Hovering a CG ultimate bipe
 

Hi,
Anyone set up a goldberg bipe to do 3d ??

Hovering a CG ultimate bipe
 

Mine does some things and not others. It does not really like harriers or elevators. The wings rock alot. I think the CG is too far forward to do them well. Blenders are a blurr followed by a very slow spin. It does an "OK" wall. It hovers pretty well. For some reason it is really hard to torque roll. It just hangs there. A click of throttle and it climbs. I don't really know why. Waterfalls are pretty huge, also the CG I think. High alpha knife edge is good once the coupling was dialed out.

Hovering a CG ultimate bipe
 

How did you dial it out?

Hovering a CG ultimate bipe
 

I use a mix activated by a switch on my transmitter for both axis. There are ways to modify the plane itself, but that usually involves a partial redesign of the tail group. I just worked on the mix until the desired results came about. I had roll coupling in the direction of rudder diflection, and down pitch coupling. I just added more mix in the opposite direction until I could hold the desired rudder inputs and the plane would fly straight.

Hovering a CG ultimate bipe
 

tailtwister, can u explain the mixing in a bit more detail please...? say in layman language. :)

thanks,
anurag

mixing
 

Most planes have this. Most pilots just hold the propper deflections to counter the roll as the mix is always changing due to power changes in the engine due to air density on different days. gassers have this change less with air. Ie right rudder causes right roll add left aileron. Simple now did I need a mix for that? Seems silly to me but if ya want them to look smooth its what ya gotta do!!
My ultimate and most my planes have roll coupling to some degree it is just the ultimate has lots of it. As it is short coupled. My pitts is even worse!!!
Thanks for the posts

Hovering a CG ultimate bipe
 

My set up is like this. Ch 2 is aileron, Ch 3 in elevator, and Ch 4 is rudder. I have a switch programed to activate two mixes simultaneously. I throw the switch, then as long as the switch is "on" my elevators (Ch 3) move slightly up (to correct down pitch coupling) based on my programed % of rudder (Ch 4) throw. I just program for example 3% of rudder throw as the starting point. When ever I add rudder (Ch 4), then 3% of that degree of throw is copied by the elevator. Then I just add or subtract the "%" until the plane goes straight. Usually a different "%" is needed for each direction. Maybe 3% for right rudder and 4% for left. It also could be drastically more. Roll coupling is programed out the same way. I mix Ch 4 (rudder) as the "master channel" to Ch 2 (aileron) as the "slave channel" I start out with a guess (5% or so) and then add or subtract "%" until the roll does not happen each direction. These mixes will only be truly exact if the same throttle setting and rudder input is used. Meaning for high speed knife edge you may need a different "%" of mix than at low speed at a higher angle of attack. Most times the mix will "help" with controling coupling at other speeds or deflections. Some radio systems offer "multi point mixing" which allows you to mix corrections for many stick inputs and always maintain the straight line no matter the deflection. I hope this helps.