A 24oz one, the OS61FX.
The OS61FX is 23.6oz with muffler.
The OS91FX is 24.3oz with muffler.
The OSFS91 is 23.8oz with muffler.
I figured to try the 61 and decide if I wanted to go to the 91FX or not. I figured if the airplane had such a strong reputation from it's kit version then a couple of things had to be true. It had to be very good with a 61 'cause that'd be what most kit builders would have used. (And they all thought it was a very good model.) I'm guessing most kit ones were built back before the "two engine sizes up" craze hit and the kit called for a 60. And it appears that the kit design builds an 8.5lb airplane. And when I estimated the finished weight from the weight of the parts in the box, it looked like my ARF was going to come out under 7.5lbs, so I figured.....
An almost 15% reduction in weight from the kit version oughta make for a great flying airplane with the engine size that made the reputation in the first place.
We'll see today.......
In a couple of hours actually.......