I built the Uproar .40 with an OS .50 ringed engine which made it very nose heavy. To balance I put the rudder and elevator servos and the charging jack in the rear as far back as they would go. People will say that's too much engine but it sure was a lot of fun. I could take off in about 5 feet. The problem I had was it was too much fun. I kept adding throw to the ailerons to see how fast I could get it rolling and eventually exceeded my skills when it became a blur. ...that's when I got online and ordered 2 more. Easy to build, with reduced throws could be a trainer. My second one is almost done. I think the third one will be an electric conversion. I'm going to build something different before the third Uproar (Slowpoke .20 with a Saito .30, ailerons and less polyhedral) I just shoehorned an 8oz. Sullivan tank into the Uproar's fuel compartment. Had to open up the hole in the former behind the tank and sand out a section of the leading edge to get it to fit. This tank is very close to the space it goes into. I was able to get it all to balance out last time without adding any weight, just moving the servos back was all it took. Someday I want to get 2 more Uproars and make the P-38 Lightening out of them. Somebody else already did it and it looks nice. Uproar is a good kit for the money. Design is forgiving of people like me who tend to modify everything.

One guy from my old flying field used a Tower .75. It was a performer to say the least.

Here is how my modified Uproar turned out. I have an OS .32SX on it and it flys great.

The uproar 40 with a 46 FX or now AX is my favorite setup to fly. This combo was nasty. Unlimited vertical no problem at 3570ft asl.