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# NACA Airfoild 6 serie nomenclature

## NACA Airfoild 6 serie nomenclature

(OP)
I have a old drawing with he following nomenclature for an NACA airfoil

NACA 64(9.5)8

Can some one tee]ll me how to interprete the number in parantheses?

In additio the the NACA airfoild I have the leading and traling edge raduis, the corde lenght the setting angle and a sketch of the profile showing the location of maximum camber (x,y location for the leading edge)

Noone in the company know how to recreate the profile

Tank you

### RE: NACA Airfoild 6 serie nomenclature

have you tried the NASA site ? ... they have all the NACA reports online

### RE: NACA Airfoild 6 serie nomenclature

(OP)
rb1957

I look at the NAC report and there is at least 2 interpretation of the nomenclature:

one it that the number in parathese is the modify thickness

the second is that the number in parenthese is the lift coeficent.

I want to be able to model the profile to analys the fan blade

### RE: NACA Airfoild 6 serie nomenclature

from the Wikipedia article:

"6-series

An improvement over 1-series airfoils with emphasis on maximizing laminar flow. The airfoil is described using six digits in the following sequence:

The number "6" indicating the series.
One digit describing the distance of the minimum pressure area in tens of percent of chord.
The subscript digit gives the range of lift coefficient in tenths above and below the design lift coefficient in which favorable pressure gradients exist on both surfaces
A hyphen.
One digit describing the design lift coefficient in tenths.
Two digits describing the maximum thickness in tens of percent of chord.

For example, the NACA 612-315 a=0.5 has the area of minimum pressure 10% of the chord back, maintains low drag 0.2 above and below the lift coefficient of 0.3, has a maximum thickness of 15% of the chord, and maintains laminar flow over 50% of the chord."

One often sees the third (subscript) digit eliminated in scholarly articles, as that value is arguably test data, not a design variable.

### RE: NACA Airfoild 6 serie nomenclature

(OP)
I do not need someone to tell me the NACA 6 serie standard nomenclature I need to know if someone knows the specific nomenclature NACA 64(9.5)8. What (9.5) means?

### RE: NACA Airfoild 6 serie nomenclature

He answered your question. (9.5) is the subscript number, range of lift coefficient. Reread btrueblood's post and try not to get so testy.

Comprehension is not understanding. Understanding is not wisdom. And it is wisdom that gives us the ability to apply what we know, to our real world situations

### RE: NACA Airfoild 6 serie nomenclature

(OP)
(9.5) cannot be the subscript number because in NACA64(9.5)8 has not lift coeficient or thicness number assuming that the design omit the dash (by mistake) after the parantheses. From what I read in the "therory of wing section" it is either the lift coeficient or a modify thickness

### RE: NACA Airfoild 6 serie nomenclature

I'm with Xollat in being confused by this.  Just to see if I'm reading it correctly is this how you would interpret the NACA 6-series.

6 The series.
4 The area of minimum pressure is 40% of the chord length back from the leading edge.
(9.5) It maintains low drag .9 above and .5 below the left coefficent which is not listed. (or it could mean .95 above and below?)
8 Would this be the thickness as in 8% which should have a leading zero to make the 2 digits it's supposed to have?

Kirby Wilkerson

Remember, first define the problem, then solve it.

### RE: NACA Airfoild 6 serie nomenclature

Somebody in Xollat's organization is not using the standard nomenclature.  Which was the point of my post.  At a guess, they (A) dropped the subscript, as many do; (B) the design lift coefficient is .95 (the standard only allows for the design lift coeff. to be expressed to nearest tenth, so they put their non-standard lift coeff. in brackets), and (C) the max. thickness is 8% of chord, ie they dropped the leading zero.  I'd not trust my guess without an example foil to measure...but think I'm close, just because an 80% thick 'foil is ridiculous and I worked backwards from there.

### RE: NACA Airfoild 6 serie nomenclature

(OP)
btrueblood,

I came up witht the same interpretation

thank you

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