Aircraft-Engine Starting Tests and Experiences in the Arctic 470218
MUCH useful information about cold starting has been compiled from tests made by the AAF in Alaska.
The present minimum starting temperature with AN-F-28 fuel and the standard priming system was found to be between 0 and -10 F for radial engines with pressure-type carburetors, and between -10 and -15 F for radial engines with direct cylinder-injection carburetion and for inline engines. The authors estimate that more effective priming systems could lower the limits to -30 or -35 F without the use of special fuels or equipment. Present limits result partly from poor starting technique and from low cranking speeds caused by improper oil dilution.
Oil dilution, however, receives strong approval from the authors, who believe that, properly used, it lengthens engine life under Arctic conditions.
Turbojets will probably be superior in cold-starting ability. Supplying enough power to crank the engine to firing and sustaining speeds is the main problem.
Discussion of this paper is included with the discussion of the paper by Mr. Bleyle, which follows. The latter article covers other aspects of the cold-starting problem and was presented at the same meeting.