Several interesting discussions are taking place right now and they have me interested in building another throttle for my B727 cockpit.I'm researching potentiometers right now and will be using precision pots that are available at Mouser. I've read the arguments about using optical encoders, but I don't have the hardware to support that configuration.My question is, how many turns on the pot should I buy, or does this depend on how they are hooked up mechanically?One-turn and ten-turn pots are available. Does the Windows calibration program take care of this no matter which pot I use?I'm thinking of using a pulley and belt arrangement, but nothing is in stone at this point.As the B727 uses three throttle, one of my concerns is the pot for #2 engine somehow being in the way of the throttle shafts. But as I said before, this is in the idea stage of this project.Any comments on which pot to use (other than an optical encoder) are appreciated.

Ideally you want to use most of the travel available from the pot. Avoid both absolute mechanical stops of the travel. Hitting the potentiometer stop before your control's more sturdy limiter is hard on the potentiometer anyway and will break it) - but at least on cheaper components there might also be some irregular areas near both ends compared to the middle area.But it's good to try to use as much of the travel as possible - like 80-90% is best - this way you get more accuracy. Of course you can use very small part of it and use the windows calibration facilities, but then you force the whole range of axis movement into a very small difference in resistance area of the potentiometer - it basically amplifies all interference and irregularities on the component. It's always best to try to use most of the travel available. It will work with less, sure, but you get best results when you do it "right".//Tuomas

Thanks for the reply. I will try and find a pot that has at least a 300 degree travel on one turn so I stay away from the travel limits.I'm also investigating linear pots at this point as well. I think 100mm of travel should be enough, but more research is required.

Think "what you pay is what you get".If you want to spend your time endlessly building throttles, then pots are a good selection, but if you want to build a throttle for actual "flying" and less for building, I am afraid that you have to think of more expensive pots - the ones that cost $35 apiece and up.Those too will eventually start making trouble like erratical and non-accurate readings that will turn the flight and taxying experience into a mini-nightmare, but will give you a bit more time to enjoy your hobby that the "standard" pots option.

I've looked at precision pots ranging upwards of $65 US. The price does not surprise me and I have not ruled out using those.Mouser has a very large selection.

If you haven't ruled out using $65 pots then you are inches away from true optical absolute encoders - the ultimate in reliabilty and precision - but for that you need the right hardware. Have you checked Beta Innovations Plasma cards? IMO, they are the best value/quality for money in multi-device analog/digital inputs and they directly support both potentiometers and encoders (relative/absolute/optical, etc.).You've been warned "what you pay is what you get" and in the long run, "cheap" adds up to becoming more expensive in $ and labor (not to count frustration) than the "expensive" one-time solutions.I should know - I plan to *rebuild* my throttles with Plasma and abs-encoders.

I wrote to BI over a week ago but received no reply to my inquiries. I guess they are satisfied with their current customer base.I'll look into the optical encoders. As I said, at this point I haven't ruled out any hardware yet.

Thank you for the reply Leo. Please don't fire anyone over this.The problem I found was that I had combined both controllers instead of allowing Windows to see them separately. When both were combined, CH software or Windows (I'm not sure which) eliminated the Z-axis on the Thrustmaster TQS.After re-loading the software I did not check this option and things are working normally again.Once more, thanks for your reply. If I have future inquries I will post them here or send a PM.Regards,Michael