I know the RV's can do rolls and loops...

[danielhv]

but can they maintain inverted flight for longer than a second or two? Whats the longest someone has maintained inverted flight?

[asav8tor]

With an inverted fuel (flop tube & Fuel Injection) , oil (christian or equiv) you can maintain inverted flight until you run out of gas. Not fun to hang in the straps though.

[pierre smith]

....will find your eyes for sure. Losing oil pressure does your engine no good and the loss of power if you don't have an inverted system shock cools your cylinders/heads very quickly.

I flew a couple of Pitt's years ago and one of them had a Christen system. We'd vacuum the floor and look for any dirt before going up an inverting. I tell ya, there's always dirt that's gonna get in your eyes.

I don't think Van had continuous inverted flight in mind but more "gentleman acro"....loops, rolls cuban 8's and immelmans etc..all positive g's.

Regards,

[gmcjetpilot]

Originally Posted by danielhv

but can they maintain inverted flight for longer than a second or two? Whats the longest someone has maintained inverted flight?

If you are asking how long oil pressure and/or engine power will last with out inverted oil and fuel (carb) when you go negative g's, I don't know, several seconds, not long. Depends on how negative as well. I really don't want to find out.

If you are asking what is the record invented flight (in properly equip planes), I don't know. I personally flew next to a guy in cruise enroute formation who was flying a RV-4 upside down for several minutes. He had all the inverted stuff. Frankly a RV with its highly cambered wing is terrible for sustaining inverted flight. It flies at a high angle of (negative) attack, so its draggy and hard to keep speed up. Pure acro planes often have symmetric airfoils and fly basically the same up or up side down.

There are records of people flying up-side down. Not sure what the max endurance record is, but I know there are records like max number if inverted spins. Not sure who keeps those records.

You should never intentionally fly negative g's for more than a second or two with out inverted fuel and more important, inverted OIL, in my opinion. I try hesitation rolls and hold the inverted for a second or two. I get very light in the seat, but I am trying to still keep + side of zero g's. It makes a mess on the belly when oil burps out the vent. If you do lose Oil P you know it when the engine surges, due to lack of oil to the prop gov (if the engine is still making power).

Yes you can fly inverted (pos g's) for quite awhile with out inverted fuel/oil systems. Example the top of a loop. You are inverted for many second but you are on the plus side of ZERO the whole time, at least that's the idea.

One maneuver you can do is pitch up to say 60 deg, half roll to inverted, than do a ballistic trajectory, allowing the plane to float and nose over slowly to say about 30 deg nose down, than half roll back and recover to level. You feed in just enough forward stick pressure to sustain it as long as possible while keeping it Pos G's. You don't have to look at the G-meter, you can feel it in the seat-O-pants. This inverted ballistic maneuver gets you time upside down but on the PLUS side of zero. It just has to be +0.1 or +0.2 g's, but you need that little bit of Pos-g's to keep the life blood juices going to the engine.

A true story, the T-28 radial engine trainers have a limited invented time due to engine oil limits, as I have read. I never flew one, but the famous Bob Hoover did. He borrowed a T-28 a few years back and held sustained negative g's too long, toasting the engine. The owner was not happy. The fear of damaging my engine keeps me away from intentional negative g's, but there's a whole world of Acro maneuvers on the Pos side of ZERO on the G meter.

[Harvey L. Sorensen]

I believe it was Patty Wagstaff who several years ago flew a Hyper Bipe inverted for several hours doing a cross country.

[DiscoStu]

With the proper fuel and oil system, there shouldn't be a limit to how long you stay inverted. I used to glide around in our A150 with the engine 'dead' as part of an airshow routine. Messy business afterwards. Running your breather tube to the tail is a wise move if you're going to be doing much inverted stuff.

As Pierre pointed out though, make absolutely sure there aren't ANY screws, nuts, metal bits or whatever in the aircraft. Dirt in the eyes is unpleasant, but a screw in a bellcrank can put an end to your life. It's happened. In one case, a Pitts took a screw in the elevator bellcrank while inverted and couldn't get enough back (up) elevator when the plane was rolled upright. Bottom line: If you do aerobatics, when anyone is working on your plane, make sure you find any dropped hardware before moving on.

Oh, and make 'empty change from pockets' part of your pre-get-in-the-airplane checklist.


Mark

[panhandler1956]

Originally Posted by DiscoStu

Oh, and make 'empty change from pockets' part of your pre-get-in-the-airplane checklist.


Mark

Along those lines, an errant cell phone or other large loose item could crack your canopy - not good for your mood!

Have fun!!

[danielhv]

I see... I understand in order to maintain inverted flight you need the proper oil/fuel system... but lets assume one does have the proper fuel/oil system... and there is no dirt on the floor , does the rv have enough downward elevator deflection to MAINTAIN (say for a minute or so) inverted flight?

[asav8tor]

Yes it does. The airplane is not the problem.


Without the inverted oil system during negative Gs the oil pump will suck air. The engine is pressure lubricated. Without oil pressure, only takes a few seconds, the engine will be damaged. This damage will quickly lead to engine failure.