I had one with an OS 46 SF with a tuned pipe. It flew great at 7.5 lbs. But, like they say, it would tip stall on takeoff if you pulled it off too soon. I never had much trouble landing it however. It had cheap GP mech. retracts that seemed to work just fine. I glassed the fuse and vertical tail section, otherwise, it might have been even lighter. It was a real looker in the air, and fun to fly. Air retracts might save a little more weight, you would eliminate the large retract servo on the mains. I also glassed the cowl to the airframe to give it a more continuous scale look.