Steve Hill 5

Disagree, Nigel. If your servo moves 20 degrees while your output arm moves 10 degrees, you still have linear - and therefore predictable - movement, but at a reduced rate. My original post came after visiting another club where I saw a new flyer on his first flight being told he needed “at least 40% expo, and 50% may be better”. Not surprisingly he took his model home in a carrier bag

Thanks guys. You have helped clarify my own thoughts. Expo is fine if you need it, pointless or dangerous if you don’t. As John says, a learner needs a decent, stable trainer. When he/she gets more advanced, then the decision can be taken to use expo or not.

.,I have driven most means of transport available, from tanks to light aircraft, and there is one thing they have all had in common. Their controls were always linear. Doesn’t matter whether it was a push bike or a racing yacht, equal inputs always resulted in equal outputs. The only time that was not true is right on the ragged edge when a small input could have a major, often unwanted, effect. The reason is obvious, predictability. Your body’s muscle memory knew that this input always produced that result. Which is a long winded way of asking why we teach new modellers to use exponential, where the same thumb movement can produce wildly differing results, at a stage in their development when above all else they need stability and predictability.

Unfortunately, Don, electricity moves a lot faster than my hands. The battery will neither charge nor discharge on my charger, which gives a “ cell or connection” error message. Having read the booklet and been suitably chastened ( thank you John) I will be disposing of the battery as recommended. Thank you to all who have replied.

I have short circuited my Li-po battery(red to black; in my defence she was very good looking). a) can it be saved and b) if it can’t be saved, what is the best way to dispose of it?