The Douglas Mark III is a British
motorcycle
A motorcycle (motorbike, bike, or trike (if three-wheeled)) is a two or three-wheeled motor vehicle steered by a handlebar. Motorcycle design varies greatly to suit a range of different purposes: long-distance travel, commuting, cruising ...
designed and built by
Douglas motorcycles
Douglas may refer to:
People
* Douglas (given name)
* Douglas (surname)
Animals
*Douglas (parrot), macaw that starred as the parrot ''Rosalinda'' in Pippi Longstocking
*Douglas the camel, a camel in the Confederate Army in the American Civil W ...
in
Bristol
Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city in ...
between 1948 and 1949.
The 350 cc
flat twin
A flat-twin engine is a two-cylinder internal combustion engine with the cylinders on opposite sides of the crankshaft. The most common type of flat-twin engine is the boxer-twin engine, where both pistons move inwards and outwards at the same ti ...
engine in the Douglas Mark III was based on a Second World War electricity generator.
As well as the 1948-9 Douglas Mark III, Douglas also produced a Mark III "De Luxe", a Mark III Sports, and a rigid-framed
motorcycle trial
Motorcycle trials, also known as observed trials, often called simply trial/s (with or without the plural "s"), is a non-speed event on specialized motorcycles. The sport is most popular in the United Kingdom and Spain, though there are participan ...
s Competition version.
History
During the Second World War the
Bristol
Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city in ...
-based Douglas motorcycle company produced stationary
generator
Generator may refer to:
* Signal generator, electronic devices that generate repeating or non-repeating electronic signals
* Electric generator, a device that converts mechanical energy to electrical energy.
* Generator (circuit theory), an eleme ...
engines using their 348 cc overhead valve
flat twin
A flat-twin engine is a two-cylinder internal combustion engine with the cylinders on opposite sides of the crankshaft. The most common type of flat-twin engine is the boxer-twin engine, where both pistons move inwards and outwards at the same ti ...
. One of these Douglas generators was used at
Winston Churchill
Sir Winston Leonard Spencer Churchill (30 November 187424 January 1965) was a British statesman, soldier, and writer who served as Prime Minister of the United Kingdom twice, from 1940 to 1945 Winston Churchill in the Second World War, dur ...
's wartime summit meeting held next to the
Sphinx
A sphinx ( , grc, σφίγξ , Boeotian: , plural sphinxes or sphinges) is a mythical creature with the head of a human, the body of a lion, and the wings of a falcon.
In Greek tradition, the sphinx has the head of a woman, the haunches of ...
in
Giza
Giza (; sometimes spelled ''Gizah'' arz, الجيزة ' ) is the second-largest city in Egypt after Cairo and fourth-largest city in Africa after Kinshasa, Lagos and Cairo. It is the capital of Giza Governorate with a total population of 9.2 ...
.
By the end of the war in 1945, Douglas restarted motorcycle production – much to the surprise of the industry, as it was generally expected that the war had led to other interests, with the company being taken over by Aero Engines Ltd, so there were not many engineering staff left for the development of new motorcycles.
The Douglas T35 used the same flat-twin 350 cc as the generator, mounted in a duplex fame with torsion bar rear suspension.
The T35 was an unexpected export success; 1947 factory records show them being exported to
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
,
Switzerland
). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...
,
Belgium
Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...
,
Santiago
Santiago (, ; ), also known as Santiago de Chile, is the capital and largest city of Chile as well as one of the largest cities in the Americas. It is the center of Chile's most densely populated region, the Santiago Metropolitan Region, whose ...
, and
Russia
Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
.
Development
In 1948, the company developed a series of motorcycles based on the T35. Designed by George Halliday, these featured Douglas "Radialraulic" forks with the front wheel spindle carried on short leading links pivoted at the rear of the fork stanchions – with springs and a damping mechanism inside the stanchions. Although the frame and suspension were innovative, the engine was essentially a generator, designed to run for long periods at a steady speed and it did not cope well with the varying engine speeds of motorcycling. There was also a tendency to sideways shaking at low engine speeds which was a feature of the horizontally opposed engine. Douglas hired former
Sunbeam motorcycles
A sunbeam, in meteorological optics, is a beam of sunlight that appears to radiate from the position of the Sun. Shining through openings in clouds or between other objects such as mountains and buildings, these beams of particle-scattered sunl ...
