of the forked rocker arm to a shoulder between the guides, to eliminate side forces on the valve stem and ensure maximum valve life under racing conditions. The Series-A Comet could do , but Phil Vincent and his racing customers wanted more. 1936 Series A Rapide Whilst working in his office at Stevenage in 1936, Phil Irving noticed that two drawings of the Vincent HRD engine lay on top of each other in a "V" formation. He set them out on the drawing board as a v-twin engine in a frame Vincents had made for a record attempt by Eric Fernihough, who no longer required it. When Phil Vincent saw the drawing he was immediately enthusiastic, and a few weeks later the first Vincent thousand had been made, with Meteor upper engine parts mounted on new crankcases. The Vincent V-twin motorcycle incorporated a number of new and innovative ideas, some of which were more successful than others. The Vincent HRD Series A Rapide was introduced in October 1936. Its frame was of brazed lug construction, based on the Comet design but extended to accommodate the longer V twin engine. It continued the use of "cantilever" rear suspension, which was used on all Vincents produced from 1928 until 1955. Other innovations included a side stand. Innovative telescopic forks were not adopted by Vincent, with both Phils believing girder forks were superior at the time and beyond. The Series-A had external oil lines – known as "the plumber's nightmare" – and a separate gearbox. With 6.8:1 compression ratio, the 998 cc Series A Rapide Vincent produced , and was capable of . The high power meant that the Burman clutch and gearbox transmission did not cope well. 1946 Series B Rapide The Series B Rapide designed during the war and released to the press before end of hostilities looked radically different to the A. The oil pipes were now internal. Unit construction allowed Vincent to combine the engine and gearbox into a single casing. Philip Vincent summarised his frame design philosophy in his memoirs, writing "What isn't present takes up no space, cannot bend, and weighs nothing — so eliminate the frame tubes!" The angle between the cylinders was changed to 50° from the 47.5° of the Series A engine to allow the engine to be installed as a stressed member. This enabled Vincent to reduce the frame to an upper frame