Adding friction to throttle lever

[Mike A]

I'm building a three-engine throttle quadrant with flap & speed brake levers based on the how-to article at http://www.flightsim.com/cgi/kds?$=main/howto/throt.htmI'm trying to come up with a way to increase the friction of the levers. Since it will be a full size replica, the weight of the levers will overcome the resistance that the potentiometers would provide and they wouldn't stay in place.I'll be using a 1/4" diameter aluminum rod as the axis for the gears which the levers will be attached to. I was thinking of using compression springs to provide a side load to add friction. I'd place them between the gears & the aluminum flats through which the rod passes. I would then drill a hole through the rod on the other side of the gear, through which I'd insert a brass wire which would hold the gear in place against the compression of the spring.Has anyone else built a throttle quadrant based on this design and/or have any ideas on how to add some friction? Thanks!Mike A.

[Guest]

Hi Mike, Why not use a threaded rod that passes through all the gears and plates. Add nuts and spring washers on each gear/plates. Use locking nuts Now you can adjust the friction but turning the nuts tighter. The rod should of course be fixed (w/o turning) to the outside frame. RgdsRoland

[Mike A]

Hi Roland, Thanks so much for your reply. That sounds like the way to go; another stumbling block removed ;)I'm building a "somewhat" reasonable facsimile of a 727 throttle quadrant, including the reverse thrust levers, so the throttle levers will have a bit of weight on them. Thanks again!Mike A.

[Guest PeterK]

PeterKWell Iv encountered 2 ways so far...My 2 throttles so far have been from a wipe control off of some video equipment...the first brakewas a piece of square platic with a hole drilled trough it and then a cut 1/2 way through a 1/16 wide slot.. This went through the pots shaft and was tightened with a small screw which increased the tension.. The other one which i use now is a spring going through the gear with plastic balls on each end...its tenstion is caused by plateson each side of the spring going through the gear..Have i lost you??? Its kinda hard to explain without pictures..pete

[Mike A]

Hi Pete,The other one which i use now is a spring going through the gear with plastic balls on each end...its tenstion is caused by plateson each side of the spring going through the gear..I think I get it... so each end of the spring is anchored to a plate, & the gear is between & parallel to the plates?Mike A.

[Guest PeterK]

PeterK..YES...Remember..If youve seen my cockpit web sit...Im usinga Video Wipe Bar off of a piece of Tv station equipment..Its a (T) handel running a long shaft 100K potPicture the bottom of the arm having a pin and spring going throughit on each end is a plastic ball...Like teflon,,very slipery...these rub against the side plates to cause the friction...The tension is linear through the full motion it does not change..Another wipe bar i have has a gear reduction because the pot is a 10 turn type...the spring goes throught the gear with the end pieces and that too has rub plates..one side is adjustable to increaseor decrease the friction..only about 1/16 of a inch play..not much..These plates are held together with a 1/2 long stand off with #6 threads inside for the screws to fit..4 hold it togetherone plate is (L) shaped to mount to the main piece of the control..Ganging the plates together using the stand offs you couldcontrol as many gears or levers as you want...Pete

[Guest firmo]

Hi Pete,Please post a picture of your friction solutions or try to draw them for us.Thanks,Firmo

[Guest PeterK]

PeterK heres a quick diagram I made of 2 Tension Brakes used on Wipe Barsthe cut on the block on the right side is 1/16"..not 1/1pete

[Guest firmo]

Ok, I get it now.Very nice.Firmo