Flying on the Cheap - Wood

To All:

A few years ago I posted an article offering some hints about how to
build an inexpensive airplane that was safe and reliable (Flying on the
Cheap, October 2001; Google will find it for you). The key point in
the article was the use of commonly available mild steel tubing for the
fuselage. Of course, that meant you had to weld and nowadays most
folks don't, nor do they want to learn. Wood's the thing,
according to non-welding folks, citing its use in KR's and Piets and
dozens of other airframes, each held as the Perfect Design by that
particular person.

The advocates of wooden airframe construction have a valid point, at
least here in the States. Because of the rise of the box stores (Home
Depot, Lowes, etc), wood is more commonly available than steel tubing
and despite what many think, there's plenty of aviation-quality wood
lurking inside the knot-hole collection at your local box store. The
task of the lo-buck builder is to cut away the non-aviation parts, glue
the good stuff together and go flying. Thanks to modern adhesives, the
likelihood of a novice builder producing an unsafe glue-joint is small.


To support the builders of Box Store Bombers I shared my woodworking
experience in several articles posted to this newsgroup (How to Make
Ribs Out of Old Orange Crates [Nov 2002], Wooden Notes [Jan 2006] and
several others). Surprisingly, homebuilding at that level is not an
especially welcome topic on the rec.aviation.homebuilt newsgroup. This
lead to relaying such information in private posts to guys who were
interested in actually building something. Like Fred. Which isn't
his name, but work with me here.

After considerable thought Fred settled upon a single-place, VW-powered
KR-ish design as being the best match for his particular situation. In
working toward that goal he didn't find much support, especially from
the only organization that claims to speak for grass-roots aviation in
America. Thanks to an income of only $25k or thereabouts, to the EAA,
Fred and the millions of people like him simply do not exist. But Fred
is determined to build and fly his very own airplane, even if he has to
use the local box store for most of his materials. Indeed, he
doesn't have much choice. The total cost for his box store lumber
will be under $100 whereas a kit of aviation-grade spruce would cost
about a thousand dollars by the time the freight was paid. The lumber
will have to be resawn and spliced but that's the reality of Flying
on the Cheap.

Fred is bucking additional headwinds in that he has zero woodworking
experience, doesn't own a table saw and has only a limited amount of
shop space. But he does have a computer and lots of determination.
With a bit of help, he has been making slow but steady progress.

Having finally gained access to a table saw, Fred began prowling the
box stores for suitable lumber. (His KR-ish design uses built-up
spars, the main spar having caps two inches square, the aft spar about
an inch.) His next message verged on panic. Did I know that ALL of
the lumber sold in box stores was incorrectly marked? Some of their
one inch wood was only three-quarters of an inch thick! And all of the
2x4's he looked at were only one and a half by three and a half!

I assured Fred that the box stores weren't trying to cheat him,
explained about rough versus finished dimensions and pointed him toward
some places on the internet where the matter was explained in more
detail. His reply sounded a bit discouraged, having realized he
won't be able to cut a 2x2 out of any piece of finish-size
two-by-something lumber. The only way he's going to get a good 2x2
stick is to start with 1x2's, spliced to get rid of any knots, and
glue them together to get his 2x2's. That's the reality of Flying
on the Cheap (why does that sound familiar...) but as a matter of fact,
except for the splices it isn't that much different than starting
with a spruce kit.

I sent him some drawings showing how to slice up a 2x4 to produce spar
caps. Because of the knots he'll probably need about eighteen
2x4's, resawn and laminated to produce the required number of spar
caps. It is labor intensive but there's surprisingly little waste
since the residue of spar cap production yields the intercostals,
stringers and tail-feather spars.

Any mention of splicing spars usually sets several heads of hair on
fire, even though such splices are an accepted practice, their details
fully covered in the old CAM or the new AC13 manuals. In fact, once
you've made up a suitable fixture to ensure all of your splices will
have the same angle, doing a long-splice in solid wood is no more
difficult than doing a short-splice in plywood. (Hint: Solid wood,
you want an angle of about 1:15. With plywood, thanks to the
orientation of the plys, you can develop full strength with angles
between 1:10 for mahogany and 1:12 for birch. As a point of interest,
boat builders commonly use 1:8 for either.)

