Guys, I am at a loss on how to hook up the air hoses for my door retract system. I am using a BVM micro switch and a air cylinder. My problem is how to hook up the air hoses using whats in the plane. The first pic shows my servo with the switch to opereate my brakes. The small clear line operates the brakes. It has its own tank and works fine using the down evelator but only works when the gear is down. The next pics show my micro switch which works when the nose wheel hits it . I don't have any lines hooked up yet. There is a connection for three lines, one on the top and two on the side. The next pic shows my air cylinder with two connection.

My question is how do I hook up the lines to push the door open and pull it closed. Do I need different air valves or can I use what I have. I even have instruction but they show a system for mains and nose door and I'm only using the main gear door. I know this sounds complicated or at least to me, so if you have any suggestions I would love to hear them.

Ken,

I am not familiar with the type of valve you show in the pictures. I have not seen that type of valve with three nipples before. I have successfully used a similar valve from BVM. Find it here at the bottom of the page:

http://bvmjets.com/Pages/Catalog/air.htm

It looks like yours might be a BVM unit but I am at a loss to explain that 3rd air nipple. You can see that the BVM unit has a hole where your third nipple is.

Steve,
All of those little button valves have three openings even the one pictured on bvm`s site. It just doesn`t have a nipple screwed into it. That opening is where the pressure releases. They work well, just have to hook up the retrac "up" side to the button and then the cylinder, it will close the door when the strut hits the button. The down side air will kick it open with the gear at the same time.
V..

Two years ago, I sat down to figure out how to do that system that he showed in the ole bandit I had (was working from memory). I was recreating it with a clippard valve. Took me 6 beers and 3 hours to get it to work right.

So if you are only 20 minutes into it, keep working, it will finally make itself out to you.

Finally I was able to do it, and as I recall, vincent's method is what worked.

Thanks for the replies. So all I need to do is run a air line from the two connectors on the switch to WHAT..... and they have a line on the top and botton of the cylinder that goes to WHERE......

Vincent, so in other words, do I tie into the main retract line for both up and down. My retracts are only air up and spring down so I guess the air up line will work both the up and down cylinder. The valve ties into the main air line and the cylinder air lines go directly to the valve.

Meekskin,
The valve to the retracts goes to each retract. on the two lines going to the front gear there should be two line (down and retracted (up)). Makes sure the gear works, then go from there.
Next cut the line going from the valve to the down position, and put a "T" in it. the new line goes to the gear door cyclinder that pushes the cylinder open. Lost yet? If not now go to the line from the valve to the gear up position and put in a "T". You need to know which of the two **** on the clippard you need to use. Stick a piece of line on the bottom and blow in it, no air should come out. If it does try another *** until you find one that it does not come out. When you push the button then it should come out. Which ever *** the air comes out of, you run a line from that *** to the closing end of the door cyclinder. now mount the clippard valve where it contacts the gear leg when the gear retracts. SHould work. Harder to explain than it really is, but it works.
Tommy

This setup won`t work with a single line retrac system. You need to tap into the gear up to close the door and the gear down side to open it. Maybe you could fabricate a spring setup on the door instead?? or use a seperate air tank with minimal to keep the door open and then the up side gear pressure will overtake it and close the door, the same seperate pressure would then bounce the door back open once the up pressure is blown off...ugh
V..

Mike James made a rubber band retractable door.

Do a search for it, it was well engineered, and would work in your situation possibly.

Thanks again guys for all the comments....I think I will try something different like some type of manusl system. Vincent, I will do a search for the rubber band method. This really sucks, since I paid about 60 dollars for the cylinder and valve and now I can't use it.

Maybe this will help.

I wrestled with the same problem for my Maverick nose gear door. Since there is only one line going to the retract you have to be a little creative. After an hour or so I came up with the attached. It works fine. The restrictor on the relief side of the button valve is optional, it reduces the amount of air used each time the doors are cycled.

If you want to do this for two mains then just tee the two retracts together, and tee the two cylinders together. Put the button valve on the side that retacts the slowest. Another option is to use two button valves, one for each side but that's really not necessary.

Joe

Joeflyer, thanks for the drawing and the comments. You diagram makes sense to me and I think I can make it work. Will give it a try because at least I understand the setup. Billy, thanks for the drawing, but I don't have the type of system your diagram shows. Mine is a single line system which to me makes it more complicated.

Joeflyer, You show on the diagram that the top outlet on the side of the button switch is restricted. Is this a correct assumption.

Meeskin,

A simple rubber-band system to hold the door open would probably work well. Do you still have the little connection points attatched to the hinges? If so, you'd enlarge one of those holes and secure a rubber-band between it and the opposide side of the door opening. It would have to be a strong enough band to defeat the drag on the unpressurized air cylinder.

Meek,

Yes. When the strut hits the button air pressure in the line from the upper cylinder nipple is vented to atmosphere through that outlet. Putting a restrictor there slows it down so that the gear door doesn't slam shut.

Joe