Human-powered aircraft

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Human-powered aircraft

A human-powered aircraft (HPA) is an aircraft powered by direct human energy and the force of gravity; the thrust provided by the human may be the only source; however, a hang glider that is partially powered by pilot power is a human-powered aircraft where the flight path can be enhanced more than if the hang glider had not been assisted by human power. Likewise, HPA inevitably experience assist from thermals or rising air currents. Pure HPA do not use hybrid flows of energy (solar energy, wound rubber band, fuel cell, etc.) for thrust. In nil wind, a flatland-long-gliding aircraft is a form of HPA where the thrust in the nil wind is provided by the running of the pilot; when the pilot loses touch with the ground, his or her thrusting ceases to add energy to the flight system and a glide begins; the pilot may or may not add energy after the pilot stops touching the ground. Humans who tow up a manned kite form one type of human-powered aircraft.

Early attempts at human-powered flight were unsuccessful because of the difficulty of achieving the high power-to-weight ratio. Prototypes often used ornithopter principles which were not only too heavy to meet this requirement but aerodynamically unsatisfactory.

The Royal Aeronautical Society Human Powered Flight Group

The Royal Aeronautical Society's 'Man Powered Aircraft Group' was formed in 1959 by the members of the Man Powered Group of the College of Aeronautics at Cranfield when they were invited to join the Society. Its title was changed from 'Man' to 'Human' in 1988 because of the many successful flights made by female pilots.

Under the auspices of the Society, in 1959 the industrialist Henry Kremer offered the Kremer Prizes of £50,000 for the first human-powered aeroplane to fly a figure-of-eight course round two markers half-a-mile apart.

First flights

A craft called HV-1 Mufli (Muskelkraft-Flugzeug) built by Helmut Hässler and Franz Villinger ^(de) first flew on 30 August, 1935: a distance of 235 metres at Halle an der Saale. 120 flights were made, the longest being 712 metres in 1937. However it was launched using a tensioned cable and so was not strictly human-powered.

A team of Enea Bossi (designer), Vittorio Bonomi (builder), and Emilio Casco (pilot) met a challenge by the Italian Government for a flight of one kilometre using their Pedaliante in March 1937. The aircraft apparently flew short distances fully under human power, but the distances were not significant enough to win the competition's prize. Furthermore there has been much dispute as to whether it ever took off under the pedal-power of the pilot alone, in particular because there is no record of official observation of it having done so. Some of the arguments for and against the validity of Bossi's claim to have done so are presented by Sherwin (1976). At the time the fully human-powered flights were deemed to be a result of the pilot's significant strength and endurance; and ultimately not attainable by a typical human. As with the HV-1 Mufli, additional attempts were therefore made using a catapult system. By being catapulted to a height of 9 metres (30 ft), the aircraft met the distance requirement of 1 kilometre (0.62 mi) but was declined the prize due to the launch method.

The first officially authenticated take-off and landing of a man powered aircraft (one capable of powered take-offs, unlike a glider) was made on 9 November, 1961 by Derek Piggott in Southampton University's Man Powered Aircraft (SUMPA). The best flight was 650 metres.

The Puffin first flew in 16 November, 1961, one week after SUMPA . Eventually its best distance was 908 metres. John Wimpenny landed in a state of physical exhaustion. His record stood for 10 years.

Puffin 2 flew on 27 August, 1965 and made several flights over a half-mile, including a climb to 5.2 metres. In 1967 Kremer increased his prize money tenfold to £500,000, for no-one had even attempted his challenging course. He also opened the competition to all nationalities as it had previously been restricted to British entries only. After this date several less successful aircraft flew, until 1972 when the Jupiter flew 1,070 metres and 1,239 metres in June 1972.

On 23 August, 1977 the Gossamer Condor 2 flew the first figure-of-eight, a distance of 2,172 metres winning the first Kremer prize. It was built by Dr Paul B. MacCready. and piloted by amateur cyclist and hang-glider pilot Bryan Allen.

Later flights

The second Kremer prize of £100,000 was won on June 12, 1979, again by Paul MacCready, when Bryan Allen flew MacCready's Gossamer Albatross from England to France: a straight distance of 35.82 km (22 miles 453 yards) in 2 hours, 49 minutes.

A Kremer prize of £20,000 for speed went on 1 May, 1984 to a design team of the Massachusetts Institute of Technology for flying their MIT Monarch B craft on a triangular 1.5 km course in under three minutes (for an average speed of 32 km/h): pilot Frank Scarabino. Further prizes of £5,000 are awarded to each subsequent entrant improving the speed by at least five percent.

The first human-powered passenger flight occurred on 1 October, 1984 when Holger Rochelt carried his sister Katrin in Musculair 1.

The current distance record recognised by the FAI was achieved on 23 April, 1988 from Iraklion on Crete to Santorini in a MIT Daedalus 88 piloted by Kanellos Kanellopoulos: a straight distance of 115.11 km (74 miles).

On 10 December, 1989 the first human-powered helicopter, the California Polytechnic State University Da Vinci III, flew for 7.1 seconds and reached a height of 20 cm.

Current activity

Machines have been built and flown in Japan, Germany, Greece, Australia, New Zealand, South Africa, Austria, Canada, Singapore, the United States and the United Kingdom, with their total number approaching a hundred.

With further funds from the late Henry Kremer, the Royal Aeronautical Society has announced four new prizes:

£50,000 for the Kremer International Marathon Competition for a flight round a specified twenty six mile Marathon distance course, in a time of under one hour,
£100,000 for the Kremer International Sporting Aircraft Competition for a sporting aeroplane able to operate in normal weather conditions, as encountered in the United Kingdom
£1,000 for the Schools Competition
£500 for The Robert Graham Competition for students for experimental research or engineering design

The eventual aim is to achieve Olympic recognition as a sport.

Airships

French inventors have built human-powered airships. By gaining lift through buoyancy instead of air flowing past an airfoil, much less effort is required to power the aircraft.