The early 2-place Lancairs, like mine, use a header tank as the distribution point for fuel to the engine.  It is treated like any other fuel tank, with a vent line that goes overboard with its open end at the top of the tank and its outlet on the bottom of the fuselage.  Fuel is drawn out of the tank from a sump in its bottom.  Fuel is fed to the header by Facet transfer pumps as required, an automatic system handles the fuel management and a sight tube verifies header tank fuel level.

Rather than dealing with the heat issues under the cowl it has always made more sense to me to keep the fuel pumps and fuel pressure regulator inside the cockpit, mounted to the back of the firewall, with only a single fuel fitting penetrating the firewall to feed the fuel rail and another fitting to transmit MAP into the cockpit for the regulator and MAP sensor.  The return from the regulator, being on the cool side of the firewall, eliminates the problem of sending heated fuel back to the header tank and should reduce the potential for a vapor lock completely.  I realize that a sump tank system (one with the central tank at the same or lower level as the mains) has some different factors in the mix, but keeping the pumps and regulator on the cool side of the firewall would still solve the problem.

I realize that most folks would consider all that fuel stuff inside the cockpit to be a large safety issue, but when you consider that everything could be plumbed rigidly with well-supported hard lines it seems to me that there is actually very little that could go wrong as long as all fittings are torqued properly and the components are located out of the way of the occupants.  If one trusts all those connections on the hot side of the firewall, where the potential for a fire starting if a leak does happen to spring is far greater, then why not apply that same trust to the cool side of the firewall, where other problems simply go away?

This subject surfaces every couple of years, and it's always nice to revisit it for benefit of the newcomers to the list... fortunately my position has always remained the same, but I'm open to new comments and welcome new discussion.  Thanks.....

 <Marv>