The weight on the box is between 14 and 15 lbs. I had a Sukhoi at 16 lbs and it flew just right with the 2.4, not even over powered. The reason I am going with the FPE 2.4 is that it is lighter than a glow engine with the added weight of 18 oz, that is the first thing. The fit is no problem as the FPE is not a big engine. If it has too much power at full throttle then I'll fly it at 3/4 or even 1/2 but when I will want that power on the verticals, it will be there. Also I am adding a slimline smoke pump so mine might weight around 16 to 17 lbs, but the plane has over 1400 square nches. My Sukhoi has only 1206 sq in. Plus two wings is more drad thatn one wing. also I like the reliability of gassers. I also own a 3.2 FPE which is going into my Lanier Kit CAP 232 80 inch wing span, weighs around 19lbs.