Let me tell you what is"fact". I built and flew the GP Sukhoi SU 31 3D with the OS 1.60 for the RC Universe review and I know for a fact that the OS 1.60 is more than plenty of power, that is here at sea level. I cant speak for higher elevations.

I have only flown it a few times but even brand new on Wildcat 10% fuel and with my Sukhoi weighing in at about 12.75 pounds there was no wanting for vertical authority. You absolutely do NOT need a gas engine on the plane that is going to push it up over 14 pounds. That would be a travesty. There is no need to add all that weight to the plane unless you just WANT to go gas. An even better engine might be a YS 1.40 sport or even better the YS 1.60DZ. That would really be the ultimate engine for the plane if you have the $$$$$.

Oh by the way, you can see the review,,, well,,,,,, in the Reviews section here at RCU. Go check it out. It was super windy so the video is just "ok" but you can see the engine doing its thing.

[link=http://www.rcuniverse.com/magazine/article_display.cfm?article_id=948]Link to RCU Review[/link]