In article ,
"Rich S." wrote:

I am building an air scoop to direct ram air to my fuel tank vents. The
vents (2) exit the bottom of the fuselage at 90° to the airstream. The scoop
will fit over the top of the vents and is shaped like ¼ of a football. It is
in the propeller arc.

The inlet area of the scoop is .84 in². There will be three 3/8" OD aluminum
tubes inside the scoop through which the air will flow. Two of them are the
vents for the front and rear tanks, while the third is the drain tube for
the rear tank fill. (There is a fuel door on the top of the fuselage for the
rear tank. The tube is intended to drain any liquid such as rainwater or
fuel overflow from the area inside the door.) Any air entering the third
tube will exit around the fuel door with only the friction loss from the
tube to restrict flow.

Am I wasting my time, or will there be enough ram air pressure to actually
assist fuel flow in the event of multiple fuel pump failure or vapor lock? I
suppose I could put a check valve in that third tube so air couldn't flow.

Rich S.




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.