I have a Yellow Aircraft brake valve. I have it all hooked up. BUT whenever I fill the airtank it only fills with the brakes on. I have tried filling the airtank with the valve the other way but air excapes out. (I have the brakes mixed with down elevator and on when I have the retracts down) When I push the elevator stick forward the brakes go off and air is let out of the valve. Why? Any help thanks!! I am sure it is something simple... IS IT THE WRONG BRAKE VALVE??

what retracts do you have?

Could be a couple things. Check your mix program. You may have a switch activated and it's in the wrong position. I use a switch for parking brake on mine, and have it mixed to dn elev.
Could have a hose backwards?
A pic may help.

I just reread your post. I don't know what tx you have, but you need to set your values on the mix the other direction. Or you could try reversing that channel first.
Keep playing with it, you'll get it.

I have retracts from yellow aircraft and yellow aircraft brake valve and yellow aircraft valve for retracts. I have the brakes mixed with down elevator when the retracts are deployed. The airtank will not fill when the brake valve is in the off position. (the valve leaks air) fully closed. It will only fill in the open position with the brakes on...

http://www.bvmjets.com/Accessories/SmoothStop2.pdf

Is the Yellow brake vavle similar to the BVM? The type of retracts should not matter. If the yellow valve is like the BVM that you have pictured, it sounds like you have the servo reversed. Also, if the linkage set up is off just a little, it will leak air. It needs to be a really straight push/pull to make it work right.
Where is your fill valve located. It should fill no matter where the brake valve is positioned. Maybe you have the fill on the wrong end?
You should "t" the line that comes right out of the air tank.

Looks like our posts crossed in the mail.
If it will only fill with the valve in a certain position= your fill valve is in the wrong line.
If the brakes are working, but with up elevator= 1- the servo is reversed or 2- your mix values are reversed
hope this helps

Everything works fine but ( i have it mixed with DOWN elevator)... Its just backwards.And it does NOT fill when the valve is in the close position like my photo only the other way.. I have a Futaba 9c

I don't think its backwards. The fill valve I do have it t'd to the airtank. It only fills when the breaks are on and when I moved the elevator forward the breaks go off and the wheels moved freely by hand... NO MATER WHAT I DO. THE TANK WILL ONLY FILL WHEN THE VALVE IS OUT... (oppisite of the pic I posted)

I wonder if your valve is for spring air type gear. Gear up, the valve opens and air pushes the retracts up. Gear down, the valve closes and the air vents out the back side. Have you tried switching the lines? I'm lost now.

Yeah I have tried switching the lines. Samething happends. I am going to go tomorrow and get a Robart brake valve and see if it makes a difference. The fill valve I got from yellow aircraft was faulty and I had to go with a robart one...

I'm trying to understand the setup. I'll assume the top line in your pic is air - in and the bottom two lines is air out. Since this is a retract valve, do both the bottom fittings get air in the same position, or do they alternate. ( up/down) I think you need a brake valve or a simple button like springair has. Bad thing is the brakes are either on or off. I'm not familiar with the Robart brake valve, I don't know if it's proportional or not. BVM's works well. I have a Mini Hobby electronic brake valve. No servo needed, turns off automatically with gear up.

Yes you are correct about the hose lines. Once I try the robart valve I will let you know. Thanks for all your help! :-) I bet its the wrong kind of brake valve!!

A comment on using down elevator to operate wheel brakes.

When you push down elevator on landing you are trying to lift the tail, which takes weight off the main gear. This will increase the chance of the wheels locking up and skidding. You really want to use a separate channel, and then pull up elevator after the brakes are applied so as to push the mains harder against the ground. You would be supprised how much greater the control is when doing it this way.

As to the right brake valve; I always have to go with the BVM Smooth Stop.

Steven Ellzey
Inventor of the Smooth Stop

When this happened to me with a Robart valve, the lines to the UP-6 brake vale were backwards (air in vs air-out)

I'm just guessing here, but from looking at the picture I think you might have it plumbed incorrectly.
Just for giggles why don't you try switching the the top line on your valve with the one on the bottom left.
I have a feeling it might work better.

Kevin W got it!! It was plumbed wrong. I switched the lines as you said and it works like a beauty!! THANKS KEVIN!

[sm=thumbup.gif]
I'm dropping the invoice in the mail today, I accept cash, or beer as payment.

I got the beer brother!! :-)

why not put your brakes on the slider?

Just easier for me when mixed with down elevator when the retracts are down.

Just remember, even a broken clock is right twice a day!

Hey Kevin, I dropped my wet tank for the first time today, it worked.

You know you and I have something in common...we were both stupid enough to put a wet drop tank on a jet!!

Now what was that they say is the sincerest form of flattery???

I thought I recognized some of the parts for a droppable tank in one of your recent threads. Glad it worked out for you.

Just remember, don't punch it off the airplane until it is empty. LOL

Kevin is one of the “old timers” in this field. Glad he still hangs around here and gives his word of wisdom every now and then.

Chuck another one for one of the most valuable contributor here on RCU.

How did you guess, dropped it after burning about 60 of the 80 ounces in it and cracked the tank. Not my finest hour.

Anyway, at least it stayed on until I dropped it. I used a metal luer fitting as the drop mechanisn and the fuel fitting. Retract servo cranks it on and off.