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Aviation History
1960
1960 - 0370.PDF
Aero Engines 1960 D.H. Gnome P.1000 Free-turbine turboprop. Ten- scage compressor with variable-incidence inlet guide vanes and first three stators, annular combustion chamber with 16 burners, two-stage compressor turbine, independent single-stage power, turbine driving through rear reduction gear, high-speed top shaft and front reduction gear to suit propeller speeds from 1,245 to 1,550 r.p.m. Overall length, 87.3in; height, 31.55in; width, 17in; dry weight, with starter and accessories, 555lb; mass flow, 12.4lb/sec; pressure ratio, 8.3:1; max rating (5 min.), 1,000 s.h.p.+144lb thrust at 26.260 r.p.m. (20,000 power-turbine r.p.m.) with s.f.c. of 0.669lb/hr/s.h.p.; recommended cruise, 800 s.h.p.+120lb at 25,120/ 17,000 r.p.m. with s.f.c. of 0.728; the P.1200 wilt have corresponding ratings of 1,150 and 900 s.h.p. with sf.c. of 0.657 and 0.71. that of the aircraft with the next best system of propulsion (pure turbojet). Bristol Siddeley are also paying great attention to air-breathing engines intended for Mach numbers con- siderably greater than 3, and have published design studies for hypersonic ramjets of both the internal and external variety. D.H. ENGINES The de Havilhmd Engine Co Ltd, Leauesden, Herts. In our 1959 review we opened with the words "Since our last engine review issue the character of this company has changed markedly." Today this is even more true, since the worth of D.H. Holdings has been purchased by the Hawker Siddeley Group, making D.H. Engines the only wholly owned powerplant firm of one of the two giant groups of die realigned British aircraft industry. Substantial business is likely to accrue from the company's purchase of a licence to manu- facture and develop the T58 turboshaft engine from International General Electric, and the resulting Gnome is described above. Various types of Gyron Junior turbojet are under development, or nearing production. Manu- D.H. Gyron Junior DGJ.I Nk 161 Single-shaft turbojet. Eight-stage compressor with variable inlet guide vanes and first stator stage, annular combustion chamber with 13 upstream burners, annular air- bleed manifold for flap-blowing, and two-stage turbine. Intake diameter, 26.4in; overall diameter at bleed manifold, 34.4in; overall length as depicted, 128.7in; max rating, 7,1001b; other details dauified. D.H. Gyron Junior DGJ.I OR Supersonic turbojet with high-augmentation afterburner. Configuration at for DGJ.2, with deletion of bleed manifold and addition of fully-variable afterburner and nozzle system; overall diameter of engine, 32.3in; diameter of afterburner, 36in: length, 191 in without intake bullet; max rating, 10,0001b (14,0001b with reheat). 370 facture of centrifugal turbojets has finished, but spares are being made for the thousands in service. Development of Gipsy piston engines is concentrated on the Major, in pro- duction as the Mk 140 for Army Skeeters and available in Mk 215 turbosupercharged form. Small batches are in production, together with a few Queen 30 Mk 2s (overhaul life 1,600 hr on trial to 1,800/ and Queen 70 Mk 2s (over- haul life l,000hr, on trial to 1,200). No air- craft-propulsion applications remain for the company's extensive range of rocket motors, although the Spectre 4 is in production for the RDS.15 a.t.o. unit for the Victor, the Super Sprite a.t.o. pack is nearing the end of its production run for the Valiant and a num- ber of RDS.33 Double Spectre powerplanrs have been produced for the first type of Avro Blue Steel. Registered HQ are at Leavesden, near Watford, where are located the Business, Pro- duction and Industrial Products divisions. At Stag Lane, Edgware, are based the Engineer- ing and Rocket divisions, Nuclear Power Group and the development and production test of piston engines. The flight test installa- tion department is at Hatfield, together with the Halford gas-dynamics laboratory and the development and production beds for gas turbines and rockets. In Soho, London, are various DOs and the technical HQ of the Nuclear Power Group. Total employees are approximately 5,000. Gyron Junior By scaling the Gyron turbo- jet to a two-fifths output the first family of Juniors was evolved in 1954 as Project Study 43. The new engine started life at a rating of 7,0001b, and the first prototype DGJ.I ran in August 1955. It enabled' Blackburn to design the NA.39, and has since been developed in that aircraft and in a Canberra, while an Ashton-hung DGJ.I A pod is investigating NA.39 intake de-icing. The first interim pro- duction engines (DGJ.2 Mk 101) are now on test. These undoubtedly incorporate a zero- stage, like the more advanced PS.50 family described below. A feature of these engines is the large bleed manifold around the combustion chamber, from which a huge airflow may be supplied for flap blowing and supercirculation (which in the NA.39 is extensive). A Rotax 1-p. air starter is fitted, and the Dowry fuel