Is this a Boost gauge?

Strange… it looks like a manifold pressure instrument rather than a boost gauge. If it read in inches of mercury, it would indicate almost exactly standard sea level pressure (29.92″) but the instrument face shows psi, which would equate to 14.7 lb at sea level. Then there’s the minus scale to consider…
It could well be a Negretti & Zambra calibration instrument of some sort, as suggested. Boost capsule testing, maybe.

Maybe breach air pressure

Thank you all, the pressure range is what worried me…could it be part of a calibration or test rig ?
Regards Mike

Left field thought : maybe air pressure gauge for breech loading mechanism for Anson ? I cannot see the scale being realistic for Boost pressure. Later Ansons had similar gauge scale with more modern gauge by Dunlop. Perhaps breech loading mechanism had the capacity to form a vacuum in the reservoir once the gun got going ? It would alert the ground service crew to ‘reverse vent’ the air bottle before fixing compressed air line to bottle to recharge the system. Taking a punt.

Thank you all, the pressure range is what worried me…could it be part of a calibration or test rig ?
Regards Mike

Yes, Boost. I think I have an identical one. Early to mid 1930’s brass-cased, large dia’.

The R engine in the S6 must have been running over 25lb boost in 1929. Anything else was working down at about +4 maximum I would imagine.

Pete

Crikey, thats a hell of a pressure range for an aircraft of the late 20’s!

[QUOTE=Versuch;2072994]I have been told that this is a boost gauge…….I am not so sure .
Over to the experts.

I think it is. It’s from the late 20’s. I have seen similar boost gauges before with the plus and minus words printed on the dial in this style, but with a different pressure range.