I have a Top Flite Contender I built a year or so back (my 5th one) with the up-swept wing tips and an OS 55AX for power. I was amazed how well it performs a knife edge - only input required is top rudder and it will go straight as an arrow. The flaps work great - mixed in 15% down elevator so there is no pitch-up upon activation. More than once I've received comments from other club members stating they don't understand how my Contender flys so well - of course I tell them it's the pilot but anyone who has a Contender built straght and light knows better. You can't go wrong with this plane, it's a blast to fly, easy to transport, and rugged. The Contender is one of the planes I always have in my fleet - the other is the Ultrasport 60.