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Aviation History
1960
1960 - 2321.PDF
PLIGHT, 14 October 1960 'he Hiller 12E Covering in a wintry sunset off ihe riverside pad of Westland's Battersea Heliport 617 power climb straight into autorotation andback into full-power climb using only the lever. After the Widgeon, in which the whole art ofSying is twist-grip and lever matching, this was a blissfully simple procedure. The rotorremained continuously in the operating range of around 360 r.p.m. and it was hardly neces-sary io watch the r.p.m. dial at all. Another happy feature of the Hiller was thattop speed was not limited by blade stall and I could drive it as fast as it would go with nomore than increased vibration to indicate maxi- mum speed. Boughton reached 105 m.p.h.La.s. near Westminster. Blade stall would occur only at 110 m.p.h. at 17,500ft, a theoreti-cal limit which the Hiller cannot in any case reach. At 1,000ft we pulled straight into ahover which I held slightly inaccurately, allow- ing the machine to sink slowly and approachthe vortex ring state of powered vertical descent. When Boughton said we wereapproaching this condition, I remembered Widgeon warnings and immediately pushedforward into translational flight. But Boughton later said that the Hiller 12E could be lifted out of vortex ringsimply by applying plenty of power. We hovered at 1,000ft, inci- dentally, with only 21 in of boost. Another highly satisfying demonstration came when Boughtonhovered a few inches off the Battersea pad and reduced power until he had full collective pitch applied and rotor r.p.m. were justbelow 300, below the normal operating range. We were carrying about two-thirds fuel and three occupants, quite close to full load.Normally, a helicopter would sink to the ground if the rotor was overpitched in this way, but Boughton just turned the throttletwist-grip and hauled us out vertically upwards, with the rotor r.p.m. rapidly increasing. At full load the 12E can be hauledvertically out of overpitching conditions at anything up to 8,000ft. Finally, Boughton showed the 12E's freedom from cross-wind orsideways flying limitations by accelerating sharply to about 50 m.p.h. some 20ft above the Thames and then whistling round ina 360° flat turn, pulling full aft stick as we flew backwards for a brief period. In cruising flight I found the Hiller easy to manage, relativelydisinclined to surge off in one direction or another, and easy to cruise with one finger on the cyclic stick and a toe on onepedal. The lever could be left alone. Noise level was moderately high, as one might expect with the engine a few inches behindone's back, but relatively free from vibration. Directional control was light and very sensitive, but decisively sprung to a centreposition suitable for cruising. There was a distinct break-out threshold.Once the throttle twist-grip was unlocked, it proved to be light and very sensitive, with strong yaw reaction to change of power.The twist-grip really seemed to be a datum adjustment for varying loads or atmospheric conditions and was best left severely alone.Rotation of the twist-grip through a detent uncoupled the throttle All the external accessories clip on to quick-release points beside the engine installation and all pipes and wires have quick attachments. Only the paddles are moved by the cyclic stick to tilt the plane of rotation of the tetering two-blade rotor. Collective pitch changing is by spider in the rotor head "Flight" photographs so that autorotativc flares and landings could be made with theengine idling. In a Widgeon, every autorotational landing must be genuinely "dead stick."I make comparisons with the Widgeon because it is my main source of experience. They are not meant to be in any wayderogatory—the Widgeon is a machine of a different kind, size and vintage and has an established reputation of its own. The 12Eis the equivalent of a general-purpose, three-seat, fixed-wing aircraft—a very versatile one at that—and naturally is a simplemachine to handle on that account. Because of the stick-position changes to be expected betweenhovering and cruising flight in a helicopter, the feel spring datum must be adjustable. I found the four-way switch in the Hillerexcellent, with firm, rapid response, so that a short jab was effective in cancelling any out-of-trim loads either laterally or longitudinally. After swanning up and down and around over the Surrey Docksand waiting for a Widgeon to clear the Pool of London area, I flew back to Battersea and made an approach and landing. I couldcontrol height with the lever and speed with the stick without any juggling or r.p.m. chasing. Rudder movement from cruising tohover was natural and well inside the maximum travel in either direction. I made a slightly messy descent from hover at about10ft, mainly because I did not trim back for a forward e.g. and there was a wind gradient over the pad. At this early stage I stilltend to fly more roughly when actually confined over a fixed pad surrounded by buildings and cranes, but I did get down withoutmaking the marshaller on the ground run for safety. I could watch the skids approaching the concrete and the attitude remainedapparently level and normal throughout the approach and landing. I did not try any quick starts and stops to assess attitude changes inrapid translations. The Americans have a genius for making themselves comfort-able even in such a vehicle as a helicopter which is basically inclined to be noisy, rough and awkward to fly. Floor carpeting,comfortable seats, civilized lap straps and a business-like layout give the 12E a Dleasant and confidence-inspiring atmosphere. Altogether, I found the 12E simple and pleasant to fly, with nonasty corners to avoid. That surplus of power is certainly the great civilizer for helicopters as well as giving really useful high-altitude capability. The 12E has been operated several times with two occupants at over 18,000ft. Optional twin carburetters andhigh-compression pistons could add another 36 h.p. and raise the nresent very respectable hovering ceiling out of ground effect to8.000ft. The development of the four-seat version as a conversion kit for normal 12Es gives some idea of the performance capabilityof the basic version. Personally, I would feel quite happy, after my 40min of general flying, to use the 12E as a personal transportand would have the same confidence in doing so as with the average three- or four-seat executive fixed-wing machine. Hiller UH-12E (one Lycominq VO-540-A1A giving 305 h.p.) Rotor diameter, 35ft Sin; overall length, with rotor fore-and-aft, 40ft B-Jin; empty weight, 1,7001b: useful load, 1,0001b; gross weight, 1,7001b; fuel capacity, 38 Imp qal (80 octane). Performance: Maximum speed at sea level, 95 m.p.h.; maximum range speed, 82 m.p.h.; speed at 75 per cent power, 87 m.p.h.; range at best cruising speed, 185 miles; endurance, V7hr; rate of climb, 1,520ft/min: service ceiling, 15,500ft; hovering ceiling in groundj'effeet, 10,100ft; hovering ceiling out of ground effect, 6,000ft.
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