Monday, May 02, 2016

Trim knob and tank valve

Riveted on the trim knob holder. The tank main shut off valve kit from Airward looked OK, but the design is not good. The idea is good, but the way it is done it creates way too much lateral moment on the valve to my liking. The valve itself is fastened to the tank by "fusing" the fittings somehow into the plastic of the tank and can't possibly take much forces before it starts to leak. It is really an incredibly poor design. First the fastening of the valve to the tank through the fittings, then the position of the valve itself that in the original layout is impossible to reach with the belts on, and impossible to see if it's on or off.

What I can do is to modify the Airward kit so that it creates no lateral moment. That is an easy fix, but it would still create lots of "tangential" moment on the fittings in the plastic. The best thing is to install a real shut off valve mounted on the airframe, but that will also create more head loss, and where to put it? Have to think about this a bit.

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