SME
Aerodynamics · Problem type
What the NACA four digits mean
Use this for “What does NACA 2412 mean? Give the camber and thickness of a 1.5 m chord.”
Diagram
NACA 2412: camber 2% of the chord at 40% from the leading edge, 12% thick.
This is an example. Type your own values to start a new problem.
yc (m)
=
d₁
100
×
c (m)
xc (m)
=
d₂
10
×
c (m)
t (m)
=
d₃d₄
100
×
c (m)
Formulas
yc
=
d₁
100
×
c
0.03
=
2
100
×
1.5
xc
=
d₂
10
×
c
0.6
=
4
10
×
1.5
t
=
d₃
d₄
100
×
c
0.18
=
12
100
×
1.5
Assumptions
•
NACA four-digit section: max camber d₁% of the chord, at d₂ tenths of the chord.
•
The last two digits d₃d₄ are the max thickness, as a percent of the chord.
•
Camber is the camber line’s height above the chord; 00xx sections are symmetric.
Step-by-step
WE KNOW
d₁ = 2, d₂ = 4, d₃d₄ = 12, c = 1.5 m
FIND
max camber (yc), camber position (xc), max thickness (t)
Step 1 · Find max camber (yc)
Use yc = d₁ ÷ 100 × c
The first digit is the max camber in percent of the chord.
yc
=
2
100
×
1.5
yc = 0.02 × 1.5
yc = 0.03 m
Step 2 · Find camber position (xc)
Use xc = d₂ ÷ 10 × c
The second digit is the camber’s place in tenths of the chord, from the leading edge.
xc
=
4
10
×
1.5
xc = 0.4 × 1.5
xc = 0.6 m
Step 3 · Find max thickness (t)
Use t = d₃d₄ ÷ 100 × c
The last two digits are the thickness in percent of the chord.
t
=
12
100
×
1.5
t
=
0.12
×
1.5
t
=
0.18
m
Check
Put the numbers back in. Both sides should match.
0.03
=
2
100
×
1.5
✓
0.6
=
4
10
×
1.5
✓
0.18
=
12
100
×
1.5
✓
Topic check
See what you know: 5 questions on this topic
New questions each time. Pass to mark it complete.
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