Is the Onex really aerobatic capable?

[mike.smith]

Just keep in mind fellow aeronauts. The Onex fuel system is designed to only operate correctly in positive G's. Negative G's could cause you to run out of gas and vent liquid from the tank vent.

And I might add, the Onex tank vents out the bottom of the plane whereas the Sonex vents on the windshield and gasoline on the windshield results in cracks. That's why mine needs replacement.

I changed my Sonex to vent out the bottom of the cowl :-)

[mike.smith]

The videos are impressive.
Did you need to modify the fuel system to support the manuvers?
Im not sure its practical but I was wondering how, if at all, the onex / sonex could stay inverted in flight. Im assuming at most ots during a manuver that causes a positive g on the airframe. But if trying to fly inverted on purpose at steady state conditions how long would be reasonable? A few seconds, not at all?
Is there a modification i should make now before i install the fuel tank that would facilitate this or is the engine and its oil sump the limiting factor?

No modifications made. The AeroInjector (no float bowl) works well as long as there is some head pressure, which is anything over 0 g's. I've never had the engine hiccup in any of those maneuvers I do. You certainly cannot stay inverted without an appropriate inverted fuel/oil system. I don't know anyone that has actually done it with a VW.

[PeterLovell]

Hi Matt,
I have installed a dry oil sump And modified the engine significantly and have 2 parallel fuel delivery systems, the gravity fed system for normal flying and an electric pump for inverted flying.
I followed the recommendations in the aero carb manual for the fuel pump and regulator.
I have had it up to +5.5g and -3G . I can climb inverted at 100+ knots.
I love my Onex and we have a few keen aerobatic pilots near here who have been giving me help and hints.
I can roll without losing any altitude, now doing hammerheads where I come down inside my own smoke.
Jeremy Monnett once said in a video that the Onex is”simply a blast to fly” and that is very much my experience.
Peter
Onex VH-BHU, number 120