Air suspension in the Velocette Dowty Olematic Forks “cushions” road shocks better than springs.
Velocette started using rear suspension by “oleo-pneumatic” legs in their sucessful Isle of Man TT models in 1937 and still use them today.
Modern large aircraft have changed from spring to air cushion, usually by Dowty.
Extracts of an email received from Dennis Quinlan, The Velobanjogent in Australia
“The photo labelled “Velocette KTT” below is incorrect as it is not a KTT model, rather a pre-war road model Mk.2 KSS & with girder front forks likely 1936-1939.
Only the factory racers from 1936 onwards used the Dowty rear struts as well as the production racer model mk.8 KTT from 1939 to the cessation of its production in 1950.
I’ve attached a composite of a works rear Velocette racer Dowty Strut with the exploded drawing of the prewar strut mechanism which differs from the postwar version in the damping mechanism.The photo of the identification plate was off a set I had on one of my mk.8 KTT racers.
To overhaul then I had been in contact with a Mr. John ( from memory) & eventually he had made up ten of the special seals used in the units which were long unavailable.
Mr John sent me the two copies of “The Dowty Story” by L.T.C.Rolt… part 1 being of most interest…
A chap who worked for me in my motorcycle instrument business years back, Felix Tydeman, was apprenticed at Dowty & surmised it was likely a job allotted to the apprentice master who had apprentices make the special tooling needed. I was eternally grateful & all Dowty required was for me to make payment to them for the airmail postage…wonderful.
I researched the Velocette connection but Sir George Dowty had passed away some 9 months before my contact with Dowty, so I could never confirm the meeting likely in late 1935 or early 1936 that must have occurred between himself & the racing chief at Velocette, Harold Willis, who sadly died during surgery in 1939.”