Balsa More Than You Wanted to Know!

 

You've always been impressed by some of the big birds you've seen at various fly-ins and once you figure out who's model it is and seek them out for a few questions, one of the first few questions will be..."who makes that kit?" Then comes the answer you didn't want to hear... "I scratch built it from so in so's plans".

Now don't despair the only difference between a plane built from a kit and one that is scratch built is that you've got to cut your own kit. One of the best parts of building your own kit is you get to choose the wood that goes in to it! But don't let your mind trick you ... you're not going to live in this plane, you're going to fly it! So don't go to Home Depot for heavy ply-wood.

I don't want to start an argument with several good friends who build some very nice and very large Warbird's. But a strong, straight light aircraft always fly's better as long as you don't sacrifice safety for yourself or other flyers with a aircraft that's structurally unsound. Keeping a light minded build also leaves room for the extra weight added by scale cockpit kits, fake radial engines and other scale amenities that add up quickly in any scale project.


Balsa Grains

A-Grain: Balsa sheet has long fibers that show up as grain lines. Its very flexible across the sheet and bends around curves easily. Watch-out it warps easily.

B-Grain: Balsa  sheet has some of the qualities of both A & B grain. Grain lines are shorter the A and feels stiffer across the sheet. It is a general purpose selection and can be used for many different jobs

C-Grain: Balsa sheet has a mottled appearance. It is very stiff across the sheet and spits easily. Great for wing ribs and light formers. When used properly, it will help you build a light yet very strong model. Four to Six pound balsa stock is commonly called "Contest Balsa"

Wood Suppliers

While each of us have our favorites, here's some quick links to get you started.

Aircraft Spruce & Specialty

Balsa USA

Balsa Wood, Inc.

Lonestar Balsa

Midwest Balsa

So...What  is Contest 4 to 6 Pound Balsa?

Contest Balsa is nothing more than balsa that should fall within 4 to 6 pounds measured by density in pounds per cubic foot.

But all you really need to do is to think about the application area of your model, especially when you enlarge plans or build larger aircraft. An investment in a nice electronic gram scale will be a big help. The chart below is a great reference for wing sheeting which can be applied to other areas of your model building. If the hobby store doesn't mind,  bring your gram scale with you when you purchase balsa for your next project so you can build lighter, larger and stronger model aircraft. 

1/16" X 3" X 36"

1/16" X 4" X 36"

Wgt. OZ Wgt. Grams

Density Lbs/Cubic Ft

Wgt.Oz Wgt. Grams Density Lbs/Cubic Ft
.3 8.49 4.8 .4 11.32 4.8
.4 11.32 6.4 .5 14.15 6.0
.5 14.15 8.3 .6 16.98 7.2
.6 16.98 9.6 .7 19.81 8.4
.7 19.81 11.2 .8 22.60 9.6
.8 22.64 12.8 .9 25.47 10.6
.9 25.47 14.4 1.0 28.30 12.0
1.0 28.30 16.3 1.1 31.13 13.2
1.2 33.86 14.4