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Aviation History
1962
1962 - 0727.PDF
725 FLIGHT International, JO May 1962 The fourth Astazou-powered SFERMA Marquis, a frequent and impressive demonstrator reduced pitch to 3° at 100 m.p.h. and the engine acted as a powerful dive-brake, allowing us to descend at between 3,000 and 4,000ft/ min with the v.s.i. right round the clock and almost back to zero again. This makes possible an astonishingly steep approach or dive into some narrow valley. Because movement of the pitch lever altered not r.p.m., but pitch and fuel input, engine power could be abruptly changed without fear of surging. An ultimate j.p.t. limit will automatically reduce power if maximum temperature is reached. Having lost height in that plunging negative-thrust descent, Bohme lowered flap and flew slowly along an autobahn. The cars below went scooting past us, the drivers staring at this aircraft which was moving so much more slowly than they. Next Bohme pushed the automatic full-power button so that we soared up again, then tripped the automatic regime by touching the pitch lever, levelled off and increased pitch to set cruising power for the return to the airfield. The landing was really a demonstration of all the Astazou's remarkable characteristics. Bohme reduced pitch and lowered flap and then dived down with reverse thrust into a very steep approach at 60 m.p.h. At the last moment he rotated into the three-point attitude, set the machine down on the taxiway and pulled the pitch lever instantly past its zero stop, through a gate into reverse pitch, applying full wheelbrakes at the same time. A Tiger Moth in a 20kt wind could not have stopped more quickly. I estimated the run as about one Porter fuselage-length, and there was perhaps a lOkt wind blowing. I asked Bohme afterwards how he felt about the Astazou—what about electrical failure and manual control of the engine, for instance? He was obviously extremely pleased with the engine. He had begun, he said, by doubting the reliability of the engine control. He had closely examined and questioned Turbomeca about what to do if one part or another failed: the prospect worried him. Now, after several years, he had never experienced the slightest trouble. He had complete confidence in the system and was tremendously enthusiastic about the potentialities of such an engine in a utility aircraft like the Porter. The first cost of the engine/propeller com bination was high by piston-engine standards, but that was about the only drawback. Turbomeca and Rat'er now offer three dif ferent reduction ratios and a variety of different propellers. For emergencies, Pilatus have provided propeller-pitch override buttons next to the torque gauge so that, should normal pitch control fail, the pilot can set a pitch which will give him a power range to allow him to complete the journey and mak. .. comfortable landing. Another switch is provided to isolate all non-engine electrics and connect the battery directly to the engine. The auto matic system can be completely switched off and manual control attempted. Somehow there is always enough left to give the pilot time to think and to look for a suitable landing place, but the failures have to be drastic or multiple before this extreme is reached. Bohme was not concerned. Potez Heinkel CM.191 There must be some speculation about the sales possibilities of a four-seat, twin-jet executive aircraft. Those who can afford such an aircraft generally also require some thing rather more airliner-like in cabins—pilots isolated in an office up front, a toilet for the executives, and so on. It is hardly surprising therefore that Potez and Heinkel, who were jointly responsible for the CM.191 conversion of the Magister trainer, seem to be looking mainly to military outlets for their new venture. There are never theless some attractive points. The Magister has provided a background of manufacturing and operational experience and a potential pool of spares which will do much to reduce the cost and difficulty of buying and running an aircraft of this type. Its possible applications are also fairly wide, particularly if it is sold to an air force as a general trainer and command transport. The prototype, with the dual registration D-9504 and D-IHAM, had flown some 35hr by the time it reached Hanover and, being subject jointly to French and German airworthiness regulations, was limited to two occupants and a maximum i.a.s. of 250kt. The front two seats and instrument panel were of strictly functional, Preparing to board the Turbo-Porter for the remarkable demonstration fight described in these columns ••>:••• :i;:SSN*:-:>M-v
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