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Aviation History
1951
1951 - 1172.PDF
22 June 1951 727 Another interesting type, to be found tucked away in a comer of the Grand Palais, is a home-made machine designated the Cantinieau-Betemps. It is a single-seat model with a piston- engine—mounted above the pilot's head—driving a conventional three-blade rotor. Its designer, M. Jean Cantinieau, told us that during the first flight, which has just been made, it performed very happily and was remarkably free from vibration. Its construction was achieved, entirely without outside financial assistance, by members of the Helicopter Society of France, of which M. Betemps (who assisted in the work) is the President. Other helicopters on show include the Bristol 171 Mark III (noted for its pleasant handling characteristics) and a model of the 10/13-passenger 173 twin-rotor type, which is expected to fly shortly. Shown by its French licencee, and adapted with a special skid undercarriage of alloy tubing, is the standard Bell 47 D-i agricultural type. Three models are exhibited of the S.N.C.A.S.E. 3120 general utility three-seater with a single rotor of three folding blades; it can be used for passenger, ambulance or agricultural duties. In this design the rotor is automatically disengaged by the centrifugal clutch in the event of engine failure. At the time of our inspection, last week-end, there appeared to be no sign of the Breguet 11E, either in model or photographic form. Power Units V^HILE the Salon places severe limitations upon what (unless "he resorts to models) the aircraft manufacturer can exhibit, power units can, on the other hand, be displayed to advantage; and, as has been the case for many shows past, Britain excels in this department. Last week we mentioned all the important engine exhibits from our own industry; the fact that we now write proportionately more about some of the French engines therefore requires no explanation. First, however, we must refer to the Rolls-Royce Avon upon the occasion of its public introduction, when thrust and consumption figures were given as 6,500 lb (2,950 kg) and 0.865 lb/hr/lb respectively. Constructional details of the Avon are still secret, but certain externally obvious features could be examined for the first time. For example, no fewer than eight blow-off valves are fitted around the axial compressor casing, and these are linked with a pneumatic ram which controls the pitch of the first row of static blades or guide vanes to be seen in the intake. This arrangement presumably has an important bearing upon high-altitude performance for which the Avon is especially noted. The "bullet" ahead of the front bearing contains the gas starter, and the supporting struts in the intake are attached tangentially to permit expansion. No new information was released about other important units, such as the Armstrong Siddeley Sapphire or Double Mamba, although the French have confirmed their interest in the latter unit for both military and civil applications. A word of praise must be accorded here to the wonderfully sectioned Bristol units, in particular the Proteus. We have never seen a more remarkable engine exhibit. Also worthy of high praise is the United Aircraft Corporation's sectioned Pratt and Whitney Wasp Major. Contrasting in appear- ance (though not in quality) with this huge and complicated piston-engine is the sectioned D.H. Ghost as for the Comet. In this unit the rugged simplicity of the high-powered centrifugal turbojet with single-sided impeller is conspicuously revealed. It is never easy to assess the progress or value, other than for research and experience, of the remarkable gas-turbine units which are produced in France. There is no doubt, however, that the Hispano-Suiza/Rolls-Royce licensing agreement is working excellently, and that the French company has done a fine job with Nene production (now understood to have run into hundreds), with the Tay, and with the design of afterburners for these turbo- iets. When the Tay is compared with the Nene beside it, the many differences are at once apparent. For example, though identical in layout and in overall diameter, the Tay has very different combustion chambers and a larger-diameter turbine. The afterburner exhibited and illustrated here is Hispano's own work. It is fitted with a two-position variable-area jet nozzle, operated by pneumatic rams. The upper and lower hinges are so arranged as to preserve a trulv circular outlet in either position. A rather shorter afterburner of greater diameter is bein? prepared for the Ouragan. Power increase at ground level, static, in both versions will be 30 per cent and at altitude and a representative speed 50 per cent, with specific consumption of 1.95 kg/hr/kg. Power loss due to pressure drop does not exceed 4 per cent, and the maximum power figure auoted is 6,500 lb (2,0,50 kg). An all-French axial unit of striking appearance is the Atar 101F with afterburner—a S.N.E.C.M.A. project of 35 in (886 mm) diameter, immense length and rated at 8,800 lb (4,000 kg) maxi- mum thrust. Three variants have been designed, the basic 101 with seven-stage axial-compressor (4.