All work and no motoring interest were making life a very stale and dreary business, and I was feeling badly, in need of some subject to occupy my mind during my limited spare time.
The interest arrived unexpectedly, in the shape of a chance copy of the “Aeromodeller,” bought at a bookstall at the outset of a tedious train journey on the commencement of a much-needed week’s holiday this autumn, on the strength of a cover illustration of a racing car of sorts. Thereupon the journey ceased to be tedious, the frequent halts passed unnoticed, and I alighted at my destination a solid convert to Messrs. Russell and Galeota, and their model racing-car schemes. Briefly, the paper was offering two prizes of 10 guineas each for the fastest 10 laps on a “tethered” circuit, for cars of under 6 and 10 c.c. respectively, the models to be replicas or free-lance designs of full-sized racing or sports cars.
This seemed right up my street. Here was something to think about, something to design, build and tune, something that might even awaken the ghosts of old familiar sounds and smells. That holiday, spent at my remote Lakeland home,. was nothing if not energetic. Tools and materials had to be found, a start made on a “bolide” forthwith. Let the gauge of my enthusiasm be the fact that I, who had not cycled since my schooldays, 22 years ago, pedalled an elderly machine 20 miles, to return in triumph with an assorted parcel of screws, glue, sandpaper, and a fretsaw, blades, and the ruins of two Arehimedean. drills; 1/8 the lot, from a picturesque blacksmith’s-cum-junkshop. The cottage toolshed was ransacked for wood and breakable furniture, the sitting-room strewn with sketches, drawings and formers, and on returning to work at the end of my leave my rucksack was hung with bits, pieces, half-cut sheets of plywood and—The Fretsaw.
Now at this stage I neither possessed nor saw any concrete hope of possessing an engine or suitable air-wheels, both these items being announced as unobtainable. Enthusiasm, plus lots of optimism, however, bade me take heart; I would build the one and find a substitute for the others. Optimism was suffering some strain, nevertheless, by the time I saw an advertisement of one, Mr. Hallam, of Poole, offering castings for a 5.8 c.c. 2-stroke engine. I roped in a friend, a highly-skilled engineer, enlisted his lively interest, and two sets were immediately ordered. “They won’t come,” We said. They didn’t. At least, they didn’t until all hope had been abandoned, and in despair I had designed a second special, propelled by a triple-geared rubber motor, “for sprint work only,” and calculated to go like a bomb for a maximum of about 80 yards. And then, miraculously, the castings arrived, and our already limited spare time became too full for words. In case anyone should he interested in the construction of one of these engines, herewith are brief details: the castings are of light alloy, and the design cuts difficult machining to a minimum. The only difficult operation is the facing and boring of the two crankcase halves, which are extended above the baffle to enclose a liner, which is supplied hone-finished, requiring only to be cut to length and the three ports cuttIng—an operation calling for reasonable care to ensure clean unchamfered port-entry In the bore. The crankshaft is built up, the crank disc being screwed and pinned to the shaft, and is carried in a single plain bearing of some length. The piston is ingeniously constructed in three parts, the gudgeon bosses and deflector being separate alloy components, the latter being filed to shape after assembly. There are no rings. A finned alloy barrel is pressed over the liner, long holding-down studs passing through the head and fins into tapped lugs in the crankcase. The carburetter is a simple mixing valve, controlled by a taper needle, and as is common practice with these small engines, speed is controlled by the ignition advance. The engine is primarily intended for model aircraft work, weighs 6.5 oz. without flywheel or coil, and is designed to develop 1/5 h.p. at 5,000 r.p.m. The cost of the castings is 17/6, and the construction of one of these miniature power-units win certainly be found both amusing and instructive by any petrol enthusiast who has aecess to a reasonably accurate lathe. I imagine, though I have yet to put the idea into practice, that they will run quite satisfactorily on lighter fluid.
Both engines are now completed and are undergoing a period of running-in, driven light from a lathe-chuck, and although in no way can they be compared to the highly efficient racing engines which are doubtless being fitted to many entrants for the 10-lap event, they are at least soundly constructed. and should give us some quite satisfying lappery.
Reverting to the problem of wheels, I have compromised with “solid” rubber tyres constructed by rolling lengths of old inner-tube along a wooden rod., solutioning the ends, and mounting the resultant “doughnuts” on wooden hubs. One of the cars is a f.w.d. plot., the other (the ex-rubber buggy) has normal rear-wheel drive, gears running in oil. An ambitious plot to construct a third car, incorporating 4-wheel drive, using both engines, “Fuzzy” fashion, is in the sketch-book stage, but must, I fear, wait upon opportunity. In the meantime, we hope to have a run for the “A.M.” 10 guineas before the year is out, and look forward to further contests in the New Year. I confess to commencing this enterprise in a somewhat shamefaced manner, feeling that I should long ago have put away childish things, but emerged into the open on finding that no less august a person than the Editor of Motor Sport had given the scheme his blessing. I must admit that my efforts to date have provided me with many hours of interesting recreation.— G. H. D.
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“The pleasure’s mine!”
Police-constable, giving evidence in a recent speeding case: “When I told him he had driven at 45 m.p.h. he seemed very pleased, and said, “Not bad for an old bus.”