A friend of mine has a Pilot Dolphin airplane with stock tailpipe. I am installing a P 120 engine in it for him and got looking at the diameter of the tailpipe and was wondering if it is large enough to prevent unwanted thrust loss. It measures 2 7/8". Pilots advertising indicates that a 140 or 160 sized engine is said to be ideal and this is the only pipe choice so it should be fine with a 120.


Also wondering what is considered to be the ideal pipe to engine spacing. This tailpipe has a large bell mouth (approx 5") at the opening tapering down to the dimension mentioned above (2 7/8"). I currently have the engine tenativly mounted with aft end of engine tail cone dead even with the begging of the bell. I am guessing that some where around half way in to the bell would be about right or ideal.