are used by the French to transport letters and passengers out of besieged Paris during the Franco-Prussian War. Between September 1870 and January 1871, 66 flights – of which 58 land safely – carry 110 passengers and up to three million letters out of Paris, as well as 500 carrier pigeons to deliver messages back to Paris. One balloon accidentally sets a world distance record by ending up off the coast of Norway. 1871 The Englishmen Wenham and Browning construct the first wind tunnel and conduct airflow experiments. Alphonse Pénaud flies his Planophore, a small rubber-powered model which is designed to have automatic pitch and roll stability. 1872 2 February – French naval architect Henri Dupuy de Lôme achieves with his airship driven by a propeller turned by eight men. 13 December – The German experimenter Paul Haenlein tests the first airship with an internal combustion engine in Brünn, Austria-Hungary, achieving ; the engine burns coal gas drawn from its balloon. The tests are stopped because of a shortage of money. 1873 The New York Daily Graphic sponsors the first attempt in history to fly across the Atlantic Ocean, using a 400,000-cubic foot (11,327-cubic meter) balloon carrying a lifeboat. The attempt is abandoned when the balloon rips and collapses during inflation. 1874 20 September – Felix and Louis du Temple de la Croix build a piloted steam-powered monoplane which achieves a short hop after gaining speed by rolling down a ramp. 1875 Englishman Thomas Moy tests a tethered aeroplane with a wing span of powered by a steam engine. German experimenter Paul Haenlein improves his airship by providing it with a car suspended below its framework to accommodate the crew and engine. This will become a standard practice in the design of later dirigibles. 15 April – In the balloon Zenith, the French Navy officer Théodore Henri Sivel, the French journalist Joseph Crocé-Spinelli, and the French scientist and editor Gaston Tissandier ascend to an altitude of . Hypoxia kills Sivel and Crocé-Spinelli during the flight and leaves Tissandier deaf. 1876 Alphonse Pénaud and Paul Gauchot apply for a patent for a power-driven aeroplane with a retractable undercarriage, wings with dihedral and joystick control. 1877 First flight of a steam-driven model helicopter built by Enrico Forlanini. Imperial Japanese Army flying experience begins with the use of balloons. 1878 Charles F. Ritchel publicly demonstrates of his hand-powered, one-man rigid airship, and eventually