Felix Hess is a Dutch scientist with a Ph.D in Applied Mathematics. In the 1960s and 1970s, he modeled the aerodynamics of boomerang flight extensively. In 1975, he published the results of his Ph.D thesis in a 555 page soft cover book called "Boomerangs, Aerodynamics and Motion". The thesis contained an excellent summary of artifacts found throughout the world, a bibliography, basic flight dynamics and detailed modelling of the lift forces on a boomerang. There were chapters on wind tunnel testing, modeling of flight paths based on photographic data captured using boomerangs thrown at night with lights, and 3-D computer results that could be viewed with special 3-D glasses. Felix no longer throws or studies boomerangs and he doesn't want his book reissued as a second edition, so the 300 or so printed copies that are (were) mostly in technical libraries have become rare collectable items among boomerang throwers.

This is a rare printout of a boomerang flight with a decent of 100 metres, modelled as though thrown from the top of a 90 metre building. The underside has "The flight path of a theoretical boomerang launched at a height of 90 metres has been calculated by a computer at the University of Groningen, Holland, programmed by Felix Hess. This approximates a launching . . . . " etc. (see the graphic below for the remainder of the text). This is quite a collectable. It is nicely framed for hanging in your living room and is the only example of Felix's results that I have seen other than in his thesis. The printour is dated on the reverse as March 1975, so it is more than 30 years old!

Because of the large size of this item, the buyer will be required to pay actual shipping charges. The shipping weight will probably be 7 - 8 pounds as it must be properly packaged to protect the glass. Pickup is highly recommended if at all possible.