Wooden Notes

To All:

The low cost and wide availability of wood in America makes it a good
choice for the budget-minded builder of simple flying machines. The
only problem is that when picking the stacks at the local lumber yard
you need to know a fair amount about wood in order to select the most
suitable pieces. Part of that chore involves visiting the local yards
- - or box stores - - fairly often in order to see the new pallets as
they're put out for sale.

Today I lucked into some outstanding shelving (!) and a pallet of 1x2
furring strips that included some superior wood. I loaded up a cart
with as much as I could afford. Waiting in the line at the register
(Home Depot has a long way to go in that department) another
homebuilder saw me as he entered the store and stopped to chat.

Although I've given demonstrations about grading lumber, including
side-by-side testing in which samples of various woods are compared to
Sitka spruce, my habit of using commonly available wood to fabricate
real airplanes is often treated with humorous condescension, as it was
today.

"Building another airplane?" he said as he started to leave, plus the
patronizing smile.

"Same one," I nodded. Actually, same ones, as in plural, except most
of this wood was destined for an on-going primary glider project.

He looked at the cart-load of lumber, started to say something witty,
finally just walked off with an airy wave. To him it was just a
cart-load of box-store lumber. Had he taken a closer look at the
furring strips he would have seen they were Western Hemlock, ran about
24 annualr-rings per inch and came from a tree that was at least six
feet in diameter(*). The grain had a run-out of less than one inch in
eight feet and most of the sticks were almost perfectly cross-grained.
That's because they were probably sawn from the cauls produced when log
was sawn into a square cant. Back in the old days, the cauls would
have gone into the kiln or boiler as fuel but nowadays they use
laser-guided computers to figure out the maximum yield from every log
and the cauls -- the camber-faced slabs from the sides of the timber --
probably went to an edger instead of the scrap heap and ended up as
saleable pieces, including my bundle of furring strips.

The shelving was another situation entirely, being plantation-grown
stuff running six rings to the inch near the edge and barely eight
toward the middle. The tree was probably about 12" in diameter when it
was harvested and probably about 30 years old. But what made these
particular pieces of shelving candidates for aviation was the fact each
piece on my cart was a center cut.

In producing construction-grade lumber the tree is cut into sections
from 12 to 24 feet in length then each section is squared and run back
& forth through the saw (or in a really big mill, through a continuous
series of saws) and turned into slabs of the desired thickness, as
dictated by the market. By comparison, the wood for masts, spars,
ladder rails, bannisters and aviation-grade lumber is usually
quarter-sawn, an entirely different proposition from plain-sawing.

The point here is that the center-cut of a plain-sawn log has EXACTLY
the same grain orientation as if it were quarter-sawn. That means it
will dry without warping and its characteristics of strength will be
uniform.

So will it be useful in an airplane? Probably. But the wood has the
final say in the matter. It's still pretty wet and the shelving needs
to be re-sawn to isolate the usable outer sections from the center.
Give it a bit of time, turning it occasionally and a fair percentage of
it should prove useable. And if not, I'll use some of it to make
Smilin' Jack and his friends some little toy airplanes; give'm to them
at Christmas; tell them it's for their grandkids.

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

The furring strips were $1.15 each and I bought twelve. The shelving
was $5.67 each and I bought three pieces. Total was $30.81 at the Home
De-pot on San Marcos Blvd. That eats up my 'airplane wood' budget for
about two months but 'long about March I'll start prowling the stacks
again. Lotta ribs in an SG-38 and every time you take it out you can
count on them kids busting a few. But by the time the thing is mostly
patches the new set of wings will be ready, along with a new crop of
kids.

The Smilin' Jacks don't know what they're missing :-)

-R.S.Hoover

(*) - - Trees are round. With a pocket loupe and your 6" machinist's
scale you can measure the chord across the arc of the annular rings of
a fine-grained scantling with a fair degree of accuracy. With that, you
can calculate the diameter of the tree at that point. Do it enough
times, just looking at the piece will give you a good idea of its
diameter.

Thank you, thank you, thank you.!
People look at me funny when I tell them that I bought my Doug fir from
Home Depot and what I'm doing with it. About 80% of my structure is
from different home depot's. If you go through thier 4x4 ($11.59 each)
you can find very straight, very tight grain. Most will have knots and
other imperfections, but since most of the wood will be cut into
smaller parts these knots dissapear. Once in a while you will come
across a piece with amazing grain. You stop, look around to make sure
no one else is watching, then grab and keep to the side.
I have to confess, since Home Depot's 4x4's limit you to 8'
sections, you need to start to become creative with the sources of
lumber. I did end up buying my spar material from a company in
Washington state. The salesman took an interest in my purpose and hand
picked the grain for me. He did a great job. Anyway, thanks VeeDub
for your posting, it helps make me feel like I'm on the right track
Lou

On 25 Jan 2006 03:08:10 -0800, wrote:



The Smilin' Jacks don't know what they're missing :-)

-R.S.Hoover


absolutely the case. I ran out of Queensland Hoop Pine that we use as
a substitute for spruce and was walking through bunnings warehouse
(the australian clone of home depot) , what did I spy but some
stunning alaskan yellow cedar. 8ft long with absolutely straight grain
and not more than one pin knot in the entire length and about 30 rings
per inch. I bought them all and sliced them up for the laminations
that form the turtledeck formers of my Turbulent. the sawdust pongs a
bit but they made superb lightweight laminated bows.

