R975 Radial engines

[Bob Phillips]

Just an update- drcowie! sorry I do not have specific mauals for the early 975 EC 3 but I don't think its very much different than the later manuals. There are 2 manuals on the G503 forum to download, one for the engine and one for accessories. I should also add that an aircraft manual for the R975 E series engines would also be very similar and are availble from a number of commercial suppliers ( Brian Asbury has a tank version also). My aircraft books identify the E series engines as having been first made in the mid 1930s, One version the 975 E 1 was rated at 365 hp @ 2100 rpm with supercharger impellor ratio of 7.8 :1 fuel of 73 octane and comp ratio of 6.1. The last model the commercial E-3 version was upgraded to 420 hp @ 2200 rpm, comp ratio 6.3 blower ratio increased to 10.15:1 and using 80 octane fuel.I believe this is the version put into tank use, with modifications.
Please note that Wright Whirlwind aircraft books are generally not as detailed as the American TM books.