Flameout when flying inverted

[Weegie]

Relative newbie and doing the training missions again & again & again and having a lot of fun

 

Anyway unguided rockets tutorial, flip the aircraft inverted and SOMETIMES (not always) both engines flameout after maybe 20 seconds and usually only the port will re light.

 

This often happens before initiating contact so (I don't think, anyway) its due to any damage (no master alarm either) and checking in Tactview I cannot see any event issued............weird

 

Is it a known issue with the Frogfoot that's been modeled in? Just cannot imagine a modern (ish) ground attack aircraft would have such a flaw when flying inverted is going to be a routing activity in weapons delivery.

 

Also flying inverted is B***DY hard for any length of time, for an old raw recruit like myself

[blkspade]

While I don't know the details for Su-25 specifically, but generally fuel flows to engines with some help from gravity. So if you aren't pulling some positive G's while inverted, you'll eventually run out of reserve during inverted flight. 20 secs is a lot time compared to the AFM fighters which seems to be 8-10secs before flame out.

 

Relative newbie and doing the training missions again & again & again and having a lot of fun

 

Anyway unguided rockets tutorial, flip the aircraft inverted and SOMETIMES (not always) both engines flameout after maybe 20 seconds and usually only the port will re light.

 

This often happens before initiating contact so (I don't think, anyway) its due to any damage (no master alarm either) and checking in Tactview I cannot see any event issued............weird

 

Is it a known issue with the Frogfoot that's been modeled in? Just cannot imagine a modern (ish) ground attack aircraft would have such a flaw when flying inverted is going to be a routing activity in weapons delivery.

 

Also flying inverted is B***DY hard for any length of time, for an old raw recruit like myself

[shagrat]

Most aircraft, modern ones included, need special cache fuel tanks or additional fuel pumps to keep gasoline flowing while inverted or pushing heavy negative Gs. The cache system is limited, so it is not a good idea to fly inverted (unless pulling at least 1 G) for longer periods of time. As far as I know especially Ground attack planes have the "every pound for air to ground" dogma, thus usually not build with additional fuel pumps...

Or in short: yep, it's normal and try to level wings again quickly after going through an Immelmann or rolling in on target.

[blkspade]

The A-10 is likely excluded from this problem since the engines are above the wing and thus need an additional pump to get fuel to them in the first place.

[Phantom_Mark]

Both my engines shut down recently when tooling around upside down in the A10C......

 

Wonder if that is a bug then ?

[shagrat]

No, it has a cache tank between the engines giving you a 10-12sec (something like that) of continuous inverted flight or negative Gs...

 

If you roll and wait the engines will flameout.

 

I noticed that with the A-10C beta years ago... was wondering what happened. Paul pointed me to the negative Gs as I was in a dive pushing the nose for quite a while.

I had read about the tank limits and thought " hell, I'm not inverted! WTF?"

Then tested a bit and yes, it was caused by negative Gs.

Inverted flight longer than some 10 seconds in an A-10 is a bad idea...

Edited December 11, 2014 by shagrat

[sobek]

The A-10 is likely excluded from this problem since the engines are above the wing and thus need an additional pump to get fuel to them in the first place.

 

The fuel won't magically stick to the bottom of the fuel tank if you're not reading positive g, pump or no pump. Most airplanes need a fuel pump anyway since gravity feeding would be too unreliable or demand way too high of a fuel line diameter to cope with flow.

[Weegie]

Ok thanks for the replies just gotta get inverted get the missiles off then get back the right way up or push up inverted I guess

 

Thanks for all the explanations

[blkspade]

The fuel won't magically stick to the bottom of the fuel tank if you're not reading positive g, pump or no pump. Most airplanes need a fuel pump anyway since gravity feeding would be too unreliable or demand way too high of a fuel line diameter to cope with flow.

 

The idea in my head was it being more of an additive force in the A-10 as opposed to subtractive in other cases. Oh well I don't fly the A-10 so much though and the only time I'm inclined to be inverted so long in a fighter is for top gun shenanigans.

[Weegie]

I thought it weird that the lesson tells you to roll inverted and pull the nose down (up??) to place the pipper on the target.

 

I know a lot of the time in GA the aircraft will roll inverted to locate the target by affording the pilot a better view, but then its usually rolled the right way up for weapons delivery. This lesson can easily be successfully completed without the inversion.

 

Besides, inversion is risky (well it is for me), the aircraft responds like a dog (except when its diving into the ground) and you risk flameout. I'm not a big fan of upside down antics except of course with fighters in combat and there you usually have sufficient air to recover safely, ground attack on the other hand one false move and its time to respawn

[sobek]

Unloaded flight or negative g is a problem for most aircraft, not only because of fuel starvation and being hard on the pilot. In most engines, when g load is gone, the oil pump will run dry resulting in a rapid loss of oil pressure.

[mvsgas]

I thought it weird that the lesson tells you to roll inverted and pull the nose down (up??) to place the pipper on the target...

The reason to roll inverted is to pull positive "G" to put the nose down on the target. You are suppose to roll back "upright" after the nose is pointing to the target. It is a normal technique, in part to help maintain positive "G" on the fuel system.

 

Here is a SU-25UB doing it

http://youtu.be/KPjCrwDJiJ4?t=5m31s

 

F-16

Edited December 12, 2014 by mvsgas

[Weegie]

Ahh thanks, that's what I'd read about the F4s doing in Vietnam, roll inverted to acquire roll upright & release.

 

Cheers thanks for the info & the SU25 Vid, I'm a confirmed Russian aircraft groupie & that was way cool.