The Scorpion homebuilt helicopter was a highly successful kit that began production in 1968. Initially, the Scorpion was sold as a single-seat model, but the Scorpion Too version with an extra passenger seat became much more popular. When the Scorpion Too was first sold in the early 1970s, the kit cost approximately $7,000, including an economical Evinrude marine motor as a powerplant. The relatively low cost made the design competitive with fixed-wing kits.
Designer B.J. Schramm intended the Scorpion series for recreational use under the experimental aircraft category, in which it has proven highly successful. The basic design has undergone a number of significant changes through the years and the later "Exec" versions remained extremely popular with kit builders and helicopter enthusiasts who could not otherwise afford expensive production aircraft.
Gift of Harry C. Theurer DDS.
Country of Origin: United States of America
Rotor diameter 24 feet, height 7 feet 6 inches, length 20 feet 6 inches
Steel-tube frame; fiberglass cockpit fairing, aluminum components.
RotorWay Scorpion Too
Before the 1970s, the level of skill required to fly and maintain helicopters, combined with high operating costs and limited range, prevented them from becoming popular with sport aviation enthusiasts. In 1968, B.J. Schramm and Robert Everts began production of the Scorpion single-seat kit helicopter. This affordable design allowed anyone with an interest in operating a personal helicopter to do so with expenses comparable to those of fixed-wing aircraft kits. The design evolved through the years into several forms that remain popular in the home-built aircraft market.
In the late 1950s, B.J. Schramm began designing a sport helicopter. By 1965, he had flown a single-seat design, called the Javelin, that he felt was ready for sale as a kit. He joined forces with Robert Everts, a former Kaman Aircraft employee, to create RotorWay Incorporated to sell and market the Javelin. They had renamed the aircraft as the Scorpion by the time they publicly announced the project in May 1968. The Federal Aviation Administration (FAA) certification process to allow Rotorway to sell the Scorpion as an experimental kit aircraft took several years. The experimental designation meant that its operators could not fly it for commercial operations. Shortly afterwards, Rotorway announced production of a two-seat design, known as the Scorpion Too.
When Rotorway first sold the Scorpion Too kit, the cost ran to approximately $7,000, including the engine. This did not differ greatly from similar fixed-wing projects. The prospective builder could reduce the cost by as much as $3,000, if he or she was able to undertake some of the more skilled assembly procedures. An affordable Evinrude marine engine, with a fuel burn of approximately six gallons per hour, powered early model Scorpion Toos. The 38 liter (10 gallon) fuel tank thus allowed a 201 km (125 mile) range. Potential pilots usually had to undergo training in normally certified helicopters before moving on to a self-guided course developed by RotorWay for the Scorpion series.
By 1972, Rotorway had produced 600 Scorpion and Scorpion Too kits. The success of the Scorpion design led to further refinements. The first was the two-seat Scorpion 133 that utilized a 133 hp RotorWay engine, which came with a turbocharger option. The design underwent a significant facelift with the advent of the Rotorway Exec. This design entered production in 1980, and featured a more powerful 145 hp engine and a larger fuel tank, along with a completely redesigned, and more aerodynamic fuselage. Further versions of the RotorWay Exec are still in production and remain highly popular in the experimental category aircraft market.
In 1976, Harry Theurer constructed the Scorpion Too in the collection of the National Air and Space Museum. He then donated it to the Museum in 1986, after accumulating 77.5 hours of operation. This aircraft serves to illustrate the variety of homebuilt aircraft, in addition to demonstrating advances in the lightweight construction in rotorcraft.
Rotor Diameter: 7.32 m (24 ft)
Length: 6.18 m (20 ft 3.5 in)
Height: 2.22 m (7 ft 3.5 in)
Weight: Empty, 354 kg (780 lb)
Gross, 528 kg (1,165 lb)
Engine: Evinrude OMC #125183, 140 hp
References and Further Reading:
Rotorway Scorpion Too curatorial file, Aeronautics Division, National Air and Space Museum