The Producer-gas Sidecar Outfit Is a Proposition
Page 35
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A SSIJMING that the ./-1. loss of power resulting from the conversion of a petrol vehicle to producer gas be a constant percentage, say 40, then one must conclude that the lower the power-toweight ratio of the vehicle the greater will be the inconvenience or positive disadvantage experienced.
The power to aveight ratios of commercial vehicles, when plotted against pay-load capacities, follow a more-or-less smooth curve, which falls steeply from about 1.2 b.h.p. per cwt. (gross) for the 10-cwt. van to roughly 0.2 b.h.p. per cwt. for maximum-load multi-wheelers, where it is practically horizontal. (See " The' Commercial Motor " dated Atheist 25, 1939.) Therefore, the smaller classes should by logical argument, be better suited to producer gas than the larger ones.
That the deduction is sound is evidenced by the success achieved with high-powered ears; having exceptionally high Power-to-weight ratios, when converted to gas. A .car' capable of 90 m.p.h., if deprived of 40 per cent. of its power, will probably still be capable of at least 60 m.p.h., which should be fast enough for most people.
Nevertheless, it is generally held, in producer-gas circles, that small vehicles —that is, vehicles with small engines— are not well suited to conversion to gas. There is another consideration, too, in such cases; space is harder to find, and to. spare, for the plant.
Accordingly, the issue is confused and somewhat contradictory, but one might be inclined, by the opinions that appear to preponderate, to regard a
motorcycle and sidecar as an unpromising subject for the .producergas converter to work upon.
However, such a conversion has been satisfactorily accomplished, and not by an expert, but by an amateur, and although it. is certainly not a commercial motor, we think its interest justifies reference being made to it on these pages. Furthermore, the sidecar outfit, as such, has a definite place in the commercial-motor world.
' Of 750 cc. engine capacity, the outfit is a Harley-Davidson, dated 1925, and. the operator, 'who made and installed the plant with 'his own hands and in his spare time, is a medical student, Mr. J. J. Wild. The apparatus does not encroach upon the passenger space.
Functioning on the dry-blast crossdraught system, the producer is made. of an old oil •drum welded to part of a milk churn, which forms the fire box, the latter being lined with fireclay. For the tuyere he used a piece of chrome-steel tube, and a brake drum forms the basis of the hopper cover.
Various other disused receptacles for every-day commodities, odds and ends of piping, etc., go to make up the rest.
Charcoal is the fuel used and a lower end of the cooler tubes, and a fairly frequent maintenance operation necessary is the draining of water that has condensed in these tubes.
At the engine end of the gas plant, the pipe is connected to the carburetter, in such a manner that the existing throttle can be used. There is, however, a farther throttle in the gas line. This is employed only to shut Off the plant when the engine is to be run on petrol. Before going over on to gas, both air intakes of the carburetter (a Schebler) -are closed. •
Air is admitted to the gas pipe, near its junction with the carburetter, by a sliding valve interconnected with the throttle lever, whilst the proportion of air to gaA' can be regulated by a handoperated sleeve embracing the airintake aperture, and arranged to vary its effective size.
For town running, Mr. Wild said, ample speed is available, but acceleration is poor. He has got used to that, however, and is content to put up with it, On the open road he has the throttle wide open practically all the time and obtains not much more `than half the speed that would be available with petrol