sitka spruce

Do you know what varieties of spruce will make good airplane parts?

Tha NACA report server has several good reports on the subject. Here is one

http://naca.larc.nasa.gov/reports/1931/naca-report-354/

The upshot is that Sitka Spruce is not magic. There are several other
varieties that would work as well. It was originally settled on mainly
because it was cheap, back in the '30s. But the value of a "standard" is
such that even though the stuff is now up to $1000 per spar, we keep
insisting on it.

I live in Fairbanks, Alaska. Up here there are literally 10's of thousands
of square miles of old growth black spruce forests. Really slow growing,
tight grained wood that HAS to be tougher'n HELL. I've often wondered if
there might be a market for it.

In Ron Webb wrote:

I live in Fairbanks, Alaska. Up here there are literally 10's of
thousands of square miles of old growth black spruce forests. Really
slow growing, tight grained wood that HAS to be tougher'n HELL. I've
often wondered if there might be a market for it.

Those are also tiny little things covered with branches (read: knots).
I shudder at the thought of how many pieces you would have to scarf
together to make anything useable. Another reason why the old growth
sitka spruce and doug fir make good aircraft structure is fewer branches
on the lower part of the trunk, which is more likely to develop under a
high canopy.

Wood is a great building material and I've enjoyed using it to make a
couple boats. For my airplane I'd rather have all metal structure just
for the consistency of the material.

----------------------------------------------------
Del Rawlins-
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/

Those are also tiny little things covered with branches (read: knots).
I shudder at the thought of how many pieces you would have to scarf
together to make anything useable.

Well...a lot of them are. I have 3 acres on Harding lake where the average
diameter is maybe 6 inches, exactly as you describe.

There are some areas, though where the growth is not so dense, and they grow
bigger. I know many stands of 2 foot diameter trees (3 in my front yard)
where the bottom 20ft or so look like they might yield a spar or 2 if cut
carefully.

They still don't get VERY big though. I wonder how big they need to be to
yield a proper spar.

On Fri, 20 Feb 2004 13:58:12 -0900, "Ron Webb"
wrote:



There are some areas, though where the growth is not so dense, and they grow
bigger. I know many stands of 2 foot diameter trees (3 in my front yard)
where the bottom 20ft or so look like they might yield a spar or 2 if cut
carefully.


If you read the old australian wartime specs for spruce they make
mention of not using the bottom 15ft of a tree because of the
increased problems with fungal attack later in the life of the
component.

Stealth Pilot
Australia

call Rob at raven aircraft
604 597 9296, in British Columbia.
He usually has a good supply of clear spruce, in good spar lengths and
thickness.

Alaska has a lot of "Alaskan Yellow Cedar" --lookitup--it is about 10%
heavier,
stronger all properties right across the board--This is a beautiful wood, I
have
built boats out of it, They call it "yellow" because ,even though it is
white when worked, if you seal it it turns a pale yellow.. there are
thousands of them dead
and still standing plus some live--but they are scattered about & you would
either have to boat, chopper or blimp them to the mill---The dead wood is
every bit as good as the growing, sometimes slightly better. Sumbody up
there otta look
into it..Jerry

Del Rawlins wrote:

In Ron Webb wrote:

I live in Fairbanks, Alaska. Up here there are literally 10's of
thousands of square miles of old growth black spruce forests. Really
slow growing, tight grained wood that HAS to be tougher'n HELL. I've
often wondered if there might be a market for it.

Those are also tiny little things covered with branches (read: knots).
I shudder at the thought of how many pieces you would have to scarf
together to make anything useable. Another reason why the old growth
sitka spruce and doug fir make good aircraft structure is fewer branches
on the lower part of the trunk, which is more likely to develop under a
high canopy.

Wood is a great building material and I've enjoyed using it to make a
couple boats. For my airplane I'd rather have all metal structure just
for the consistency of the material.

----------------------------------------------------
Del Rawlins-
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/

On Fri, 20 Feb 2004 18:42:30 -0600, Jerry Wass
wrote:

Alaska has a lot of "Alaskan Yellow Cedar" --lookitup--it is about 10%
heavier,
stronger all properties right across the board--This is a beautiful wood, I
have
built boats out of it, They call it "yellow" because ,even though it is
white when worked, if you seal it it turns a pale yellow.. there are
thousands of them dead
and still standing plus some live--but they are scattered about & you would
either have to boat, chopper or blimp them to the mill---The dead wood is
every bit as good as the growing, sometimes slightly better. Sumbody up
there otta look
into it..Jerry


I think people are looking. you can now buy alaskan yellow cedar in
bunnings here in western australia. only noticed it available this
year.
looked promising but a bit knotty.

(bunnings is our Home Depot Clone)

Stealth Pilot
Australia

On Fri, 20 Feb 2004 09:17:43 -0900, "Ron Webb"
wrote:

Do you know what varieties of spruce will make good airplane parts?

Tha NACA report server has several good reports on the subject. Here is one

http://naca.larc.nasa.gov/reports/1931/naca-report-354/

The upshot is that Sitka Spruce is not magic. There are several other
varieties that would work as well. It was originally settled on mainly
because it was cheap, back in the '30s. But the value of a "standard" is
such that even though the stuff is now up to $1000 per spar, we keep
insisting on it.

I live in Fairbanks, Alaska. Up here there are literally 10's of thousands
of square miles of old growth black spruce forests. Really slow growing,
tight grained wood that HAS to be tougher'n HELL. I've often wondered if
there might be a market for it.


Ron
when the spruce is dried to 12% moisture content you are looking for
20 lb per cubic ft for A grade and 24 lb per cubic ft for B grade.
(among all the other criteria)
your stuff would probably be too dense. it might just be ok for
propellors if you can get knot free lengths though.

I have a similar problem in Australia. all the Queensland Hoop Pine
that I can lay my hands on comes in at 34 to 36 lbs per cubic ft. It
is just too heavy for aircraft work.
I've been looking at a single seat Corby Starlet and the difference is
enough to turn a limited aerobatic aircraft into a curvature of the
earth climb out dog.

Frank Rodgers in Australia reworked the french Jodel D18 to use oregon
pine (douglas fir) instead of spruce and I believe this entailed a
complete redesign.

......ohhhh drat.
Stealth Pilot
Australia