That is, if you don't have scavenge pumps and air/oil separators top and bottom in your engine, as any truly inverted system should.
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That is, if you don't have scavenge pumps and air/oil separators top and bottom in your engine, as any truly inverted system should.Flying inverted (a negative G maneuver) for more than a few seconds causes the oil in the crankcase to drain into the upper portion of the engine, creating a dry sump and the overspeed and damage to the oil pump.
But what do you do when blue and green are chasing each other around the dial? What then?
Don't know, but I suspect some Japanese fighters did, as I've read accounts of Zeros and Hayabusas flying inverted for extended periods. The Wright 1820 (out of a T28) we had at mech school had scavenge pumps top and bottom.And how many WW2 era engine models did?
It's not only about the aircraft. Operating under sustained negative G is really uncomfortable for the pilot, and 30 seconds is a really long time. Even an aerobatic routine won't likely have sustained negative for 30 seconds.I found out a few years ago that even modern jets (F-14, F-16, MiG-21, etc) can not fly 0g inverted for prolonged periods. Depending on the airframe, the oil system and/or the fuel system will not be able to maintain supply. In my ignorance of modern aircraft design I had assumed that this problem would have been dealt with, but it seems that it is not really considered a problem? IIRC the F-16 is limited to 30 sec in Mil and 10 sec in AB due to the fuel system, while the F-14 is limited to about 30 sec due to the oil system. I think the MiG-21 is limited by the fuel system.
I have heard this from a Tomcat pilot. He told: "The American Instructors warned us to not do aerobatics, 0 and Negative G related flights, unless really necessary." The reason as he told, was impacts on Pilot's health and machine limits as well.I found out a few years ago that even modern jets (F-14, F-16, MiG-21, etc) can not fly 0g inverted for prolonged periods. Depending on the airframe, the oil system and/or the fuel system will not be able to maintain supply. In my ignorance of modern aircraft design I had assumed that this problem would have been dealt with, but it seems that it is not really considered a problem? IIRC the F-16 is limited to 30 sec in Mil and 10 sec in AB due to the fuel system, while the F-14 is limited to about 30 sec due to the oil system. I think the MiG-21 is limited by the fuel system.
Didn't you mean "negative one G inverted"? Zero G, whether inverted or upright requires an anti-gravity arc flight profile, which is even more challenging than inverted one G for fuel and lubricant systems, as the fluids tend to float in midair and avoid both top and bottom pickups. In any case the geometry of the flight path and the power of the aircraft severely limit the duration of the zero G condition.I found out a few years ago that even modern jets (F-14, F-16, MiG-21, etc) can not fly 0g inverted for prolonged periods.
This is really a Biff question as far as modern times, but back in Vietnam days there wasn't much utility in prolonged inverted flight, other than rolling over briefly to scan below. If your ECM says you've got a SAM coming up, it's kind of handy to roll over and try to spot it. The strobe on your screen tells you about what direction to look and you should pick it up pretty quick.Just as a Question: Could it also be related to different Roles they have? I mean that Tomcat is not a Fighter like F-5 or not a Fighter-Bomber like F-4. In other word, different designs for different usage.
That was an interesting discussion for me! learnt some new things. Thank you.I am thinking that we are hijacking the Quotes and Jokes thread, and maybe this discussion about fuel feed ability under 0 or negative g should have a thread of its own??
Would the Moderators move the appropriate posts to a new thread??
Panic?But what do you do when blue and green are chasing each other around the dial? What then?
Not only that, but all the stuff they dropped when they were doing PDM at the Air Depot tends to come falling down and fill up the canopy. Nuts, bolts, screws, bits of wire, screwdrivers, wrenches, watches, cigarette butts, ham sandwiches, used condoms, small pets, the owner's manual for a 1976 Volare, you name it.Operating under sustained negative G is really uncomfortable for the pilot, and 30 seconds is a really long time
Check 6 check 6!!!! He is on intermidiates now and gaining.