It was with fear and trepidation that I poured four gallons of fuel into the tank for the first time, exposing the entire system -- all the fittings from the tank to the engine and back to the tank -- to gasoline. I had tested the tank itself when I first built it back in North Carolina (see earlier post detailing that particular Klöster Föken), but the rest of system had never seen fuel, much less pressurized fuel. When I first added the fuel, I did so with the fuel valve in the cockpit closed, limiting the gasoline to about half the fittings with gravity. providing the only pressure (~0.5 psi). All appeared well. I then opened the cockpit valve. Seemed OK. When I switched on the pump, however, I immediately had a leak which I eventually traced to the fitting going to the fuel flow meter. Tightening this seems to have fixed it.
For the actual measurement of the flow rate, the manual says to remove the fitting at the gascolator outlet, slip a 5/16-inch fuel hose over the fitting, turn on the pump and measure the time required to pump one gallon into a gas can at waist level. The time is not to exceed 180 seconds.
The first problem with this scheme is that without completely removing the bottom cowl, which involves detaching the oil heat exchanger from the cowl (a major PITA), the fuel fitting must be accessed from above. I did remove the piano hinge wires from the lower cowl, allowing it to swing down a few inches with the oil cooler still attached. With the new RV-12s, the oil cooler is no longer attached to the cowl, eliminating this headache.
The second problem is that a 5/16-inch fuel line doesn't come close to fitting. The male threads on the fitting measure about 0.55 inch, so a 1/2-inch line fits well. I used a short segment of 1/2-inch, a right-angle fitting, then the rest 5/16-inch. The right-angle fitting made it possible to hook it up from above.
The time required to pump one gallon was 170 seconds. Next up is doing the purge process to get the air out of the oil lines and lifters, burp it, and start the engine!
I recently returned from my 36th pilgrimage to Oshkosh. The big news at the show was the final publication of MOSAIC, the long-awaited update to the rules governing Light Sport aircraft and Sport Pilots. It's simple now: any aircraft with a clean stall speed, Vs1, of 59 knots or less can be flown by a person holding a Sport Pilot certificate. All of Van's airplanes with the exception of the RV-10 qualify. No medical. Retractable gear with a variable-pitch prop: check. Wanna fly a 182 or a Stearman? You're good.
