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Aviation History
1960
1960 - 2320.PDF
616 FLIGHT, 14 October I960 D.H. DOVE 8 in the Air ... north at 1,200ft to clear the Hatfield area and made 145kt i.a.s.With max. continuous power of 2,700 r.p.m. and 42in we then climbed at lOOkt and passed 4,000ft with 600ft/min on the v.s.i.At about 5,000ft I flew level and tried stability and control harmonization. The feel was very pleasant, with light forces andgood response. Turns could be made accurately with either rudder or aileron alone and closing of the throttles caused only a gentle,progressive nose-down change. Both trim controls were effective, and exceptionally well-geared and accurate. Rate of roll was ratherslow and I could feel some cable stretch or bracket bending, but there was quite adequate lateral manoeuvrability for all normalpurposes. The Dove felt like a good aeroplane for instrument flying, which some of the American light twins are not. At 7,000ft and about 150kt I closed the throttles and held theDove level. Speed fell off very slowly and a clear buffet appeared at 75kt. At 70kt, the Dove broke slowly downwards in the stall andone wing tended to drop. With stick-back pressure released, the aircraft recovered in a dive and could be levelled out immediately.With 20° of flap the buffet came at 65kt: at 62kt I still had aileron control and we broke into the stall at 60kt and recovered in thedive. 1.3VSL was 95kt i.a.s. with 20° of flap and 84kt with 60°.Flap moved very slowly, so that the trim changes were slow and they were in the expected sense for both flaps and wheels. At 84ktwith some power, wheels and 60° flap down, we went downhill at l,000ft/min in a typical comfortable approach. The 60° settingis best left for the final approach and can produce a precipitate descent with power off, comparable to that of the Cessna range. Still at 7,000ft I set up a 90kt climb at full power with theaircraft clean, and Thornton throttled back the starboard engine, the less favourable single-engined case. Safety speed (1.2 ofminimum control speed) was 84kt in this condition; and at 90kt I found no unexpected characteristics. Control forces were reason-able and there were no sudden lurches. Even at 7,000ft we achieved a climb of about lOOft/iriin and this was greatlyimproved when Thornton later feathered the propeller. At this height we made something over 90kt with 2,400 r.p.m. and 34in;and we reached 105kt with the rated power of 2,800 r.p.m. and 40in. All forces could be trimmed out. Restarting simply involved setting appropriate controls and pressing the feathering button toinitiate unfeathering. We returned to the circuit for two landings. Downwind, Iselected gear and flap at HOkt, made the few remaining settings, and turned on to base leg at 90kt. With power, the approach wasvery comfortable with good visibility, pleasant control and plenty of accurate trim available. The landing was easy to judge andclosing of the throttles during the round-out produced no un- pleasant trim changes. Touch-down itself was simple and well-cushioned. I crossed the hedge at 80kt and rolled for about 600yd without trying to stop short. , I back-tracked for a second take-off and then achieved what isconsidered virtually impossible in a Dove—a swing on take-off. It happened mainly because I was seeing whether the brakes couldhold full throttle, which they virtually did. I let the brakes go suddenly and the swing was rather more a departure in the wrongdirection. I corrected it with brake and asymmetric throttle before the rudder became effective. For the final landing I triedfull flap and no power, waiting till I was sure we must overshoot, but I had to use plenty of power in the end as the 60° of flapproved extremely powerful. Again the landing was uncomplicated. In fact, the Dove 8 is a straightforward aircraft, retaining all itstraditional gentlemanly handling and nice co-ordination. But it now offers higher cruising speed (210 instead of 202 m.p.h.) andbetter single-engined performance than ever before. Furnishings and equipment have been brought up to the latest standards. Themain point seems to be that even a revamped Dove is pleasanter to fly than some of the latest American light twins and still offersunique capacity and sumptuous amenities. de Havilland Dove 8 (two de Havilland Gipsy Queen Series 70 Mk 3 giving 400 h.p. each) Span, 57ft; length, 39ft 3in: wing area, 335sqft; wing loading, 26.71 b/sq ft; tare weight, 6,3251b; gross weight, 8,9501b; power loading, 11.18lb/h.p.; normal usable fuel capacity, 165 Imp gal. Performance: Cruising speed at 60 per cent METO at 8,000ft, 187 m.p.h.; cruising speed at maximum weak mixture power, 210 m.p.h.; s.oa-level rate of climb, 1,135ft/min; single-engined rate of climb, 295ft/min; service ceiling, 21,700ft; take-off distance to 50ft, airline technique, 2,320ft; best performance technique, 