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Diagram of shockwave patterns produced by James Reichard’s annular wing space launch vehicle. US Patent Office The destruction of the C.450 effectively fin- ished the French programme and, although the Germans briefly revived some of Lip- pisch’s annular wing proposals a few years later, these clever designs went no further in Europe. Zborowski continued to undertake consultancy work for German companies such as BMW and he died on 16th November 1969 at Brunoy, France. Convair Model 49 Starting in 1960 the US Army began to con- sider a new Close Air Support (CAS) aircraft because it was eager to break their depen- dence on the USAF who mainly used the Republic F-105 Thunderchief strike fighter in this role. Although the F-105D was considered to be a very capable delivery system by the USAF, the army felt that it was too fast in the close support role and they wanted a new heavily armoured VTOL aircraft with flexible performance and substantial firepower. This gave birth to a series of specifications for a new CAS design known as the Advanced Aer- ial Fire Support System (AAFSS), which were issued to a number of major defence con- tractors. Convair at San Diego in California responded with an unusual proposal, which bore something of a resemblance to the SNECMA C.450 Coléoptére and some earlier BTZ designs. Known as the Model 49, this two-man annular or ring wing ducted-fan design seemed to fill the gap between a heli- copter and fixed-wing aircraft, while also tak- ing on some aspects of an armoured ground vehicle. The only obvious disadvantage was a tilting cockpit that made the Model 49 a very complex piece of engineering. The aircraft had an approximate overall length of 30ft (9.14m), reducing to 26ft 7in (8.1m) when the cockpit was fully tilted, and the wing diame- ter was 22ft 9in (6.93m). The suggested empty weight was 14,000Ib (6,350kg) rising to 21,000 Ib (9,526kg) fully loaded, and the pay- load weight was estimated at 1,500 Ib (680kg) to 5,000 Ib (2,268kg). Two co-axially mounted contra-rotating three-bladed rotors with variable pitch were located within the wing to propel the Model This drawing of the Convair Model 49 annular- winged VTOL combat vehicle shows the cockpit lowered in the right-hand illustration. Bill Rose Fans and Ducts { b wae 49. Driving the rotors through clutches and gear reduction would be three turboshaft engines located in wing nacelles, which were capable of producing at least 3,000hp (2,237kW). First choice was the Lycoming LTC4B-11, with Pratt & Whitney’s JFTD12, the General Electric T64 or Allison’s T56 consid- ered to be suitable alternative engines. The duct would enhance the level of thrust from the relatively small rotors and, although there was no cyclic pitch control, the aircraft was expected to handle like a helicopter but with better reliability. Pitch and yaw vanes were located inside the annular wing. 149 Reichard annular wing space launch vehicle. US Patent Office