jetflyr

I've tried to get in touch with Kevin and Ed up at Great Northern, but they haven't goten back to me.... so I hope someone can help
I finally got my 1 year old Trim wheels and brakes into an airframe, but have only full lock, or no braking action at all.
I had thought that the brakes were proportional,and would have some variable resistance settings
Any help and/or advise is appriciated!
Thanks
Greg

JohnVH

My Feedback: (38)

Thats pretty much how mine worked too. My brake valve was not very proportional.

Brian B

My Feedback: (5)

My Trim brakes seem to be on/off also, maybe a little proportional action, not much. No problem though, as they dont seem to lock up the wheels. Fine with me.

rcav8tr

We are still looking into the issue that Greg has raised. We are currently doing some of our own testing and talking with Trim as to what might be the cause. When we have a solution, we will let everyone know.

Just as a point of information, each valve is tested at the factory before being shipped.

If you have any questions, please do not hesitate to contact me.

Sincerely,
Ed

Woketman

My Feedback: (6)

I have three or four sets of TRim wheels and brake valves. I have used at least two of the valves that I have, maybe three. I have never had a problem. They have always worked well and been fully proportional. You do have to spend some time on set up to be sure it is done right. Can you tell us more about the set up?

Glorfindel

Did you get my 2 last email Ed?? I'm still waiting for the Trim brakes and the Yellow plastic tank for my Stingray....

Gordon Mc

My Feedback: (11)

I have no idea how Trim brakes work, so please excuse my ignorance here - but since the brakes are said to 'lock' no matter which valve is used - could it be something as simple as requiring lower pressure ?

The reason I ask this, is that I run my BVM brakes at about 100 PSI ; my Glennis brakes, on the other hand, need only about 30 PSI - if I have brain-fade and put 100 PSI in them through sheer habit, then they don't seem to work proporionately either - but when run at the recommended 30 PSI they are fine.

Gordon

rcav8tr

Hi Claude

Please see e-mail in your inbox.

Sincerely,
Ed

Thud_Driver

My Feedback: (1)

Note that the area of proportional brakes is only ~1.5mm of travel which is quite narrow. Trim shows a way to get the linkage set so you can get some amount of servo travel which gets this range of motion for reasonably large stick travel. The trick is to get the braking action set in the 60-80 degree rotation range from neutral on the servo. I use a down elevator mix which also sets the range of servo motion in conjunction with the linkage geometry. Also you have to "arm" the brakes by setting the servo to just start the air flow in the valve. I do that with a mix from the gear switch. Takes awhile to set up and the instructions could be a bit better. It also helps to use O-ring lube on the brakes. Stops on landing aren't bad but even with all that, stops in the pits are not always smooth.

Maybe somebody can scan in the Trim instructions for the servo arm geometry.

f106jax

My Feedback: (16)

My Trim brakes also seemed to be limited to either on/off using a proportional valve. The quick and easy fix was to remove the brake O rings and work silicone O ring lube onto the O rings. It does help to wear rubber gloves while doing this otherwise you will have difficulty picking up small items for a while. Since performing this lubrication, I've had proportional braking. I hope that this solves your problem.

Woketman

My Feedback: (6)

I too lube the brakes and do not have problems with them locking. They seem fully proportional to me.

jetflyr

Hey Mark,
I've got as much/little throw as I could get to keep from locking up. Next step was as Mike suggested, lubing with silicone grease.
I'm using a Futab 9C with the brakes on the right slider, not a two step with down elevator as the "instructions" show for a JR.
I won't be playing for the next two weeks But will lube them before then, and hopefully Ed will come up with a simple fix. Just out of curiosity...what air pressure are people using? (Another consideration...)

Thanks
Greg

Woketman

My Feedback: (6)

I use one tank for retracts and brakes. I always fill to 120 psi, so after sucking the gear up, putting them down and landing I probably have 80 to 90 psi left. Be careful what you lube them with as some stuff is incompatible and will make the O rings swell. I ordered a huge bag of O-rings from All O Rings.com. I odered Butyl N (I think) which is compatible with petroleum and so I use Vaseline for lube (that way I always know that if Dan Massey is at a jet meet I can always get some lube!!!). Works great!