I'm new to the jet world, and I'm in the midst of putting together a Tamjet Rafale. I've noticed by looking around that some people use two different airsystems. One for brakes, and one for the retracts. Is there an advantage to doing this? Why not just use one system for everything?

Thanks in advance
Sam

you're just lessening the chances of loss of both systems. some people run a single system with no problems but it's nice to still have breaks if you're gear failsafe dropped the gear due to a loss of air pressure, with a single system, you loose everything.

kc

Run brake on seperate system.
Just incase you loss air on retract. You still had brake.

Makes sense...Thanks

Sam

Tam is clearly joking here to me, so you lose air in your retracts, exactly what are brakes going to do for you? The paint job has now become your brakes!!

I look at it exactly the other way around - in case your brake system leaks (as happened often in the days when I still used a Smoothstop), separate air systems means you still get to drop the gear.

Spring Airs will drop if air pressure is lost.
then the brakes are the brakes

I've been using one air system for years, only ever had a couple of problems, and that was before, when I was using two air systems. In the beginning I had two air systems cause I was told that's the way to do it. Then I came up with an imporovement.

Have one air fill, and on that air line, put a T with a check valve on each side, that way, you have two independent air systems that you only have to fill one time at one valve. The pressure will build evenly in both systems.

The only person who didn't like that was my buddy Todd, cause he pressurizes his air system to about 60 PSI instead of the typical 100 everyone has been putting on their retract system.

Each his own I suppose.

Spring air only good for lighter gear and no gear door.
If the wire or strut got little sticky somewhere. It will not come down.
Both air system is the best. Ofcourse until it leak...[:@]

I run one system with the brakes plumbed into the "down" landing gear line. Gear will be down before any brake leaks keep you from getting "3 green"

Not necessarily. Don't forget that the gear need to be down for takeoff too, not just for landing ! If you have a slow leak in the brake system you could be venting air before you even get airborne, such that by the time you go to suck the gear up your pressure has dropped enough to leave you in a kind of no-mans land - gear unlock to come up, but not enough air to pop the gear back into a down lock.