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Post by spar on Sept 5, 2007 12:13:30 GMT 1
Some planes are marketed as having "fully symmetrical airfoils". What are they and why are they special?
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Post by kalnaren on Sept 5, 2007 13:13:06 GMT 1
The proper name for a symetrical airfoil is "laminar airfoil". Whereas in conventional airfoils the thickest part of the wing occurs at about 25% chord, on laminar airfoils the thickest part occurs at about 50% chord. The transition point between laminar and turbulent airflow is moved back (ie, the airflow stays laminar longer), and thus the wing produces more lift than a similarily sized non-laminar wing. Overall, the wing is more effecient. However, laminar wings usually have some very nasty stall characteristics. Take the P-51 for example.
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bearweasel
Flying officer
illegitimus non carburundum
Posts: 25
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Post by bearweasel on Sept 6, 2007 1:01:25 GMT 1
Sorry to burst your bubble, kal, but the Dictionary Of Aeronautical Terms says a symmetrical airfoil is: "an airfoil that has the same shape on both sides of its center line. A symmetrical airfoil has a very small change in the location of its center of pressure as it's angle of attach changes." Like a helicopter rotor blade...
Laminar airflow: "A type of airflow over an airfoil in which the air passes over the surface in smooth layers with a minimum of turbulence. A laminar flow airfoil is designed in such a way that the boundary layer has a minimum thickness, and nearly all the air flows in smooth layers. Laminar flow of hte air decreases the drag produced by the airfoil."
However laminar flow wings do have some sharp stall characteristics.
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