Hello,
I was trying to get a feel for what folks here think the best .40-.50 sized aerobatic bipe is? I am mainly looking for an ARF since I will also be building another plane for a spare .46 I have laying around. I was looking at the Nitrto Models Ultimate and the Cox Ultimate. Both seem like they are pretty equal, but the Cox seems like it rolls faster. I have also read the GP Ultimate kit was really good, but not really looking for a kit bipe. Please throw in your 2 cents.

-Shane

There's a boxxer arf isn't there? That's what I'd go with, but I don't have any experience with the other's.

World Models Ultimate 40 would be an option for you also.
Flies great with a .46. You can keep it fully assembled when you bring it to the field since the wing span is 42".

Sig SunDancer 50 great bipe. looks best in the yellow orange IMHO.

We got the world models ultimate bipe and put a magnum 46 on it. No matter what we tried it would never fly well. just didn't seem locked in and was a little heavy for my taste.

You are right on the money with your statement regarding the Ultimate 40 not getting the feeling of being "locked on". Probably due to it's size. Over time you get more comfortable with it.
Still and easy ARF to assemble and fun to fly.

Can't believe anyone hasn't mentioned the GP Super Skybolt. Maybe not a true 'aerobat' but it'll do any manuever I tell it without hesitation. Great flying plane. Match it up with any .91FS, you'll be happy.

I have the Great Planes Super Skybolt and it's not a .40 to .50 size bipe, it's considerably larger. Cox also has a 40 size ultimate and Nitro Planes are advertising some 40 size bipes too.