Author Topic: ABC-Douglas  (Read 2894 times)

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Offline Doug

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« on: 24 Oct 2018 at 03:56 »
A, B, C, D; D is for Douglas...

Following on from the post here:

about S.L. Bailey, and specifically about his special 1912 350cc racing Douglas built by Granville Bradshaw that lead to the first ABC engine. It seems initially the ABC was offered as just an engine that could be fitted into other maker's existing frames.

From "Granville Bradshaw, a Flawed Genius?" by Barry M. Jones (Panther Publishing, 2008, ISBN  9780956497574)

"Inspired by Bailey's success with the modified engine, Bradshaw designed and built his first ABC motorcycle engine in the winter of 1912/13, primarily as a replacement engine for those existing motorcycle engines fitted in the fore and aft, Douglas fashion, though this was itself developed from J F Barter's 'Fee' of 1905. Bradshaw's new engine was 492cc, 3-1/2hp horizontally opposed 'square' twin (69 x 68mm). Lubrication was by splash system; the engine weighed barely 40lbs."


"The new ABC motorcycle engine was revealed to the public in April 1913 and was fitted into a Zenith frame which Freddie Barnes then raced on the Brooklands track. Improvements rapidly followed,starting with pressure-feed oil lubrication system and in May 1913, a modified valve gear.

Due to complications in modifying other maker's frames to accept the fore and aft ABC engines. Bradshaw got both Earnest Humphries at OK Supreme and the Collier brothers at H Collier & Sons ('Matchless') to build special frames for him into which the new engine could be fitted. By June 1913 the ABC engine had reached production status and was soon selling to private owners of Douglas, Edmund, matchless, Zenith and PV (Perry Vale) machines. One such PV was entered in the 1913 London Exeter MCC trial and gained a Gold Award for completing the grueling course."

This may explain the following image found in the archives of the British Registered Designs Office. An ABC engine in a very Douglas frame.

The striking out with ink the non-relevant portions of the photograph was a common Registered Design practice.

This was submitted June 24, 1913 by William Douglas:

The only design claim being registered was the mounting brackets for the engine. Initially it appears Douglas was going to claim the overall shape of the frame, but changed their mind!


Offline cardan

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Re: ABC-Douglas
« Reply #1 on: 29 Oct 2018 at 09:19 »
Hi Doug,

The bike shown on the Registered Design application is described in Motor Cycling, 29 July, 1913. The final paragraph reads: "To avoid any misunderstanding we would inform our readers that this machine is a special model, built to the order of an amateur, and that Douglas Bros. have no intention of constructing any others on similar lines, as they will concentrate all their efforts on the manufacture of their own 350 c.c. and 500 c.c. machines next year."

The full article is on the ABC Road Motors website

So it would seem that the slightly-stretched Douglas provided a test bed for the early ABC engine.