Airmail

摘要

I am very glad that the July 2013 Electric Flight cover photo depicts only a model, because no radial engine I know of can run with an even number of cylinders per row. I was just admiring the Electric Flight March 2013 cover of the DHC-2 Beaver floatplane and realized it had what appeared to be the only Pratt & Whitney 985 radial with eight cylinders. Nine is the usual number for this engine, Radial engines have an odd number of cylinders to allow the firing order to remain evenly spaced, as it fires every other cylinder, The cam ring is also interesting. I like Electric Flight magazine and have been flying RC since 1970 with a Heathkit radio I assembled myself.