This LZ-1A was built initially as a Sikorsky R-6 and TOC with the USAAF as 43-45480. The frame was selected for testing with the new Doman rotor-hub system. The blades are held on the hub similar to a variable-pitch airscrew blades and the rotor incorporates a gimbal mounting to provide the necessary tilting of the rotor disc. The flight tests were started in early 1950 with remarkably good results and so the larger LZ-2A Pelican followed. The LZ-1a is now on display at this super museum.

The utility helicopter LZ-5 utilised Doman's unorthodox gimbal mounted, rotor head system with no need for flap and drag hinges dampers. The type did not go into production and only three prototypes were built, the first two of which were purchased by the US Army, as the YH-31, but ultimately rejected as the rotor system was deemed too complex for practical field repair. The third prototype flew extensively in Canada as CF-IBG and in the US, France (Paris Air Show in 1960) and Italy with the registration N812, and is now on display at this super museum.

Ex USAAF Hoverfly II 43-45480 converted post-war by Doman Helicopters Inc for rotor blade development tests. The American Export Airlines flying boat in the background is the world's only surviving Sikorsky VS-44A, NC41881 "Excambian" (c/n 4402).