1930's ? altimeter ID

Whilst not wishing to hijack this thread, I’m after a slip bubble similar to this one fitted to G-AESZ for fitting to my Chilton build:

Any leads would be appreciated!

I’ve already found my altimeter, a 20,000 ft Mk XIIIB, which appears mint and worked perfectly in the Moth up to 4,500ft not so long ago. Apart from the slip bubble, a serviceable Chipmunk RPM gauge would be useful too…

Dave

Hi Dave

I believe that Retrotec make repro’s of this type of clinometer “slip bubble”.

Bob T.

Helicopter – a close eye on EBay will usually turn up a Chipmunk RPM .

P & P
There is another RAF instrument manual issued that dates before the AP1275. It was issued in 1921. It does not have Section Reference numbers as it predates that system. It uses Mark numbers when referring to instruments.

Send me a picture of the altimeter in question and I will attempt to identify.

Whilst not wishing to hijack this thread, I’m after a slip bubble similar to this one fitted to G-AESZ for fitting to my Chilton build:

Any leads would be appreciated!

I’ve already found my altimeter, a 20,000 ft Mk XIIIB, which appears mint and worked perfectly in the Moth up to 4,500ft not so long ago. Apart from the slip bubble, a serviceable Chipmunk RPM gauge would be useful too…

Dave

Hi P&P

AV 572 is the Smith’s number for the Altimeter type.

It is possible that those instruments that have RAAF printed on the dial, were modified by the service department of the RAAF. I have seen a number of instruments which have come from Australia, that have either had their serial number or makers name blacked out, or even erased completely & replaced by a new serial number etc.

In general, when aircraft first left the factory, they would have been fitted with specific types & marks of instruments, but at some point in their service life, they may well be fitted with different types or marks of instruments during repair, to prevent the aircraft from being grounded due to not having the correct ones available, eg- a MK IVa airspeed indicator may have been fitted to a type that would normally have a MK V fitted, or vice versa.

Bob T.

Aircraft clocks

Aircraft clocks, I am a beginner in all of this and you seem to know quite a few things. My kids look at my gauges and call them ‘clocks’ so you have captured the zeitgeist well !

What are the references, eg AV 572 you are referring to? I only have AP 1275 1937 to refer to and the odd cockpit photo. I wish there was something for the 1930’s like the 1946 RAAF schedule of aircraft instruments which can be got on ehooray

In David Luff’s ‘Bulldog’, pg 42, there is what looks like a 28,000 ft altimeter, 17,000 ft on outer ring, in the cockpit, a cousin of the altimeter in this thread. That cockpit layout is also what I am beginning to understand what most Brit cockpits looked like in the 1930’s, whoever designed it must of had a flagon of port or mistress on the table at the same time, a real mess of a layout. I have this instinct that gauge design followed fancy rather than any definate specification, but you could probably put me straight.

I have in my hot hands as I type a Smith & Sons 20,000 ft alt, 15,000 limit on outer ring, steel case, glass 2 7/8, with ‘windows’ on the outer circumference to light the face. Can you ID this ? As it is 41 degrees C outside I am in Australia, so I guess it must be something out of Wapiti, Bulldog, Seagull, Demon ?

I have also seen a Australian Demon cockpit photo with Negretti & Zambra oil temp/pressure gauges & turn & slip with RAAF overprinted on the gauge faces, which I guess is a marketing flourish from the folk that produced Afghan Hind gauges in Dari script. All this makes me think that gauge design was as free and easy as the hippie era, and there are no hard rules, unless you can set me straight.

My instinct is that gauges were put in with ‘what was available’ during a/c service life, with changing circumstances meaning there really isn’t any hard and fast rule about cockpits, within the context of equipment of the era.

For completeness the stated dial dimensions are:

AV.563, 3.5″
AV.572, 3″

The Mk V is calibrated to 16000ft and seems to have been made by both Short & Mason and T. Wheeler.
The Mk VA appears to have been made by both Short & Mason and Zenith and is calibrated to 20000ft.
The Mk VB is a Smiths Model AV.563 calibrated to 28000ft. According to the specification the dimensions are shown on drawing A.B. T. 8/92.
My data shows that the case is 4 7/16″ in diameter. The case size for the Smiths AV.572 is 3 7/8″.

Yes those dimentions are correct for the diameters of the flanges, the ones I stated are for the diameters of the dials/glass.

It would be interesting to find out what types used the AV.572.

Bob T.

The Mk V is calibrated to 16000ft and seems to have been made by both Short & Mason and T. Wheeler.
The Mk VA appears to have been made by both Short & Mason and Zenith and is calibrated to 20000ft.
The Mk VB is a Smiths Model AV.563 calibrated to 28000ft. According to the specification the dimensions are shown on drawing A.B. T. 8/92.
My data shows that the case is 4 7/16″ in diameter. The case size for the Smiths AV.572 is 3 7/8″.

Hi P&P

After seeing a photo of it, I too thought it might be a varient of the MK V, however, as soon as I had seen it in the flesh, I realised that it was too small to be one. MK V’s are approximately 3.5″ across the dial, where as this altimeter is only 3″ across the dial.

I have seen something similar in an old photo of the instrument panel of a Comper Swift.

Can’t say I’m partial to Gin, Bristol Bombay’s however :D.

Cheer’s.
Bob T.

Mark VB Altimeter

6A/1 Non Luminous Mark VB altimeter, 6A/9 Luminous.
Guessing it was fitted to 1930’s bomber or transport, something designed to go ‘above the weather’.
From what I have seen, Smith & Sons, Negretti & Zambra, Short & Mason all supplied instruments to military & civil in the 1930’s without AM markings until just before WW2. your bezel has been cut to fit against some other instrument, maybe a later install of a blind flying panel ?
This could be the altimeter from the Wapiti that flew over Everest, or the Bombay that supplied gin to Raffles hotel in Singapore….

Many thanks for the ID, do you by any chance know which aircraft types they were fitted to ?.

Cheer’s.
Bob T.

Smiths AV.572 Altimeter

Its a Smiths AV.572 calibrated to 26000 ft.

They were available in 5 standard calibrations in feet and 4 in metric.

Your other choice was if you required the dial markings to be luminous or non-luminous.