Question: Under what circumstances could a glider actually glide to the visual horizon, without the benefit of a tailwind? (By visual horizon I mean a point on the initial horizon from the highest starting altitude.)
- Never. Even a glider with carbon fiber wings and an aspect ratio of extraterrestrial proportions could not approach a glide ratio of 100 to 1 in earth’s atmosphere.
- Using ridge lift, some sailplane pilots have soared well beyond several horizons.
- It might, using magnetohydrodynamics, similar to certain experimental submarines.
- As one ascends, the ratio of horizon distance to absolute altitude actually decreases, and well under 20,000 feet, this value actually approaches the glide ratio of some sailplanes.
The answer is number 4. From a yes/no standpoint, choice 1 is incorrect (though the statement about L/D not coming near 100 is true). Choice 2 is also quite correct, but not as mathematically elegant, and 3 is nonsense. At about 17,000 feet, the horizon-to-absolute altitude ratio is about 50, and at 25,000 feet, the horizon/height ratio is about 40! (Thinner air actually does nothing to a sailplane’s L/D, and some gliders have gotten quite high. The absolute altitude record for sailplanes is currently about 49,000 feet.)
Subject: The First Birdman
Question: Who was the first person to fly in a heavier than air machine?
- Orville Wright; December 17, 1903.
- Clement Ader, in the Eole, October 9, 1890.
- Felix du Temple, 1874
- Sir George Cayley*, 1849
It depends on what you mean by ‘to fly’. If you mean a powered, sustained, and fully controlled flight from level ground, followed by a climb and descent to ground no lower than what you’d taken off from, well then the commonly accepted answer is probably Orville Wright on December 17, 1903. But Clement Ader, a Frenchman, designed and built a bat-like machine powered by a steam engine driving a tractor propeller. It lacked any kind of control surfaces and was unable to maintain sustained flight (though it did travel some 160 feet). Felix du Temple’s aircraft became airborne only after plunging down a steep ramp. The last one is actually the most amazing, because of it’s surprisingly early date. Sir George Cayley’s machine did have control surfaces, but they had to be ‘set’ before flight (not much good there). Also, of the four choices, it was the only one that was non-powered. After several short glides using only ballast, Sir George delegated this epic achievement* to the son of a worker from his estate near Scarborough, England; his identity remains unknown. In 1853 also, his coachman made a longer flight across an entire valley on the estate. (The more comical record of history was that upon landing, the man quit his post on the spot, saying that he was not being paid to fly.) So, I say it’s that unsung lad, and that it’s number 4.
Subject: Fire When Ready, Gridley
Question: The earliest use of armament aboard aircraft and the use of aircraft as military weapons occurred
- on an experimental basis before World War I.
- on April 1st, 1915, when Jean Navarre of France scored his first victory with a rifle.
- on October 5, 1914, when a French gunner named Quenault shot down an enemy airplane with a machine gun mounted in the front of the engine nacelle.
- on August 14, 1914, when the French sent two Voisins to attack Zeppelin sheds at Metz-Frascaty.
Number 1. Actually, airborne armament was used well before WWI. As early as June 1912, the US Army began trials using machine guns mounted in a Wright Model B biplane, and on June 30, 1910, Glen Curtiss had dropped dummy bombs on an outline of a battleship buoyed on Lake Keuka, in New York. The aviation industry in those years really wasn’t set up for mass production, and so for military purposes and standardization of equipment, as well as tactical applications across squadrons, things began slowly. The primary task for aircraft had started with reconnaissance from free balloons. It was soon realized of course that it would be possible to keep the enemy from acquiring information by shooting him down (or otherwise forcing him back to earth). Also, the relationship between the machine gun and the propeller did at first cause some technical difficulties…