ORIGINAL: Aussie Bart
UMS controller capacitor seems to be the culprit as I had suspected earlier, all of my units are at least 12 months old and have never failed but they are also fitted with the 10u 35 volt caps as standard.
The UMS valve (in my cases) really does not seem to take much power to move. I tend to use the Bluebird thin wing digital servo that is rated at 5 kgs/cm. The piano wire link I use from the servo arm to the valve spool is fitted right next to the hub of the servo horn and maybe 10 mm (1 cm) distance out from the horn screw which give a theoretical force of 5 kgs. Because the spool movement is so short, you need to keep the servo arm attachment as short as possible anyway. I like the idea of John Mac about using the retract servo, I might try that on the F14 when I fit that out.
As mentioned earlier, once you fit the Festo Pilot Check Valves your main will become rock hard, just try and remember to put some safety wire or similar on the tube where ever it goes over a barbed fitting. The reason the mains feel softer compared to the nose is the angle the cylinder sits on and therefore the force ratio it can achieve. With the Festo valves, my Mig sits on its mains for literally weeks (and has no reason to ever leak down), I actually end up with flat spots on the tires....
As for the manifold arrangement of the valve, it is already set up with the 3 ports, I also fitted 4 mm to 3 mm reducers on each port to allow the tube fit up. If you have a look at my earlier post at the top of this page there are 5 photo's (scroll across), I am not sure why but the 5th photo seems to be just an icon that you need to click on, this photo is actually the hydraulic circuit showing just how these valves are set up and work, I hope you guys can see this ok, if not let me know and I will try and post again.
Like most of you, I would be really keen to see if JL have resolved this problem although it seems that no one has any idea if the ''upgrade'' even exists. I was going to buy the SU27 and although I know how to fix the gear (it has the same setup as the Mig), in principal I won't buy it until I know they have addressed the issue because from where I sit they continue to sell aircraft with UC that is guaranteed to fail and they don't care.
I hope you all have a merry Christmas and behave yourselves, unfortunately I have to tell you that during this holiday season I will have to fly my Mig in this glorious Aussie weather on retracts that work just oh so sweet.