I just got a tape measure out and those measurements are correct, its 51" from the tail end to the motor, so this doesnt include lenght to the spinner so it will be a tad longer and one wing panel is 28 1/4 " ..but it is very light, I havent flown mine yet..but I have no doubt that it will fly very well on a .50 , I'm using a jett46 on mine and I'm confident that will do the trick although as bob27s has mentioned without further mods like installing retracts( and there are no provisions to do so) its not going to be super fast.. as for installing the 90, I had the same idea before I bought it.. when I got it, I soon changed my mind about putting my Jett 90l in it.. I'm not saying it cant be done but to me it would be to extensive to modify the front to fit the large engine and I think it would need some serious re-enforcement to cope with the extra load, not to mention balancing issue's

it's not a bad little plane , but IMO I would choose a different F20 to put retracts and a large engine in.. I sort of look at it like this..whats the point of getting an ARF then having to perform surgery rebuild half of it and then hope it all holds up to the improvements..I would get something more accommodating to what you want the final result to be

.but then again what do I know!!!???!!!