Onex brakes

[Onex107]

I'm having a problem with the brakes not holding when I do a runup. At about 1800 rpm the plane starts to move and I can't stop it until I idle back to 900. I installed a foot pedal attached to the hand brake to assist and it still isn't enough. What's my problem? What are you guys doing about brakes?

[MichaelFarley56]

Which brake system have you installed in your Onex? Is it the mechanical brakes with the upgraded drums? The hydraulic system?

[Onex107]

It's the original system, mechanical with steel drums. I'm going to pull a wheel and see what's going on in there. They feel like I have grease or oil on the bands. They hold up to 1800 rpm and then break loose and go.

[Onex107]

I think I solved my own problem. The brake levers are bottoming out on the small block that traps the end of the cable sheath. Either I haven't tensioned the brakes enough or, and this is what I'm going to do, I'll move the block up higher on the plate.

[752mr]

Thanks for finding this problem. When I read your post I checked my brakes and found I had the same problem. Glad I didn't find it on my first flight. I raised the blocks and that solved the problem. After reviewing the prints I believe a change may be in order here.