Hi all, I know this is a tacho, a Smiths Venture ATH4 to be precise. I know it's used to measure rotational speed and ft/m /sec surface speed.
It belongs to a friend of mine, passed on from her father, he was an avionics tech. She knows for a fact it was used at Cranwell during the war, where he was serving.
Question is, what
specifically would he have used it for? Any ideas?
Bests,
Giz