The all-composite, joined-wing, ducted fan Ligeti Stratos was originally conceived in 1982 by Charles Ligeti, of North Balwyn, Victoria, Australia.
A self-taught aeronautical engineer with a background in mechanical and chemical engineering, Ligeti began developing and building his aircraft at his home workshop, assisted by his wife Helena.
The joined-wing layout was first demonstrated in a hang-glider which was entered in the "Bird Man Rally" – a mostly humorous spectacle which features the demonstration of human-powered flight by pilots leaping from a jetty into the sea while strapped to the most unlikely contraptions.
In 1983, a variety of free flight models and a radio-controlled quarter scale model were designed, built and tested. The design was refined to meet Ligeti's chief criteria; lightweight, with high performance and good glide characteristics and compact enough to be transported on a trailer in one piece.
The project was moved to a hangar at Essendon Airport, Victoria, and Charles hired several people to help produce the aircraft.
The first full-sized Stratos prototype was built between 1984 and 1985. Charles Ligeti made a 45 minute first flight on 25 April, 1985. He reported that the aircraft had exceeded his performance expectations.
The aircraft empty weight is a mere 172 lbs, light enough to qualify as an Ultralight in the United States, but unable to be operated in that category because of its demonstrated performance of over 124 kts maximum airspeed.
Ligeti Aero-Nautical Pty. Limited was established in that year and East West Airlines CEO Bryan Grey provided seed capital to the project.
In 1986, the Stratos was displayed at the EAA Fly-In at Oshkosh. It also made an appearance that year at the Seattle Air Fair and the Vancouver World Expo. The airplane received good press coverage, with television segments and print articles appearing in the ‘86 Flight International, May ‘87 Kitplanes and other magazines internationally.
During that time, Ligeti Aero-Nautical received about 200 orders for the Stratos. The standard kit was expected to sell for AU$11,599 (US$7,500) without engine.
A mold for the production version was completed in late 1986. A target was set to produce 20 aircraft in the spring of 1987. A two seat version was also planned.
During a short test flight of the new highly modified production version in September 1987 the airplane stalled during approach to landing and Charles Ligeti was killed. The flight had been conducted under Australian experimental flight rules which at that time limited fights to below 500 feet. The rule has since been changed.
The production team continued work but the venture halted after a few months.
The only remaining prototype aircraft is in the possession of the Ligeti family. Ron Ligeti reports that the aircraft is in excellent condition and airworthy, although he does not fly it to preclude its loss or damage.
Ron, an accomplished aeronautical engineer who currently works on advanced military fighter aircraft, is creating a second generation version of the aircraft. Working from original notes and reverse-engineering the prototype, he has created CAD drawings, dimension tables and production documentation.
The designs for the second generation will be released as Open Source through this web site, and development will continue and expand though a community of skilled collaborators, enthusiasts and individual builders who are interested in contributing to the fulfillment of Charles Ligeti’s original vision of a compact, super-efficient, high performance personal aircraft.