Redaxis

Can anyone please help with a small problem on my jet, the retracts have worked perfectly for the last couple of years. Then last weekend, when I flick the retract switch to close them, the nose wheel stays down. I have to lower the main gear and then put them away a 2nd time, this works every time and can replicate this with the model on a stand, so it's not a weight problem pushing down on the unit.

It always gets stuck down on the first time, then works perfectly, I can raise and lower them until it runs out of air. Until I switch the model off and then the next flight the same happens.

What I have tried so far, I have added lubricant in the air system (BVM oil). The retracts are controlled by Xicoy Air Valve, main wheels and front all on one valve, I have now isolated the front retract from the mains and used a separate Xicoy valve to test. So front on one valve the mains on the 2nd. Same problem.

I know the air system is leak free as will hold pressure for weeks/months. I have tried from a 100psi all the way down to 50psi, same results.

Does anyone know where I can look to solve this problem?

FenderBean

I would recommend cleaning everything in the nose, and inspect it. You could have some wear or build up causing just enough friction that requires extra movement to break free from. Re-lube o-rings as well and if that all pans out try a new valve to check.

Redaxis

Thank you, I will try removing it and giving it all a good clean.

Tried a new valve already.

FlyJ

This sounds like blow-by. This can happen with old dry o-rings. Basically the air is escaping around the o-ring to the exhaust side. If you’re disassembling the retract, replace the o-ring on the piston.

Redaxis

Thank you, I will get the retract unit out and look.

Appreciate the replies