NEW AERO ENGINE

Evening Post, Volume CXVIII, Issue 34, 9 August 1934, Page 13

NEW AERO ENGINE

LETTER H. DESIGN

TWENTY-FOUR CYLINDERS

(From "The Post's" Representative.) LONDON, June 28.

An aero engine with .twenty-four cylinders, built to unorthodox design, has completed successfully the severe "type" test of 100 hours' running required by the Air Ministry of all engines intended for use in military aircraft. It is air-cooled and has the cylinders arranged in four banks of six like the uprights of the capital letter "H"—two banks vertical and two inverted. The interconnecting gearing takes the place of the crossbar of the letter.

Fitted to ii Hawker "Hart" military biplane, the now engine has. increased maximum level speod to approximately 200 miles an hour, which is considerably higher than the top speed of the standard "Hart" with the standard engine.

Great importance is attached to development qf this type of power unit, because of certain important advantages gained by sits use^ Most important is the small frontal area of the engine—an attribute of tho unusual cylinder arrangement; the powerplant, therefore, is extremely compact and offers littlo parasitic "drag," or resistance to movement through the air. Further, tho individual cylinders are small, and extremely high crankshaft speeds are possible; this again means big power output for small frontal area and promises performance in singlo-ougined military aircraft equal to that which might be expected from installation of a considerably moro powerful air-cooled motor of orthodox design.

The engine is the product of Major. F. B. Halford, who has designed many successful types of aero engine, . and comes close upon the success of the "Kapier" sixteen-eylinder "H"shaped powerplant, which is now in production at the Napier worka at Acton. It is called the "Dagger." Records taken during the 100 hours' test showed that the engine, which is supercharged, develops 610-630 h.p. at its normal speed of 3500 revolutions a minute in atmospheric, conditions equivalent to those obtaining at 10,000 feet abovo sea-level. Its maximum output is delivered at 12,000 i'eet, and reaches £05 h.p, *