Monday, 15 June 2009

Discovering Pterosaur flight - Part 2

The design of Flying model pterosaurs was taken a stage further in 1957 when Erich von Holst made a flying model of Rhamphorhynchus. This model was powered by a coiled elastic band which was connected to a rocker device which flapped the wings of the model. The tail sail had to be horizontal to stabilise the model in flight. From this experiment it was clear that the Rhamphorhynchus form had the potential to be a very good flying animal.

In the 1970's a bat expert (Cherrie Bramwell) and an engineer (R G Whitfield) teamed up to examine and analyse the joints of large pterosaurs. They defined the range of movement in the wing joints and proposed a postural model for Pteranodon. G R Whitfield had flown a fully controlled life size model in 1973, but that model was eventually destroyed in a crash landing. This work was an extension of the Hankin and Watson work and was to provide a basis for future flying models.
Stephen Winkworth was a model aeroplane builder who had an interest in anything that flies. In 1984 he designed a pterosaur flying model, based on the Bramwell and Whitfield work which was flown in January 1985 on the cliffs along the Dorset coast. The model was filmed for the BBC television production "Pteodactylus Flies". This 15 foot wingspan model was an excellent radio controlled glider, though to overcome some stability problems, additional stability fins had to be incorporated in the design.  

The Quetzalcoatus Project was started in 1984 and in December1985 Paul MacCready flew a half size flying model of Quetzalcoatlus. This flying model was much more sophisticated than the balsa and fabric model of Stephen Winkworth and used aviation technology for its construction. It had an autopilot device and a recovery parachute which could be controlled from the ground. The project was used to produce an IMAX movie in 1986 for the Smithsonian Air and Space Museum in Washington D. C.

Up to this point, the flying models of Pterosaurs had all been gliders or simple flapping models, using aeroplane aerodynamic theory in their production. The Stanford Project, which was supported by National Geographic was intended to build a flying model that worked like a real animal. This was an ambitious project and had an extensive team headed by Margot Gerritsen. The model flew in many forms, first taking to the air in 2006 with a stabiliser tail boom to allow the electronic movements to be tested. The model was air lifted and launched at altitude by a carrier plane. The Stanford model was nicknamed Herki and featured in the TV program "Sky Monsters", which is now available on video.

What next?......

Holst E. von.,
1957, Der Saurierflug, Paleontologische Zeitschrift, 33, pp. 15-22. 7 figures.

Bramwell C. D. & Whitfield G. R., 1974, Biomechanics of Pteranodon. Philosophical Transactions of the Royal Society, London, B.267, pp.503-581

Winkworth S., 1985, Pteranodon flies again. New Scientist, 3 January 1985:32-33

MacCready P,, 1985, The Great Pterodactyl Project. Engineering and Science, November 1985: 18-24

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