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Weedhopper JC-24C

Wingspan 8.5 m (28 ft)
Length 5.6 m (18 ft 6 in)
Height 1.8 m (6 ft)
Weight Empty, 73 kg (160 lb)

John Chotia crafted the basic JC-24 (JC for John Chotia, 24 for his 24th design) airframe in 1976. Few could foresee the Weedhopper's success after it first flew in May 1977 but in 2001, dealers in the United States continued to sell single- and two-seat Weedhoppers. When ultralight aircraft were very popular during the 1980s, dealers in Belgium, France, and Italy sold these aircraft and factories in Europe, and the Middle East built them under license. Weedhoppers appealed to many people because the aircraft costs less than most ultralights to purchase and operate.

Chotia worked at the National Aeronautics and Space Administration before turning to ultralight aircraft design. He claimed that the Demoiselle 20, designed by Brazilian aeronautical pioneer Alberto Santos Dumont, inspired him to create the Weedhopper. During his teenage years, Chotia took up hang gliding but he soon tired of the numerous inconveniences associated with the sport-finding suitable launch sites, waiting for good weather, etc. He began thinking about designing and building his own powered airplane. Chotia started designing the Weedhopper's wing in high school and he flew the prototype in 1977, a pre-production aircraft the following year, and finally initiated series production of Weedhoppers in 1980.

The Weedhopper model C first flew during August 1980. This version was much improved over the earlier A and B models. Chotia died in October 1981, just days before his 35th birthday, while testing another ultralight that he designed called the JC Rocket. The Rocket was abandoned but work continued on the Weedhopper. In 1983, the Weedhopper factory shipped a C model to California and asked graduate aeronautical engineering students at the California State Polytechnic University at Pomona to study the aircraft. After testing a Weedhopper inside the university wind tunnel, the students concluded that the Weedhopper had a very robust airframe that could withstand at least 8 Gs.

The group advised the factory to switch to a heavier fabric that would add strength to the wing structure, and to add more ribs to the wing. The firm heeded the student's advice and increased the rib count from nine to eleven. The students also recommended adding a lower surface to the wing and closing the gap in the fabric at the wingroots. Personnel at Weedhopper installed a lower fabric surface that extended from the leading edge back to cover about three-quarters of the wing and they narrowed, but did not completely seal, the wingroot gap. The university team also suggested changing from a rounded wing trailing edge to a sharper profile but this modification would have made the aircraft too fast to comply with Federal Aviation Administration regulations that governed the maximum level flight speed of ultralight aircraft and the left the trailing edge remained unchanged.

The biggest single improvement to the C model came about when Weedhopper switched from the 25 horsepower Chotia power plant to a Rotax 277 engine that produced 28 horsepower. By 1996, the 40-horsepower Rotax 447 powered this ultralight. Probably because it is one of the first C models, the NASM Weedhopper is fitted with the original Chotia engine.

Weedhoppers cost less to purchase than other ultralights because the design was very simple. There was no gas gauge. The pilot estimated the fuel level by observing the liquid through the sides of the opaque gas tank. Nosewheel steering was manual and the pilot used his feet to push an aluminum tube that pivoted the wheel left or right. Chotia designed the wing without aileron control surfaces. He used only conventional flight controls (elevator and rudder) on the tail to guide the airplane. Fast aircraft not only cost more to design, they are more expensive to operate. Weedhopper pilots set no speed records as they cruised sedately above the earth at about 43-56 kph (30-35 mph), but the exhilarating experience of flight also cost them no more than a few dollars. Keeping the Weedhopper simple and slow allowed Chotia to sell the aircraft as a kit, complete with engine, for $4,095 in 1982. In 2002, ultralight pilots could purchase an improved Weedhopper model 40 kit, complete with a Rotax 447 engine, for $7995.

Low purchase and operating costs helped Chotia's original company, Weedhopper of Utah Inc., to sell more than 3,000 Weedhopper B models, plus another 2,500 C models. After 1983, Nova-Air and Weedhopper Inc. sold between 3,000 and 4,000 additional JC-24 ultralights. By 2002, dealers had sold nearly 15,000 Weedhoppers world wide.

The NASM JC-24C was the first Weedhopper scrutinized by the staff of "Ultralight Pilot," a magazine published by the Aircraft Owners and Pilot's Association. Three staff members spent 37 hours and used two kits to finish building a single Weedhopper C. Poorly-written instructions and careless manufacture of several parts caused long delays in completing the aircraft. They flew the ultralight airplane for 20 hours before donating it to the Smithsonian Institution. Those hours were full of adventure. Before one test flight, carbon monoxide poisoned the pilot just minutes before takeoff. Another flight ended in a crash that injured no one but substantially damaged the airplane.

Copyright 1998-2000 National Air and Space Museum, Smithsonian Institution (revised 11/18/02 R. E. Lee)

Aircraft of the Smithsonian

Weedhopper JC-24C Weedhopper JC-24C