I have been flying for a good while now. I have never used the expo option in my radio, and I really don't even know what exactly it does. I can't find my manual to read up on it so I thought I might as well ask. I have been trying to get into 3D but I do not think My set up is correct to do the maneuvers. Could the expo be why I can't do the maneuvers correctly? I just want to know what it does, and how do I know when to use it. Thanks for any information. Justin.

"Expo" refers to exponential servo throw rates which can be se on computer radios. A negative expo set on a channel gives less sensitivity at close to the neutral position of the stick and more movement toward the endpoints.

on futaba negitive expo makes the center of the stick less sensitive, this is good for mpst planes with high rates to make normal flying easier, i use -20 on most elevators to make them less twitchy. on the throttle it'll make it more linier in responce.
+ expo makes things more twitchy around center. on JR its the other way round

Hi Justin,

OK, expo - -

Forgetting the effects of geometry for a second, normally the control surface will move a given amount for a given amount of transmitter stick movement.

That's the set up you have now.

But it's a good idea to have less sensitivity in the middle of the stick movement than at the extremes. This would mean that very accurate adjustments could be made to the control surface around their straight and level flight positions, but when sensitivity wasn't needed, at the extreme of the movement, it is still available.

Exponential movement allows this to happen by taking the linear nature of the movement and dipping the curve so that the further you are away from the centre, the greater the effect of moving the sticks.

Negative exponential (in Hitec, but it may be different in other radios) will reduce the sensitivity in the centre, whereas positive exponential will increase the sensitivity in the centre (used sometimes in the rotor control of a helicopter)

Incidentally, see here :-

http://www.hitecrcd.com/Support/Manu...pse7Manual.pdf

for the Hitec manual that explains it far better than I could!

You will need Adobe to read that, but if you haven't, come back to me here and I will email you the manual.

Hope that helped!

-David C.

Thanks a lot guys. I completely understand it now. This has helped a lot. Thanks for all of the information. Justin.

if you want to fly 3d , you need a 3d'able plane.
what are you trying to 3d with?

Razzle 3D...

so you got the plane for it!

when i learnt i started with loads, once i got it the plane wasnt reacting quick enough, i turned the rates right up and expo down.

Well, I starting learning without expo on so I got use to it. Is it any easier with the expo?

I will not say expo makes it easier, what I will say it that it makes a more sensitive plane easier to fly. I have had a plane with a significantly AFT CG handle good with 60% expo on the elevator.

i too learnt without, so i dont ned it, i have built in expo, and its damn good, but i do use a little just to help