"Rich S." wrote in message ...
"Orval Fairbairn" wrote in message
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It depends on how fast you are going. At 200 Kt,you may get about 2" or
so of ram air pressure, which translate to about 1 PSI.

I would probably need it most at best glide speed - you know, when there's
that eerie silence up front.

Say 80 mph or so.

Rich (knots are for boats) S.

Fuel tank venting can be tricky. If you have two tanks, and
there is a "both" position on the fuel selector valve, any difference
in vent pressure will cause one tank to flow faster than the other. If
the difference is large enough, it could actually prevent fuel from
flowing from the lower-pressure tank.
This arrangement has caused accidents in homebuilts in the past,
and it's the reason that certified airplanes having interconnected
tanks (the "both" position) must also, by law, have interconnected
tank venting to keep vent pressures equal.
Ram pressure won't be worth the effort, if you're counting on
pressure to make up for failed pumps. The fuel pressure, and therefore
flow, would be very inadequate and the engine would quit anyway.
The area of the scoop will have no effect on ram pressure.

Install a generic automotive electric fuel pump. Not expensive.

Dan