Spruce

I've located a source of spruce in British Columbia that appears to be very
good. http://www.timberwright.ca/aircraft.html
anyone dealt with them?

This is for Spars, BTW.

The spruce they supply is uncertified, air -dried and unfinished, but
exceeds the criteria for certification.
They can't certify it as they don't have the equipment,but it is for a
homebuilt. The only thing I'm concerned about is the air dried part of
this. I can get it kiln dried near me, though. Anyone know if this is good
practice? Anything I should be looking out for here?
BTW, their price is half of what ACS is looking for the same dimensions.

"Caveat Empty Headed." wrote

The spruce they supply is uncertified, air -dried and unfinished, but
exceeds the criteria for certification.
They can't certify it as they don't have the equipment,but it is for a
homebuilt. The only thing I'm concerned about is the air dried part of
this.

The air drying portion is not a concern, if it has been done correctly, and
it has been drying long enough. Air drying is slower, more stable and
consistent.

Ask that he do a moisture check, for any piece you select. You need to
slice off a piece of the stock you are planning to buy, at least one and a
half times the length, of the largest dimension (thickness or width) and
check in the middle of where the cut was made. If he doesn't have a meter,
or won't do this, walk away. checking on the outside is close to
meaningless for air dried. I don't recall what the % is supposed to be, or
where to find that information, but I would guess 8 to 10 percent.

Also, look very carefully for compression fractures. They are hard to spot.
Good luck.
--
Jim in NC

Morgans wrote:
I don't recall what the % is supposed to be, or
where to find that information, but I would guess 8 to 10 percent.
-------------------------------------------------------

15% for airplanes. Boat work (spars & masts) might go as low as 8% but
10 to 12 is more the norm.

Basic rule for Sitka spruce -- the farther you get from the water, the
poorer the spars (boat OR plane).

It's probably worth a ferry ride to see what they've got. Since 1997
or thereabouts someone raped the last stand of old-growth up on the
north end of the island and it had some really good trees.

If the grain is true it generally dries true, so long as it's properly
supported and turned every now & then. No problem to stack a few
sticks in the rafters for a couple of years. It doesn't check like DF.

Even a big airplane, you're only looking at about 100 bf, finished.
Buy it rough (ie, full size), do your own sawing, even with 100%
wastage (ie, kerf = finished) you're only looking at 15 to 20 sticks of
1x6x16'.

Nice stuff to work with.

-R.S.Hoover

"Caveat Empty Headed." wrote in message
...
I've located a source of spruce in British Columbia that appears to be
very
good. http://www.timberwright.ca/aircraft.html
anyone dealt with them?

This is for Spars, BTW.

The spruce they supply is uncertified, air -dried and unfinished, but
exceeds the criteria for certification.
They can't certify it as they don't have the equipment,but it is for a
homebuilt. The only thing I'm concerned about is the air dried part of
this. I can get it kiln dried near me, though. Anyone know if this is good
practice? Anything I should be looking out for here?
BTW, their price is half of what ACS is looking for the same dimensions.

"certified aircraft spruce" is rather a misleading term anyway. Who
"certified" it? The FAA certainly didn't, they are not in that business and
do not certify wood.

There is a set of guidelines for selecting wood that meets the quality
standards for aircraft use that was published back in the thirties. I have
it around somewhere but it is the middle of the night and I don't want to go
looking for it. I believe it is ANC18 or some such. You can obtain a copy
from the EAA library. They will photocopy it and send it to you for a very
reasonable copy charge.

Any "certification" of aircraft wood is done by whoever selected the pieces
and he is "certifying" that they met those standards. They cover things
like grain lines per inch and degree of slope of the grain as well as
moisture content. The flaw in wood that is hardest to see is probably a
compression failure. This happens when the log or board was bumped or
shocked sufficiently to overload a line of cells in the wood causing them to
rupture. There is not necessarily a visible dimensional change. They
usually show up as a shiny line one or two cells wide after the wood is
planed. The piece of wood containing that line of ruptured cells will fail
WAY easier than the undamaged wood and will likely break in what we call a
"brash" break. It will just break along that line with no splintering and
will break very suddenly.

