quote]ORIGINAL: mxaexm


I'm looking for an engine for my newest project, Sig Mid Star 40. My question is which engine would be perfect for this kit.

Would you rather buy new Super Tigre G40 or ST 45 or used OS 40...., TT 46?

Thanks all!!!
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Each person has his/her favorite/s. Like buying a car, sometimes you get whtever you really want, and sometimes whatever is the most practical for your job to be done.

The Mid-Star has Wing Area 630 in², and weighs around 5 Lb. That is well below the rule-of-thumb that defines a SPORT model which is 100 square inches wing area per 1 # of model weight. That is a 5# model should have at least 500 sq. ins. wing area to be less than a fire-breathing monster. (This rule begins to fade out with models having over 800 square inch wings.)

IMO, the TT pro is a very favorite engine. I have one NIB for a year now. I still run OLLLDDD Super Tigres. The ST 45 is an ABC engine and, considering it is ABC, is a very long life engine as much as the ST Ringed engines. The ST 51 is an outsatnding sport or scale engine. ST carbs are bored for the .51 and will give excellent handling. The 40 and 45 require a bit more attention, however the 45 ABC requires less break-in.
For your selected model, the ST .45 will be a reliable engine and give many hours of excellent performance. Do a fast break-in using a 9-6 or 7 wood prop, well balanced. Fly the machine with an 11-5 first time. After that you are on your own and as aircraft Captain, use whatever prop your little heart desires.