145 years ago, a practical aircraft design.
145 years ago, on this date, August 18th, 1871, a practical aircraft design was presented:
18 August 1871: Alphonse Pénaud demonstrated the first inherently stable airplane when he flew his model Planophore at a meeting of the Société de Navigation Aérienne at the Tuileries Gardens, Paris, France. The model airplane had a wing span of 18 inches (46 centimeters), a length of 20 inches (51 centimeters) and weighed 15.9 grams. The model was powered by a twisted rubber band which drove an 8 inch diameter (20 centimeter) two-blade propeller positioned at the tail in a pusher configuration.
At this demonstration, Pénaud’s Planophore flew 131 feet (39.9 meters) in 11 seconds.
The craft gained its stability from several features that later became common in aircraft design. The wings curved upward toward the tips, creating a dihedral effect. A horizontal stabilizer at the rear was mounted with a lower angle of incidence than the wings. Pénaud’s use of the twisted rubber band became a common feature of aircraft design models.