XB-7 Sunbeam

The island nation of Avernia has been spared the destructive wars that plague the northern mainland states, but its remote location has hindered civilian trade. Its rich natural resources and forward-thinking leaders have provided generous grants to inventors who are looking for solutions. The young science of aviation is an especially promising field, and the XB-7 Sunbeam is a highly advanced, if unorthodox, expression of this nation’s engineering prowess and optimistic futurism.

Design Features

- During its development, the Sunbeam’s designers prioritised high speed, long range and endurance. They believed a radical flying wing layout would offer more lift, less weight and less drag than a more conventional airframe. The first aircraft in the XB series – which started as unpowered gliders – provided these advantages but suffered from some dangerous flaws: yaw control was marginal while pitch control ranged from responsive to vicious. Wingtip stall at lower speeds and higher angles of attack was another major problem, especially for later aircraft with more sharply swept back wings – which otherwise performed well at high speeds. Although swept wing technology is still not fully understood, the Sunbeam’s twin vertical tails and rudders give it more stability than a pure flying wing; they also double as wing fences which reduce the chance of wingtip stall.

- The Sunbeam’s retractable undercarriage improves high speed performance and gives the propellers good ground clearance during takeoff and landing. A steerable nose wheel improves control while taxiing and skids on the lower tail fins help protect them from rough landings.

- A supercharged V12 engine is housed in the fuselage between underwing air intakes. It drives contra-rotating propellers via a short cam and gears; this system is mechanically complex but provides a lot of thrust while generating neutral torque.

- The short nose and bubble canopy provide excellent forward visibility. As these aircraft are unpressurised pilots typically wear oxygen masks when flying at high altitudes. Standard equipment also includes warm gloves, boots and underclothing, white helmets with tinted visors, parachutes and bright orange “sunbeam suits” worn to aid search and rescue teams in case of emergencies.

- As the propellers pose an obvious risk to pilots during bailouts, the first Sunbeams’ spinners were fitted with small explosive charges to blast off the blades before pilots left the cockpit. Later models are also equipped with primitive ejector seats – an innovation copied from captured Tarkavian military aircraft provided by Khandarian agents.

- The Sunbeam’s streamlined airframe, high power to weight ratio, and large fuel tanks in the wings give it excellent speed, range and endurance. During its first tests it surpassed its designers’ requirements and set many new performance records. Its disadvantages include limited internal space and inherent instability; test pilots’ reports of a high workload outside straight and level flight suggest the concept needs refinement before it sees more widespread use.