Featherlite 21cc, major surgery and throttle coupled spark advance electronic ignition in a .40 size Twist 3D. Unlimited vertical, slows to a crawl to land thanks to thick airfoil, radar gun sez 70 mph flat out. Removed the toy like graphics and applied airplane type trim. Flown hard, this is the third season. Four aonce fuel tank gives 12 minute flights. Redline oil 50:1.