On 22 Feb 2004 14:42:05 GMT, (Harry Burns) wrote:

Nobody seems to have mentioned yellow poplar. Last time I checked the specs. I
remember it came in at about 5% over spruce in strength-to-weight. However, I
have never been able to find a grading standard for it. As of yet, I have no
idea if the sticks they sell at Lowe's and Home Cheap-O would get the job
done... even for an unpowered glider. No way to know how many rings per inch,
straightness varaiations, etc. are acceptable. Ditto on the Doug. Fir that is
stocked in the same bins. If anyone knows what these standards are, please
e-mail me.

I went with Sitka spruce in my Wright machine because of historical accuracy...
but even then, the Wrights used West Virginia Silver Spruce, not Sitka. I
still havn't figured out exactly which species that is, but it seemed work well
for them.
On a side note, Wilbur and Orville also made use of white pine twice. Once in
the1900 glider, and again in the 1904 Flyer. It worked OK for the very limited
performances of 1900, but in the 1904 machine, it was all eventually replaced.
Seems that pine had a tendancy to shatter when the plane crashed, while spruce
was much more resiliant.

Harry


I was interested in working with the spruce that grows in the Wasatch
range of southern Utah two summers ago. A bark-beetle killed all the
old 200 year old trees three years ago and devastated the forest. I
took a chain saw and cut a 10 foot section of a downed tree into some
ATV loading ramps that are about 3 inches thick by 12 inches wide and
10 feet long. They dried out in a couple months and I still use them.
It's amazing how light they are and how strong. I often demonstrate
to people who are with me when I use them how light they are. People
are amazed. They seem almost like balsa. They are roughly 2.5 cubic
feet of wood but even a small woman can lift them and put them into
place on my pick up real easy. Yet, I can drive an 800 pound ATV with
me on it, full of fuel and it only bends a bit.

Strong stuff.

I have no idea what species these spruce were either. The forest is
completely repopulated with younger trees now and in 100 years it will
all look the same. I'll bet anyone could use these for airplane
building. All you'd have to do is have a mill cut some raw stock and
simply test it for bending moments, shear, compressibility and tensile
strength.

Harry:

Did you participate on that team who built the Wright Flier they tried
to fly on the anniversary of the Wright's flight?

BWB