Retracts

[Ron Gray]

Have you tried operating the control valve by hand, rather than the servo? The reason I say this is that the servo could be moving the slide bar too much, I had exactly that problem on one of my installations and it became obvious when I operated it by hand and could hear the air leaking when I moved it too much. As a result I change the end limits and servo centre for that channel on my Tx and the problem went away.

Edited March 25, 2023 by Ron Gray

[Artto Ilmanen]

28 minutes ago, Ron Gray said:

Have you tried operating the control valve by hand, rather than the servo? The reason I say this is that the servo could be moving the slide bar too much, I had exactly that problem on one of my installations and it became obvious when I operated it by hand and could hear the air leaking when I moved it too much. As a result I change the end limits and servo centre for that channel on my Tx and the problem went away.

Yes,

 

I have operated it only by hand - although I have not played with moving the spool at different lengths. But, as I have operated it by hand there is no excessive force or side play applied. But, I can try again. Let’s see.

 

[Artto Ilmanen]

ok - I played with the air control valve moving the spool in different length manually. No help, see video

 

 

[Paul De Tourtoulon]

The only ones that have never given me any trouble are the Robart ones, a spray of silicone grease now and then,

as for the servo throw I use a sliding bar with a wheel Colette on each end and a piece of silicone fuel tubing to keep the valve drawer in the right place, I can take a photo of my 20-year-old plane with it still working in it.

 There are electronic ones, but they don't like a lot of pressure.

 

 

 Ps I also have a couple of those leaky blue ones "any offers",,,😅

[Artto Ilmanen]

Thanks Paul,

 

I may try new O-rings as I need not get them in other sizes, too. If it doesn’t help then a new one, most kikely a Robart blue

[Frank Skilbeck]

Bit more money, but the other option is to go for one of the Jetronic electronic valves, fitted them to my mates 190 and it works really well. You can adjust the speed to.

[Artto Ilmanen]

thanks Frank 

 

what is the secret sauce of the Jetronic electronic valve?

[Frank Skilbeck]

It uses solenoid valves to control the air, on my mates 190 we pump it up to 110 psig and it holds it there. It also has the option to isolate the air at the valve after a period of time, so if you had say a leaking retract unit, you'd only lose air from the section of line downstream of the valve (note on my mates 190 we had to disable this feature as the tailwheel retract isn't the locking type).

 

It's a neat unit that replaces the servo and air valve, they do a whole range of units for different types retracts whether they are air up/spring down or air up/down. More info here

[Jon H]

i thought you meant fill valve as well. 

 

Not seen that sort of leak on my units at all so its new for me. I would change the O rings and lube it up with some grease before spending big money on a new valve. 

[Artto Ilmanen]

9 minutes ago, Jon - Laser Engines said:

i thought you meant fill valve as well. 

 

Not seen that sort of leak on my units at all so its new for me. I would change the O rings and lube it up with some grease before spending big money on a new valve. 

Thanks, Jon,

 

So you have had better luck with ESM similar control valve units? 

 

Anyways,  easy to test now as the system is now at hand. 

Edited March 25, 2023 by Artto Ilmanen

[Jon H]

yea i have had no bother with them at all. only used 2 of them mind you but both without issues

[Artto Ilmanen]

1 minute ago, Jon - Laser Engines said:

yea i have had no bother with them at all. only used 2 of them mind you but both without issues

Thanks - then most likely I should be good with new quality O-rings. Let’s see

[Ron Gray]

IMO the slide bar in your vid is too far in, pull it back a bit. That is exactly what I had with mine, I pulled the bar back a bit and it sealed. I reasoned that the O ring was going past the air tube so let the air out along the bar, moving it back meant the O ring was the ‘right side’ of the air tube so blocked any air from escaping.

[Artto Ilmanen]

31 minutes ago, Ron Gray said:

IMO the slide bar in your vid is too far in, pull it back a bit. That is exactly what I had with mine, I pulled the bar back a bit and it sealed. I reasoned that the O ring was going past the air tube so let the air out along the bar, moving it back meant the O ring was the ‘right side’ of the air tube so blocked any air from escaping.

 

Ron, although it was not seen on the video I did try exactly what you write - no help, unfortunately. But I will change the O-rings. With any luck I should be good, if not, then a new valve.

 

But I also need to ensure I use proper grease - any recommendations? Just normal vaseline or something else?

Edited March 25, 2023 by Artto Ilmanen

[Ron Gray]

As Paul said above, silicone grease would be good. 

[Artto Ilmanen]

Oh, I see - Paul did mention that. 

 

Thanks Paul & Ron

[Ron Gray]

As a matter of interest does it leak from both ends?

[Artto Ilmanen]

31 minutes ago, Ron Gray said:

As a matter of interest does it leak from both ends?

 

I tried again - I also dismantled the thing but no aid -  it leaks from both ends. I also tried to play with the slide bar one more time. see video.

 

 

 

 

 

[Paul De Tourtoulon]

I tried jet tronic ones, and they wouldn't open over 6/7 kilos, they jammed shut.,

 want two up for sale,,,🤐

[Artto Ilmanen]

Ok, thanks for everybody for valuable advice - I certainly know how to fix my air control valve issue now.

 

Another thing: I need to get a pump to fill the air tank at the airfield.

I have been thinking of a Robart hand pump or some electric ones. My starter runs on a 3S lipo so maybe I could use it as a power source for the pump. Also, a quality gauge is obviously needed.

 

What kind if setups do you gents use at the field to fill the air tank?

[Frank Skilbeck]

3 hours ago, Paul De Tourtoulon said:

I tried jet tronic ones, and they wouldn't open over 6/7 kilos, they jammed shut.,

 want two up for sale,,,🤐

I assume you mean 6/7 barg, the one on my mates plane operates fine at 7.5 barg, it is operating on a 2s lipo system though

[stu knowles]

If you connect the two outlets together in the way that you have you will get an apparent leak as one tube would be driving the retract and the other will be open to the air.

Attach two separate tubes, each with one end blocked and try again

[Paul De Tourtoulon]

10 hours ago, Artto Ilmanen said:

Ok, thanks for everybody for valuable advice - I certainly know how to fix my air control valve issue now.

 

Another thing: I need to get a pump to fill the air tank at the airfield.

I have been thinking of a Robart hand pump or some electric ones. My starter runs on a 3S lipo so maybe I could use it as a power source for the pump. Also, a quality gauge is obviously needed.

 

What kind if setups do you gents use at the field to fill the air tank?

Mine is a cheap one, probably £10 at the time running on a 3s 2200 lipo.

[Jon H]

9 hours ago, stu knowles said:

If you connect the two outlets together in the way that you have you will get an apparent leak as one tube would be driving the retract and the other will be open to the air.

Attach two separate tubes, each with one end blocked and try again

 

good point, didnt spot that

[Artto Ilmanen]

9 hours ago, stu knowles said:

If you connect the two outlets together in the way that you have you will get an apparent leak as one tube would be driving the retract and the other will be open to the air.

Attach two separate tubes, each with one end blocked and try again

 

good remark - now that you say it it's obvious.

 

Will try again although I do believe the problem persists