I once had an undiscovered compression failure in a wood spar on a
Taylorcraft I was flying. I did a steep turn and the airplane suddenly
rolled out of the turn. The rear spar broke completely off right at the
rear spar fitting where it connected to the fuselage. I looked out the
window at that wing and the trailing edge was up about a foot and flapping!
The only thing keeping the wing on the airplane was the two wing struts and
the forward wing spar connection. If it had been a cantilever wing with a
single spar I would have watched one wing go fluttering away! There was no
visible damage on the outside of the wing at both an extensive annual
inspection and an extensive preflight inspection. No wrinkles in the
fabric. No curves or kinks in the trailing edge. The actual physical
deformation was only a few thousandths of an inch. The wing broke at less
than two G's.

The recent AD on Champion aircraft is an inspection for compression failures
in the wing spar caused by minor damage near the wing tip. That was what
caused the compression failure on the Taylorcraft that was responsible for
my having to have the seat cushion surgically removed from my rear end! It
gets you attention when a wing spar breaks suddenly.

I so have a few samples of spruce spar stock with compression failures in
them that have been cut out of otherwise good material. I will probably
have them around my hangar during the 2005 rec.aviation flyin at
Pinckneyville on May 20, 21, and 22. If anyone is coming to the flyin, drop
Mary an email at so she can plan for the groceries for the
meals.

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( PJY )

According to expert testimony in one case regarding a failed wing spar in a
Citrabia, a compression failure can occur when the tree is felled.

I have seen some websites concerning the AD note on the Champion aircraft
which have micro-photographs of what a compression failure looks like. It
is very interesting and worthwhile to check out.

If the compression failure possibiity bothers you too much, you can go to
the aluminum spar failure sites and look at fatigue failures in aluminun.
They are much easier to spot. There should also be sites for fiberglass
spar failures, too. I expect that almost anything used as a spar has failed
from time to time.

The spar in my present aircraft is wood.

Colin

COLIN LAMB wrote:
According to expert testimony in one case regarding a failed wing
spar in a
Citrabia, a compression failure can occur when the tree is felled.

I have seen some websites concerning the AD note on the Champion
aircraft
which have micro-photographs of what a compression failure looks
like. It
is very interesting and worthwhile to check out.

------------------------------------------------------------

Roger that. The compression fracture often occurs in the rebound when
the tree hits the ground.

For a big tree of potentially prime spruce the feller may elect to top
it first, a task not for the faint of heart. A bed of second-growth is
then prepared, into which the tree is felled. No hard strike on the
ground and no rebound. They will ten cut away the lower twenty feet or
so, which will often be used for sounding boards and the like, and be
left with a clean stick up to 80 feet long.

But rather than becoming masts, spars or aircraft wood, the odds are
the tree will end up as fast-food packaging in Japan, Taiwan or Korea.
(Sitka spruce imparts no taste to food.)

If the tree was felled in the Tongas National Forest the lumber company
will pay the American tax-payer approximately $1.70... for the entire
tree. Clearly, we Americans have the best government money can buy :-)

-R.S.Hoover

The Pacific Northwest used to have large stands of Sitka Spruce trees.
Alas, they were mostly cut down for airplanes - World War I airplanes to be
exact. Processing plants were set up on the Columbia River right next to
Fort Vancouver, so the military could assist in running production full
tilt.

Colin

COLIN LAMB wrote:
The Pacific Northwest used to have large stands of Sitka Spruce
trees.
Alas, they were mostly cut down for airplanes - World War I airplanes
to be
exact.

-------------------------------------------------------

I guess they missed a few trees here & there. According to an FPL
report from the 1930's there was about 45 BILLION board feet of
havestable Sitka spruce in American forests and about three times that
amount in Canada.

But not in large stands. You'll occasionally see a pocket of nothing
but Sitka spruce but it normally grows in mixed stands, usually with
Western Hemlock. That's because of a little bug called the Spruce
Weevil. In the wild, growing in mixed stands, the spruce weevil isn't
much of a problem but it's deadly to single-specie stands of Sitka
spruce, as people have discovered from single-specie 're-forestation'
projects. Major thigh-slapper to foresters. Millions of dollars
wasted to produce square miles of Spruce Weevil fodder. [The weevil
attacks the new growth; you end up with a stunted, ground-hugging shrub
-- a 'forest' less than chest high.) USDA still has a lot to learn
from Mother Nature :-) (Today, the largest stands of Sitka spruce are
probably in Europe.)

The reality of Sitka spruce is that only 6% to 8% of an A-class log is
liable to meet aircraft-quality specs. Even then, the stick has to be
quarter-sawn before it can be accurately graded which means the sawyer
is liable to lose money on the deal unless he knows he's got a market
for it.

