|
|
|
 |
|
|
|
Historic Planes
Ornithopter: An ornithopter is an aircraft that flies by wing-flapping. Many examples exist in nature such as birds, bats, The first ornithopters capable of flight were constructed in France in the 1870s. They were powered by rubber band or, in one case, by gunpowder charges activating a bourdon tube, which flapped the wings (Gustav Trouvé, 1870). Practical applications for ornithopters capitalize on their resemblance to bird flight. The Colorado Division of Wildlife has used ornithopters to help save the endangered Gunnison Sage Grouse. Ornithopters resembling birds of prey cause the grouse to remain on the ground so they can be captured for study. Ornithopers can also be used to drive flocks of birds away from airports, where they pose a safety hazard. AeroVironment, Inc., led by Paul B. MacCready (Gossamer Albatross), has developed a remotely piloted ornithopter the size of a large insect for possible spy missions. As demonstrated by birds, flapping wings offer potential advantages in maneuverability and energy savings compared with fixed-wing aircraft. Many attempts at manned ornithopter flight have been made, only a few of which have been successful. Adalbert Schmid developed a motorized, manned ornithopter that made extended flights in 1942 (Weltluftfahrt, March 1950, p. 195). From 1990-1995, Vladimir Toporov and students built a tow-launched ornithopter that reportedly could be made to climb as a result of the pilot's muscular effort. Currently (as of 2004), a team at the University of Toronto's Institute for Aerospace Studies, headed by professor James DeLaurier, is working on an engine-powered, manned ornithopter designed to take off unaided. Biplane: A biplane is a fixed-wing aircraft with two main wings of similar spans, normally one mounted above, and the Biplanes were most successfully marketed in the early days of aviation when the wing sections used were very thin and consequently the wing structure needed to be strengthened by external bracing wires. The biplane configuration allowed the two wings to be braced against one another, increasing the structural strength. Another advantage was the more compact layout with a shorter wing span, which led to greater maneuverability. The big disadvantage of the biplane layout was that the two wings interfered with one another aerodynamically, each reducing the lift produced by the other. This meant that for a given wing area the biplane produced more drag and less lift than a monoplane. Once thicker wing sections and improved structural materials were introduced, removing the need for external bracing, monoplanes quickly superseded biplanes and the latter now exist only in specialist niche roles. Triplane: A triplane is a fixed-wing aircraft equipped with three sets of wings, each roughly the same size and mounted |
and insects. Man-made ornithopters are usually on the same scale as these flying creatures, though some over scale, manned ornithopters have also been built. 
other level with, the underside of the fuselage. The upper wing normally overlaps the lower wing, and vertical or slightly raked slender struts are often positioned symmetrically on either side of the fuselage (connecting the rigid sections of the upper and lower wings into a strong box structure). When the upper and lower wing overlap only partially, this is known as stagger; it is designed to minimize aerodynamic interference between the two wings. Forward stagger (where the upper wing is further forward) is most common, but backward stagger has also been used, notably in Beechcraft Staggerwing.Aircraft built with two main wings (or three in a triplane) can usually lift more than can a similarly sized monoplane of similar wing-span, but most biplanes also have a third horizontal surface, either a tailplane or a foreplane, to control the pitch, or angle of attack of the aircraft. Either or both of the main wings can support flaps or ailerons to assist lateral and speed control. 
one above the other. Typically, the lower set of wings would be level with the underside of the aircraft's fuselage, the middle set level with the top of the fuselage, and the top set supported above the fuselage on struts.