July 24, 2009 -- The world's first successful flight of a self-powered, rudderless, flapping aircraft has been achieved by engineers from AeroVironment. The NAV, or nano air vehicle, operates by using two flapping wings, which also function as the rudder, elevators, ailerons and engine. With its two wings, the NAV is able to hover, move forward and backwards, and change its elevation. In flight, the NAV almost appears to replicate the movements of a hummingbird. Simplified, most airplanes and helicopters today fly using the same principle: Air rushing over a shaped and immovable wing (or helicopter blade) produces an area of high pressure below the wing and an area of low pressure. The difference pushes the wing up in the direction of low pressure, creating lift. An airplane is steered using adjustable flaps on the ends of the wings and at the tail, which also help steady the aircraft. "It's extremely complicated and technically challenging to come up with ways to control an aircraft with two flapping wings,"said Matt Keennon of AeroVironment, "but this is the closest anyone has come to a rudderless, flapping aircraft." Related Content:
AeroVironment wouldn't explain how the two wings accomplish flight, citing its contract with the Defense Advanced Research Projects Agency (DARPA). However, Guido de Croon and Rick Ruijsink at Delft University of Technology in the Netherlands have their own theory about how AeroVironment's NAV flies. The two men, along with their colleagues at Delft University, have created three flapping-wing aircraft of their own, known as Delfly I, II, and Micro. The Delflys are flapping-wing aircraft, but differ significantly from AeroVironment's NAV. The Delflys have four flapping wings and a rudder, which in theory makes it easier to control than the rudderless, two-winged NAV. According to Ruijsink and de Croon, the shape of the wings isn't quite as important for flapping-wing aircraft as it is for fixed-wing aircraft. While a fixed-wing uses a smooth flow of air over the wings to create lift, a flapping-wing separates the air into two flows. The two European researchers also suspect that AeroVironment changes the wing's angle to move NAV forwards or backwards. Tipping the lead edge up would move the airflows to the rear of the wing, moving the aircraft backwards. To move forward, the lead edge of the wing likely tips down, moving the airflows, and the craft, forward. Get More NewsSpiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates.Oldest Hebrew Writing Possibly FoundAncient inscriptions on a 3,000-year-old pottery shard could make history.Rare, Prehistoric-Age Reptile Found in N.Z.A tuatara has been spotted on the New Zealand mainland for the first time in 200 years.Iceman Has No Living RelativesOetzi, the 5,300 year-old frozen mummy, left no living genetic legacy.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.It's Official: People Are Warming the PolesHumans are conclusively to blame for polar warming, say scientists.Eight-Armed Animal Preceded DinosaursWhat may be one of Earth's first animals was no bigger than a coaster and had eight arms.Phoenicians Live on in People's GenesOne in 17 Mediterranean men may be descended from ancient Phoenicians.Pesticides, Fertilizers Linked to Frog DeclineA pesticide is found to promote parasites among amphibians.Hubble Telescope Taking Photos AgainThe Hubble Space Telescope is once again snapping stunning photos of the universe.Andean Mummy Hairs Show Hallucinogen UseScientists find direct evidence of hallucinogenic drug use among ancient Andeans.Opals on Mars Reveal Planet's Long Wet PastOpals found on Mars suggest the planet has been wet for much longer. |
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