NEW AIR LINERS

Hokitika Guardian, 9 May 1936, Page 6

NEW AIR LINERS

, .REMARKABLE ENGINES f

WORLD’S LARGEST! ORDER

LONDON, May 1.

Many hundreds of work people are -engaged continuously day and night “on tfie execution.of the largest single prder for aero engines ever placed by an air transport .company. For the '.new ..Short monoplane flying boats ; which are being built at. Rochester -for the Empire routes. Imperial Airways. heeds, 116 engines aud an hdditiorial. 40 engines as “spares” for use when overhauls. are in progress. In -aggregate ,qntput .these. motor—Bristol , Pegasus Xc air-cooled rndials—account ./for more than 150,000 horsepower. Th ew/yill : drive the new boats ,at,, about ranldngr/tKem 'easily as the commercial flyiiljg;./boats iii existence.'. /',■/. " ' In' less than 12 months , the' manufal-

luring area of the Bristol engine shop has been doubled, and/in the midst of military orders on an unprecedented scale the company is dealing calmly yvitli this record commercial contract. ./ The Pegasus/Xc engine represents ' the most: modern, thought in the design and building of ' poppet-Valved aero-.,.' engines. It is /fie latest in a series of nineTcylinder. etigines of basically similar type, having the.-same bore, stroke and swept'volume, which have been vn. constant evolution, production and use for more than 15 years; In spite of its iiicteasjed power, the most recent Pegasus engine is lighter than, any previous series. All kinds of new ideas are embodied in its design. The , cylinder hestd ahd barrel has been’ redesigned to give’ more efficientcorfH; bustion and much greater effective cooling area. The exhaust Vajves'''are\ cooled by sodium and '‘slellitedy gt#. protect them from the corrosive action of. leaded 'fuel. Provision is mhde, for installatidn of; aV contr’ollable-pitch air screw. , The. carburettor is improved. , AV new kind 'of exhaust-gas collector ring (> is also an efficient' silencer.Special., drives are, embodied for-work-ing .the accessories, including the supercharger,/ magnetos/ .electric geneh--htor and/the fuel and. oil. pumps; between them th,ese ; .! drives absorb- 70, h^p.,;leaving, a maximum of. 000 h.p. ’|o be delivered at the; airscrew hub.:.. ‘ Several .hundred thousand drawing pflieg Hours were spent in .the evolution ‘ and design . of 1 the motor. Two thousand precision, drawings Were pre.■: pared for its manufacture in quantity.! 'Special ~singie-cylincler, test runs total-) ;mpre. tlran/a Thousand, hours, at'.powers- representing maximum output; oil the main,engine, though maximum): 'PPW% is ' normally used only for; a. few,piinutes at, take-off.- In- addition; 39ft .hours of normal dcvlophipht running and .100.0. hours of “overload” running, at powers greatly in, -excess of, normal/output/were dope on complete engines/ This aggregate of more than. 50.00 .hours ..of development iw-nn-, ning involved 500 milion crankshaft revolutions and. the burning of 130,OOO'gallons of fuel. Figures; such as these underline the complexity of , the work of aero engine development, the tremendous organisation that is required and tht vast expenditure involved. They, ,expiaiu why the design and building of aero, engines, especially in the liiglipowered.’ categories, must be a task engaging enormous technical resources .and . tllie highest standards of craftsmanship. • ' 1

. And'the pace of development shows np sign of slackening. Research is proceeding, on lines which may mean that the Pegasus Xc, marvel of enjgineeriug though it is, will represenlt the culminating point in devlopment of the nine-cylinder air-cooled pop-p.et-valved radial motor, to be succeeded by the sleeve-valved units that: tfio Bristol Company has evolved in 11 years of dfduous work to the stage of successfuiypreduction. Some time in the near future the sleeve-valved mqtor, which constitutes yet another triumph of British engineering genius (.in a \yhere Others have failed, will offer- formidable,