1,740ft; landing from 50ft, 1,910ft; best performance technique, 1,800ft; stalling speed, with 60 flap. 74 m.p.h.; range with standard tankage and full airline IFR diversion and stand-off allowances, 550 miles; fuel consumption at 60 per cent power at 8,000ft, 27.6 Imp gal/hr. HILLER 12E in the Air By Mark Lambert No 134 of the Series HILLER have recently introduced two new versions of then-long line of UH-12 helicopters. One is the 12E and theother is its four-seat version, the 12E-4. Last week I was able to fly the 12E three-seater which has spent some time inBritain on a demonstration tour for the British agents, Helicopter Sales Ltd. Even with my slightly limited background of a score of hours onWidgeons and 20min on Sikorsky S-62,1 can see that the 12E is a pretty effective chopper. It has, if anything, a surplus of powerwith its 305 h.p. Lycoming VO-540 engine and nearly all its parts are designed for a 2,500hr major overhaul life. Certain smallparts are scrapped and replaced at 375hr, 650hr and l,150hr intervals, but maintenance has been simplified and reduced asmuch as possible. Much of the structure and transmissions has also been redesigned since earlier versions. In fact the basicairframe is that of the H-23D Raven, for which the US Army demanded an almost unheard-of overhaul life.i A whole range of accessories can be quickly attached to the j. airframe by quick-releases and quick-disconnect couplings. They*~ include hydraulic hoist, agricultural spray-kit, single or twin supplementary fuel tanks, cargo racks or hook and alternativeundercarriages. Other optional extras include dual controls, navi- gation and landing lights and beacon, radios, shoulder harness,"custom" interior, heater and defroster, tinted canopy, air-to- ground loudspeaker and rotor brake. The machine I flew, fromWestland's Battersea Heliport, was registered N5376V and had most of the accessories which might be considered luxury fittings,plus the loudspeaker. The control column handgrip carried an "up-down" switch and cut-out button which, by selecting the; appropriate arming switches under the seat, could be made to serve hoist up and down and guillotine, cargo hook release or spray:'.,.-. on/off and dump. A heel pedal next to the captain's right foot :?f served a mechanical emergency release for the cargo hook and .. r could be operated with full rudder load applied in either directionwithout loss of control. The three occupants sit on a single bench, the pilot in the middle\';.: with his legs astride the instrument pedestal and the pupil or co-pilot on the left. I flew with Hiller pilot Bob Boughton and ourphotographer beside me and found just enough elbow and between-leg room for comfortable control. The great bubblecanopy gave a virtually unrestricted view and afforded space ahead of the pedestal for radio and a bundle of life-jackets. The two all-metal rotor blades are mounted on a tetering headwith a spider for collective pitch-control. Cyclic control is achieved entirely by tilting the whole plane of rotation by altering the pitchof the two paddles. While conferring a good deal of aerodynamic stability, these paddles also contribute something to lift and therecent streamlining of the paddle arms has restored the equivalent of 3 h.p. in drag reduction. Abrasive walk-way paint is appliedas a form of turbulator. Controls are conventional without any boost, weights in thecontrol runs serving as vibration dampers. Hardly any steady loads seemed to be fed back into the control column, but a four-way trimbutton on the stick operated electric motors which positioned the datum of feel bungees. A trigger-like switch activated theintercom, and radio transmission was selected by a switch between the two radio controllers. I prefer the traditional English con-tinuous intercom and single press-to-transmit switch, but the Hiller arrangement is typically American. Standard engine instruments and controls, twinned rotor/enginer.p.m. dial, altimeter and a.s.i. were grouped tidily on the pedestal, together with a fuel gauge in pounds giving a direct indication offuel weight rather than quantity. Starting up was very simple. The rotor began to engage by itselfas soon as the engine ran and warm-up was made at nominal r.p.m. For take-off, the throttle twist-grip was used to speed the systemup to 2,750 r.p.m. with just below 300 rotor r.p.m. After that, the lever remained perfectly co-ordinated with throttle and no furthertwist-grip manipulation was required. This was virtually equiva- lent to the constant-speed transmissions of turbine helicopters andmakes the Hiller an ideal cheap trainer for pilots destined for turbine helicopters. To avoid the "twist-grip happy" approach ofpilots trained on Widgeons, Boughton actually locked the twist- grip when I first flew the Hiller, but I was able to go from full-
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