Bixler 2 C of G help

[grahamt]

Hi everybody, I need help with my Bixler 2.
Just to give you some idea of where I'm at. My first plane was an Apprentice 15e which I take off ,loop , roll etc. and land, without using the "oh crap" switch or "safe" modes.
I have now acquired a Bixler 2, but am really struggling to keep control of it once in the air under power, if I kill the throttle a modicum of control returns. I think I'm having C of G problems, but I cant find it written where the C of G should be from the leading edge of the wing. Are there any known issues that crop up with the "Bixler2" like the "Bixler1" for example, had loose wings from time to time.
Many thanks
Graham

 

[MT Alex]

The COG on the Bixler should be right on the carbon spar.

 

[FlyingMonkey]

I'm guessing the measurements are in centimeters.

It's going to try to climb while under power. I balance mine so that when I shut off the power, the nose slightly drops. Just enough that it will keep gliding without touching the elevator.

What exactly does it do while under power? Does it try to roll, pitch, yaw?

 

[ssteve]

I've found the bixler 2 fairly sensitive to weight changes and needing a fair amount of weight added up front to balance correctly. I use the front line of where the foam spar cover is. I use a lot of flaps on the bixler though as I think it handles wind better when it's nose heavy, but stalls a little easier, so the flaps help give it some lift and keep stall speeds slower.

 

[joshuabardwell]

Just a smidge behind the front of the front foam spar cover seam on the wing. I don't share Steve's experience with regard to flaps. My Bixler 2 flies great with the flaps up and has no problem with lift. I give it about 20% flaps plus a little camber on the ailerons when I want to climb, as the motor is a bit under-powered. More than about 60% flaps gives it such a slow stall speed that it loses a lot of control authority and is hard to steer.

 

[grahamt]

Thank you everybody for the C of G and the tips. I have found at least part of my problem, the back plate on my elevator horn was about to fall off, newbie mistake. Now glued in place.
Flying monkey, I'll get back to you after i've had a chance to try it now that the elevator is fixed, in the mean time thank you for asking what it was flying like. It was a wild ride when your switching between full and half elevator for no apparent reason, the battery wasn't moving so the only thing I could think it might be was C of G. Hindsight is a wonderfull thing, if you survive the event. I must be a glutton for punishment, had 4 tries with the battery in different positions, all 4 were wild.

 

[joshuabardwell]

Definitely glue the back plate of all those servo horns down. I used the same contact cement that came with the plane. I didn't trust the plastic tabs to hold it by themselves for a minute.

Also, I would suggest slipping some pieces of fuel line, a tiny O-ring, or something like that around your clevises. Make sure it is far enough back not to bind against the control horn at extreme throws. I didn't have any of those things, so I put a small zip-tie around the clevis, then used a smidge of super-glue to make sure it didn't slide forward or back. The clevises that come with the Bixler are friction-fit, and I was worried about them coming loose in flight.

 

[grahamt]

Thanks Josh
All control horns are now glued and all clevises have rubber tube fitted.