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Nov. 2, 1965 R Nov. 2, 1965 R. M. sTEFHENS 3,215,366 ROTORCRAFT 5 sheets-Sheet 1 Filed May 16, 1963 NVENTOR Nov. 2, 1965 R. M. STEFHENS 3,215,366 ROTORCRAFT Filed May 16, 1963 5 Sheets-Sheet 2 NVENTOR _(% (er Nov. 2, 1965 ' R. M. STEPHENS 3,215,366 ROTORCRAFT Filed May 16, 1963 5 Sheets-Sheet 3 Nov. 2, 1965 R. M. sTEFHENS 3,215,366 ROTORCRAFT Filed May 16, 1963 5. Sheets-Sheet 4 çº/rzzzzzzzzz!}}}}}}zzzzzzzzz! NVENTOR Nov. 2, 1965 R. M. STEPHENS 3,215,366 ROTORCRAFT Filed May 16, 1963 5. Sheets-Sheet 5 | NVENTOR 3,215,366 United States Patent Office Patented Nov. 2, 1965 2 3,215,366 the turbo-propellers its rotor is then in the unloaded con ROTORCRAFT Robert Melling Stephens, 296 Matheson Ave., Winnipeg, dition, that is, without benefit of power and consequently Manitoba, Canada autorotates, but still contributes 50 percent of the lift. Fided May 16, 1963, Ser. No. 280,804 Autorotation occurs because of a natural imbalance of 11 Claims. (C. 244-7) drag between the advancing and retreating blades in trans At the present time the only aircraft capable of operat lational flight. The retreating blade having its back to ing city-center to city-center in the short haul range, e.g., the wind, so to speak, has the greater drag. With the 200 to 300 miles, is the helicopter. Its relatively low four-bladed rotor of the second embodiment of present speed of 175 miles per hour coupled with a high passenger invention this condition still exists but to a much smaller mile operating cost are its chief drawbacks. In 1957 the O degree, by design generating just enough centrifugal force Fairy “Rotordyne” which operated somewhat along heli in the unloaded condition to counteract blade flutter. copter lines underwent a series of tests. It was designed However, with the two-bladed rotor of the first embodi to remedy particularly the high passenger-mile operating ment having a wider chord and greater depth there is cost of the helicopter, which it did very successfully but greater rigidity in the blades and the necessity to auto brought in its wake its own problems, chiefly noise, hot 15 rotate when in the unloaded condition is absent. In trans oil splattering and excessive vibration. These difficulties lational flight the rotor would be halted and secured in were never fully overcome and it was finally abandoned the transverse position lying directly above the fixed wings in 1962. and so becomes a secondary airfoil. The distinguishing Conventional high speed fixed wing airliners require design feature of the blades is that the upper surface is for take-off a mile-long runway, which is not available 20 highly cambered and symmetrical and thus generates lift in city-center; and if vertical-take-off-and-landing (VTOL) consequent upon air flow from either direction whether characteristics could be given to this type of aircraft, such rotating or locked. This is a unique feature basic to the improvement would be without parallel in the history of invention and is believed to represent a new concept in aviation. rotor design. With a conventional airfoil profile, for It is in this short-haul 250-mile range that the type of 25 instance, and with the blades locked in the transverse posi aircraft like the Vickers “Viscount” propelled by turbo tion, one blade would provide lift while the opposite blade prop engines finds its niche, and while its speed is no would record a negative lift force. match for the turbo-jet it has a cruising speed 2/2 times It should be noted that the blades in all embodiments that of the helicopter including the Fairy “Rotordyne.' herein described have their chord line in line with the Its lower wing loading compared with turbo-jet would be 30 plane of rotation, consequently have in themselves no of great assistance if VTOL characteristics could be ap angle of attack, yet create lift. This lift is further in plied. creased and uniformly so on all blades operating in trans Present invention seeks to retain all the advantages of lational flight by giving a fixed angular elevation to the this turbo-prop aircraft and couple with it VTOL charac plane of rotation at the pylon to the same degree possessed teristics. In appearance however the type of craft in 35 by the lower fixed wing, possibly 3 degrees. At this angle vented resembles the Fairy “Rotordyne” which incidentally the lift on this type of blade is considerably enhanced and is different from the helicopter only in that the Rotordyne the high drag on the blades somewhat compensated, with has in addition a fixed wing of short span in the high wing the rate of autorotation being