I recently bought and flew the arf FS powered by an oslas 25..a friend of mine bought the same setup..BE CAREFUL...his went straight up and down and so did mine...destroying both planes..I'm no expert, but I'm convinced the CG is way too far aft. I had a chance to see the innards of mine after the crash...the profile is a junk boxlike construction..the wing center area snapped like a toothpick..the only part I kept was the bellcrank and leadouts....I'll tell ya, the next time I spent 50 bucks, it will be for balsa and plans..this was my first and LAST arf.....I enjoy building my own even more after after seeing this mess. Hope this helps anyone considering the ARF version