Lightning, static, ammunition and refueling discussion

Thats a good question, I dont honestly know! But I do know that aircraft are supposed to be earthed before refuelling takes place, problem unique to helicopter if they are being refuelled with the rotors running is that static builds up in the rotors.

PETERTHEEATER wrote:

canberra wrote:

A little bit off topic slightly, but is there any real risk from lightning setting off small arms ammunition? And by small arms I include aircraft cannon shells.

30mm ADEN gun ammunition has electrically initiated primers; they are not struck by a firing pin as percussion caps are.

So presumably the answer with that type of ammunition is yes, it is possible in theory?

We still have the lightning conductor rod and earth strap in place on the roof of the Pyro Store at Twinwood Farm.

TTFN,
PB

Arcade wrote:

PETERTHEEATER wrote:

canberra wrote:

A little bit off topic slightly, but is there any real risk from lightning setting off small arms ammunition? And by small arms I include aircraft cannon shells.

30mm ADEN gun ammunition has electrically initiated primers; they are not struck by a firing pin as percussion caps are.

So presumably the answer with that type of ammunition is yes, it is possible in theory?

Yes.

But remember, if an unprotected building used for the storage of any high explosive munition whether bomb, shell or ammunition is struck by lightning - whether or not the the munition is electrically intiated - there is a real risk of fire, explosion and propagation. That's why the regulations concerning explosive storage is strict in respect of protection, traversing and safety distances. Even the type of packaging is designed with safety in mind.

For WW2 built airfields the requirement was to provide quick and temporary storage so the regulations prevailing then were 'relaxed' when required and at times even went 'out the window' at many bomb storage areas due to receipts exceeding the authorised capacity.

Can you please explain how the ADEN shells work then if they dont have a percussion cap?

canberra wrote:

Can you please explain how the ADEN shells work then if they dont have a percussion cap?

At the risk of going off the original topic;

Electrical primers for 30mm ammo contain a mix of an explosive and a conducting composition. When the round is in position for firing a 'firing pin' (actually an electrical contact) is touching the cap. When the trigger is pressed, an electrical voltage is connected to the firing pin and goes through the cap to earth. In doing so, the molecules jump around and generate heat which fires the primer and the cartridge. This happens in milli-seconds.

Electrical initiation was developed to speed up the rate of fire of the gun because percussion mechanisms are slower and more complicated. The other factor at the time of development in the late 40s/50s was safety. That is electrical primers were considered to be safer that percussion primers.

Ironically, the latest ADEN development uses percussion firing for safety due to the higher risk of initiation by Radio Frequencies (RADHAZ) caused by the proliferation of RADARs and other emitters.

I had always just made the assumption that it involved magnesium or similar.

Interesting about the return to percussion caps - makes a lot of sense though when you think about it!