designer
Erling Poppe
Erling Poppe (12 November 1898 – 1970) was an Austrian-born English-raised motor vehicle designer who studied engineering in Birmingham, England, and designed Packman & Poppe Motorcycles, Sunbeam S7 and S8, Sunbeam motorcycles and Gordon (1954- ...
as Technical Director,
Freddie Dixon
Frederick William Dixon (21 April 1892 – 4 November 1956) was an English motorcycle racer and racing car driver. The designer of the motorcycle and banking sidecar system, he was also one of the few motorsport competitors to have been success ...
as their specialist engine tuner and Walter Moore (who designed the
Norton CS1
The CS1 was a Norton motorcycle between 1927 and 1939. Originally built as a TT racer, and Norton's first design of an overhead cam engine, it proved successful as a ''TT Replica'' road bike.
After the early 1930s redesign of Norton's cammy mo ...
) as Works Superintendent.
The result was the 1949 Douglas Mark III, which had improved performance through an uprated cylinder head, combustion chambers, and pistons. Douglas also produced a Mark III "De Luxe", a Mark III Sports, and a rigid-framed
motorcycle trial
Motorcycle trials, also known as observed trials, often called simply trial/s (with or without the plural "s"), is a non-speed event on specialized motorcycles. The sport is most popular in the United Kingdom and Spain, though there are participan ...
s Competition version with high-level exhausts and a less deeply valanced front mudguard.
There never was a Douglas Mark II, and the Mark IV was short-lived, so the end of the line of development was the Mark V produced between 1951 and 1954, when it was replaced by the
Douglas Dragonfly
The Douglas Dragonfly is a motorcycle designed and built by Douglas motorcycles in Bristol. The last motorcycle produced by the company, the 1955 Dragonfly was an all-new motorcycle built to use an improved version of an existing engine. Despite ...
.
Competition success
Motorcycle trials
Motorcycle trials, also known as observed trials, often called simply trial/s (with or without the plural "s"), is a non-speed event on specialized motorcycles. The sport is most popular in the United Kingdom and Spain, though there are participan ...
rider David Tye worked for Douglas as a sales rep, competing at weekends in the factory trials team. In 1950, he won the Nevis Trophy and the Special First Class Award in the demanding
Scottish Six Days Trial
The Scottish Six Days Trial is an internationally recognised Motorcycle trials competition, which has been running since 1909 (with breaks for the two world wars) making it the oldest motorcycle trials event in the world. Motorcycle riders from al ...
riding the Douglas Mark III Competition model. The low
centre of mass
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may ...
of the flat twin was useful for trials control but it did have a clearance problem over the rough ground. Occasionally one of the carburettors would be knocked off, but the team developed a "quick change" replacement and always kept spares ready.
Works rider Don Chapman
on the Douglas Mark III Sports gave Douglas their only major successes in motorcycle racing by winning at the
Silverstone Circuit
Silverstone Circuit is a motor racing circuit in England, near the Northamptonshire villages of Towcester, Silverstone and Whittlebury. It is the home of the British Grand Prix, which it first hosted as the 1948 British Grand Prix. The 1950 ...
in 1950. Securing a win by 19 seconds, Chapman was awarded the ''
Motor Cycling
Motorcycling is the act of riding a motorcycle. For some people, motorcycling may be the only affordable form of individual motorized transportation, and small-displacement motorcycles are the most common motor vehicle in the most populous co ...
'' magazine prize for "most meritorious" performance in the Clubmans races.
See also
*
List of Douglas motorcycles
This is a list of Douglas motorcycles please add to it or update where you can:
See also
*List of AMC motorcycles
*List of Ariel motorcycles
*List of BSA motorcycles
*List of Norton motorcycles
*List of Triumph motorcycles
*List of Royal Enfi ...
*
List of motorcycles of the 1940s
This a listing of motorcycles of the 1940s, including those on sale, introduced, or otherwise relevant in this period.
Motorcycle
*Acme motorcycle (1939–49)
* AJS 18
* AJS 7R
*AJS Model 16
* AJS Model 20
*AJS Porcupine
* Ariel Red Hunter
* ...
References
External links
Douglas Mark III in Motor Cycle magazine
{{DEFAULTSORT:Douglas Mark Iii
Mark III
Motorcycles introduced in the 1940s