When using expo it is not mentioned if it is Plus or Negitive Expo.Can someone explain how expo's work?How they benifit the flying.

Expo is used to soften up the stick around neutral to make the plane more easilly controllable on high rates. For JR and Airtroncis, you need positive expo to soften it up, for Futaba and I believe Hitec too, negative. To check, set the rates as the same (set low rates to the same throw as high rates). Then turn the expo up way high positive on one of the rates. Move the stick about a quarter throw. If it moves less on the throw with lots of expo, then you need positive, if more, then go with negative.

Expo is used to soften up the stick around neutral to make the plane more easilly controllable on high rates. For JR and Airtroncis, you need positive expo to soften it up, for Futaba and I believe Hitec too, negative. To check, set the rates as the same (set low rates to the same throw as high rates). Then turn the expo up way high positive on one of the rates. Move the stick about a quarter throw. If it moves less on the throw with lots of expo, then you need positive, if more, then go with negative.

2000 words...
Postive EXP is of little use to most of us.
JR doesn't provide it.

My Airtronics radio uses positive expo.

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Positive expo is rarely used... and as mentioned, not all radioes have this option.

Since the servoes move in a sirkle we in fact have positive expo to the rudders if we don`t use expo-settings in our radioes! This is not known by all pilots i think So if you set the expo (negative) to 10-15% you get a linear ruddermovement, and if you increase the exposetting you soften the senter.

For my normal planes and sailplanes I use 10% on all rudders, and for 3D I prefer 50% to the elevator, 40% to the ailerons and 20% to the rudder where I do not want softening. As you might understand: the 10% setting is just to get linear movement, and for 3D I have found my preferances. These are individual.

Fraid not Joo. You'll find that the rudder horn is also moving in an arc. If the servo arm and the horn are the same length from the pivot point, it is a 1 to 1 ratio.

Right Flypaper, as long as we think of 3D-models where we have 45` rudderthrows, but for the more "normal" types of precision models the rudderthrows are usually less than half the throw (in degrees) which the servo run.

25 percent on low rate 50 percent on high rate for Ail Elev 40 percent low rate 60 percent on high for rudder is a good start if it is to sensitive go more and vise versa. Futaba use Negitive JR use Positive.

Lee