General => Douglas Motorcycles - General Discussion => Topic started by: eddie on 11 Aug 2009 at 07:34

Title: Prototype??? Douglas
Post by: eddie on 11 Aug 2009 at 07:34
Hi All,
         Can anyone throw any light on the machine in the attached photo? For many years, this was thought to have been just a design exercise and that the bike never actually existed, but recently, I came by the bottom end of an engine of this type. Having cleaned it up, I found that all holes for studs, etc. have been marked out and bench drilled - so, probably produced prior to any jigs being made. Generally, the layout is the same as the T35 engine but the flywheel assembly is a smaller version of that in the DV60, and the barrels and heads look to be as used on the generator engines of the period (1939/40). The timing gears have a different pitch (14DP) to the later engines and the front camshaft bushes are flanged and much larger to allow camshaft removal without splitting the crankcases. Ignition is provided by a BTH Dynamag.
      From the drawing, most parts look to be fairly easily replicated - the biggest problem will be the gearbox. Can anyone help with any details? There are 2 possibilities - the gearbox may be similar to the early T35 'box or could have the bevel gears on the input shaft (as on the DV60) - so that the shafts lay across the frame. From the crankcase castings, I have established that the bellhousing flange turns out (rather than inward as on the T35) and there are 8 equi-spaced 5/16" studs for attachment.
           Any help will be greatly appreciated,

( drawing-750.jpg)
Title: Re: Prototype??? Douglas
Post by: trevorp on 11 Aug 2009 at 12:01
looks like set up for trials do the carby tubes go into bell housing
maybe the fore runner to the competition
Title: Re: Prototype??? Douglas
Post by: eddie on 11 Aug 2009 at 18:57
By a strange twist of fate, this could be considered a forerunner of the Comp. This drawing was produced on 1st May 1939 - just over 4 months before the outbreak of war (during which, civilian motorcycle production was suspended). Soon after the end of the war, Douglas announced 2 new models - the T35 as we know it, and a rigid frame standard model. Rumour has it that, as the torsion bar frame was proving a good seller, only 3 of the rigid frame models were made, but the initial batch of frames were utilised at a later date (with some modifications) for the Competition model. As is known, Douglas were one of the first manufacturers to announce totally new models after the war, so some secret testing and development must have been going on during the hostilities - hence the existence of my engine.
      As can be seen from the attached photo, the main castings are very much like the later T35 models, except that it has a smaller, finned sump and just a platform but no flange for the magneto.