Air System Problem
 

Im setting up my air system for my gear and I'm having a bit of a problem. Im using the Robart 167VR (Red Valve) and I'm getting leaks constantly when I shift the rod. I realize Im only suppose to move it a quarter inch so Im taking that into consideration. Does anyone else use these with success? What other system is out there that is fool proof, I'm tired of messing with sub par crap.

Luis

RE: Air System Problem
 

Is it leaking around the rod?

RE: Air System Problem
 

Best I can tell, its leaking via the ports that are there to adjust the speed of the retract. I took them off because I didnt want a delay, but it leaks there regardless.

Luis

RE: Air System Problem
 

Put them back on and back the needles out until you get the speed you want.

RE: Air System Problem
 

I should also say that Im bringing the system up to 100 PSI. It hisses pretty good until it get down to about 40PSI then stops. Funny thing is that I can fill the tank up to 100PSI with the gear retracted but when I bring them down is when it leaks real bad. Any suggestions?

Luis

RE: Air System Problem
 

I never liked the adjustable Robart valve---Get a non-adjustable version and your troubles will go away----Or go with an Ultra Precision Valve which has guaranteed adjustability and WON'T LEAK!!![8D]

Kevin

RE: Air System Problem
 

I ended up carefully applying some hysol 9462 like a caulking joint between the fitting and the valve body on mine. Keep it off of the needles however. If you don't need speed regulation, I would use either a plain robart or preferably a BVM unit.

RE: Air System Problem
 

Thanks for the info guys. Found out it was a main retract that was leaking... have adjusted the retract and no more leaks from the valve but it still doesnt hold air for more than 15 minutes.

The search continues

Luis

RE: Air System Problem
 

I use the Robart red valve with my Robart retracts in my Reaction54.

I have removed the needles completly. I put a little silicon oil in the lines. I can leave it pumped up all day with no leaks. I can get three or four flights (retract cycles) from one tank of air.

You must have another leak somewhere.

Regards

RE: Air System Problem
 

Tom. how much silicone oil do you use and do you put it into the entire system or just the valves? Thanks, Richard

RE: Air System Problem
 

Hi guys!

The needles in the red robart valve are restrictors for the vent-line, so it doesn't matter... What kind of tube do you use? The brass-nipples on robarts are pretty small so I suggest to just use robart-lines and connectors.

Take some water with soap, put it on all the connectors and watch out for bubbles :D

Greetz,
D
avid

RE: Air System Problem
 

Check the air cylinders on all the gears and you will find your problem. One or many of them might have a blow back air leak.

RE: Air System Problem
 

Hi Richard,

I got the oil from BVM. It comes with a little syringe. I jut put about 1cc into each line that goes to the retracts. Then I put some into the line that goes to the valve. You get a little oil escaping when you disconnect the wing . I havn't put any more in and I have had >40 flights with this model. I guess you would need to put some more in after a while.
I don't think it will stop leaks but just seems to make everything work smoother.

Regards

RE: Air System Problem
 

I had a couple of big time hair fires also with the same situation [reported by B1Driver] before I stopped swearing at the valves. The oil in the system seems to prolong cylinder seal life but I guess you finally reach a point where you either rebuild the cylinders or ditch them altogether ... ?

Mike

RE: Air System Problem
 

Thank for the inputs guys.. Im going now to check the cylinders on the retracts. The retracts are the ones that come with the A-10X jet that I bought from Todd at Dreamworks. Anyone else have this problem with those retracts?


Luis

RE: Air System Problem
 

Luis, if you read through the a-10x threads, your not the first to see this problem. Todd at one time was selling Robarts for an upcharge on the difference. I want to say it was around a hundred bucks. Don't know if he can exchange on warranty? But I'd ask.

RE: Air System Problem
 

I FOUND THE CULPRIT!!! One of the mains cylinder is leaking around the cap when the gear on on the gear-up cycle. I've gone through the whole system and corrected some bad fittings but this cylinder is leaking REAL BAD. I'll call Todd tomorrow and see if I cant get a one for one exchange. At first I thought it was every cylinder but it turns out to be just the one. Thanks everyone for your help.

Luis

Anyone got a fix for this or is the cylinder shot?

RE: Air System Problem
 

Todd is at Florida Jets.

RE: Air System Problem
 

Hi Luis,

I've had the same problem with every red robart valve I have tried and I have since removed them from my jets. The blue ones don't seem to leak as badly but I think the red ones are junk. Ditch 'em!

Craig.

RE: Air System Problem
 

I agree that the Robart red valves are total junk! I have had a couple of them leak as well too.However I also had one of the Robart blue valves that leaked really bad.I have since gone strictly to the newer BVM high flow gear valves or UP units.The BVM high flow valves are only like 15 bucks more and work flawlessly everytime!The UP valves are more $$, but if you need more versatility on certain gear/door setups then they are the way to go;)This is just my opinion of course

I feel that with the amount of $$ we have invested in our jets,saving a few bucks on a gear valve isn't worth it when you go to put your gear down only to realize that they arent working at all! So my opinion is( long story short) that if you pay a little more now for a higher quality gear valve you won't take a chance later trashing your expensive paint job or ordnance on a gear up landing!!:DThis of course doesnt do you any good if you have a leak in your gear directly but it surely knocks out one more potential headache in your gear setup.I also always use a pair of air gauges to monitor air support,these are your best friend too!


Steve

RE: Air System Problem
 

Talked to Todd today. Seems to be a faulty O-Ring in the retract cylinder and he said he'd fix it up for me. Im gonna check out those BVM valves, most likely buy 2 of them. Thanks again everyone.

Luis

RE: Air System Problem
 

Can I make a suggestion? As long as you are blowing $40(?) or so on two new valves, check out the Jettronics electronic valves. I LOVE them. Makes life a whole lot easier.
Also, hemostats are the best way of running down air leaks, just start clamping things off, working from one end of the system to another.
You should be able to hold your air overnight, at least. At least. If not, you WILL have gear problems.
Check out any plastic t-fittings, they leak a lot.
Also make sure you cut your tubing dead square. I use a special cutter from Clippard.

RE: Air System Problem
 

B1 Driver, JMP makes a nice valve that is simple and moves lots of air, cost is $20. They don`t leak either. V..

RE: Air System Problem
 

causes of leaks :

cylinder
drum if the breaks leaks
connections specially some tubes also plastic connectors sucks
o rings for cylinders , valves, sequencers ...etc

if its done right and maintained all models and makes are good

RE: Air System Problem
 

Steve

Do you still have those junks? I will pay for the postage if you send them to me free.

FWIW. 99.99999% of the time when you get air leaking from the actuator; the culprit must be a faulty gear air cylinder. Spend few minutes and think about the mechanics of how the whole pneumatic landing gear system operates (including the actuators) and you will understand what I’m talking about.