Black 6 Thu 19th Apr update re Spit II

[camber]

Originally Posted by JG5_emil

Ivan/Banks
"up to the rated altitude this will increase boost (about 12lb./sq.in. at sea level)."

It looks to me that 12 Lb boost is only possible at or close to sea level and that the amount of boost decreases with altitude, which makes sense to me. Is this correct or wrong?

Hi Emil, it is Fruitbat said, a bit of extra info:

The supercharger can deliver about +20psi at sea level with throttle valve fully open, so the boost controller quietly (without moving the pilot handle!) moves the throttle valve to give +12psi if the red cutout is on. When altitude has increased to where the supercharger maximum output is +12 psi, the boost controller cannot control any more (both the pilot's throttle handle and actual throttle valve are at 100%), and the boost will drop from then on.

This will happen a bit earlier than if the boost controller was on +6 1/4 boost, so the full throttle height is lower for +12psi than +6 1/4 psi. It is still >15000 feet though.

The gate system is different though because it gives a set throttle valve position...it will give the higher boost at takeoff, then decay quite rapidly to the lower controlled value (and stay there) as you climb. I think the system should act exactly the same if you are through the gate or not, above a few 1000 feet.

camber