I posted this in the aero forum, but I though it might be more appropriate here.

A while back I asked for opinions why this Byron GeeBee was climbing (looping almost!) at full throttle and diving at low throttle settings. Well, I blocked it up and checked all the incidences and the engine thrust line. Now being a FG fuse with the horizontal stab and wing fairing molded right in, you'd think with a Byron kit there would be no problems.... Well I have -1 on the horizontal stab, +3 on the wings and 3 degrees of down thrust! The down thrust is fine but the others make for one crazy looping plane. It's possible I could have messed up the H stab maybe a degree but the wings are impossible to mess up the incidence. This is my first plane I've build that didn't fly perfectly strait on it's first flight. That's because I always check this kind of stuff. Thinking Byron had taken care of it for me was a mistake, but others that reviewed the kit said it had no bad habits (scared of losing a advertising account?). Any thoughts, maybe I should at least make the horizontal stab +1?

Thanks,
Shaun Bell

That's ridiculous. That's a total of 4 degrees decalage. It looks to be a semi-symetrical airfoil, you should have 1 degree max angular difference. Do whatever it takes to reduce the angular difference. Shame on them !

On my JDM model "Z", I have the stab at zero, and the wing at plus 1/2 degree.

Shame on Byron. You can't expect it to fly that way.

> Jim

So I'm not insane! You're right abou the airfoil, it's semi-symetrical. I guess given the wing fairings are moulded into the fuse, all I can do is bring the horizontal stab to at least +3 degrees leaving a 1 degree declalge. Do you think that will work?

Shaun Bell

Yes, that should work. I can see now why they used 3 degrees downthrust, to negate all of that lift generated by that huge incidence. You may want to eventually reduce some of that also. How much power are you running ?

> Jim

I'm using the stock G62 setup. I just found out on RCC that the Hostetler R2 plans were based off the Byron model. The only difference was the plans left the down and right thrust to 0 instead of 2 and 3. In the plans it calls for +2.5 on the wings and 0 on the Hstab. Well, I'll start hacking the stab up and play around with the down thrust.

Thanks,
Shaun

Jim- a few years ago "my daddy" talked me into the WM Midget Mustang. Nice Arf to assemble and of course overpowered it. Thing is it never flew "right." It was just a handful and I was a bit myst because countless threads claimed how great it was and here I have a flying nightmare.
* I have pretty much had it in a closet most of the last 5 years and finally it was a do or die thing. In February I borrowed his incidence meter and came out 2degrees neg. This was an ARF! So I decided to strip it , recover in a nice hot red with white underside, re-did the front end a bit. Brought the incidence back to zero. I brought it out a couple weeks ago to fly it.
*As usual I was ready for a wild ride. This thing flew so smooth I was nervous just waiting for something to happen. It was like flying a trainer. Incidence really does play a big part here.

Yes, a G-62, I was afraid of that being one of the contributing factors. That's one hell of a lot of thrust to deal with. It's not that big an airplane. Hostetler's +2.5 degrees is a hell of a lot more realistic then Byron's +4 degrees. I try to get the incidence as close to zero degrees as possible, and if I err, I want it to be slightly on the plus side, that's why I said plus 1/2 a degree. My engine is at 0 - 0, and it likes it that way.
Yeah Mike, I know that yo Daddy is yo GuRu, and rightly so. Don't it feel good when it all comes together ? Hope to see yer both in about a month.

> Jim

Some might think the G62 an old clunker, but at 21lbs the plane is literally ripped off the turf! You could get away with a lot smaller engine, but I need the 2000mah pack in the nose just to balance it LOL! How about a light 80cc twin, now that would be one crazy ride.

Shaun Bell

Hi Shaun: I don't know the specs on the Byron, but I think that my "Z" might be a little larger at an 85" span and 24 lbs, but I'm not exactly sure. I'm using a Brison 3.2 ci engine, and it pulls it with some authority. I too needed to push things up front to make it balance, not only the ignition module and battery, but 20 oz tank as well, sits in front of the firewall.

Best of luck.

> Jim