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)

"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

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!

wrote:
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.


wood fuselage ultralight?
pass... thank you anyway.

I'm very familiar with the Lohle.

Any kind of mis-hap is bound to find splinters in -um- tender anatomy.
Sorry guys, I just have a different bias.

All-you-men-eee-umm!

In nature it's a white power, but it cooks down real nice.

Fabulous stuff, guys! Manly stuff!

And it's shiny, too.

Far superior to wood in most every way. (well, except buoyancy)

Heck of a lot cheaper, too. (: just mho. ymmv. :^)



Richard

http://www.home.earthlink.net/~tp-1/

"Richard Lamb" wrote in message
k.net...
All-you-men-eee-umm!

In nature it's a white power, but it cooks down real nice.


Ooh - are you gonna get it now!

Rich S.

"Richard Lamb" wrote

Any kind of mis-hap is bound to find splinters in -um- tender anatomy.
Sorry guys, I just have a different bias.

I remember reading an article written by a (I think) French couple, who had
some time of mishap during either takeoff or landing, and the result was a
rather high energy crash. They credit the wooden structure with saving
their life. Seems wood is very adept at absorbing energy, and the cockpit
was designed strong enough to stay mostly intact. They walked away with
very minor injuries.

Anyone else remember this? It was a few years ago, I'm guessing at least 5.

As far as your choice of materials, whatever turns your crank. That is
about as personal as your choice of toilet seat material. I like wood.
Nice and warm to the keester. g
--
Jim in NC

Speaking of high energy crashes...

A few years ago a friend of mine, with his wife, was attempting a
landing that went wrong. He was flying an RV-6 and, somehow, lost
control of the plane on landing.

He careened off the runway to the left, dragging the left wing tip in
the grass, went through a barbed wire fence complete with metal posts,
through a blackberry thicket and then it got interesting.... The
thicket was at the top of a cliff next to a gravel pit and the plane
ended up at the base of the 60 foot cliff nose down in between two piles
of gravel. The nose of the RV was buried in the gravel and the wings
were buried in the two piles of gravel. The contents of the fuel tanks
drained out instantly (cut open by the metal posts) into the gravel.

He suffered a small cut on his left arm from the broken canopy and his
wife, in the right seat, suffered a crushed ankle from the collapsing
fuselage around her right foot.

The RV may not use wood construction but it certainly is well designed
for pilot/passenger protection.

John

Morgans wrote:

"Richard Lamb" wrote


Any kind of mis-hap is bound to find splinters in -um- tender anatomy.
Sorry guys, I just have a different bias.


I remember reading an article written by a (I think) French couple, who
had some time of mishap during either takeoff or landing, and the result
was a rather high energy crash. They credit the wooden structure with
saving their life. Seems wood is very adept at absorbing energy, and
the cockpit was designed strong enough to stay mostly intact. They
walked away with very minor injuries.

Anyone else remember this? It was a few years ago, I'm guessing at
least 5.

As far as your choice of materials, whatever turns your crank. That is
about as personal as your choice of toilet seat material. I like wood.
Nice and warm to the keester. g

"John Ammeter" wrote

The nose of the RV was buried in the gravel and the wings were buried in
the two piles of gravel.

The contents of the fuel tanks drained out instantly (cut open by the
metal posts) into the gravel.
The RV may not use wood construction but it certainly is well designed for
pilot/passenger protection.

Sounds as though a harried landing turned from bad to worse to better.

I suspect the gravel was a savior. It slowed the stop, by absorbing energy
when it buried the plane. Less G's are a "good thing." g The fuel
soaking down into the gravel also made it harder to ignite, I would think.

So the moral of the story is to always crash into a gravel pile? ;-)
--
Jim in NC