NAZI SECRET

Bay of Plenty Beacon, Volume 2, Issue 144, 8 April 1940, Page 6

NAZI SECRET

CARBURETTERS DISPLACED BY DIRECT INJECTION METHOD Many German aeroplanes have engines in Avhieh the petrol is injected direct into the cylinder. This obviates the need for a carburetter, with its complications and liability to impairment by ice formation. Secrets of the system were obtained from a Heinkel 111 K bomber shot down in Scotland in the autumn. By permission of the Air Ministry, Flight, tlie technical weekly, publishes a full description, Avith photographs and drawings. Engines in which tin's method is employed have been tested in flight in this country, and research is continuing. The system embodies the use of a feed pump regulating the flow through injectors of tiny particles of petrol direct into each cylinder. The petrol is injected in a fanwise spray, and comes into contact with supercharged air heated under pressure . One advantage is the elimination of freezing, which is prolific of air accidents. This is especially important in the operation of aircraft in Arctic zones and at great altitudes. The fuel taken from the HeinkePs tanks proved to be "87 octane" and it is believed that one of Germany'.', main reasons in embodying direct injection has been the possibility of using low-grade fuel. Nowadays, for high performance aircraft, fuel of "100 octane-' is used. The limits to which petrol injection pump components have to be i manufactured are very fine, and it is estimated that the HeinkePs outfit cost not less than £;$()() to produce. Against this may be set the fact that periods between overhaul are lengthened, although servicing work can be carried out only by specially trained mechanics. It is stated that the internal fin-i-sh of the engine in the shotdown 'plane is of a high order, but hhe external appearance and detail work do not approach the standard of British engines.