Fortunately, that reality works both ways. Since the major expense is
in the wastage and labor of resawing, if you can find a nice balk of
Sitka spruce and do the cutting, curing and grading yourself, you can
save over 90% compared to store-bought 'certified' spruce. (During the
height of the Depression, in order to save on freight and reduce
wasteage, Bill Piper Sr. drove to Oregon and hauled hand-selected loads
of spar-stock back to Pennsylvania on a rented trailer.)

Some lumber companies here in California still run their own barges
down from the PNW (Dixieline is one) and are willing to throw a log or
two on the load and even mill it to your spec. Assuming your pockets
are deep enough :-)

On the other hand, Western Hemlock is an acceptable substitute for
Sitka spruce and is about 8x more plentiful, plus the yield of
'aircraft-quality' timber is 10% to 12% for the same size log.

-R.S.Hoover

groups.com:


COLIN LAMB wrote:
The Pacific Northwest used to have large stands of Sitka Spruce
trees.
Alas, they were mostly cut down for airplanes - World War I airplanes
to be
exact.

-------------------------------------------------------

I guess they missed a few trees here & there. According to an FPL
report from the 1930's there was about 45 BILLION board feet of
havestable Sitka spruce in American forests and about three times that
amount in Canada.

But not in large stands. You'll occasionally see a pocket of nothing
but Sitka spruce but it normally grows in mixed stands, usually with
Western Hemlock. That's because of a little bug called the Spruce
Weevil. In the wild, growing in mixed stands, the spruce weevil isn't
much of a problem but it's deadly to single-specie stands of Sitka
spruce, as people have discovered from single-specie 're-forestation'
projects. Major thigh-slapper to foresters. Millions of dollars
wasted to produce square miles of Spruce Weevil fodder. [The weevil
attacks the new growth; you end up with a stunted, ground-hugging shrub
-- a 'forest' less than chest high.) USDA still has a lot to learn
from Mother Nature :-) (Today, the largest stands of Sitka spruce are
probably in Europe.)

The reality of Sitka spruce is that only 6% to 8% of an A-class log is
liable to meet aircraft-quality specs. Even then, the stick has to be
quarter-sawn before it can be accurately graded which means the sawyer
is liable to lose money on the deal unless he knows he's got a market
for it.

Fortunately, that reality works both ways. Since the major expense is
in the wastage and labor of resawing, if you can find a nice balk of
Sitka spruce and do the cutting, curing and grading yourself, you can
save over 90% compared to store-bought 'certified' spruce. (During the
height of the Depression, in order to save on freight and reduce
wasteage, Bill Piper Sr. drove to Oregon and hauled hand-selected loads
of spar-stock back to Pennsylvania on a rented trailer.)

Some lumber companies here in California still run their own barges
down from the PNW (Dixieline is one) and are willing to throw a log or
two on the load and even mill it to your spec. Assuming your pockets
are deep enough :-)

On the other hand, Western Hemlock is an acceptable substitute for
Sitka spruce and is about 8x more plentiful, plus the yield of
'aircraft-quality' timber is 10% to 12% for the same size log.


OK, let's say i go to the nearest supplier who has (allegedly) got some
Sitka of the correct quality. Let's say he has some boards about 12 foot
long and about 6 inches square.
OK, I think I can manage a ring count and gradient as well as seeing if my
spars will come out quarter sawn. after that, i'm lost. I think I can
probably spot a fracture on a raw board and moisture isn't realyan isue
since i know someone who can kinln dry it for me, but aside formall this,
what am I really looking for?

OK, let's say i go to the nearest supplier who has (allegedly) got some
Sitka of the correct quality. Let's say he has some boards about 12 foot
long and about 6 inches square.
OK, I think I can manage a ring count and gradient as well as seeing if my
spars will come out quarter sawn. after that, i'm lost. I think I can
probably spot a fracture on a raw board and moisture isn't realyan isue
since i know someone who can kinln dry it for me, but aside formall this,
what am I really looking for?

Theres an old AC on the subject. Also look thru AC43.
Another place to look is for "LADDER GRADE" wood.
Older fire department ladders were wood and had very similar
requirements as airplane spars. Asking for ladder grade wood
is easier to do than to ask for airplane spar stock. Now that you have
more places to look, go find what you need. Take a plane and put a few
strokes
on the end of what you might need, look it over. You should be able to
find what you need. NOW DON"T TAKE MY HEAD OFF, I didn't say
to substitute ladder grade for AC43 wood. I just said that the specs are so
close
that asking for ladder grade wood gets you a bunch more places to check out
and doesn't get people afraid of liability...... Scott.