Help Wanted With Mk5a Clinometer

Many thanks for all your help Gentlemen

A belated thanks aircraftclocks.

The difference between the Mk. V and Mk. VA might be nothing more than protests from manufacturers leading to a slight increase in the maximum weight allowed for in the Spec. Hence from 155 to 155A.

Out of interest, I have a copy of R.A.F. Drawing 1964W, dated January, 1917. This shows a Mk. V Cross Level with a much simpler, bayonet attachment for the lamp holder. I’ve never seen an example of this type. Perhaps it never made it past the prototype stage?

The hunt continues!

Now, can anyone explain the difference between the Mk. V and the Mk. VA?

I don’t have the answer but…..

From a Department of Aircraft Production publication, Aeroplane instruments (2nd edition) dated February, 1918

“Mark V and Va only differ from Mark IV in having an electric lamp at one end so that the bubble can be seen at night.”

Having a look at the specification documents I have, these are amongst them

17th July, 1916.
ROYAL AIRCRAFT FACTORY SPECIFICATION No. 101A.
(Cancelling R.A.F. Specification No. 101).
CLINOMETERS FOR USE ON AEROPLANES.

30th May, 1917.
ROYAL AIRCRAFT FACTORY SPECIFICATION No. 155A.
(Cancelling R.A.F. Specification No. 155).
MARK V.A. CLINOMETER WITH ELECTRIC ILLUMINATION FOR USE ON AEROPLANES.

The difference could be explained in the earlier cancelled specification, RAF 155.

For the record, the drawing numbers are given as 2346/W, 2347/W and 2348/W.

As others have said, this was pretty much the standard cross-level from late WWI to the 1930s, although the Mk. VII was substituted in very hot climates due to a tendancy for the glass tube of the Mk. VA to burst through liquid expansion.

Now, can anyone explain the difference between the Mk. V and the Mk. VA?

From memory these were fitted to many types from late WW1 through to the 1930’s.

Bob T.

I have found the clinometer listed as being fitted to both the Bulldog Mk2 and the Hyderabad, according to AP1393 and AP1318 respectively.
I suspect most aircraft in the 20’s would be candidates for this instrument to be fitted to.

http://www.aerovintagespares.com/avspares/Sopwith_Aircraft_Parts.html#a301

Have one fitted in the rear panel of the Moth Major. Understand it is ex Hind

It would look exceptionally good in one of my Avro Avians! 🙂

From AP1275 dated around 1939, and they were pretty old things then!