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Old 11-06-2002, 06:04 PM
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Ollie
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Default Reynald's number

Every aircraft wing operates over a range of speeds from stall to top speed. Because reynolds number is proportional to air speed the wing is associated with a range of reynolds numbers. Also, a tapered wing has a variety of wing chords along its span so, the reynolds number which is proportional to chord varies along the span of a tapered wing. Aircraft that operate over a wide range of altitudes experience air with a range of densities. This further extends the range of reynolds numbers associated with the aircraft because reynolds number is also proportional to air density. This is a practical consideration for models that are flown from fields at sea level and also from fields at 5000 feet like Denver where the performance is quite different.

Simple reynolds number explainations may satisfy curiosity but they aren't very useful to apply to aircraft design, selection and operation unless they have a lot of detailed technical and mathematical content.