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