In a letter to the Chief, Bureau of Naval Weapons dated March 30, 1961, Verticraft Corporation of Northridge, California noted its inability to submit a proposal for the Tri-Service VTOL at the time of writing, the primary reason being that information was requested and received too late (March 10, 1961) for the required preparation. The letter was written by Alexander Krivka, President of the company.
Verticraft felt, however, that it had a very unique vehicle which combined high forward speeds in a true VTOL aircraft; it asked the Bureau of Naval Weapons if a proposal could be submitted at a future date.
Since the design was so unusual, it was necessary for Verticraft to fabricate a full-scale single-duct, production model called the Verticar in order to obtain design information; two photos of this aircraft are shown above. At the time of writing, the vehicle was undergoing ground testing; however, the existing 200 hp turbo-shaft engine was not sufficient for flight testing the vehicle. Verticraft asked if it could qualify under a Research and Development Program to receive assistance in their testing program; it claimed that test results to date had indicated a lift to power ratio of greater than 6 lbs/hp.
The company welcomed inspection of the Verticar by the military and offered to furnish any additional information required. Krivka also sent copies of his letter to the Air Force and Army, but none of the services appear to have been interested in the proposal.
The two-duct Verticar shown in the accompanying drawings had an airfoil-shaped fuselage which provided all of the lift necessary for horizontal flight. There were two air ducts containing counter-rotating propellers located in the front and rear portions of the fuselage which provided the vertical lift. The propellers were shaft driven from two Pratt & Whitney JFTD12A-3 turbo shaft engines with bypass modifications allowing the exhaust gases to go straight aft for forward propulsion. The vehicle was controlled in vertical flight through control vanes in each air duct and in the engine exhaust ducts. In horizontal flight, control was achieved through a conventional rudder/elevator system plus the control vanes in the exhaust ducts. Four wheels were provided for road travel with the front wheels being steerable and the rear wheels being driven by a four-cylinder air-cooled engine.
The two-duct Verticar was 48 ft long, 13 ft high and 10 ft in width. Gross weight of the vehicle was 29,700 lbs and the maximum speed was 420 kts. Additional characteristics of the design are listed in the data sheet above.
Unusually, in order to increase cargo area, load carrying capacity, and/or improved performance, Verticraft claimed that two or more vehicles could be locked together and controlled manually by a single operator.
The Navy’s response has not been located, but it was most certainly unfavorable, as there is little in the historical record to suggest that the Verticar ever made it off the ground. If any reader has further information on the vehicle, Verticraft or Alexander Krivka, please contact the editor or comment below. A patent search has yielded patents for a rotary wing aircraft and a steam-powered aircraft issued to Krivka in 1971 and 1976, respectively, but no patents resembling the Verticar.
All images from NARA Archives II, College Park, MD, RG 72