furloughed ual

My Feedback: (31)

I've got an UP6 brake valve that doesn't always release the brakes....more often than not, if I re-apply the brakes, it will release....sometimes it takes more than one try.....makes it a real issue when doing touch and goes with a 45lb jet.....accelleration with the brakes on is really tough, especially uphill

Servo travel is not the issue, since it obviuosly releases the brakes most of the time.....anyone had this happen and is there a fix....I was gonna call UP but forgot....I'll try Monday, but thought I'd post here until then...
Thanks.

Vincent

My Feedback: (61)

I have had that happen too. Never paid it much attention, just waited a second or two and it released. What type of brakes are you using with the UP6, it does not work the same with all wheels and brake setups.
V..

furloughed ual

My Feedback: (31)

it's on a SkyMaster Mb339 with SM wheels and brakes....a second or 2 is life or death while shooting touch and goes.... I actually had it stay on to the point where nothing would release them sfter engine start....I had to pull the out line to the brakes and let the pressure out....worked fine after that.....

Tom Antlfinger

My Feedback: (24)

I have had this happen on both my UP-6's and now on the BVM Smooth Stop II on my Bobcat.....

I have taken the cylinder out(careful with the snap ring......very hard to replace if you lose it......then clean the unit inside and out with isopropyl alchohol. I use a fine wire, I think .021 to purge all the orifices. I don't take out the O-rings. Then I reassemble using O-ring grease I use on my Nikonos Underwater camera O-rings, sparingly, avoiding filling the orifices. I like that stuff better than the more liquid or jelly stuff BVM recommends for his valves.

This has worked every time for me.

Tom

pratorian

just wondering... why do you apply brakes on a touch & go ?

furloughed ual

My Feedback: (31)

I have brakes preloaded and set to a soft setting when I pull full flaps.....we fly at 6500' on a 650'runway.....in the summer, the density altitude can be as high as 9500'....much differnet than most at sea level ( I love going to meets "down low in the good air" ) I have a mix to automatically disable the brakes when the throttle stick is 2 clicks from full throtle....this is very similar to any transport category (airliner) full scale aircraft.....when we push the thrust levers forward on a go-around or a balked landing on a fullscale, several things happen automatically to prevent twisted aluminum and huge fireballs....2 of the most important being the anti-skid/autobrakes automatically release and the ground spoilers on the wing automatically retract if already deployed, cleaning up the wing and allowing it to do what wings do.....fly....

Normally, when I do touch and goes with the Mb339, just as the mains are about to touch the runway, I go to full throttle and the brakes will automatically release.....should I decide to abort for any reason, the brakes will automatically re-engage to help stop when the throttle stick is pulled back.....