Setting The Servos And Control Throws.
If you have got as far as this, you have gone a lot further than most in setting up your model properly!
The next step is to make the most of your radio gear's capability, whether or not it is computerised.
By the time you have got your model to this stage, you'll have messed around with the trims, the dual rates and the servo travel. You almost certainly will have reduced them from the original set-up. Computerised gear is great but it makes you lazy! Rolls too fast? - set the aileron servo travel to 50%, fly on rates 60%, need a bit of trim? - use the trim offset memory. Sound familiar? Guilty!
We've all done this, the $64,000 question is "what next?".
A servo is designed for operating over a typical arc of ±30°. In the (not untypical) case above, the aileron servo is actually operating over 50%x60%x±30° which is....±9°! What's wrong with that then? If you look at the power output from a servo, generally speaking there is very little power output over the ±6° in the centre of the servo's travel - in short you have programmed away most of the servo's power that you'll be using. The "blow-back" or air resistance will greatly reduce the actual movement of the control surfaces.
The first thing to note is the physical movements that you currently have set and any offsets for ailerons, elevator and rudder. What you are trying to do now is to maximise the servo travel for the maximum required control surface movements so you reset the dual rates, trims and servo travel to maximum - if you have computerised gear, these can be set to above 100%, provided that you don't make the servo "over-travel".
The next step is to get back to your original movements using mechanical adjustments only. To reduce the control surface movement, you will have to move the clevis at the control surface as far away from the hinge line as possible. If the control surface movement is still too great, move the clevis at the servo end closer to the center of the servo. Make sure however that the clevis doesn't bind up with the servo arm, particularly in the "pull" direction. (A good way round this is to use ball joints fixed to the top of the servo arm rather than clevises). By the time you've done this, the neutral position will probably have moved so disconnect one end of the control rod and screw/unscrew the clevis until you return to your original neutral position.
Carefully check that all the control surfaces and servo arms are free moving over their entire range of travel and that the neutral positions and travel ranges are as before. Now reset the low rates to about 75% of maximum travel.
The model is now ready for another test flight. My experience is that after you have carried out this process, the model will be "twitchier"! For "twitchier", read "more responsive". This is entirely due to a decrease in "blow-back" and effective use of the servo's power range. You may have to reduce the control throws again but by now, you know that this should only be done temporarily on the transmitter. Establish the new required movements then alter the mechanical linkages to suit. Something for nothing? Sure is!