Anybody using a vacuum venturi driven gyro on a slow plane?
My plane has (came with) a gyro turn and bank, driven by a venturi mounted under the fuselage, between the landing gear. It never worked, at speeds up to 80 kts. The instrument itself works (verified on the bench with a vacuum pump) but the venturi draws no vacuum. It wasn't plugged, but I took it off and cleaned it anyway, driving at 80mph in the car it produces some vacuum, but not the 2" the instrument requires (I haven't put it back on the plane yet).
From what I understand, they're rated at 100 mph, so a venturi that draws 2" of vacuum would only draw 1/2" at 50 mph, but being in the prop blast... I don't know. I shouldn't really need it in a plane like mine, but I had one in my T-Craft years ago and it saved my butt once when I waited a little too long to turn around in bad weather, so it's comforting to have.
Dana
My plane has (came with) a gyro turn and bank, driven by a venturi mounted under the fuselage, between the landing gear. It never worked, at speeds up to 80 kts. The instrument itself works (verified on the bench with a vacuum pump) but the venturi draws no vacuum. It wasn't plugged, but I took it off and cleaned it anyway, driving at 80mph in the car it produces some vacuum, but not the 2" the instrument requires (I haven't put it back on the plane yet).
From what I understand, they're rated at 100 mph, so a venturi that draws 2" of vacuum would only draw 1/2" at 50 mph, but being in the prop blast... I don't know. I shouldn't really need it in a plane like mine, but I had one in my T-Craft years ago and it saved my butt once when I waited a little too long to turn around in bad weather, so it's comforting to have.
Dana