*;: 1 compression ratio) and annular combustion chamber; the 101E with water injection pro- vided for, and the 101F with afterburning as well. The Atar 101 has passed some official test runs and a version is to fly in an Salmson's nine-cylinder 200 h.p. helicopter unit with fan cooling is known as the Model 9NH. The weight is 360 Ib. Ouragan at the display on July 1st. Production has been ordered. Normal take-off thrust is 6,170 lb (2,800 kg) and for maximum cruising it is 5,000 lb (2,300 kg) with specific consumption of 1 kg/hr/kg. The same constructional group S.N.E.C.M.A., again exhibit their slim, attractive turboprop, the TB.1000 of 1,450 s.h.p., and mention is made of the 1000A giving 2,000 s.h.p. for take off. However, these units are still in the development stage. The 14X, a small two-row radial, is in the 800 h.p. class and both civil and military versions, differing in altitude rating, are to be produced. In the very-small-turbine field Turbomeca have a whole series of unique little units which demonstrate the possibilities of per- fecting a simple design and then scaling it up (or presumably down within limits). The company's 200 lb (100kg) thrust Pime'ne' is becoming well known, while later units—the 330 lb (150 kg) Palas and the Marbore 1 and 2 of 660 lb (300 kg) and 840 lb (380 kg) thrust respectively, have each completed successfully some hun- dreds of hours of running. The little Pimene1 is, of course, flying in several primary and lately, auxiliary power unit applications. Its specific consumption is 1.08 kg/hr/kg. Sharing basic design, features, but having "double-flux" or secondary, by-passed air flow is the 485 lb (220 kg) Aspin 1. And, related again, are the two turboprops—the 160 h.p. Oredon and 275 h.p. Artouste—and, finally, several auxiliary groups for pres- surization and so on, among them the Pimedon and Palouste. Few of the smaller piston-engines shown in Paris are new, although Salmson's 200 h.p. nine-cylinder radial for helicopters is an exception. This is designed for vertical mounting, and has fan cooling. Blackburns, of course, show the 185 h.p. Cirrus Bombar- dier, which in some installations—the Skeeter, for example—is to do similar work to that of the Salmson. The Bombardier 702 has S.U. fuel-injection and tidied-up accessories. It is approved with Rotol C.S. airscrew. Potez and Minie again show a large variety of units, and once more, apparently unchanged, the ingenious one-off Lutetia 6-cylinder 12-piston radial appears. Certain unconventional units are to be found in the Salon, although little information is forthcoming about them. For example, among the Arsenal exhibits (incidentally, the vast French- built Jumo and 24H units are again displayed but are more of academic and shipping interest) is a V.i-like pulse-jet giving 330/420 lb (150/190 kg) thrust, and a "stato-propulseur"—an athodyd of just under 20 in (500 mm) diameter and to give 1,100 lb (500 kg) thrust at 620 m.p.h. (1,000 km/hr). It comprises the shaped duct and a grid carrying twelve sprays or burners. Last to be mentioned among the unconventional jets, but by right first in the interest it has caused, is the Escopette (S.N.E.C.M.A.), an auxiliary pulse-jet with no moving parts, baffling in detail of operation and resembling a combination of organ pipe and walking-stick. Readers will recall earlier references to the Escopette when examples first flew in the Emouchet glider. The weight of the equipment and mounting complete is 11.2 1b (5.1 kg), and the maximum thrust 22 lb (10 kg), although up to 40 lb (18 kg) have been produced with improved materials. According to the fuel-delivery pressure, thrust and specific consumption vary between 6.5 and 22 lb, and 2 and 5.5. grm/kg/sec respectively. Starting is automatic with the aid of a miniature sparking-plug. Diameter and length are respectively 6.18 in (157 mm) and 113.3 in (2,880 mm). Much of the duct behind the combustion chamber operates at red heat, and the frequency of combustion is 100 impulses/sec (compared with 40 impulses/sec for a V.i). Needless to say, the resultant noise is tremendous.
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