...and now the D-C SPITFIRE Mk. II 1.0 cc. DIESEL DitVits ,,CHARLTON'S Mark IT Spitfire 1 c.c. diesel super- sedes_the original model Allbon Spithire introduced early in 1953. Although it has the same bore and stroke, however, it inherits litle from its predecessors save one desirable characteristic: easy starting. The Mk. I Spitfire was a_good engine; one that could be confidently recom- mended to a raw beginner and we were sorry 10 see it go, but it must be admitted that the new model seems equally as good—added to which it is a good deal cheaper and should also have greater resistance to crash damage Just as the earlier Spitfire was, in 8 Honstrowce 2 ene ENGINE "0. well made, strong and_pleasing- ly finished... be relied up- on to give good ser- effect, a sleeved down version of the then highly popular 1.49 c.c. Javelin, the new engine is based on the Sabre 1.49 which replaced the Javelin nearly three years ago. ‘Once again, the smaller capacity has been obtained by reducing the diameter of the cylinder bore by 0.10 in. The Spitfire II uses many of the basic parts of the Sabre, is virtually identical in respect of the bottom components and thus its installation is interchangeable with the larger engine. In external appearance the engine differs in having a different ¢ of prop driver, a hexagon nut OU ell Wadher “batead “ot the Sabre’s spinner-nut, a revised com- pression lever with stop pin to assist beginners, and a green, instead of |, anodised cylinder barrel. The engine is assembled around a_neat pressure die-casting com- prising crankcase, main bearing and lower part of the cylinder casing. It has strong, deep-section beam mount- ing lugs, ‘through which two long screws are passed to retain the back- plate. ‘These screws are also used to mount the detachable plaetic fuel tank, or they can be replaced by longer ones to enable the engine to be bulkhead mounted. Asis common practice with small engines, the main bearing is not bushed, the crank-shaft running in the crankcase material. ‘A normal type of plain, flanged cylinder sleeve is used.” “Assembly is very simple, the lange, at exhaust level, dropping onto ‘an annular seating inside the main casting and being retained by the - one-piece cylinder barrel which drops over the linet and screvis into the top of the casting. As is frequently the practice of this manufacturer, no attempt has been made to maintain close contact between cylinder liner walls and cooling barrel, but the liner is quite thick and no trouble with overheating is experienced. 385LODEL AIRCRAFT J" The Spitfire II is well made, strong and pleasingly finished. It can, undoubiedly, be relied upon to give good service to newcomers to the hobby (for whom it is primarily intended) or to the established modeller who wants an easy handling small engine for general purpose ying. Specification ‘Type: Single cylinder, air-cooled, reverse-flow scavenged two-stroke cycle, compression-ignition. Shaft type rotaryvalve induction, "No sub-piston supplementary sir_in- Sheen. Conical top piston with ig contra-piston. Stroke: 0.420 in. Swept Volume: 0.0596 cu. in. (0.976 c.c) Stroke/Bore Ratio: 0.984 : 1. Weight: 3.2 02. General Structural Data Tumble finshed presure die-cast LNL2 aluminium alloy erankease and rain. bearing with ‘detachable reat cover, Fulldise,non-counterbalanced Crankshaft ofnickel-chrorne steel, heat treated, running in plain’ betring Forged’ Hiduminium RR.36. alloy Connecting rod. Ground aad lapped Meehanite stan running in hard ened steel, radially ported, cylinder liner, Machined and colour anodised cylinder “bee! “apd heady with eSmpression stop. “Alloy prop driver fitted €0 taper Ga shaft.” Bras spray- bar assembly, angled back 15) deg. Combined beam” and 00. point bulkhead mounting: lugs.” Detach able transparent plasti fuel tank, Test Engine Data ‘Running time prior to test: 2 hours, Fuel used: Mercury No. 8. Performance Stop pins, and similar devices to limit compression-lever rotation, used to be quite common in the early days 356 i, fe 27. The component parts of the Davies Charlton Spicfire ‘Mkill con be clearly seen In this photo- graph of dicscls. They are a sensible pre- caution on a beginner's engine, firstly, because they reduce the risk of damage to con-rod, gudgeon-pin, or crankpin, through attempts. by ‘the uninitiated to start the engine on too high a compression setting, and, secondly, because they minimise the extent t6 which the beginner can get muddled in finding the ° correct setting—especially if he, or someone eke, has, as often happens, previously fiddled ‘with the compression screw and disturbed the factory setting. ‘Their only disadvantage is that they tend to limit the extent to which the engine can be controlled onthe largest and smallest props that it is Capable of farming. Tie the cake of beginners’ engines, however, this is not important as the prop sizes generally used will be within fairly close limits—normally 9 to 7 in. dia. and 3 to 6 in. pitch with the Spitfire. ‘As remarked earlier, the Spitfize TT js an easy starting engine and its general handling characteristics are NOVEMBER 1958, without vice. On test, we found the ols easy” to adjust and non- critical. ‘The rearwards-inclined nieedle-valve is helpful in keeping the fingers at a safe distance from the prop. Power output was fractionally below that of the Spitfire I tested earlier, but was, nevertheless, quite good for an engine of this type and the specific perlormance expressed in bhp,/litre and bum.e.p. was, in fact, slightly above that obtained from our test of the Sabre. The engine delivered a maximum of just under 8 oz. in. torque (equivalent to 2 bam.ep. of approx. 53 Ib,|sq. in.) at 8,000 ¥.p.m. and the peak b.h.p. was 0.082 at approx. 12,600 r-p.m. Power/Weight Ratio (as tested): ong bib. ‘Specific Output (as tested) : 82 b.h.p./ litre. m= tea ia =) = D-C_SPITFIRE MK.II