We had a demo flyer at our Sept Open House with a Wasp powered by a OS LA46. He was asked a lot of questions about the plane. He indicated it weighed less than 4 lbs and it was built from a mail order kit. The plane flew fantastic although a lot had to with the pilot. I fly a Morris Fun Design/Rossi 45 RE and 2 Dazzlers (OS46FX & OS46SF). All weigh over 4 lbs and I believe weight has a lot do with a Fun Fly's performance.