"News" wrote in message
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In message , Chris J Dixon
writes

https://www.youtube.com/watch?v=3ZxcDmICweg
Quite interesting bits of kit.

Interesting indeed.

Yeah, particularly the way it unfolds itself at the end.

I could not see a counterweight,

There wasn't one.

although there must have been one.

Nope, there's wire that replaces it instead.