Good Day, I believe the RAF MK I aircraft clock is very rare. Very few were made, and even fewer survived WWII. The sole maker is believed to be T & F Mercer. I acquired a T & F Mercer MK I (Serial No 327/40) twenty plus years ago. Some years later, I acquired a second MK I, this one made by H.HUGHES & SON, (Serial No 179).

I have never seen another H.HUGHES MK I, and wonder if anyone else has?

I have tried to attach a photo of both clocks to this note, without success. Best Regards, Robert Skinner England.

Consolidation of three separate topics into one...

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Robert Skinner posted December 26, 2020 12:10

"Further to my recent post. I hope to attach a photo of both RAF MK I's. On the left is, "REF No. 6A433 Serial No.327/40 T&F Mercer St Albans CLOCK MKI" with AM and a Crown on the back of the case. On the right is, "Ref No 6A433 Serial No.179 H.Hughes & Son Ltd London. CLOCK MKI" with AM and a Crown on the hinged bezel. Regards Robert Skinner in England."

[Robert's image attached below]
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Hi Robert: Thank you for posting these pictures of your MK 1's. I know very little about these clocks however I have owened a Mark V and a Mark IV-A pilot watch. Can you explain to me the different applications for these clocks/watches. Thanks

Hello John, Sorry, but I know nothing about the Mark V other than I think it was a Royal Flying Corps watch from WWI? The RAF MK I aircraft clock dates from the late 1930's just before WWII. Very few were made, and even fewer survived WWII. The sole maker is widely believed to be T & F Mercer. I acquired a T & F Mercer MK I (Serial No 327/40) twenty plus years ago. Some years later, I acquired a second MK I, this one made by H.HUGHES & SON, (Serial No 179). I have never seen another H.HUGHES MK I, and wonder if anyone else has? The MK I is believed to been used in pre WW II Short Singapore and Supermarine Stranraer Flying Boats, and in some early Mk I Sunderland Flying Boats. It is believed to be the only aircraft clock that required a separate winding key. The clocks were wound, and the time set by the ground staff before a flight. Best Regards Robert in England.

Hello John, Regarding your MARK V, if you can look back to past posts from Grant Perry, Gregg Crocket and Ben Roberts, dated OCT 2005, there is a discussion on the Mark V. In the posts, mentioned is page 30 of a book by Z M Wesolowski, which features the Mk V. Hope this helps. Regards Robert.

HI Robert> Thank you for your reply. I am somewhat familiar with the MK V (I think my Mk V is somewhere in Greg Crocker's post). I was inquiring about the usage of the Mk 1 which you have adequately answered. Thank you and Happy New Year, John