Balsa Wood Properties
Kurt Krempetz 3/06
Balsa Wood
Balsa wood is a very
interesting material and is typically used for construction of model airplanes.
Balsa is technically a hard wood, because of the shape of the leaves. It is not
the lightest wood, but it is the lightest wood which has some strength.
Actually Balsa wood’s strength to weight ratio and stiffness to weight ratio
is very good, better than any man made material that I am aware of. It is not
considered to be a great material to use for the design of most things because
its properties vary greatly.
Like with most woods, balsa wood does not have well defined mechanical properties. Its properties vary greatly with the gain direction of the wood and the moisture in the wood. But if one wants to do some design calculations some rough properties are needed. Below is a table of balsa wood properties which I use to do design calculations. These values were obtained for other books and websites, along with some of my own measurements.
Properties
Light under 5 lbs/ft^3
.00289lbs/in^3 1.31 g/in^3
Medium 5 to 9 lbs^ft3 .00289 to .00521 lbs/in^3 1.31 g/in^3 to 2.36
g/in^3
Heavy over 9 lbs/ft^3 .00521 lbs/in^3 2.36
g/in^3
Compressive strength
Light 680 lbs/in^2
Medium 1750 lbs/in^2
Heavy 2830 lbs/in^2
Tensile Strength
Light 1100 lbs/in^2
Medium 2890 lbs/in^2
Heavy 4670 lbs/in^2
Elastic Modulus in compression
All 66700+-10300
lbs/in^2
Elastic Modulus in Tension
All 185,300 +- 65400
lbs/in^2
Formula to Calculate Wood Pounds in Ft^3.
Weight in Grams x 3.81453
------------------------------------------------------------- = Wood
in Lbs/ft^3
Wood Thickness Width in inches
Length in
in decimals of X and decimals.
X inches and
an inch.
decimals.