Flame out

[rextar]

Just took off turned her on her back and tryed a negatove g push over....

Both engines flamed out,, no re ignite!!

Wow!

[lobo]

This is a realistic limitation of the fuel system. At negative G, the collector tank will supply the engines with fuel for 10 sec at max power. The APU is also limited for approx 10 sec negative G. From the -10A manual. You can fly under negative g conditions briefly.

[rextar]

Well every days a school day, great stuff

Thanks for that lobo!!

[rextar]

One thing i noticed was she ran well in inverted flight

No problem.

[lobo]

One thing i noticed was she ran well in inverted flight

No problem.

 

Ahh but for how long? ;)

[rextar]

To be honest lobo quiet a while i did a run along a rail track inverted for easy 1 minute

All said no negative g was pushed

[aaron886]

Technically, if you want to stay level while inverted, you have to be at -1... so...

[bradleyjs]

Lobo is correct - there are plenty of aircraft that don't have the capability to pump fuel when inverted in a Neg-G situation .. not sure if it apples to the more current F-16/18/15/35/22 fighters - but the "older" aircraft do have that limitation -- if you read the appropriate [for the aircraft]its Dash-1 it will have a "Warning" item that mentions the limitation.

 

Just speakig from experience ... ex-USAF...

 

But, how cool is it that it's implemented? !

[effte]

If you have a look at the requirements, you'll see that limited -ve G capability is pretty much a must for a combat aircraft. Spitfire Mk I/II (with the addition of the interestingly named device) and on, they've pretty much all had it. You simply do not want to have to roll inverted if you want to change your trajectory downwards more abruptly than a ballistic trajectory. The RAF learned that the hard way.

 

On the other hand, prolonged inverted flight has no practical use outside of airshows. If it's more than a limited amount of time, you are better off just rolling the aircraft around so it can do what it is supposed to do the way it is supposed to do it most of the time.

 

Hence, most if not all aerobatic combat aircraft will have limited capability for -ve G. Not unlimited, nor be without it, but limited capability.

[kingpinda]

I thought I read somewhere that the early a-10 models flew inverted to get a lock/fix on their ground target. Then reverted back to normal flight and then dropped their bombs fired missiles etc.

 

Anyway. The hurricanes were even worse. WITHOUT flying inverted the engines of these crates sputtered when pulling negative g's in a dive.

[lobo]

Exactly bradleyjs! The amazing thing is that this is modeled. Another interesting thing I found (and this goes to rextar's post above), is that when taking the jet and rolling inverted and holding altitude at –1g, the fuel starvation occurs after approx. 50-65 sec. Roll upright, relight both engines. Once at full power, roll inverted (same as above -1g), the engines now flameout after approx. 15 sec... I restarted the mission i.e. clean aircraft and it is repeatable. 1st flameout at approx. 50 sec, after relight next flameout inverted at much less time around 15 sec...

I have a theory. It seems that the collector tank is full when you go inverted for the first time, then after relighting and going back to full power, roll inverted and the engines flames out much quicker the second time. My theory is that the collector tank (which is gravity fed) does not have time to completely fill again. Is it possible that ED has modelled this to such a level?

Thoughts?

[Teej]

You can also stall one engine with the right sort of snap roll.

 

The wings can be snapped, too...from just aerodynamic loads with no weapons.

[Teej]

Let me just say that it's a VERY bad time to forget about the inverted flight limitation when you're doing an inverted run 5' off the runway.

 

Fortunately I was doing 320 knots and the relight was easy. ;)

 

I hadn't flown A-10 for a while and was messing around after doing Frazer's FPS test. Heheheheh.