Inverted with a flop tube?

[RV7Ron]

Hey guys, as I get ready to take delivery of my wing kit, the issue of a flop tube is coming up and whether I really need one? If I have a FI system with no inverted oil, how long can I expect to be inverted without having a fuel starvation and/or oil problem? I dont plan on extended inverted flight, but would like to be able to flip 'r upside down for a little while if the mood strikes. Also if I were to add an inverted oil system later, how hard would it be to install a flop tube after the fact?

[ken westlund]

Ron, I installed flop-tubes in both wings in my 7. I have not flown yet but like you thought about extended inverted flight at a later date. It seems it might be quite an undertaking to put the tube in later. The fuel pick up is located differently as is the fuel tank sender. Although it probably could be done it would be much easier before you close the tanks. You will at least, in my oppinion, have to remove the tanks from the wings to install at a later date. K

[Vern]

See my post under aerobatic engine today

[sandifer]

Ron, to start - check out Ron Schreck's great post from a couple days ago:

www.vansairforce.com/community/showthread.php?t=51286

What is your mission? Do you want to leave open the option for doing competition-style negative G maneuvers? If not, you can "flip 'r upside down", all you want...you just can't sustain inverted flight. You can be inverted under positive G with no fuel/oil delivery issues. Oil pressure will immediately drop off with the onset of negative G. Unless you have an inverted system that will re-establish oil pressure under negative loading, you don't want a lack of oil pressure for more than a few seconds.

That being said, it would be pointless to have a flop tube if you will NEVER install an inverted oil system. Why not install both the flop tube and inverted oil system now, while it's much easier? Then the capability will be there whether you use it or not.

[RV7Ron]

Originally Posted by sandifer

That being said, it would be pointless to have a flop tube if you will NEVER install an inverted oil system.

This statement is exactly the kind of answer I was looking for, that pretty much sums it up. Thanks for the info guys.