Exclusively for Aviation Week, Scaled Composites has taken the wraps off the last design by company founder Burt Rutan, who retired in April. You can read the story in next week's Aviation Week & Space Technology.
All photos: Scaled Composites
The Model 367 BiPod 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 his retirement.
The BiPod was brought from preliminary design to its first flight on 30 March 2011 in just four months. So far, the aircraft has made several short hops along the main runway at Mojave, California, each time propelled briefly into the air by building up speed using the battery-powered driving wheels. The electric-powered propellers are not yet installed.
The flight-capable BiPod will have two 450cc internal-combustion engines, one per fuselage, driving generators feeding a distributed electrical power system. In road mode, this will power 15kW motors on driving wheels positoned aft in each fuselage behind steerable nose wheels.
In flight mode, the electrical system will power four 15kW motor-driven propellers, two on the wing and two on the horizontal stabilizer linking the tails. Lithium batteries in the nose, which are recharged in flight, provide additional power for takeoff and a reserve for at least two landing attempts in the event of an engine emergency.
The BiPod is designed to be driven like a car from the left-hand cockpit and flown as an aircraft from the right side. With a steering wheel in the left cockpit and flying controls in the right, the throttle is the only interlinked system between them.
Span is 31ft 10in with wings attached, and 7ft 11in with the wings removed and stowed between the fuselages. As an aircraft, it is designed to cruise at 200mph and fly for around 530 miles in higher-power mode and up to 760 miles at 100mph. As a car, the BiPod is designed for freeway speeds, urban driving and garage storage, with a range of 820 miles on a tank of gas and 35 miles on batteries alone.
Scaled has taken the wraps off the BiPod to gauge outside interest in further development, as building roadable aircraft and kitplanes is not the Northrop Grumman subsidiary's business. Here's what the fully developed BiPod would look like, as a car and as an aircraft.
Scaled used the BiPod development effort as a chance for some of its new engineers to work with Rutan before he retired. President Doug Shane says Rutan "was here all the time - he worked really damned hard - and that was a good lesson to all our young engineers that you don't get something for nothing."
Shane says the frenzy of activity over the winter was reminiscent of his early career designing and building homebuilt aircraft. Daily Rutan worked on the shop floor with a team of fabricators and "could commonly be found sanding, shaping and fitting the unique details of the BiPod design late into the night - long after the shop technicians had clocked out."
"Furthermore, in order to meet Burt's personal deadlines, a large portion of BiPod's fiberglass and carbonfiber airframe was laid up over the weekends by a team of young volunteer engineers who were excited to test one more aircraft pior to his retirement," says Scaled.
Lest we forget, here's a quick look back at some of the other unique designs in the long and illustrious career of Burt Rutan and Scaled Composites: