WW2 pic background id wanted

the general consensus is that its BD no one is saying that it isn't but i would like to pin it down 100% even though thats reasonably unlikely

Yes, I would endorse Boscombe too.

A&AEE were involved around late 1942/1943 in clearing UP (later known as RPs) installations on various aircraft types.

That's a nice pic of the rocket installation. The orginal 3.5 inch diameter motors with the armour piercing (anti-tank) projectile - borrowed from the famous 25 pounder gun - adapted to screw into the front of the motor tube.

As an Apprentice armament fitter, we were constantly informed by our instructor that the AP rocket was urgently developed for use against Rommel's tanks in the Western Desert but it was found that only a lucky hit on a vital part of a tank was effective.

A 60 pound HE head was developed for use against U-Boats but tests showed that a sub with a 1 inch thick steel outer hull could easily resist near misses and a direct him from a salvo was difficult given the gravity drop and dispersion.

Someone decided to try the AP round against subs and it worked better than predicted. Short rounds into water produced an upward curving trajectory which would easily punch through a subs hull. Short attacks with AP rockets became the preferred weapon.

Meanwhile, A&AEE had tried the HE round against tanks and found that a hit anywhere on the tank caused the turret to fly off!

Consequently the intended use of each head was switched, AP against subs and HE against tanks and locos. Serendipity!

UP?

Unguided Projectiles?

Moggy

No. The UP stands for Un-rotating Projectile which was the early 'code' for what later became RPs (Rocket Projectiles)

The UP rockets were used in batteries and launched vertically from the ground with HE heads as an anti-aircraft weapon. As with any projectile, what goes up must come down so I would not have liked to be underneath the falling debris! Unexploded AA shells were bad enough!