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Aviation History
1962
1962 - 2206.PDF
FLIGHT International, 27 September 1962 Much more information is now available on the Ryan VZ-II than could be included in the cutaway drawing (from the same aspect) published in our issue of December 21, 1961. A, nose-fan inlet louvres; 6, nose fan; C, nose-fan reverser doors; D, zero/zero ejection seats; E, conventional control column; F, lift control lever; G, hydraulic com partment; H, electrics compartment; J, fuel tanks; K, bifurcated intake; L, cross-over duct; M. nose-fan supply duct; N, main fan closure; O, exit-louvre actuator; P, two-position landing gear; Q, flap; R, aileron; S, jetpipes; T, thrust spoilers; U, lift fan; V, variable-incidence tailplane; W, elevators; X, rudder; Y, ]SS engines, Z diverter valve figurations claimed to be capable of installation within wings of only 5 per cent t/c ratio. Beneath each fan is a series of 13 spanwise exit louvres, which are ganged together and driven by tandem actuators in separate hydraulic systems energized by pumps on both engines. The pilot has a lift lever, operated like the collective-pitch of a helicopter, with which he positions the louvres. With the lever fully down they are almost shut, but raising the lever rotates them progressively towards the vertical position. When the lift exceeds the weight the VZ-11 rises vertically. Hovering roll control at up to 30°/sec is obtained by conventional sideways movement of the control column, which opens the louvres further on one side and partially closes them on the other. Yaw at up to 50°/sec is obtained from the rudder pedals by deflecting the louvres forwards beneath one wing and aft beneath the other. For transition to wing-supported flight, the pilot moves a small thumb wheel on his control column which progressively turns all louvres to the rear to accelerate the aircraft forwards. The undercarriage is retracted at a height of about 70ft without changing trim and, when forward speed reaches 120kt with exit louvres fully deflected, the diverter valves are actuated and the inlet and exit doors shut. For landing, the aircraft is throttled back and the flaps and under carriage are lowered. When a trimmed condition is achieved at about 150kt at a height of 100ft, the inlet doors and exit louvres are automatically opened by the actuation of the diverter-valve control, and the engine throttles are gradually advanced to main tain altitude. The fan exit louvres are steadily turned to minus 10° to bring airspeed almost back to zero, and the approach takes place nearly vertically, at a sink of approximately 4ft/sec in a level attitude. The final gentle flare is accomplished with the lift control, so that the aircraft touches at almost zero sinking speed. In all phases of flight, control in the pitching plane is accom plished by the X376 nose fan, Which is a smaller version of the X353 fans and takes 10.5 per cent of the gas available from the engines. Its intake is normally shut by narrow longitudinal doors Which do not restrict pilot view when open. The efflux from the nose fan passes downwards, the middle portion escaping between the large doors C. These doors, which form part of the nose profile when closed, are curved to deflect the discharged air. When the pilot's control column is fully forward, the doors are rotated so that they catch all the air from the nose fan and discharge it out wards and slightly upwards to give a net downward force of 801b. With the stick fully aft, the doors are rotated outwards so that nearly all the air passes between them, resulting in a net upward thrust of 3001b. Maximum angular movement of the VZ-11 in the pitching plane is 20°/sec. Thrust spoilers are provided behind the engine jetpipes so that the engines may be run up to military power with the aircraft at rest before operating the diverter valve. This is even more important during the transition from forward flight, for the loss of one-quarter of the lift when the fan doors open must be made good at the earliest possible moment. Movement of the diverter valve takes 0.5sec, and with the engines at full power the lift fans spin-up to full r.p.m. in 2.5sec. The lift fans are handed to rotate in opposite directions, to eliminate any resultant gyroscopic couple. Prime contract for the VZ-11 is held by General Electric, who are supplying the lift and propulsion systems and will manage the research programme under contract to the US Army Transportation Research Command at Fort Eustis, Virginia. They have subcon tracted the design, construction and basic flight testing of the aircraft to Ryan Aeronautical Company at San Diego, California. The first of two flight specimens is scheduled to fly next June. A fortnight ago Ryan announced that they had been authorized by General Electric to proceed with Phase 2 of the programme. This authorization, originating from the Army's Transportation Research Command, releases the remaining $3.6m of the original $ 10.5m funding for the prime contract. Under Phase 2, Ryan will receive an estimated $1 in addition to the $3.5m allotted under Phase 1.
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