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#1
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NACA Numbers???
How are they decoded? The aircraft I am constructing has the NACA
Airfoil number of 65(3)518-A7. Any comments or suggestions are welcome. Thanks, Clark |
#2
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The NACA 5-digit airfoils are set up in a similar manner
to the 4-digit airfoils. The primary difference is the use of a different camber line. In a 5-digit airfoil, 1.5 times the first digit is the design lift coefficient in tenths, the second and third digits are one-half the distance from the leading edge to the location of maximum camber in percent of the chord, and the fourth and fifth digits are the thickness in percent of the chord. For example, a NACA 23015 airfoil has a design lift coefficient of 0.3, has the maximum camber at 0.15c, and is 15% thick. Additionally, the first three digits indicate the mean line used. In this case, the mean line designation is 230. The 5-digit airfoils use the same thickness distribution as the 4-digit airfoils. This example is displayed below. NACA 23015 NACA 230 mean line (230) 15 thickness, % (15%) NACA 2 (design lift coefficient * 10) / 1.5, (0.3) 30 2 * (position, maximum camber), (0.30 / 2 = 0.15c) 15 NACA 23 0 type of camber line used 15 "c hinds" wrote in message om... How are they decoded? The aircraft I am constructing has the NACA Airfoil number of 65(3)518-A7. Any comments or suggestions are welcome. Thanks, Clark |
#3
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c hinds wrote
How are they decoded? The aircraft I am constructing has the NACA Airfoil number of 65(3)518-A7 6 is the series number (near-laminar, low drag), the first 5 is the location of minimum pressure (50% chord), the second 5 is the design lift coefficient x 10 (0.5) 18 is the thickness (% chord). The subscript 3 means it's near-laminar (or low-drag) within +/- 0.3 CL of the design CL, or at lift coefficients from 0.2 to 0.8. The a-number (should be less than 1) is the chordwise percentage of the airfoil that has a uniform pressure distribution, in this case (probably) 70%. Clear as mud. Dave 'keep it clean' Hyde |
#4
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Thank you! Clear and concise.
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