we also get a eucalyptus timber sold as "ash" or "oak" but is actually
eucalyptus deligatensis or something similar. I have seen lengths that
look absolutely perfect propeller wood. my guess is $aus70 retail for
a propeller's worth of wood.

half of this alternate wood selection is having the courage that it
will be ok in use, and that comes from an appreciation of the loads
and stresses that the components get subjected to in flight.

btw my hoop pine comes from a guy who uses it to make apiarists honey
bee boxes. he is evidently absolutely stoked that some of his bee box
wood will some day fly as an aircraft :-)

Stealth Pilot

.... now corky scott should build himself a little single seat wooden
aeroplane with a 1600cc vw engine conversion done by himself.
cheap as chips. he'd have a ball without breaking the bank.
(hey corkie send me an email and I'll reply with enough details to
work from)

Yes, there is no magic inherent in the wood coming form an "aircraft"
vendor. As long as you follow the AC 43-13 rules as to species, grain
and drying and some wood sense, your wood may be purchased anywhere.
There is no PMA issued to a forest!

"Stealth Pilot" wrote

the sawdust pongs a

Could you give a yank wood butcher an idea of what pong is in relation to
sawdust?

Thanks.
--
Jim in NC

On Wed, 25 Jan 2006 18:02:37 -0500, "Morgans"
wrote:


"Stealth Pilot" wrote

the sawdust pongs a

Could you give a yank wood butcher an idea of what pong is in relation to
sawdust?

Thanks.

I can honestly say that you probably wouldnt know ...since spruce
grows in your locale and neither it nor QHP have any aroma.

pong - an obnoxious smell, in this case the malodourous scents
emanating from the sawn alaskan yellow cedar.

It seems there would be a market for an australian-american
dictionary. ...we'd publish one if only you'd go metric :-)

Stealth Pilot

"Stealth Pilot" wrote

It seems there would be a market for an australian-american
dictionary. ...we'd publish one if only you'd go metric :-)

The *real* problem would be in making the first "smellobetic" dictionary, me
thinks. g

So it is kinda like how some of our red oak smells like "dog ****."
--
Jim in NC

That Alaskan yellow cedar is MARVELOUS WOOD !!! I bought some of it 30
yrs ago to build an air boat---had some left over to build pipe-organ
wind chests & still had some to use in my airplane-----Look at the specs!!
10% stronger ( and heavier) than Spruce --right straight across the
lines for ALL the strength specs. Can't hardly see the grain, beautiful
white stuff-(till you wet ot or varnish it--then a pale yellow) --I
bought it from a place that made wooden screen doors---(aluminum storm
doors= no more wood)

Stealth Pilot wrote:
On 25 Jan 2006 03:08:10 -0800, wrote:



The Smilin' Jacks don't know what they're missing :-)

-R.S.Hoover



absolutely the case. I ran out of Queensland Hoop Pine that we use as
a substitute for spruce and was walking through bunnings warehouse
(the australian clone of home depot) , what did I spy but some
stunning alaskan yellow cedar. 8ft long with absolutely straight grain
and not more than one pin knot in the entire length and about 30 rings
per inch. I bought them all and sliced them up for the laminations
that form the turtledeck formers of my Turbulent. the sawdust pongs a
bit but they made superb lightweight laminated bows.

we also get a eucalyptus timber sold as "ash" or "oak" but is actually
eucalyptus deligatensis or something similar. I have seen lengths that
look absolutely perfect propeller wood. my guess is $aus70 retail for
a propeller's worth of wood.

half of this alternate wood selection is having the courage that it
will be ok in use, and that comes from an appreciation of the loads
and stresses that the components get subjected to in flight.

btw my hoop pine comes from a guy who uses it to make apiarists honey
bee boxes. he is evidently absolutely stoked that some of his bee box
wood will some day fly as an aircraft :-)

Stealth Pilot

... now corky scott should build himself a little single seat wooden
aeroplane with a 1600cc vw engine conversion done by himself.
cheap as chips. he'd have a ball without breaking the bank.
(hey corkie send me an email and I'll reply with enough details to
work from)

Well, I wuss'd out and went with Sitka on my Wright machine, but only
b/c I didn't know anyone who would murder a West Virginia silver spruce
tree for me. ...that stuff's kinda hard to find, for obvious reasons.
One of the Wright recreators did use it, but then they also had a $7
million budget.

I've been entertaining the idea of building a Chanute-Herring glider
from alternate wood like doug fir or possibly yellow poplar. Anyone
got specs on yellow poplar? Didn't see it listed in AC43-13.

"wright1902glider" wrote in message
oups.com...
I've been entertaining the idea of building a Chanute-Herring glider
from alternate wood like doug fir or possibly yellow poplar. Anyone
got specs on yellow poplar? Didn't see it listed in AC43-13.

Harry...............

All I have is this table, copied from one of the old Emeraude newsletters:

Essence Spec. Grav. Tension (psi)
Yellow Poplar .44 8600
Alaska Cedar .46 9900
Douglas Fir .43 to .50 9000 to 10900
Fir .40 to .42 8400 to 9400
West. Hemlock .45 11000
East. White Pine .37 7600
West. Red Cedar .34 7100
Sitka Spruce .41 9400
Port Orford Cedar .43 10200
East. Cottonwood .43 7700

Rich S.