1961 Apr 13, 1965 Ryan Aeronautical Company Electric aerospace propulsion system
US3249323 * Apr 25, 1962 May 3, 1966 Piasecki Aircraft Corp Closure for vtol aircraft
US3330502 * Sep 17, 1965 Jul 11, 1967 Rolls Royce Aircraft
US3379395 * Aug 9, 1965 Apr 23, 1968 Gene W. Smith V/stol aircraft
US3447761 * Jun 12, 1967 Jun 3, 1969 Boeing Co Supersonic airplane variable-sweep integrated airfoil system
US3519227 * Oct 20, 1967 Jul 7, 1970 Rolls Royce Mounting means for an aircraft engine
US7857253 * Apr 26, 2006 Dec 28, 2010 Urban Aeronautics Ltd. Ducted fan VTOL vehicles
US20160201602 * Jan 14, 2015 Jul 14, 2016 The Boeing Company Methods and apparatus to vary reverse thrust of aircraft engines
WO2002098732A2 * Jun 4, 2002 Dec 12, 2002 Romeo Yankee Ltd. Vehicles particularly useful as vtol vehicles
WO2002098732A3 * Jun 4, 2002 Mar 18, 2004 Romeo Yankee Ltd Vehicles particularly useful as vtol vehicles
U.S. Classification 244/12.3, 244/52, 244/55, 60/228, 244/15
Cooperative Classification B64C29/0075
European Classification B64C29/00B3E