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I would like to build the RV-4 .40 size kit and put an OS 4-stroke in it. The recommended 4-stroke size is .48 - .70, I don't need to have 3-D type performance but don't want a "dog" with marginal power either. The OS 56 FSa sits right in the middle of the recommended range. Will the 56 do what I am looking for or would I be better served by going with the 72 FSa? I would rather use the 56 if it is adequate, for weight and size reasons. Also any info on how the engines fit? I appreciate your opinion and advise.
Thanks,
Don

Bax

My Feedback: (11)

The .56 four-stroke engine should give the RV-4 adequate power for most flying, including moderate aerobatics. It will certainly not be an over-powered "fire breather". Keep the model as light as possible, and you'll do well. The .56 four-stroke engine will fit very well.