regulated by the design of position carrying half the total load, while the other half the lower camber. In the embodiment having the four is carried by the rotor. On the other hand a helicopter 40 bladed rotor the lower blade contour will resemble the rotor carries all the load all the time. lower surface of the standard wing profile N.A.C.A. 23012 In the present invention the fixed wing is dimensioned while the two-bladed rotor, likewise a three-bladed rotor, to carry approximately 90 percent of the load and its if used, would have its lower surface flat except at the rotor the 10 percent balance. The percentages relate of nose and trailing edge which would be rounded off. The course to translational (forward) flight at cruising speed, 45 lower surface of the N.A.C.A. 23012 is unsymmetrical while in vertical-take-off as in landing the rotors would and the drag on it would be slightly greater when its sustain all the load. The difference between the rotor of back was to the wind, consequently would autorotate the Rotordyne and the present invention is one of function slightly when unloaded. as well as design, and as a contingent consequence the With the Fairy “Rotordyne” means were incorporated aircraft requires a change in configuration from the high 50 to obtain collective adjustable pitch whereby all four wing position of the Rotordyne to the low wing position, blades could be given a uniform angle of attack which for reasons to be explained later. in the VTOL regime provided equal lift on all four blades. At this angle the blades of the 90-foot diameter rotor have The Rotordyne acquired its excellent VTOL character a co-efficient-of-lift maximum of 1.4 and at maximum istics by means of a fuel-fired jet at the tip of its enormous 55 revolutions provided a rate of climb of 1600 feet per 90-foot diameter four-bladed rotor. These are the tip jets minute. responsible for the hot oil splattering; and being located With the present invention no such manipulation is right at the wing tip, some of the fuel escapes unburnt. necessary, the blades deriving their great lift by an entirely They were also responsible in operation for most of the different principle to be explained later. From 5 to 7 noise. These jets were Supplied with highly compressed 60 times more lift per square foot of blade area can be air ducted from a pair of turbo-prop engines located out generated depending on the mass of compressed air made board under the fixed wings of the aircraft astride the available for ejection at the trailing edge. Obviously fuselage. under proposed regime a much smaller diameter rotor is In cruising flight the Rotordyne being driven solely by needed for the same lift, with all the accruing advantages. 3,215,366 3. 4. The two blades of the rotor of this invention as depicted coming slipstream below, reversing the natural flow at in the first embodiment are divided chordwise into a front the trailing edge. With this modification and the use of portion and a rear portion. The rear portion receives this cold air instead of hot exhaust a C max. 7.5 could be compressed cold air ducted via the pylon from the turbo anticipated. The type of slit illustrated in 2.13b of course prop compressor located on the wings and because of the was devised to produce the required lift without the un high pressure involved must be contained within ducts desirable forward thrust previously mentioned when as having a cylindrical form, from which it is ejected through sociated with the fixed wing but this would be no detri a series of narrow slits at intervals running the length of ment to a rotating blade, consequently the arrangement the blade adjacent to the trailing edge, as well as from illustrated in 2.13a or a compromise with 2.13b would a jet at the tip of the blade. O lend itself to better advantage provided the jet on the The front portion of the blade forms a series of longi underside were moved forward sufficient to bring the tudinal ducts along which flows the large mass of ambient center of pressure (lift) midway of the chord. If this is air entering at the top of the camber at the hub to be not done the blade will twist and the lift will be greatly centrifuged by the rotation of the blades then, heated and lessened. It will also be necessary to vary the angle of exhausted at the tip to provide propulsion. The com 5 the jet sheet in accordance with the variation in velocities bustion chambers are placed at a distance of 3 feet ap as they exist from the root to the tip of the blade as it proximately from the tip of the blade to ensure that the rotates.
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