Batteries

[bernard towersParticipant @bernardtowers37738]

I don't know many people in my neck of the woods with missile launchers!!!

[Howard LewisParticipant @howardlewis46836]

You would be surprisee at just how much current a relatively small primnary or secondary cell can deliver, even if only for a short time (No pun intended! )

It may be a 1500 Ma hr AA , but for a few seconds, it can probably deliver quite a few Amps..

Every time you engage the starter on your car, the starter probably draws several hundred amps from a battery of quite small amp hr capacity.

(A 4 litre diesel might well draw over 400 amps on a cold start, from a 75 or 100 amp hr battery. )

Howard

[george baker 1Participant @georgebaker1]

Hi

IIRC in ww2 there was a self destruct circuit on a bit of radar equipment with a test button, swap switch, Press Test put back in flight mode. I read of a story where a technician did not swap the switch before Pressing Test button,

Last night on PBS America they said the Norden bomb sight used a Thermite self destruct charge. That would go with a Bang

George

[SillyOldDufferModerator @sillyoldduffer]

Posted by george baker 1 on 07/02/2023 17:41:35:

…

Last night on PBS America they said the Norden bomb sight used a Thermite self destruct charge. That would go with a Bang

The story of the Norden Bomb-sight is amusing I think. Judging by what was said at the time, Americans were extremely proud of what they claimed to be the last word in precision bombing, and they took elaborate security precautions to stop anyone else learning how to make one. Including a self-destruct charge.

Unfortunately the Germans already knew all about the Norden from a spy, one of their rare successes. They weren't impressed by it, noting the Norden was considerably heavier, more complicated and expensive to make than their bomb-sight, which claimed similar performance.

Worse, it was found that a Norden super-accurate in the peaceful sky over a practice range in Arizona struggled to deliver in Europe. The problem was European bad weather – cloud, fog and rain – plus gunfire forcing the pilot to duck and weave.

Accuracy was a difficult problem. After photographing what was really underneath when bombs were dropped, the RAF found in 1941 that only 5% of their aircraft were within 5 miles of the target. So the RAF switched to electronic systems, only using optical sights when it was certain the target was in view. The AAF weren't far behind, suggesting maybe the Norden was something of a publicity stunt, possibly a propaganda boost that also disguised a shift to electronic methods.

Dave

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