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Engine basics => Engine set up tips => Topic started by: kevin king on March 10, 2023, 02:32:04 AM
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If you had a larger airplane which motor of the 3 would be the most powerful one? ST 46, ST 51 or LA 46?
Thanks.
Kevin.
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If the airplane is of generous proportions, the ST G-,51 , hands down. i would even put one in a SIG Chipmunk if that group of engines was hat I had to choose from. If the model is down sized a bit from there, I would probably choose the LA.46. I like the classic run of the ST.46, and if one had a good ring fit on a standard version, that engine can give what most people want. Put in a Brian Gardner ABC piston/liner conversion, and you get the benefits of what the LA.46 offers. I have flown a 60 ounce Legacy 40 with an LA.46 for power for several years. At it's size and that weight, I think that is the upper range for the LA.46. A ST.51 will have that extra grunt if you need it and if/when I build another, that's what it will have in it. The Legacy 40 is at 565 sq.in. for wing area, so that I think would be the limit for a LA.46 and anything close to 60 ounces. I don't know if even a converted ST46 would handle that. Having said that, a SIG Chipmunk is reported at 570 sq.in. and the ST.46 is what a lot of guys dropped into the nose of that airplane for best power. Anything at or over 600 squares, the ST.51 is the best choice I think.
Type at you later,
Dan McEntee
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If the airplane is of generous proportions, the ST G-,51 , hands down.
Have to agree with that. Many years ago I used a G51 in an 810 sq inch/59 ounce model and the ideal flying speed was with a continuous 4 stroke from go to whoa. I've never used either of the other two engines mentioned but back in the day I used an Enya 45 model 6001 quite successfully. At one of the competitions the then Aussie champ (Peter White) asked me what I did to get the Enya to run just like his ST 46 but all I could say was it was box stock and used my usual 75/25 fuel :).
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The ST G.51 is one of my favorite engines. So far, I haven't used the Brian Gardner ABC conversions, but have flown the same G.51 with a GMA-spec retimed R/C cylinder and also a stock CL timed cylinder. The engine seems to work very well with a wide variety of propellers...11-6 APC, 12.25 x 3.75 APC, 12x5 APC and 12.5 x 5 Thunder Tiger Cyclone. Easily flies a 65 oz 700-ish square inch ".60 sized" stunter.
I'm not a fan of the ringed piston configuration, but I also haven't had a need to change rings frequently or anything like that. It makes re-assembly a PITA due to the ring being pinned. The windows in the cylinder are pretty large, thus the pinned ring is required. I think the ABC setup will be awesome! D>K Steve