ahhh c'mon man !!!!

I already did MS a few yrs ago, so I'll do probably do Tenn since I've never been to that one if they have it this yr. We like to hit new shows every year.

Johnny H.

Woketman you have it right concerning having to maintain two completely seperate air systems (without leaks) at two different pressures. This is one of several major problems with Glennis wheels and brakes. If you use normal pressure (100 psi plus) the Glennis brakes will either (a) lock up (even though Dennis says they won't) or (b) blow the bladder out of the brake. Having a second complete air system just for the brakes is not nearly as simple as Dennis would have you believe. It certainly requires more than just as additional air tank like Dennis spells out in his post. You also need a filler valve, gauge, additional air line, 'T's, and everything else that goes with any other air system. I guess you could use a regulator to provide the low pressure for the brakes. Regulator? Just one more thing to go wrong. And where would you get one?

First time you fill the air systems (additional low pressure one for Glennis brakes) and get confused in the heat of the day and fill the brake system up to normal air pressue (100 psi) of all other standard brake systems you will end up with either locking brakes or a blown bladder and no brakes and no air.

Conversely to Dennis' theory of first having brakes rather than retracts I will take the retracts every time and land without brakes. Landing with the wheels up even with no brakes makes an awful mess of the belly of an airplane.

Answer to problem is not to use brakes requiring a completely seperate low pressure air system. I don't know of any other brake system on the market that won't work with high pressure. Standard "O" ring type brakes are far more reliable and easier to maintain. The "greasing" of "O" ring type of brake is not nearly the problem some make out to be. As Woketman says cleaning and greasing the brakes once a year is all that is needed

Jack Mathias

Just my two cents, I do run 2 seperate air systems. One for my retracts and doors, and a 2nd one for my brakes. The reason is that with retracts requiring air to lock in the up position as well as the down, I want to make sure my air pressure is going nowhere but to those retracts. While it's true that having pressure for brakes is pointless if the wheels don't come down, having brakes linked into the same air system as retracts gives just that many more connection points for failure. I like having as few pieces of airline and T fittings as possible in an air system. True, using 2 systems does require an extra filler valve and tank, you don't HAVE to have a pressure guage in the line, we got along for years without them, but it does allow for 2 individual simpler systems as opposed to one bigger complex system. You have to use 2 servo's and valves anyway, so the extra weight and expense is not much at all.
I've never used glennis brakes or wheels so I can't comment on the amount of pressure needed, all I know is I've always run 120psi for my retracts and 100psi on my brakes and never had any problems.

I've been on the Bruce Tharpe website & noticed this Kavan brake for the Reaction 54 http://www.btemodels.com/r54brakepkg.html
Anyone used one?, the concept looks good. What do you think Mike? (originator) - John.

Barely enough to hold a 54 sized plane at idle, at least the way it is used just on the nose wheel on the R54. Using two may not be bad but, it is also used as nose weight on this plane... yes its heavy.

What are the recommendations for Airpower brakes? I have a SM Gripen on its way to me.
Do they require grease?
What air pressure do you use?

Thanks,
Joe

Thanks for the input Mark, sounds barely enough. I have fitted a Dubro mechanical brake on the noseleg of my (unflown) model & it worked o.k. on the 120 size prop driven model so this may be the better option. - John.

Jack

I'm a bit puzzled by your comments on the 2nd Air System? Why are you concerned about the cost of a 2nd Air Tank and some tubing a fill valve a selector valve and servo what can this possibly cost $150 tops?

The only way to go is 2 Seperate Air Systems and the real truth is my Brakes never leak period they will have pressure for months. My landing Gear I am lucky if I can go for 8 hours.

Running dual pressure concerns you becuasue you might fill the Brakes to a higher pressure? I assure you there are so many greater mistakes you can make other then this. Try Labeling them and marking a small Rede Mark on the airgauge when you get to Max pressure for that system.

I own just about every brake system out there and have to tell u all of them aren't perfect. But the Glennis system is very good in that he is putting pressure on a greater surface area with there design.

Just my 2 cents since we all have $$$$ in these things.

Ian

I've used the Trim wheels from Ed @ GNM on 2 jets now, and I'll likely use them again. My Stingray originally had a cheaper alternative on it, but the saying "buy cheap, buy twice" comes to mind... The Trim wheels/brakes and the Trim valve work excellent from my experiences, after greasing the hub with Parker O-ring lube.

I also use 2 independent air system for the same reasons a Jeremy mentioned, although I only have one inlet for both systems on my Hotspot. Its a single inlet valve, followed by a T, then a check valve to each system. I run both systems at 120psi and see no reason to change since the brakes are activated with my trainer switch. Modulation isn't exactly a concern, and it seem to work well... I tried down elevator mix when the gear's down, but eventually it bit me.

Kelly

Anyone seen this one? None of the problems listed here. In fact two air systems with 120psi each and a fully proportional brake valve - just that simple. Stock standard setup, followed the directions, and they hold at full power. These are the types that use the Glennis setup

Dennis

From a pure probability standpoint, anytime you add more components to a closed system, that increases the probability of a total system failure unless the added components function in a redundant capacity.

If anything in a separate brake system would fail causing you to lose air pressure then all that is lost is brakes. However if a component in a separate landing gear system would fail then you are out of luck anyway and it wouldn't matter if the brakes were part of the system or not.

If channels are an issue, the retract valve and a simple button valve (controling the brakes) could operate off of a single servo. Using a button valve just fill the brake tank to an optimum pressure.

You can also use a single channel and use a proportional valve on the brakes.