Question: Who was the first person to build a rubber band powered airplane, and what was so special about it?
A) John Stringfellow, 1868
B) Alphonse Pénaud, 1871
C) Alexander Mozhaiski, 1884
D) Samuel Pierpont Langley, 1891
The answer is choice B. Born in 1850, Penaud was the son of a French admiral, and a gifted pioneer of aviation design and engineering. Because of a hip disease he walked with the aid of crutches and so was unable to attend the Naval School. He was the originator of the use of twisted rubber to power model aircraft, and his 1871 model airplane (which he called the Planophore) was the first truly successful longitudinally stable flying model. In addition to the use of a twisted rubber motor driving a pusher propeller, this machine introduced two important principles to practical aeronautics: the wings were curved upwards at the tips, in effect having dihedral, and the rear-mounted horizontal stabilizer was set at a smaller angle of incidence than the wings, in fact at a negative angle of -8 degrees. (The principle of dihedral had been worked out by Sir George Cayley, although at the time Pénaud was not aware of Cayley’s work.) Today we know that a negative setting for a rear-mounted tail is necessary for longitudinal stability (the pitching down of the nose due to the wing lift being behind the center of gravity coupled with the pitching up of the nose due to the negative lift of the tail). The Planophore was successfully flown at the Tuileries Gardens in Paris in front of members of the Société Aéronautique on 18 August 1871, for about 130 feet and stayed in the air for over 10 seconds. He went on to design a full sized aircraft with many advanced features, but was unable to get any support for the project, and committed suicide in 1880.