Making up a scarfing fixture tends to drive a lot of homebuilders crazy
as they fiddle and tweak, trying to achieve a precise angle of 3.8
degrees for a long-splice. Or 7.1 degrees for a boat-work 1:8. The
truth is, the precise angle doesn't really matter. What matters is
that all of the pieces be cut to EXACTLY the SAME angle... and that the
splice be strong enough for the task at hand. This degree of accuracy
can be achieved using nothing more complicated than fixtures assembled
from scrap wood, one for scarfing solid stock, the other for scarfing
plywood. In each case the wood gets clamped in the fixture and the
same cutter - - a portable circular saw - - is used on both.

(As you might suspect, scarfing actually begins at the box store. When
picking the stack for lumber having the proper grain and run-out, you
envision the cuts you'll make when resawing. In many cases you can
orient the piece so that any knots fall entirely within the pieces you
are cutting off, leaving you with a knot-free stick.)

When using box store lumber for airplanes or boats there are a host of
details bobbing just beneath the surface, ready to sink the unwary.
Most of those details can be resolved with a dose of plain
old-fashioned Common Sense, such as keeping your saw-blades sharp,
adjusting the rate of your cut according to its depth and so forth.
Fortunately the details tend to be fail-safe. And self-educating
because of it. Do it wrong, you'll end up with a part that can't
be used. But once you get the hang of it, splicing longerons or spar
caps is no more complicated than checking the air in your tires.

- -

For more than fifteen years millions of low-income but air-minded
Americans waited for Light Sport Aircraft to become a reality. Sadly,
that reality is airplanes and flight training which remain too
expensive for the average American. As the LSA concept turned into
vapor-ware I began receiving more mail from people like Fred who have
decided to follow a different drummer. On the whole, I think this is a
good idea. Based on more than ten years of such messages, folks like
Fred cleave closer to the ideals of grass-roots aviation. These folks
have learned more about their engines and airframes than the typical
kit-builder and some have acquired a remarkable depth of knowledge in
engineering and aeronautics. But I don't think we'll see Fred at
Oshkosh - - it's simply gotten too expensive. Indeed, I've a hunch
a lot of these fellows will end up flying 'black' - - completely
off the books of any Agency or organization. Not because they want to
but because it's the only way they can keep the Dream alive.

-R.S.Hoover

More power to Fred... I hope he can stay the course and get a flying
machine...

denny

wrote:
To All:

A few years ago I posted an article offering some hints about how to
build an inexpensive airplane that was safe and reliable (Flying on the
Cheap, October 2001; Google will find it for you). The key point in
the article was the use of commonly available mild steel tubing for the
fuselage. Of course, that meant you had to weld and nowadays most
folks don't, nor do they want to learn. Wood's the thing,
according to non-welding folks, citing its use in KR's and Piets and
dozens of other airframes, each held as the Perfect Design by that
particular person.

The advocates of wooden airframe construction have a valid point, at
least here in the States. Because of the rise of the box stores (Home
Depot, Lowes, etc), wood is more commonly available than steel tubing
and despite what many think, there's plenty of aviation-quality wood
lurking inside the knot-hole collection at your local box store. The
task of the lo-buck builder is to cut away the non-aviation parts, glue
the good stuff together and go flying. Thanks to modern adhesives, the
likelihood of a novice builder producing an unsafe glue-joint is small.


To support the builders of Box Store Bombers I shared my woodworking
experience in several articles posted to this newsgroup (How to Make
Ribs Out of Old Orange Crates [Nov 2002], Wooden Notes [Jan 2006] and
several others). Surprisingly, homebuilding at that level is not an
especially welcome topic on the rec.aviation.homebuilt newsgroup. This
lead to relaying such information in private posts to guys who were
interested in actually building something. Like Fred. Which isn't
his name, but work with me here.

After considerable thought Fred settled upon a single-place, VW-powered
KR-ish design as being the best match for his particular situation. In
working toward that goal he didn't find much support, especially from
the only organization that claims to speak for grass-roots aviation in
America. Thanks to an income of only $25k or thereabouts, to the EAA,
Fred and the millions of people like him simply do not exist. But Fred
is determined to build and fly his very own airplane, even if he has to
use the local box store for most of his materials. Indeed, he
doesn't have much choice. The total cost for his box store lumber
will be under $100 whereas a kit of aviation-grade spruce would cost
about a thousand dollars by the time the freight was paid. The lumber
will have to be resawn and spliced but that's the reality of Flying
on the Cheap.


Aircraft wood doesn't necessarily have to come from Wicks or Aircraft
Spruce: it has to meet the requirements as set forth in AC 43-13 et
seq. You can find aircraft wood or get it sawn if you know what to look
for. But using wood that clearly is out of those spec is going to cause
trouble.

