P-51 Guns not firing when when upside down

[Waffle]

I read somewhere that that the P-51 couldn't fire when inverted due to the way ammo was fed. I presume this was due to gravity . If so, I'm sure other planes were also not able to fire inverted.

Anyone have any knowledge or reference to this?

I'll see if i can dig up where iI read it.


Ah-ha - found it: from mustangsmustangs.net

The controls for the machine guns were a switch to turn them all on and the trigger to fire them located on the stick. There was no ability to turn on combinations of guns; when you pulled the trigger, all guns that had ammunition available fired.
The B/C models had 4 guns and the ammo was loaded with 5 tracers 50 rounds from the end. Frankly I cannot recall how many rounds the armorers said we had in each gun. But the lousy arrangement of the ammo belts feeding the guns often led to the loss of the guns if firing when pulling anything over 3 g's.
In the D model, our inboard guns had 500 rounds per gun and the two outboard guns in each wing had 220/250 rounds per gun. I hedge on the amount in the outboard guns as my armorers told me 250 rounds per gun; however, there seems to be some disagreement as to total rounds listed in various publications. The figure of 1880 rounds total seems to be the official figure.
The guns in the D only quit firing if you attempted to fire in the inverted position. The guns did not actually jam, but failed due to not being able to pull another round into the firing chamber and we had no way to charge them in mid-air. I never had them stop due to a "g" loading.
The D model also fired 5 tracer rounds when each gun was down to its last 50 rounds. Obviously when the 4 outboard guns expended their ammo, the only guns with any ammo were the inboard ones; one in each wing.
I trust this answers your question.
Cordially, Art Fiedler

[Bodhi]

Positive G loads upside down would not be "upside" down to the gun or the spent casings, they should fire as before.

The reason I was told they would not fire upside down was if negative G's were present, then they caused jams by the guns ejection shoot not fully removing the spent case.

[Hornet33]

I have read that the problem with the early model (B/C) ponies was that the 4 .50's were mounted at a 45 degree angle in the wing. This was done because the wing was so narrow top to bottom. With the guns mounted at this angle it caused the ammo belts to bind under a moderate G load thus causing the guns to stop firing. The D model corrected this with a thicker wing among the other improvments made to the basic pony airframe.

[Midnight]

I personnaly would like ot see this added to the game. I think there is a valid point in realism to have guns jam do to pilot induced errors.

1. Firing while inverted or pushing negative G - Many guns relied on gravity to remove spent casings from the ejector chutes, like the P-51D for example. If the wing was upside down when firing, the spent casings would accumulate in the chute and would eventually cause a jam by preventing caings from ejecting out of the gun.

2. Firing for extended periods without allowing the guns to cool. Some guns could not handle the temperature buildup of continuous firing. The results of no cool down time between bursts could be melted barrels or rounds cooking off, or even explosive rounds (like HE tipped cannon rounds) going off in the chamber.

3. Firing under high G loads. Some gun and ammo feed designs were not good for this. P-51B for example.

[Schutt]

Also some guns would not stop fireing when overheated... talk about most ammo spend cause gun kept fireing.

[bolillo_loco]

im not too sure about spent cases causing a jam due to inverted flight. the .50 cal bmg did not rely upon gravity to eject spent cases. it has a positive extracter that flings the spent cases out of the gun with enough force that no matter what the posistion they will be ejected. other reasons could cause jams I really do not know.