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The Welbike was a British single-seat motorcycle produced during World War II at the direction of Station IX — the "Inter Services Research Bureau" — based at Welwyn, UK, for use by Special Operations Executive (SOE). It has the distinction of being the smallest motorcycle ever used by the British Armed Forces. Between 1942 and 1943, 3,641 units (plus a prototype and some pilot models) were built and, although not much used by the SOE, some were issued to the British 1st and 6th Airborne Divisions and some were used at Arnhem during Operation Market Garden. The Italians, Germans and Americans also developed small motorcycles for their airborne forces during World War II. ==Development== The original prototype was designed by SOE motor cycle enthusiast Harry Lester, from an idea developed by Lt. Colonel John Dolphin, the Commanding Officer of Station IX, the secret Inter-Services Military Research Establishment based in a mansion called The Frythe (latterly owned by the pharmaceutical company GSK) an hour's drive north of London near the town of Welwyn in Hertfordshire,〔(【引用サイトリンク】title=British Army Officers )〕 which had been taken over for the war effort.〔(【引用サイトリンク】title=Special Operations Executive )〕 Powered by a Villiers single-cylinder two-stroke petrol (gasoline) engine, the Welbike was designed to fit into a standard parachute airdrop container long, high, and wide.〔 Once deployed, they were easily assembled and ready for use as quickly as possible.〔 The name ''Welbike'' comes from the custom that all the clandestine equipment devised at Station IX in ''Welwyn'' had names starting with ''Wel'', e.g., ''Welman'', ''Welrod''.〔(【引用サイトリンク】title=WWII Welbikes )〕 There was very limited space in the airborne equipment container, so the Welbike, which was carried in the container at an angle, had no suspension, no lights and just a single rear brake.〔 The fuel tank was as small as possible and, because its bottom feed point was located lower than the carburetor, had to be pressurised occasionally by a hand pump built into the tank. The range on maximum capacity of of fuel was at about . Tanks were pressurised before the Welbike went into action to save time. The Welbike was then packed into the parachute container with the rear wheel to the base of the parachute canister, which had a percussion head to minimise damage on landing. Once it hit the ground all that was needed was to twist the handlebars into position and lock them on spring-loaded pins. The saddle was pulled up and the footrests folded out ready to push start the two stroke engine and ride into action. The aim was that a paratrooper could remove the Welbike from its special green container (which was marked in white lettering with the words ''Motor Cycle'') and its easily identified coloured parachute, and be on the road within 11 seconds.〔(【引用サイトリンク】title=Welbike Scooter )〕 The prototype survived extensive drop testing at the Special Operations School at Arisaig in Scotland where it was demonstrated to the commando forces.〔(【引用サイトリンク】title=Memories of Inter Services Research Bureau )〕 The prototype was then sent to the Excelsior Ltd for further development. A number of pre-production "pilot" machines were built for further testing and experimental modifications at the Airborne Forces Experimental Establishment at RAF Sherburn-in-Elmet near Leeds in September 1942, including dropping them from aircraft to land by parachute. The Villiers engine was found to be seriously underpowered when ridden by a fully equipped soldier, so it was retuned for maximum power.〔 The simple design of the Welbike meant that it was easy and quick to produce and from 1942 went into full production for issue to airborne forces. By 1943 it was also being widely used by ground assault forces, including the Commandos and the Royal Marines Commando units, particularly for beach landings at Anzio and Normandy. The small size of the Welbike meant that it also proved very useful as a general airfield transport by the Royal Air Force and aircrews based in the large Far East airfields would 'stow away' a Welbike if they could find one.〔 There were three production versions of the Welbike. The first 1,200 were known as the Mark 1 and were really the developed version of the original prototype with tuned engines. These did not have a rear mudguard fitted however. One thousand four hundred Mark 2 Series 1 Welbikes were produced and these had a range of minor modifications, including the addition of the rear mudguard. The final batch of 1,340 was the Mark 2 Series 2 and had 'saddle' fuel tanks with a splash shielding between them and an improved filler cap, as the original design required the removal of the pressurisation pump which was too time consuming.〔 In combat situations, however, the Welbike could prove a liability as paratroops needed to get under cover as quickly as possible and had to find the Welbike containers before they could even start to assemble them. The difference in weight between a parachutist and a container meant that they often landed some distance apart, rather defeating the purpose, and some were captured by enemy forces or lost before they could even be used. The low power and small wheels also meant that they struggled to cope adequately with the often rough battlefield roads so were often abandoned by troops who found it easier to continue on foot.〔 Another problem for the Welbike was that, by the time it was in mass production, much larger gliders had been developed that could carry bigger and more powerful motorcycles such as the Royal Enfield WD/RE.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Welbike」の詳細全文を読む スポンサード リンク
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