finishman2000

My Feedback: (7)

I'm trying to add some "down" as I power up the speed. I have everything working right now but would like to add this feature to stop the ballooning i'm getting at full throddle.
I did a Pmix-1 Master CH#3, M<=S (+) 0%, M=>S (+) 5%, slave CH#2

This worked but only on the right servo, it did what I wanted it to do....but... the left didn't do anything.
So: I did the same exact setup on PMix 2 slave CH#1
Then the other onwe worked and not the first. I did assign them to the same channel (A)

Can this be done??
Thanks, Cas

Montague

The Tracker does the P-mixes to the channel number, not the control function. So the mix is working exactly as you're programming it to work.

What you need to do is use 2 mixes set to the same switch. Both with Master as channel 3, one with slave channel 2 and the other with slave channel 1. You'll probably want the same % for both as well.

skypilit

My Feedback: (2)

Or check the thrust line of the engine. If it does not have enough down thrust, it will make the plane pull up when you hit the throttle. A few washers behind the engine (or mount) can usually solve this problem.

skypilit
my hanger:[link=http://skypilit.rcuniverse.com]skypilit.rcuniverse.com[/link]

Montague

Actually, that's a good point. Climbing with throttle is usually fixed by changing the airplane setup, not with mixing.

Also, try reflexing or raising both ailerons a little. If the ailerons are too low they act like flaps and cause balooning with airspeed.

Flight test and see if the problem is due to airspeed or power.

Also, a nose heavy airplane will climb with airspeed more than one with the CG back a bit. Try moving the CG back and see if the problem lessens.

finishman2000

My Feedback: (7)

Thanks for the tips but we're talking about electric foam planes here...and very quick, 80+mph.

skypilit

My Feedback: (2)

Even more reason to check the thrust line of your motor. With the power you are puting out for that kind of speed, everything has to be perfectly lined up (or the perfect angles of up/down and lt/rt thrust) to achieve straight flight. I have had to tweak many models to get my thrust right, even the ARF's. Once I get it right, it will fly straight with little or no up/down movement or tourque differential. I don't know a lot about foamies, all I have is a couple of GWS park fliers, but I suspect this is a problem with them too. It's not the fuel (or lack of) you are burning, it's the properties of having a very fast spinning prop stuck to the front of an airframe. I have not found a plane where this problem cannot be corrected with thrust line varience.

P.S. WOW. A foamie doing 80+ mph? Thats incredible! I would love to see some pics and specs!

skypilit
my hanger:[link=http://skypilit.rcuniverse.com]skypilit.rcuniverse.com[/link]

Montague

Fast foamies, whatever, the aerodynamics are the same for electrics and wet power. You need to trim the plane out. Figure out if the problem is airspeed or motor thrust related, and fix approprately, you'll have a better flying plane all around. Mixing it all out at the TX is really a bandaid, espeically if you mix the wrong thing.

If you trim for full speed level flight, start a level pass, then suddenly pull off the power (don't stop the prop, but just enough power barely keep it moving), what happens? If the plane changes pitch in a hurry, it's a thrust line issue. If it changes trim slowly as the speed bleeds off, then it's airspeed, not thrust.

If it's airspeed, try shimming the wing or reflexing the ailerons.

Fwiw, I have a GWS spit with a brushless motor, it's pretty quick. Reflexing the ailerons about 1/8" made a huge differnece in the way it flew at full power.

finishman2000

My Feedback: (7)

My point was that the mounts for most of these fast wings (Micro jet, twin jet hopped up strykers, etc) are already supplied. They aren't like my glow stuff where I can shim the mount and turn the engine a little more to the right. The plane I'm talking about here, the Multiplex Micro Jet the motor is mounts opposite what I would do. It actually causes the problem I know but it just zip ties the motor in, no play really.
Thanks, Cas