Author Topic: What was innovative - 1913 Douglas 2.75hp  (Read 4709 times)

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Offline buzzer

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What was innovative - 1913 Douglas 2.75hp
« on: 12 Jul 2008 at 09:15 »
Am hoping someone can help a newbie with a question relating to the 1913 Douglas 2.75hp as I'm trying to do some research for a project. Have skimmed through the technical article section on the forum and just wondered if anyone could summarise what was technically innovative about this particular model?

Many thanks for any information!

Offline Doug

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Re: What was innovative - 1913 Douglas 2.75hp
« Reply #1 on: 15 Jul 2008 at 14:41 »
New for 1913 was a new design of valve mechanism. While 1913 was the second year for mechanically operated inlet valves, in 1913 they took on an entirely new form that they retained right to the end of 2-3/4hp production in 1927.

With that they reverted back to gland nuts and a curved shape to the intake manifold, last seen in 1909.

In 1913 engine capacity was increased from 340cc to 349cc by enlarging the bore one millimeter to the dimensions 60 x 60mm stroke.

A slightly larger petrol tank was fitted, with larger openings for the oil and filler caps.

On the frame, the gear change quadrant and the petrol tank supports were now brazed to the frame.


Offline MRD

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Re: What was innovative - 1913 Douglas 2.75hp
« Reply #2 on: 15 Jul 2008 at 16:18 »

I believe that the engine may have made its first appearance the year before in 1912 on the works racing machines (seen elsewhere on this site).
It was obviously better performing as the engine was used the following year on production machines.
I'm not sure about the other improvements but I expect they were tested on these machines first. As with most preproduction improvements.
But your right as to going into production for 1913.
Regards     Martin
« Last Edit: 15 Jul 2008 at 16:37 by MRD »