FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1926
1926 - 0602.PDF
AUGUST 26, 1926 THE ARMSTRONG-SIDDELEY "GENET Normal Power 65 b.h.p. at 1,850 r.p.m. (See also page 531.) THE " Genet " is the latest and smallest of the well known Armstrong-Siddeley series of static radial air-cooled aero engines, its general design following that of the " Jaguar" and of the " Lynx," and naturally incorporating all that THE ARMSTRONG-SIDDELEY "GENET " : Front view. Note the mounting on the front of the engine of magneto, oil pump, etc., in very accessible positions. extended experience in the production of these engines has shown to be of value. While built primarily to compete in the Daily Mail light aeroplane competition, the " Genet " has been developed on lines that will allow it to be produced on a commercial basis for use on light aeroplanes generally. Being of the static radial type, it scores on the grounds of accessibility, sim- plicity, and ease of maintenance, three vital qualities as far as the owner-pilot is concerned. The radial arrangement also 9O 80 10 60 5O 30 20 \ / / \—1 f M / f • -«=i— 0-8 0 7 O-6 0 5 a IOO0 1200 MOO 1600 IBOO 2OOO 22OO ft. P.M. is particularly convenient when adjustments or dismantling become necessary. Main Features of the Engine The engine has five air-cooled cylinders which are arranged radially and measure 4 in. by 4 in. bore and stroke. Its normal revolutions are 1,850 per minute, at which speed it develops 65 h.p. When speeding up to its maximum of 2,035 r.p.m., some 75 h.p. are obtainable with a standard compression ratio at 5-2 to 1. The petrol consumption at the rated horse-power is 0-575 pints per brake horse-power hour, and the oil consumption 1 pint per hour, 80 per cent. Shell aviation and 20 per cent, benzole being the recom- mended fuel, and Castrol " R " the recommended lubricant. The unit complete with one magneto, carburettor, air-intake, short exhaust pipes, propeller boss, and speedometer drive scales 168 lbs., while its overall cylinder diameter and length are respectively 32-6 in. and 30-1 in. The Construction of the Engine The five steel cylinders are screwed into steel adapters 1 ocated in the aluminium crankcase, where they are locked BO 75 65 60 55a; xm BORE & WEIGH STROKE T . . ~~* ' «*? * X 4 ins iee ibs. —• » . / A B.H.E.P y •—n— y I3O 120 no 1500 1600 1700 1800 1900 2OOO 2 lOO R. P. M. Power and fuel-consumption curves of Armstrong- Siddeley " Genet " engine. Power curve, etc., of Armstrong-Siddeley " Genet " engine. with a double cone lock ring. The aluminium alloy semi- spherical heads are shrunk, screwed and lock-ringed on to the cylinders, the valve seats and plug bosses also being shrunk in. There are two inclined overhead valves per cylinder, the exhaust being made of cobalt chrome, and the inlet of stain- less steel. Duplex valve springs and tubular steel push rods are operated by roller ended tappers, the latter being driven by a slow-speed camshaft worked from the crankshaft through the medium of two epicyclic gears. The crankshaft runs on ball bearings, the front main bearing taking the propeller thrust, while the propeller journal loads are taken by a plain bearing contained in the front cover which also serves as an oil retainer for the oil on its way from the pump to the crankshaft. The master rod is made in one piece, while the master ring and the auxiliary rods are of " H " section. The " Y alloy forged pistons are fitted with two rings and a scraper ring above the floating gudgeon pin, and one scraper ring below it. Ignition is provided by an accessibly placed B.T.H. magneto driven by bevel gear from the crankshaft. For the competition only one plug per cylinder is fitted, but provision is made for another to be added on the standard engines. The mixture is controlled by a Zenith carburettor, a mixing fan being provided in the induction system as on large Armstrong-Siddeley aero engines. The lubrication relies on the dry -ump system, the pump unit incorporating the pressure and scavenge pumps, which are driven by a vertical shaft from the crankshaft, and being most accessibly located in front of the engine. The scavenge pump, which is 50 per cent, larger than the pressure pump, transfers the oil from the engine to the tank, the pressure pump being relied upon to feed the lubricant from the tank to the crankshaft. 532
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
