sitka spruce

Badwater Bill wrote:

On 19 Feb 2004 13:28:10 -0800, (al pernell) wrote:

anyone know of good sources for spruce stock other than Wicks and Aircraft Spruce

I just read this entire thread and found it interesting. The last
airplane I built was made out of Canadian White Pine, which nobody
here mentions. The white pine in northern Canada (where it's cold)
grows very slowly and has very dense ring structure. It is almost as
strong as Sitka Spruce with just a slight weight penalty.

It worked real well. I flew the airplane for 5 years with absolutely
no problems. The planking was of birch and mahogany ply, but the
main load bearing portions of the structure were Canadian white pine.

BWB

Sounds perfect!
You think they'd take $1.70 a tree?

Richard

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

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

On Sun, 22 Feb 2004 16:17:52 GMT, (Badwater
Bill) wrote:




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.


bill you need to add impact strength to that list of characteristics.
you know, the impact test done in an Izod tester with a notched
sample.
many of the alternative timbers have all the rest of the
characteristics matched but are too brittle for safe use.
Stealth Pilot

The Minimax line of kits use mostly pine. I didnt get any spruce in
mine. Good clear pine and Douglas fir is very adequate for airplanes.

I think the reason why the Wrights, Chanute, Herring, Avery, etc. prefered
spruce, aside from obvious factors, was that it was very impact resistant. In
the pioneer era, it was considered normal to smack wingtips, chaw turf,
noseplant, WHACK, and otherwise "crash" on a routine basis. For example, the
landing gear on my 1902 glider consists of twin 6" high x 1" wide skids...
that's it. Ya wanna land? You're gonna smack the sand with some part of the
plane.

Later, my best guess is that the availability of good spruce, and its cost
relative to aluminum, made it the defacto standard until aircraft speed, size,
and power dictated switching to all-aluminum. Of course, in small aircraft
if you don't have a reason to change, why change? Now that most of the good
spruce is gone, we have a reason to start looking again. Either that, or a
good excuse to drive to Highland. (No Grandma, I really came here to see you!
Oh that lumber on top of my car... oh, that's um.. uh...that's uh... I'm
building a pipe organ... yeah, that's it... a pipe organ)

Harry