Balloon Busting Questions

[Mogadeet]

Greetings!

I've got a few questions here I would appreciate answers for.

1. Could standard military ball ammunition from aircraft machine guns ignite a balloon? Cause other catastrophic damage? If so/not, why?

2. Did the Fokker DVII have trouble with incendiary ammunition due to excessive heat in its ammunition storage?

3. Was it common to attack balloons with normal MG ammo?

Thanks Bunches!!!!!

Mogadeet

[Ransom E. Olds]

Ordinary ball cartridges would be very unlikely to set a balloon on fire, tho of course a plain ball bullet (lead in a metal jacket) could cause structural damage and injury to balloon personnel. I'm not sure what you mean by "normal MG ammo." A normal ammo load for a fighter in the first war would have included tracer, AP, and incendiary bullets to work mayhem on the structure, fuel, and crew of the enemy aircraft being attacked.

Perhaps in the case of attacking an observation balloon the ratio of incendiary and tracer would have been upped at the expense of AP. Ball cartridges, if belted, would have been used primarily to reduce the total number of special purpose loadings if that were necessary. I've never been clear about the problem of incendiary cartridges in the D.VII but assume they (they belted cartridges) were subject to unusual heat because of some aspect of the plane's structure, location of exhaust manifolds or some other issue. Ransom

[Alkali Jones]

Hey Mogadeet,

Frank Luke's plane (SPAD 13) had a different gun to fire incindiary ammo. I believe it's called a GRAS gun and was 11mm(?) instead of .303.

Dan S

[Ransom E. Olds]

There were Vickers guns chambered for the 11 m/m Gras cartridge in which incendiary bullets could carry a good deal more pyrotechnic material than the regular .303 gun. There was an earlier thread on this forum about the 11 m/m Vickers. The German fighter aircraft of the Great War were armed with 7.9 m/m guns, essentially similar to the .303, though an enlarged Maxim of 13 m/m caliber was under development at the end of the war for antiaircraft and antitank use. Ransom

[stephen]

1. Could standard military ball ammunition from aircraft machine guns ignite a balloon? Cause other catastrophic damage? If so/not, why?

No. No fire on the projectile, no ignition of the hydrogen in the balloon.

2. Did the Fokker DVII have trouble with incendiary ammunition due to excessive heat in its ammunition storage?

Someone else, please.

3. Was it common to attack balloons with normal MG ammo?

No, it was very abnormal. Balloon missions were usually designated in advance. Very seldom were they random.

[Rod_Filan]

No fire on the projectile, no ignition of the hydrogen in the balloon.

This isn't entirely correct. The hydrogen in the balloon needs to be mixed with air before it can be ignited. It's the free hydrogen that burns first.

Hydrogen Combustion

In the summer of 1916, three new types of British machine gun ammunition which had been under development for years became available for general use. Two types, named "Pomeroy" and "Brock," after their inventors, were explosive bullets. The third, called "Buckingham", was a phosphorus incendiary bullet. Any one of these bullets was only marginally effective when fired at a zeppelin, but when mixed, they formed a lethal combination. The explosive rounds blew holes in the zeppelin's gas cells, allowing the hydrogen to escape and mix with the oxygen outside, forming an explosive mixture. The incendiary bullets then ignited the mixed gases! This new "mixed ammo" sequence was to become Britain's wonder weapon against airships.

DARK AUTUMN
The 1916 German Zeppelin Offensive

I hope that helps explain the fire delivery, although there were other methods i.e. Le Prieur rockets, with the same intents and purposes.


Cheers

[Mogadeet]

I'm getting some really informative and interesting replies. Thank you all very much.

Mogadeet

[Gregvan]

Hi,

As far as your question No. 2: Yes. Quoting from Alex Imrie, German Fighter Units June 1917-18: "During February 1917 a copy of the British phosphorous ammunition had been produced (Phosphor F) and was 100 % effective at a tange of 100 M against balloons...Given the official designation Ph-Munition on 15-3-17, the ammunition could ignite a balloon at a range of 400 m, and an aeroplane if the tank was hit from the same distance...Experiments continued to extend the useful range...although it was known to be unstable and as a result had a very short storage life. Trouble with the Ph-Munition reached a peak in July '18 when it was used on the Fokker DVII. The ammunition boxes on this machine were close to the mass of the engine...As a result, in hot weather the cartridges were subjected to high temperatures, a problem compounded by insufficient louvres to allow the cooling air passing through the radiator to escape quickly. Using phosphorous ammunition under these conditions when it was near the end of its storage life or possibly the extended life, aggravated by petrol contamination from nearby leaking fuel tanks, resulted in the self-ignition of rounds. Whether or not the exploding ammunition actually pierced the fuel tank was of little importance...the aircraft burst into flames. This hazard was eventually alleviated by introducing additional cooling louvres to prevent the concentration of very warm air highly charged with petrol vapor in the forward fuselage and by reducing the period of safe life for the Ph-Munition."

[Rod_Filan]

Originally Posted by Greg

"During February 1917 a copy of the British phosphorous ammunition had been produced (Phosphor F)
[..]
"...in hot weather the cartridges were subjected to high temperatures, a problem compounded by insufficient louvres to allow the cooling air passing through the radiator to escape quickly. Using phosphorous ammunition under these conditions when it was near the end of its storage life or possibly the extended life, aggravated by petrol contamination from nearby leaking fuel tanks, resulted in the self-ignition of rounds."

Thanks for posting that. Alex Imrie's explanation makes perfect sense when you consider the simple construction of these rounds. Although I haven't yet found a photo or plan of one, this describes its inherent danger well enough:

The Buckingham bullet (Mk VII bullet) was an incendiary/tracer bullet based on phosphor, invented by James Buckingham in 1914. The bullet contained an incendiary filling which percolated through an annular hole, the seal of which melted on firing, the phosphorus igniting on contact with the air.

Cheers

[Ransom E. Olds]

If the German incendiary cartridges were of the fusible alloy plug type, sufficient heat in the ammunition boxes would melt the plugs, permitting the white phosphorus material to self-ignite. Once one cartridge did this, it would be likely to cause near-by cartridges to do the same. The bullets wouldn't likely be propelled out of their cartridges cases with enough velocity to even perforate the ammo boxes, but the conflagration taking place in the boxes would more than enough problem to deal with. Ransom