To bypass or not to bypass, that's the question!

So I made some measurements today, and with full wings (45 liters, a little over 12 gals) the fuel flow was 15 l/h (4 gals /h).

So yeah, I don't believe fuel flow would be adequate at takeoff pitch with say only 4 gals of fuel remaining (go around situation).

Your a good person Mark.

15L/hr will keep a rotax 912 ULS running indefinitely in Cruise BUT as you say, a diffrent matter at the critical take-off power/stage.

Well done. RW will be well satisfied as I am.😈

All fuel systems are different in different planes. Things like a low wing vs a high wing. Different fuel hose sizes, routings, ect, ect.... Each plane would have to be tested individually. I probably shouldn't post this, butttt.

I had a Flight Design CTSW and have over 2K hours in them. Because people were locked into the 2.2 psi low fuel pressure info which is a good psi not to exceed lower. But I did a test on my CTSW (high wing). I removed the inlet and outlet fuel hoses off the mechanical pump and joined them together with just a metal tube. I ran the engine and it could get full rpm without any sputtering. Then I reattached the fuel hoses to the mechanical pump and removed the pump off the engine and just let it sit there. I put a blind plate over the pump mounting hole to not lose any pressure or oil. Then I ran the engine with basically a dead pump in line. It ran fine, but going over 5K rpm would make it cough and sputter. So you could have flown it under 5K rpm somewhere for a safe landing. So my test on my plane only showed it could run with a dead pump and with just head pressure.

This was on this plane and fuel system and isn't representative for other aircraft. I would never recommend trying to fly like this, but I was curious about a head pressure and or a dead pump. I've personally never seen or heard off a TOTALLY dead pump. They do fail open.

Last thing is a do believe in electric backup pumps and or a bypass for some fuel / pump setups. Like I mentioned different aircraft have different setups. It isn't a one size fits all when it comes to our system components.