Matt,

I would say the 10% drag. I know a 10lb Black Magic VF3 with the drag on it will NOT fly the Masters pattern COMPETITIVELY with an OS 1.40RX, but it does just fine with a YS 1.70 or electric setup with a lot of torque at close to 11lbs. Heck, my old Mantis at 9 3/4lbs still had problems in the summer heat in Muncie getting through the top of climbs with authority. I'm not saying they are not good engines, but I dont think they are a viable top level engine any longer. If they were, then why arent more people running them in Masters and FAI. I wouldn't have swtiched to YS had I not that it would be beneficial. I didn't do it just for the heck of it. I LOVED my OS 1.40's and ran several of them to near death.

Renegade,

A thin fuse doesnt mean less drag. There are many other areas to create drag without a really wide fuse. The mid-rex may be thin, but it is still a large airframe.

I don't claim to know all the ins and outs of drag as i'm not an aerospace engineer. However I have flown enough designs to know the differences.

Arch