I know a lot of guys put OS 15's. Remember to use the small LiFe pack 200 mah should give 3 flights. I use this pack on most small planes. I use about 30-40 mah per flight. Just fly one flight recharge till see how far can go. It is a very light pack.
This engine will fly in a very scale manner. If need any help with install let me know. I have converted about 20 different planes from electric to gas.