INTRODUCTION

INTRODUCTION

THE GIPSY MAJOR SERIES 10 is the smallest or the current range of de Havilland Gipsy engines. The basic design follows the familiar Gipsy pattern. It is an air-cooled, four-stroke, in-line engine with push-rod-operated poppet valves, and in common with all Gipsy engines, except the Gipsy I and Gipsy II, it is inverted. Among the aircraft powered by this Series are the “Chipmunk”, the Australian “Drover” and the Swedish “Safir”

There are two marks of this engine in service, the Gipsy Major 10 Mk. 1, and the Gipsy Major 10 Mk. 2 : each mark having variants to suit different installations. The main differences between the marks and their variants are summarized below.

THE GIPSY MAJOR 10 Mk. 1-1 was developed from the Gipsy Major 1. It has aluminium cylinder heads permitting the use of fuels containing up to a maximum of 4,0 ml. Tetra-ethyl-lead (T.E.L.) per Imperial gallon. A manual mixture control is provided, enabling the weakest mixture for maximum power conditions to be maintained within the maximum weak-mixture cruising limitations, and providing adequate control to obviate over-rich mixture during all other conditions of flight. Fuel is supplied to the nonnal float type of carburettor by a pair of diaphragm type fuel pumps operated by eccentrics on the camshaft. Dual ignition is provided by a p.1ir of independent rotating-armature type magnetos and screened or unscreened ignition equipment may be fitted as required. The principal bearings are lubricated by oil under pressure from a spurgear pump. and the oil is returned to the aircraft tank by two similar scavenge pumps. Provision is made for a three­ jaw electric starter but no other engine-driven accessories can be fitted. Alternative engine speed indicator (E.S.I.) drives may be fitted, giving single or dual engine-speed (l to I) or quarter-engine­ speed (I to 0·25) as required. The propeller hub is located on a I in 10 tapered extension of the crankshaft by a key.

THE GIPSY MAJOR 10 Mk. 1-3 is similar to the 10 Mk. 1-1 except that the rear cover has been redesigned to provide drives and mounting faces for a generator and a vacuum pump, and incorporates a single engine-speed (I to I) E.S.I. drive.

THE GIPSY MAJOR 10 Mk. 1-7 (mod. 2244) is identical with the 10 Mk. 1-3 except that a dual engine-speed (I to I) E.S.I. drive is incorporated, and a special propeller spinner attachment is provided to suit a particular installation.

THE GIPSY MAJOR 10 Mk. I-IA. l-3A and 1-7A (mod. 2385) are, basically, similar to the 10 Mk. 1-1, 1-3 and J-7 respectively, except that they have the strengthened crankshaft with the parallel splined propeller shaft as fitted in the Gipsy Major 10 Mk. 2, to permit the fitment of a Fairey Reed metal propeller. The crankcase and the top cover are modified to accommodate this crankshaft, and the modified crankshaft bearings are of the Hoyt white-metalled type. As with all other variants of the Gipsy Major Series 10 engines, provision is made on the induction manifold for Ki-gass priming.

THE GIPSY MAJOR 10 Mk. 2 is a development of the 10 Mk. 1-3. It has a strengthened crankshaft \\ith a No. 1 S.B.A.C. parallel splined propeller shaft, and Vandervell main bearings in place of the white-metalled type ; the crankshaft is strengthened by increasing the diameter of the main journals by 1 mm. Sodium cooled exhaust valves permit the use of fuels containing up to S,S ml. of T.E.L. per Imperial gallon, and a stainless steel heater muff on the induction manifold is fitted ; there is provision for Ki-gass priming. The rear cover incorporates a single quarter­ engine speed (1 to 0·25) E.S.I. drive {pre-mod. 1634 the 10 Mk. 2 bad the 1 to 1 drive as fitted to the 10 Mk. 1-3), and a twelve-jaw starter dog permits the use of a cartridge starter as an alternative to an electric starter.

THE GIPSY MAJOR 10 Mk. 2-1 (mod. 2290) is similar to the 10 Mk. 2 but incorporates certain external modifications to make it installationally interchangeable with the 10 Mk. 1-3 in the Auster JS 'L. These modifications include : a special induction manifold and starboard ignition harness : fuel pump priming levers ; engine-speed (1 to 1I) E.S.I. drive ; propeller hub for Fairey Reed propeller with modified spinner attachment ; and a three-jaw starter dog on the crankshaft­ this last feature precluding the use of a cartridge starter.

THE GIPSY MAJOR Mk. 8 is the R.A.F. version of the 10 Mk. 2 and reference should be made to page ix for further information regarding this engine.