0G maneuvering

[palou89]

I guess this is sort of a dumb question, but is there any "risk" in doing prolonged 0g maneuvers in a c150/52/72 sort of airplanes? (3-4 seconds, and repeatedly)

I´ve never really thought it could cause any problem to the airplane as they are certified for -1.52g in the normal category, but recently I herd from an instructor that you shouldnt do it as oil drips from the breather line splatters all over the inside of the engine cowling. Plus that got me thinking if there could be other complications related to the 0G, like oil being battered around by the cranckshaft and thus leading to the formation of bubbles in the oil (or maybe starving the engine for oil??).

Could this maneuver (0g during 3-4-5 seconds) cause fuel starvation in a c152 (carburated engine)?. In section 7 of the PIM, I dont see any fuel reserovir tank on the fuel diagram. However, if the engine actually stopped due to fuel starvation, as soon as flight at 1g is reattained, the engine should start right away given that the prop would still be turning, fuel would be available again, and mags are producing sparks all the time.

I know there is no such limitation in the POH, but this is kind of an old plane, and I would like to know if any of this is possible. Ive never came across any problem while doing 0g

[Piltdown Man]

How long can you hold zero g in a spam can? The thing is not capable of storing or generating enough energy to allow a zero g manoeuvre to last for very long before you arrive at Vno/ne. And unless the book says you can't do it, you can. But the question I have is why would you want to?

PM

[sycamore]

Go and look at a Cessna with the engine cowlings off and talk to an engineer about the crankcase breather; it is probably a tube out of the top of the crankcase,which vents out of the bottom of the cowlings; it may/may not have a neg.G trap/nonreturn valve in it.Even so, you are going to get venting and oil over the aircraft/inside the cowlings etc.If you want to spend time cleaning it all-fine,go ahead; further, you are `lifting `the oil in the sump away from the scavenge and pressure pump,aerating it more so possibility of foamed oil and pressure loss.Now talk to the engineers about poor oil circulation,and no oil to bearings,and how much that costs- now think hard about your `astronaut zero-G training`.....Could be costly.
If you want to spend time weightless,then be sensible and go and fly a proper aerobatic aircraft,where the fuel and oil systems are designed for it...