Wschertz@aol.com wrote:

I think there are different functions for a header tank.  Ed's is to supply a
place for the fuel to return from the excess flow without having to plumb
back to the wings.  The expected flight time with only the fuel in the header
tank is very short.  The standard(?) Lancair has a header tank of ~3gallons
which might give 20 min flight time.

A consideration for design is what happens in a high nose up attitude.  If
you have a header tank on the firewall, being gravity fed from the wings, and
if the header tank is vented, I can see the possibility of having the fuel
drain back into the wing tanks during a steep noseup attitude.  Ed's doesn't
have that problem because of the vacuum pulled by the high pressure pumps.
Check one of Tony Bingells books, he shows a ground test that should be done
prior to (first) flight that entails putting the nose high, the tail low, and
verifying that your fuel system will deliver the required flow when the tank
has minimum fuel in it.

Bill Schertz

The Aircraft Rotary Engine Newsletter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org