Hi, Can somebody please explain to me what expo is? The DX6i manual does not explain it. My thoughts are that it gives finer control of the plane when moving the sticks only a small distance but then as you move the control sticks towards max you get the fast response that you need. Is this right?

If so, does anyone have the ideal setup for a T28 trojan with the Dx6i transmitter?

Thanks,
Adam_Fozz

I think you have the basic grasp of what expo is. It can also be used to "increase" sensitivity when the sticks are moved a small amount but I personally do not know anyone who uses it for that.

There is no ideal setup. What I like you may hate. Pick a percentage, maybe 50%, and give it a try. Then try 25%, then 75%. Eventually you'll find percentages that work for you.

I'm currently flying a Sig Astro Hog and a Tower Uproar 60. I think I have around 40% on ailerons, zero on elevator, and 75% on rudder. My brother flies both planes with zero on all controls. It really is a matter of personal preference.

Carrell

You basically hit the nail on the head. Expo makes the servo respond in a non-linear manner to the stick input. This could be used to make the surface move less than the stick input to soften sensitivity or more than the input to increase sensitivity. It is generally only used to soften control sensetivity around center though. It can be really helpful on some very responsive airplanes.

On your Spektrum radio, a positive exponential value will soften the controls while a negative exponetial will make it more sensitive. This is the exact opposite of Futaba and other radios. With them, negative expo softens the controls near center.

On your T-28 Iwould try it with no expo. The recomended control throws fly the plane well and it is a fairly gentle flyer.

I've gotten into the habit ( it may be a bad one) of beginning with 30% positive expo on all of my models except those I know will be twitchy out of the box. I go higher with those, and even run some 3D at 100% rates and 80% Expo. High rates and 30% expo for the T-28 works out well for me as it smooths out smaller stick movements.