On 10 Nov 2003 17:04:49 -0800, (Dan
Thomas) wrote:

"Rich S." wrote in message ...
"Orval Fairbairn" wrote in message
news

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.

I think you will find even certified planes like Bonanzas have an
either, but not both.

As I recall the Cherokee was the same way, but didn't have aux tanks.

Ram pressure won't be worth the effort, if you're counting on

It probably wouldn't be enough to push the gas half the height of the
tank unless you were really moving.

Roger Halstead (K8RI EN73 & ARRL Life Member)
www.rogerhalstead.com
N833R World's oldest Debonair? (S# CD-2)

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