The Ryan Aeronautical X-13 verti-jet was an early prototype vtol developed during the 1960s. Attempting to utilize new jet age technology, the X-13 would have sat on it's tail surface flying straight up like a rocket for take off. The amount of skill and precision required to take off and land the vehicle made it unappealing to the US navy and airforce, dooming the project to fail. Only two prototypes still exist, and only one can be seen at the Smithsonian museum in Washington DC