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Aviation History
1946
1946 - 1455.PDF
JULY 25TH, 1946 FLIGHT 99 Two New Power Units 3,000 h.p. Napier Sabre VII Rolls-Royce Merlin for Airlines LATEST of the Napier Sabre piston engine range, the Mk VII,is distinguished in having provision for water/methanol in- jection. It is substantially the same as the Mk V in most other respects, but develops considerably more power. The Mk VI unit, referred to elsewhere, is virtually the Mk V with annular radjator and can be installed with or without cooling fan. j the Tempest installation 28 gallons of 60/40 per cent thanol-water mixture is carried in one wing and is delivered a Plessey motor and pump unit. A Napier air separator has also been developed for the system. The Sabre VII has fuel injection into the eye of the super- charger impellor, and the anti-detonant fluid is injected from a shroud around the fuel supply nozzle. Maximum delivery is at the rate of 200 gal/hr, and the normal proportion of water/methanol mixture to fuel is 45: 55 per cent in F.S. gear and 30:70 per cent in M.S. gear. The pump is fitted close to the starboard-side rear-engine bearer. Possibly due to the sleeve valves and their effect on com- bustion efficiency, Sabres have always given little or no exhaust flame. The Mk VII is now fitted with twelve individual stub pipes on each side. A single-lever cockpit control for the whole power unit is a commendable feature of the current engines. Data for the Sabre VII are as follows: Capacity, 36.8 litres Output, 8^ b.h.p./litre. Weight, 2,500 lb. Specific weight, 0.83 Ib/b.h.p. Maximum power with water/methanol injection: 3,050 b.h.p. at 3,850 r.p.m. + 17J 1b boost. The Sabre VII installed in a Tempest looks a very business-like power plant. Note the twelve separate exhaust stubs. • Another in-line engine with a radial-like installation, the J>795 n-P- Merlin 620 has been developed for the Canadian- built Douglas D.C.4.M. AS a result of experience with Merlins during the war years,Trans-Canada Airlines have decided to use these power units for their trans-Atlantic services, and the Rolls-Royce Company have developed the Merlin 620 specially for the purpose. The "102" from which the "620" is developed was the first engine to pass the British Air Registration Board's new civil type test, and thus the Merlin, so famous in war- time, has mude a fitting entry into the field of post-war civil aviation. Last week the first Canadian-built D.C.4 M.I with Merlin 620 engines made a successful initial test flight. T.C.A. have been operating Avro Lancasters and Lancastrians across the Atlantic since 1943, and Merlin 620s have been developed fpr operation under the severe climatic conditions anticipated on this route and in Canada. A Lancaster with Merlin 600-type engines last week crossed the North Atlantic fo Dorval via Ruineana and Gander flying at 25,000 feet. Mr. Partington, Rolls-Royce representative, flew as second pilot. Consumption tests are now being made. The 620 embodies the latest Merlin features, including petrol injection, and is of the two-stage supercharger with inter- cooler type. The radiatoi system is a development of the Avro Lincoln installation and has the same characteristic appear- ance. At the nose the diameter is 56 inches, and it increases up to 60 inches at the mounting to conform with the D.C.4 bulkhead and enable the existing undercarriage arrangement to be retained. A further development, the Merlin 621, basically similar to the 620, will replace the 102s as power units for the Tudor Is and Us, and details will be available shortly. Accessories for which provision is made on the Mk.620 in- clude a Douglas cabin blower. Power figures are as follows: — Take-off: Cruising: M.S. at 10,250 F.S. at 23,750 Emergency; M.S. at 4,500 F.S. at 16,750 ft ft ft ft Max. Climbing and M.S. at 10,000 F.S. at 20,500 ft ft 3,000 2,650 2,850 3,000 3,000 r.p.m. r.p.m. -,r.p.m. - r.p.m. Hr.p.m. - -f 20 H 9 +• 9 h 2O h 20 1 lb lb lb lb 1b Emergency Cruising: 2,850 2,850 r.p.m. -r.p.m. - +• 12 +• I2 lb lb 1 1, I; I, I I 1 ,74O I75 ,l65 795 ,650 • 4°5 b.h.p b.h.p.b.h.p. b.h.p.b.h.p. b.h.p.,340 b.h.p. The water-methanol pump and motor are mounted low down on the starboard side of the Sabre VII. CANADIAN AIR TRAFFIC "DASSENGERS carried by Trans-Canada Airlines in May*- numbered 22,596 compared with 21.558 in April, accord- ing to statistics released. Air mail for the month totalled189,057 lb compared with 211,545 1b for the previous month. Air. express carried amounted to yo.051 1b in May against92,829 1b in April,
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