Anyone recognize this Tacho?

I am pretty sure I saw one of these instruments on sale in a Melbourne antique shop a couple of years ago.
From memory it was in an old picture theatre very near the train station at Footscray.
Given this is very close to where military aviation started in Australia (Point Cook) this makes sense.

I remember looking at it and thinking it was big and heavy for an aircraft instrument.

Hi Mike
The luminous & non luminous instruments I have seen that were made by the same manufacturer, are basically the same with the exception of the paint & engraving on the face, some were even converted from non luminous to luminous at a later date, they were just given different part ref numbers to distinguish one from the other. The 6A ref numbers stamped on the instruments, were post WW1.
There were several other manufacturers of the MK V, appart from North & son, Elliott, & Short’s, each made the instruments to their own design.
The drawings that I believe aeroclocks is reffering to, are those held at the PRO, these were drawn by the Royal Aircraft Factory, who also made instruments to their own design.
I believe that the basic specifications for the MK V, as with the earlier types, were drawn up by either the Royal Aircraft Factory or the Air Department etc, & then given to the manufacturers, who designed their own instruments to match those specifications, the spec’s probably included size of dial face, size of numbers, width of body etc.

Bob. T

A Big thank you to you all for your help,I am interested
that the Non Luminous,appears to be almost a completely,
different design,so it wasnt just an appliction of paint!
Regards Mike

Serial number of the Mk V

Robert for my interest what is the serial number of your instrument?

I have a Non-Luminous MKV made by S Smith & Son London. It has the gearbox and cable in place. I am not sure of the date of manufacture or what type it was fitted to.

As promised here are the photos of the North type Mk V

I have just realised that I have the specification for this instrument. It was built to specification RAF130 dated 25 Jan 1917.
The drawing associated with it is 1675/X. I do not have this drawing but get the impression it is a GA drawing which will not show the inner details. Given that there are 2 types, by 2 manufactures, I am sure the drawing is only GA.

I will post the pictures latter once I have scanned them.

Hi Mike

The main gearbox where the drive cable attaches to is missing, this item would be fairly easy to make if you can borrow one to copy from, the other item that appears to be missing is the part that fits between the gearbox & the top of the case, this item would be quite difficult to make from scratch, but not impossible.
Should you decide to part with it, I’m sure the guy’s building the replica Comet at Derby, would welcome it’s donation “not sure if one was fitted to the original DH 88 Comets”.

Bob. T

That would be great if you can,its a faint hope,but
something similar could be made to fit.
Regards Mike

MK V Mechanical revolution indicator

I think this is a WWI instrument as it appears in FS133, PROVISIONAL VOCABULARY OF STORES FOR THE ROYAL AIR FORCE, May 1920 (later AP133) as 6/99, non-luminous and 6/100 luminous.
I find that by 1927, AP1275 shows it as 6A/117 (luminous) and 6A/118 (non-luminous). It appears to have got into the first version of the AP1086 early in the 20’s as well.
It’s an interesting instrument as there are two types, the “North” and the “Elliott”. If interested I can post photo’s of the inner mechanism.

More details as follows
tacho is 5 1/2 inch across,4 inch face and 3 1/4 inch deep.
The face reads
North & Sons ltd
London & Watford
Mk V
Luminus
No 25493 s

It does have the arrow on the back,
Sopwith you have VERY good eyes!
You cannot make it out ,but the larger mechanical parts have been removed
leaving the mounts,and more intricate parts.
Thanks to all who have replied.
Mike

If we are putting out requests for help I could do with 2 for the Comet as well. I have been looking on e-bay but none seem to pop up.

Ken

Looks like a MK V of some discription, does it have an A above an arrow on the rear case, if so it is more than likely WW1, or has it got a crown, or AM on the back, if so it is post WW1.
One of many made by North & sons, as well as other manufacturers.
They were fitted to WW1 types such as the Bristol F2b, RAF SE5a, Sopwith Snipe etc, as well as many inter war types.
Could do with one for the Snipe.

Bob. T

Versuch – nice collection of Mk2’s in the first photograph.

All with time elapsed hands as well!

Any chance of:

– dimensions

– rear view

– confirmation of the details printed on the face (I’m assuming it says Scintilla, but what else?)

– lightweight construction or heavy?

TIA

Got similar but less flange..its thirties as previouly stated,and identical internally to car speedos of the day!
RPM range is correct for a Gipsy Major. One ive got is i believe Dragon,but depends on angle of drive for different installations! P/N should be on face, in pivot area of pointer..

Were any WWI aero engines capable of doing 2600 rpm?

i think it may be early 30’s, I have seen similar in light aeroplanes and actualy looks similar to what may have been fited to the DH 88 Comets.

Ken

OOps…now for the real photo…