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Aviation History
1961
1961 - 0821.PDF
GHT, 15 /wne 1961 831 80 per cent (the gauge was marked in this way) instead of itsa-, -age powered 90 per cent. Having shown the propensity to w;. ider directionally, Newton engaged a directional autostabilizer wl ;h "nailed" the Huskie to a heading regardless of bank.A; ilication of bank in fact simply caused a side-slip and a good de ; of rudder, ahead of bank, had to be applied to force the auto-st;1 lilizer round onto a new heading. /ith directional autostabilizer and the gadgets at the tail, theK; nan is really pleasant to fly and Newton said he had done fixed- wi::g type GCAs right down to the ground. The wheel under- ca. iage is suitable for run-on landings at up to lOOkt and the metalpavs surrounding the wheels allow the helicopter to remain sur- faced in marshy ground where a man would sink in. At 70kt,Nc-vton cut power, reduced collective pitch and made what was virtually a fixed-wing approach, round-out and float, applyingpower again just as we were about to land in a field. Normally thi re is enough energy in the rotor for a comfortable zero-speedtouchdown without power. When I took over I found the Huskie very heavy to fly, withsome feed-back from the rotor and quite heavy spring feel. Trim adjustment was needed after changing attitude. I also saw how themachine was inclined to wander directionally, but had no great trouble keeping it straight. It was a gentlemanly wander. Withstabilization, a good hoof of rudder put it into a steady turn. I speeded up to lOOkt by leaning the Huskie forward and pullingincreasing power. It became directionally a great deal more sensitive and felt as if it were working pretty hard. Kaman aregoing to put in unduplicated power boost to hide some of the feed-back. Duplication will not be necessary because manualcontrol is straightforward. In a normally fully powered machine, manual control after hydraulic failure can be extremely heavy workand it may even be impossible to hover. The larger Sikorsky types, of course, have dual systems with full safety and no manualreversion. The Huskie has been very carefully laid out for rescue work inaccordance with the lessons learned in Korea by the US Marines. It should be very good at its job, and is certainly easy and forgivingto fly. The penalties of once-per-rev vibration and heaviness are not too high a price to pay for the very good qualities of themachine for its specialized role. My last type was the Alouette III, which differed basically from theothers in having a fixed-shaft turbine and rotor rotation in the opposite sense to that employed by Bell, Hiller and Sikorsky. Themachine I flew was the one that had made the impressive landings DATA Agusta Bell 2MB (D.H. Gnome giving 1,000 h.p.): Rotor diameter, 44ft; empty J*le'ght, 4,2801b; maximum gross weight, 8,5001b; maximum speed, 147 m.p.h.; "Bering ceiling in ground effect, 9,200ft; range, 250 miles. Kaman H-43B Huskie (Lycoming T53LI giving 850 h.p., limited to 725 h.p.): Jo.or diameter, 47ft; empty weight, 4,5001b; gross weight, 9,1501b; cruising speed, *2 Ti.p.h.; maximum speed, 129 m.p.h.; service ceiling, 25,700ft; range, 210 miles. •jurf Alouette III (Turbomeca Artouste 3B giving 880 h.p., limited to 550 h.p.): Rotor diameter, 36ft; empty weight, 2,3001b; gross weight, 4,1901b; cruising speed, '18 im.p.h.; hovering ceiling out of ground effect, 13,100ft; range, 345 miles. at 19,700ft in the Himalayas last November. The Alouette's three-blade rotor turns at a very fast 360 r.p.m. directly coupled to the governed engine, and power-demand controls fuel input. Powerindication for the pilot is by an instrument sensing collective pitch and Sud had devised a very cunning method of judging the weightof the helicopter and the power margin remaining for manoeuvre. The collective pitch corresponding to maximum usable enginepower at sea level is 7.5 and this rises to something over 10 at maximum height. A white segment next to the pitch scale on theinstrument accordingly shows the heights opposite the appropriate maximum collective pitch. While this forms a rough guide, actualdensity taken from altimeter and o.a.t. gauge can be set on a small rotary computer round the instrument rim against the pitch settingwhich the pilot finds necessary to hover. The pitch required and the density will, because of the constant-speeding rotor, define theweight of the helicopter. The pilot can therefore allow people to load the cabin indiscriminately and lift off every now and then tocheck his gross weight. In addition he can hover, assess the weight, and also read from the computer the pitch margin he has left formanoeuvre. Brief pressure of one finger is required to rotate the computer ring and the collective pitch is stable enough for briefhands-off hovering. So the pilot can accurately predict his per- formance in a tricky location, regardless of fuel state or otherfactors. He can also predict his performance at a greater altitude by reference to the scales. Sud stressed that, during operations inhigh mountains, this is a most valuable adjunct, because clients are rarely able or willing to weigh their freight before loading. The Artouste 3 turbine gives 880 h.p., but only 550 h.p. is usedand this power can be retained up to 16,400ft. Blade stall limits flying at full gross weight to heights below 13,800ft. In sea-leveloperation the r.p.m. remain remarkably constant, even during rough applications of full collective pitch at the hover and duringreally steep turns at top speed. I was flying with Sud pilot D. Prost, who really threw the Alouette around demonstrating its remarkableagility. I flew with a great deal more circumspection, but I liked the machine better than any of the others. Both cyclic and collectivecontrols were fully powered, but there was an almost ideal com- bination of response and lightness with slight break-out force. Iwas very much on guard against applying wrong rudder, in view of the opposite rotation of the rotor, but when I brought theAlouette to the hover I really could not tell in which direction I had to apply rudder, even though I sat and thought about it. Pedalmovement was very small and force imperceptible. During the cruise at about 150km/hr (93 m.p.h.) I needed a good deep push ofright foot to keep straight, but in the hover the pedals were virtually centred. Visibility through the wide, near-bubble nose was excellent. Ihad the impression that fore-and-aft attitude changes with changes in speed were fairly high. Because the machine was barely furnished,noise level was high and composed quite distinctly of turbine scream, rotor roar and airstream noise. Normal cruising speed wasstated to be 190 to 200km/hr (118 to 124 m.p.h.), which is pretty fast. At such speeds, the Alouette was not especially noisier andcertainly performed remarkably well, even in high-g manoeuvres. Noise would be a problem for people working near Alouettes andI notice that the British Army and other operators use ear pro- tectors. Otherwise the Alouette is stimulating to fly and is as muchlike a fighter as the Huskie is like a bomber. Incidentally, 1 know of no other helicopter, even in the constant-speeding brigade, whichactually has no twist-grip on the collective lever. The Alouette has a rather smooth, shaped hand-grip. The closing incident in this helicopter trilogy was Prost's returnto base in the fringe of a corking rain storm while the Hunter Two-Seater was demonstrating and the tower had forbidden otheraircraft to fly. He just sneaked in over the hangars, whirled round in a steep turn and put down right amongst the airliners. Quicklyhe taxied through a narrow gap and stopped in the hangar mouth. We were pushed into the back of the hangar before we had got outof the cabin. Those Sud pilots know their aircraft and their airfield—and the controllers—like the backs of their hands. The Alouette III prototype flown by the author seen, left, up in the Hima- layas and, right, flying more normally over France
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