Pots - best choices - Wire wound/Slider/Conductive Plastic...?

[Guest captain777]

Trying to pick the 'smoothest' and long lasting pot for my throttle quadrant. (throttles, speed brake, trim)Can anyone recommend a type that works well, without losing it's sensitivity or performance over time?

[Guest MikePowell]

Hi Thomas,Here are a couple issues to consider. One is lifetime, another is linearity. Many pots have a nominal lifetime of only 50,000 cycles. This is a little low for something that will get continuous use. Pots with lifetimes of 1,000,000 cycles are available, you just have to look a bit. Bournes, for example makes some.Linearity comes into play when you want two or more pots to track nicely. For example, consider multiple throttles. You will get your best linearity from a wire wound pot, particularly a multi-turn unit. This will create something of a challenge for you in linking the lever movement to the pot rotation.Linear movement pots (AKA "slide pots") have the disadvantage of being open so dust can get inside. Don't have any figures on these, but it seems to me that not being sealed, their lifetime would be limited.A precision, conductive plastic element pot would be a fair choice. A multi-turn wire-wound pot would give better linearity at the cost of more complex coupling mechanics. Don't expect long life from a pot without a lifetime rating. If it's not listed, it's short.An alternative is to look into long throw, LVDTs. You can get linearity, and because there are no sliding contacts, long life. They are expensive, require additional electroncis, but turn up often on Ebay.Mikewww.mikesflightdeck.com

[Guest captain777]

Mike. Thanks for the note. I went over your LVDT 'whitepaper' on your site and read it (for the 3rd time!)...it finally all made sense!I think I will take the plunge and use LVDTs for the twin throttles to preserve linearity and because the long throws on my units need a long throw device. I'll probably use regular 100k pots with high rated cycles on the rest of the unit. I'll bother you later on with more LVDT questions as I progress. Thanks.Any one else use LVDTs?

[Guest MikePowell]

Thomas,There are a few leading edge guys over at Viperpit.org who have used short throw LVDTs on a Cougar stick mod for what must be the ultimate F-16 stick. It converts the Cougar from a movement-actuated to force-actual control. As I understand it, it mimics the real F-16 about as close as possible.Extraordinary!Mikewww.mikesflightdeck.com