system incorporates a single-circuit spill burner gallery, hydraulic all-speed governor and mechanical top-speed governor trimmed by the j.p.t. control. The front end is heated by bleed-air and a Lucas pump serves the fuel- operated inlet-guide-vane actuators. Air- cooled turbine blading is probably employed. By adding a zero-stage and two rows of variable stators (controlled by a function generator supplied with an r.p.m. signal) the company have evolved the PS.50 family. Under development since October 1957, this engine is matched with a high-augmentation afterburner and fully variable nozzle to pro- vide a propulsion system for Sight at Mach numbers greater than 2.5. As the DGJ.10R it has an important application as the power- plant of the Bristol Type 188, which will fly this year. This application is reflected in the engine's special constructional materials and compre- hensive control system. Equipment includes a Rotax pneumatic starter, Dowty two-circuit spill-burner fuel system, Delaney Gallay fuel- cooled oil cooler, port and starboard power take-offs, twin drive faces for hydraulic pumps, and a Hobson-Microjet control for the after- FLIGHT, 18 March 1960 burner and variable nozzle. The latter can be convergent, or convergent /parallel with re- heat, or convergent/divergent at the design (high supersonic) flight Mach number. A? Luton Napier have installed a pair of T.188 powerplants in a Javelin, which after some delay is about to fly. Bench trials are in hand under simulated high-altitude supersonic con- ditions at the NGTE. Mention may also be made of the DGJ.20, designated PS.50 Phase 2, with a bell-mouthed intake casing. Gnome Sirce 1951 D.H. Engines have exchanged technical information with Inter- national General Electric, and in February 1958 it was announced that a licence had been purchased to manufacture and develop the T58 (q.v.) as the Gnome. This gave the British firm a tremendous advantage in the market for shaft turbines in the 1,000 h.p. class. Unlike its competitors, of which there were then several in Britain, the T58 was already highly developed, having run some 8,5OOhr in the USA and flown in helicopters. D.H. Engines are developing the Gnome in both fixed-wing (P-series) and helicopter (H) versions. Owing to their similarity to the T58, the latter are more advanced in develop- ment. A number of Gnome H. 1000s were manufactured last year, and the first went on to the bench on June 5. Although roughly equivalent to the T58-GE-6, these engines are entirely British, and are fitted with a Lucas fuel-metering system working in con- junction with an electric computer (around the intake) developed by D.H. Propellers. Flight testing started in August in a Whirlwind and the Gnome-P.531 Wasp flew a few days ago. Current Gnome H.1000 applications include the Whirlwind (new aircraft and conversions), Wasp and Agusta 101G; and the Gnome would also be fitted to the Vertol 107 or Sikorsky S-61 for BEA or other European customers. Production engines of DG:.2 rat- ing differ from their predecessors in that the computer is airframe-mounted, while the elec- tric-throttle actuator is relocated on the left- hand side. The bulk of current production is for RAF Whirlwinds, in which the engine will enter service early next year at a lhr rating of 1,000 s.h.p. Production engines on 25hr special-category tests have indicated a poten- tial exceeding this level, and early develop- ment is planned to take advantage of the temperature and gas-generator r.p.m. in hand to uprate the engine, initially to 1,175 and ultimately to more than 1,400 s.h.p. Turboprop Gnomes are now being assem- bled and bench testing of the P. 1000 will shortly begin. In these engines the existing primary gearbox drives an upper high-speed shaft housed in a casing from which the power section is hung. The powerplant mount- ing points are located on the rear primary box and front secondary epicyclic box. The latter will provide a final drive to a three-blade DH reversing propeller specially designed for the engine. The configuration overcomes the diffi- culty of driving a propeller from a rear free- turbine, and also allows the complete power section to be readily detached, while leaving the gearboxes and propeller undisturbed. In multi-engine STOL aircraft—such as the Integral—the primary gearbox can be linked by layshafts to maintain the drive to all pro- pellers in the event of engine failure. The first important application of the P.1000 is in the de Havilland D.H.123 twin- engine transport. Flight testing is scheduled to begin early next year, probably using a DC-3. During 1961 the engine is scheduled to enter production and complete its type certification at the P.1200 rating of 1,200 s.h.p. D.H. have also designed the Coupled Gnome, initially rated at 2,200 s.h.p., in which two power sections drive through freewheels to a single high-speed shaft. Overhaul life of the first Gnomes to enter
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