An autocad model of the BiPod in flight.
The BiPod's typical Rutan DNA is especially visible here.
The BiPod, arguably Mojave's most lightweight aircraft, lands nearby the heaviest, Orbital Sciences' Stargazer.
Four decades of Rutan magic summarized in one photo: the venerable Long-EZ salutes the BiPod passing below.
Burt Rutan poses with the Scaled team that built the BiPod.
Status: company-owned demonstrator
Type: hybrid-electric roadable aircraft
Powerplant: 2 x 450cc engines, 4 x 15 kW motors
Significant date: 30 March 2011 (first flight)
The Model 367 BiPod has been largely advertised as Rutan's final design at Scaled before his retirement. It is a two-seat, hybrid-electric roadable aircraft. Originally conceived as a rapid, low-cost electric testbed, the effort evolved into a flying car and was accelerated to allow Rutan, a long-time advocate of personal electric aircraft, to see the vehicle completed before he retired.
The BiPod program was conceived as a rapid, low-cost electric test-bed using as many COTS components as possible. During initial conceptual design studies, Scaled found that many of their propulsion system characteristics were well aligned with the drivetrain needs of a roadable vehicle and expanded the research program to include a “flying car” airframe. With the impending deadline of Rutan’s retirement, Scaled Composites pursued an aggressive schedule and successfully achieved first flight of the BiPod vehicle within four months of beginning preliminary design. The entirely new design will operate as a high-performance airplane with STOL capabilities, 200 mph maximum speed, and 700 mile range or as a road commuter vehicle capable of freeway speeds, urban driving, and garage storage.
Rutan and his team took a novel approach to solving many of the design challenges associated with a roadable aircraft. Scaled placed a large emphasis on developing a configuration that was safe for ground operations, yet still efficient at high flight speeds. Accordingly, BiPod’s twin fuselage configuration provides a low-drag enclosure for a robust, 4-wheeled chassis with two cockpits, while providing a protected storage location for the wings and tail surfaces during ground operations. Two internal combustion engines, one per fuselage, provide power to the rear wheels and to propellers located on the horizontal stabilizer. Lithium batteries in the nose provide additional energy for take-off and in the case of an engine emergency. The vehicle’s center of gravity is positioned for ground operation stability, while aircraft rotation is enabled by direct blowing of the horizontal stabilizer and by applying power to the rear wheels. The use of electric power transmission decouples engine location from propeller location without the need for mechanical shafts and gearboxes, enabling BiPod’s unique geometry.
The vehicle performed well during initial ground and flight testing. The low center of gravity and wide track resulted in a stable, controllable road configuration both on the skid pad and at freeway speeds. Initial flight tests indicate that the vehicle is stable and controllable. Scaled is continuing to test and develop the BiPod configuration and hybrid propulsion system, with the goal of using similar systems on future unique aircraft configurations. Despite the inherent inefficiencies associated with energy conversion steps, Scaled Composites believes hybrid systems may offer advantages for specific mission requirements, such as distributed propulsion, multi-mode operation, or energy recovery. Furthermore, the use of carbon fuels provides better energy density and a lower gross take-off weight for the same range when compared to electric-only vehicles. Ultimately, the BiPod configuration will provide a unique propulsion system test bed in an operational flight vehicle, providing Scaled Composites experience with a number of different powerplants and associated systems.
Will the BiPod really be Burt Rutan's final design? “I’ve done a new type on average one a year since 1973,” he said. “Do you think I can stop that?”
Population: 1 [N367DF]
Wingspan: 31 ft. 10 in.
Drive mode width: 7 ft. 11 in.
Length: 21 ft 6 in. (6.57 m)
Width: 8 ft (2.44 m)
Maximum cruise speed: 200 mph
Flight range: 780 miles
In roadable form with the wings retracted the BiPod certainly doesn't look like your average car, rather like a couple of submarines on wheels!
The BiPod in roadable configuration oddly echoes the Italian Taruffi « Tarf 500 » twin-bodied car of 1949 (below).