AIRCRAFT ENGINES.

Otago Daily Times, Issue 21258, 12 February 1931, Page 20

AIRCRAFT ENGINES.

COMPRESSION IGNITION. IMPORTANT DEVELOPMENTS. (Fbom Oue Own Coebespondent.) LONDON, January 2. Within the last few days details have been revealed of work done to Air Ministry instructions in the conversion of certain types of Rolls-Royce aero engines to “ compression-ignition " working. Experts at the Royal Aircraft Bstafiliisfyment, Fnrnborough, have designet} special component part# for a "Condor’' 650 h.p. unit, and, in its new guise, the engine has maintained steady ahd economical output of power. A second engine, in form a converted “F” type unit {developing in its normal petrol-burning shape about 500 h.p.) is being fitted with special parts for oil burning and will begin test running‘early this year. Power units of this type possess great advantages in aircraft operation, apart from the vastly diminished risk of fire. They consume less weight o. fuel than a petrol engine and are far less' complicated. Further, the successful engine of this type is certain to be more durable and to require less attention than even the best petrol-consuming units. The explosive mixture in the cylinders is firqd simply by high compression without the intervention of sparking plugs connected to a magneto or accumulator. Fuel economy in , any kind of internal combustion engine depends to a large extent on the pressure at which the mixture is fired and the ‘ compression-ignition ” unit is accordingly less >radons of fuel than a petrol motor. The result is that, although the oil engine is inevitably heavier tha:- the petrol-consuming engine, it is much more economical on long flights. It is generally estimated chat, employing “ compression-ignition ” motors of weights which could be attained in the./present state of knowledge, an aeroplane would become more economical than a petrol-burning craft of equivalent horse power after the first ten hours of flight. In this way the effective range of aircraft may be considerably increased without adding to the laden weight of the machine at the moment of ascent.