Type: high altitude non-stop round-the-world record aircraft
Significant date: 1981
Burt Rutan made his reputation with innovative designs for homebuilt aircraft, including the VariViggen, VariEze, Long-EZ, and others. In 1981 Burt designed a rather remarkable aircraft with a specific mission. He and brother Dick had conceived the idea of a non-stop, non-refueled, around-the-world flight in 1980. They predicted the project would take 18 months. It took 6 years.
The Model 76 Voyager aircraft was designed and fabricated for a single mission: Fly around the world non-stop non-refueled. Dick Rutan and Jeana Yeager formed Voyager Aircraft Inc. (VAI) and planned to get this aircraft built and to achieve the goals of setting new distance records and to attempt the Round-the-World Flight. The Voyager was optimized for long range and intended to shatter (even double) existing distance records.The structural weight would need to be as low as possible in order to accommodate the fuel required for such a mission.
In mid 1982, VAI and RAF agreed to a team plan where RAF and Burt would design, build and flight test the aircraft to prove its structure, flying qualities and performance. VAI would then equip it with special engines and props and the navigation systems required, and conduct the record flights. The configuration selected was a twin engine pusher-tractor tandem wing vehicle made from graphite and paper, with twin booms connecting the tip of the forward wing through the center wing terminating at the vertical fin. The cabin was only large enough to accommodate the crew of two and provisions for the estimated 9 day flight. Power came from two engines, one at each end of the fuselage.
Construction of the Voyager began in the summer of 1982, with a first flight two years later. The airframe was built without metal components. The main material used was a composite sandwich of paper honeycomb and graphite fiber, molded and oven-cured. Weight-saving materials kept the airframe to a structural weight of just 939 lbs. Soon, after nearly two years work by a very small team, an awesome aircraft emerged. Its fabrication was done by some very hard work by a few dedicated people.
RAF contracted Bruce Evans, an early VariEze builder/flyer who virtually lived with the project, working continuous long hours on everything from tooling to structure and systems. Jeana and Dick also made a full-time commitment to the building process. Wedged in with the Solitaire development, the Voyager was a primary task for all the people at RAF. Bruce Tifft donated the interim propellers for the initial flight tests. Chuck Richey, a Scaled engineer and VariEze builder/flyer donated detail design work for the landing gear system.
The Voyager's prepreg carbon fiber tape/nomex honeycomb sandwich structure required the team to build a special, large oven for bagged 250 degrees cure skins. Bruce and Dick travelled to Utah to use Hercules autoclaves to cure the carbon spars for the immense 100 foot plus wing. The team was assisted by donations of materials and tooling help from Hercules, Aircraft Spruce, Wicks, Brock, Task Research, American Cyanamid and Hexcell. Ken Brock's donation included fabrication of the high-efficiency oleo landing gear assemblies. These units were works of art, weighing only a couple dozen pounds each but supporting an aircraft weighing as much as a business turboprop aircraft.
Structural sample testing was conducted as the first step in the program to determine the lightest materials and fabrication processes available appropriate to the vehicle requirements. It was determined that .010-inch graphite tape skins, with 1/4-inch Nomex honeycomb core would provide adequate structure, and, with suitable application of film adhesive, would also be an adequate fuel barrier. The spars were made from graphite tape and Nomex cores, and were autoclave-cured by an outside vendor.
The result was an airplane with a structural weight/gross weight fraction of only 9%; significantly lower than any existing man-rated airplane. This was key to the Voyager's success, because the amount of fuel carried, in relation to the vehicle's takeoff weight, had the strongest influence on range. Voyager was, in effect, a flying fuel tank. Though designed to fly slow, its fuselage aerodynamically resembled a high speed racing aircraft. Like spacecraft, its structure was highly refined and optimized to support fuel weighing over 10 times the airframe weight.
From December 14 to 23, 1986 "Voyager" piloted by Dick Rutan and Jeana Yeager flew around the world covering more than 46000 km. The rear engine, a 110-hp air-cooled Teledyne Continental IOL-200 ran for all but 8 minutes of the flight, when a fuel feed problem shut it down. The front engine, a 130-hp, air-cooled Teledyne Continental O-240, provided takeoff and climb power, and backup for the rear engine. Both engines swung aluminum Hartzell constant-speed, variable pitch propellers. In the cramped cabin, the on-duty pilot (sitting on the right) flew the airplane, navigated, communicated with the ground, and transferred fuel to keep the airplane in trim. The off-duty pilot (lying on the left or behind) helped with navigation and flight monitoring, managed flight logistics, and rested—though in fact, neither pilot got much rest during the nine-day flight.
Voyager’s official average speed during the around-the-world flight was 116 mph. Its altitude averaged around 11,000 feet, climbing as high as 20,500 ft. Voyager’s route was set with the help of a team of meteorologists who guided the pilots around storms and into favorable winds. On December 23, 1986, the Burt Rutan-designed Voyager aircraft landed at Edwards Air Force Base in California, completing the first non-stop, non-refueled flight around the world by an airplane. Its flight of 26,366 statute miles lasted 9 days, 3 minutes, and 44 seconds, piloted by Dick Rutan (Burt’s brother) and Jeanna Yeager. Its gross takeoff weight for the record flight was 9,694.5 lbs., of which 7,011 lbs. was fuel, carried in 17 tanks. When the flight ended nine days later, only 140 lbs. of fuel remained.
To say that Voyager was a success would be an understatement. Voyager’s flight was a stunning triumph, accomplished by Rutan’s project team, a host of volunteers, many small private contributions, and no government sponsorship. Not only did it perform an aviation "first", it more than doubled the existing absolute range record for airplanes on its 9-day long flight. Today, the Voyager aircraft is displayed in the National Air & Space Museum in Washington, D.C. The centerpiece of the Voyager Exhibit in the EAA AirVenture Museum at Oshkosh is a full-scale replica of the Voyager’s fuselage and cockpit/cabin.