Just as I was doing the final proofing on PWG I had some useful information from Vernon Williamson who owns the first of Joe Potts ‘JP’ cars. I had captioned a picture of one of the first two JPs at Dundrod in August 1950 as being driven by Mirrlees Chassels because that’s what it says in the programme and the race reports. But according to Vernon, Dr Chassels eyesight wasn’t too good that day (seems there was some sort of problem with the track doctor – a hangover perhaps?) and Ron Flockhart took over the drive;  Be that as it may, the caption was changed as more information emerged from Vernon about the JPs.

Joe Potts had hillclimbed a Cooper at Bo’ness and Rest and Be Thankful in 1949 and reportedly raced at The Curragh in Ireland. It is known from factory records that early in 1950 Vincents supplied him a Black Lightning twin engine (998cc)and a Grey Flash single engine (499cc). Later he had one of the rare speedway engines but I am not sure what car that was for.

His first race appearance with a Vincent was at Silverstone for the British Grand Prix meeting on 13 May 1950 with the dark, probably green Cooper as pictured below in the paddock. He was eighth in his heat and his finish in the final isn’t recorded .


Several points can be noted about this car and readers might like to add their own observations.

It has the small brake drums which are believed to be the original aluminium wheels used before the magnesium type became available, maybe as an optional extra, sometime in late 1948. The wire-spoked steering wheel is characteristic of the earlier cars too. On the other hand the twin filler cap header tank which normally accompanied the recirculating oil systems of the Vincent and JAP big twins tends to suggest, maybe, a later car. Of course the later, or a modified tank could simply have been fitted to an earlier car when it had a recirculating oil engine installed. Or maybe it was supplied as a 500 (which is what Potts used in 1949) with the equipment and dimensions to suit a big-twin?

Note how low the two-exhaust pipe holes are. These can only be to accommodate a ‘low-slung’ Vincent with the semi-integral gearbox cut off so that the engine would sit lower without the Vincent clutch fouling the chassis rail. Usually an Albion gearbox was used and it is thought that is what Potts did. There is no record of him competing with the twin before this Silverstone photo, but it is probable that he had tried the engine in the car (wouldn’t you?); thus the twin exhaust holes that can be seen. Here is a Cooper Vincent with the engine in the normal ‘high’ position –  it’s John Green with a new car at Goodwood on 27 May 1950.

John Green Goodwood 27 May 1950 001

Potts’ next outing, and his first with a twin, was at the Manx Cup race at Douglas Isle of Man on Thursday 15 June when a  host of Cooper twins competed and all broke down. Strangely Pott’s was entered with a JAP twin and there is no direct evidence what he ran but it would seem probable he would have used his Vincent twin.

There is a photograph of the other side of his car at Douglas in PWGl which shows he didn’t have the bulge in the engine cover for the front carburettor which Vincents normally required. That suggests he was running a JAP but on the other hand, if the engine was lowered he wouldn’t have had a problem with carburettor clearance. Starting from the back row, Potts only lasted for two laps of the 18 lap race over 69.81 miles.

He competed at Bo’ness hillclimb on 24 June apparently with the 499 Vincent when he was a poor second to Comish Hunter. He was  at Rest and be Thankful a week later again running second, but closer, to Comish Hunter’s Cooper JAP. There is film at*&search_join_type=AND&search_fuzzy=yes in the National Library of Scotland that shows him, if only briefly, in a bronze or gold coloured car and that seems to be the last we see of Joe Potts in a Cooper. Potts was the first car to start.

Within a few weeks the first two JPs were in action at Dundrod on 12 August 1950 with Ron Flockhart in a Vincent twin-engined  twin-tubular chassis and a distinctive steering rack position forward of the Cooper-type front suspension. The body could be Cooper or is more likely a replica with a slightly longer nose, maybe to accommodate the forward mounted steering rack. There is a photograph of this car in PWG, as is mentioned above, and when I find it I will add a picture of the other car at Dundrod where neither did very well.


4 thoughts on “”

  1. The general idea is that I keep posting stuff here and that way I publish a lot of material that would otherwise never see the light of day. As already mentioned there is all the big-twin Cooper stuff I have collected but not used in PWG.

    Then there is the great mass of stuff which Graham Howard had collected and which is now in the Graham Howard Collection. There is a lot of video that has hardly ever been seen and right now I am uploading to the PWG Facebook page some really good stuff from the VSCC library.

    Currently I am trying to find out how this website business works. It is all very clunky. You have to write something and then post it to see what it looks like. Then you have to go back and fiddle with it and post it again. Its a bit like computers were before Apples and Windows came along – not very WYSIWYG – remember those days?


  2. Hi Terry,
    Congratulations on the new book – it looks to be a superb publication and obviously requiring tremendous effort to produce it.

    On your latest note and the article about Joe Potts, a few things for your trivia collection:
    • If you visit Frank Trento has compiled some details on all of the Vincent Black Lightnings and it shows the engine number of the Joe Potts Lightning twin; and
    • Re “the no bulge in some Cooper rear engine covers”, by fitting a Vincent Comet head on the front cylinder of the normal Vincent twin, this puts the front carburetor on the same side as the rear carb which may account for “no bulge” when fitted with a Vincent twin. The Black Lightning motors also came with both carbs on the left hand side.

    Kind regards,
    Kerry Horan


  3. Here are a couple of complementary lists of Vincent engines NOT for factory bikes. The Joe Potts engines are clearly identified but others are mysteries (seems I can’t post pictures in Comments!) Will try in another spot.


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