Nitro Wing,

Thanks for posting that video of your Yak with an O.S. 160. Looks like fun. For Christmas the wife gave me a GP SU31 3D. I'm excited about it and trying to figure out the engine. The manual reports an expected flying weight of 13 - 15 lbs (although various publications including RC Flyer report they built at weights closer to 12 lbs). I'm debating between an O.S. 160 and trying to find a Moki 180 (found one on eBay). A guy at our flying field told me he thought the OS 1.60 may not give me as much vertical out of a hover that I would want. Could you tell me what the Yak weighed (approx) on the day you flew it? It seems to me you have plenty of power. Do you have a Perry pump installed? Thx.