The biggest problem with flying costs are not traditional simple
airframes: they are the overpriced ridiculous powerplants and high
storage costs.

Direct drive VW made sense in 1965. Not today. Use a liquid cooled car
engine and a redrive, perhaps a Honda since they are attractively
priced as JDM pulls.

On 10 Aug 2006 05:23:38 -0700, "Bret Ludwig"
wrote:




Aircraft wood doesn't necessarily have to come from Wicks or Aircraft
Spruce: it has to meet the requirements as set forth in AC 43-13 et
seq. You can find aircraft wood or get it sawn if you know what to look
for. But using wood that clearly is out of those spec is going to cause
trouble.

wood is just an engineering material, one of many, it has to meet the
strength requirements put on it by the loads on the airframe.

ac43-13 contains a description of what woods that have met the
requirements usually look like. it is the structural characteristics
of the wood that are important not the visual appearance.

btw I agree totally with Veedubbers comments on wood sourcing and wood
selection. none of my wood comes from certified sources.

Stealth Pilot

"Bret Ludwig" wrote in message
ups.com...

wrote:
To All:

A few years ago I posted an article offering some hints about how to
build an inexpensive airplane that was safe and reliable (Flying on the
Cheap, October 2001; Google will find it for you). The key point in
the article was the use of commonly available mild steel tubing for the
fuselage. Of course, that meant you had to weld and nowadays most
folks don't, nor do they want to learn. Wood's the thing,
according to non-welding folks, citing its use in KR's and Piets and
dozens of other airframes, each held as the Perfect Design by that
particular person.

The advocates of wooden airframe construction have a valid point, at
least here in the States. Because of the rise of the box stores (Home
Depot, Lowes, etc), wood is more commonly available than steel tubing
and despite what many think, there's plenty of aviation-quality wood
lurking inside the knot-hole collection at your local box store. The
task of the lo-buck builder is to cut away the non-aviation parts, glue
the good stuff together and go flying. Thanks to modern adhesives, the
likelihood of a novice builder producing an unsafe glue-joint is small.


To support the builders of Box Store Bombers I shared my woodworking
experience in several articles posted to this newsgroup (How to Make
Ribs Out of Old Orange Crates [Nov 2002], Wooden Notes [Jan 2006] and
several others). Surprisingly, homebuilding at that level is not an
especially welcome topic on the rec.aviation.homebuilt newsgroup. This
lead to relaying such information in private posts to guys who were
interested in actually building something. Like Fred. Which isn't
his name, but work with me here.

After considerable thought Fred settled upon a single-place, VW-powered
KR-ish design as being the best match for his particular situation. In
working toward that goal he didn't find much support, especially from
the only organization that claims to speak for grass-roots aviation in
America. Thanks to an income of only $25k or thereabouts, to the EAA,
Fred and the millions of people like him simply do not exist. But Fred
is determined to build and fly his very own airplane, even if he has to
use the local box store for most of his materials. Indeed, he
doesn't have much choice. The total cost for his box store lumber
will be under $100 whereas a kit of aviation-grade spruce would cost
about a thousand dollars by the time the freight was paid. The lumber
will have to be resawn and spliced but that's the reality of Flying
on the Cheap.


Aircraft wood doesn't necessarily have to come from Wicks or Aircraft
Spruce: it has to meet the requirements as set forth in AC 43-13 et
seq. You can find aircraft wood or get it sawn if you know what to look
for. But using wood that clearly is out of those spec is going to cause
trouble.

The biggest problem with flying costs are not traditional simple
airframes: they are the overpriced ridiculous powerplants and high
storage costs.

Direct drive VW made sense in 1965. Not today. Use a liquid cooled car
engine and a redrive, perhaps a Honda since they are attractively
priced as JDM pulls.

I must dissagree. "Fred" appears to have settled on what could be termed a
light, single seat, ELSA which should need roughly 30 to 45 HP. The VW
should be ideal for the purpose.

Peter

"Peter Dohm" wrote in message
...
I must dissagree. "Fred" appears to have settled on what could be termed
a
light, single seat, ELSA which should need roughly 30 to 45 HP. The VW
should be ideal for the purpose.

No matter what he builds from Home Depot lumber it isn't ever going to be an
ELSA.

"Gig 601XL Builder" wrDOTgiaconaATcox.net wrote in message
...

"Peter Dohm" wrote in message
...
I must dissagree. "Fred" appears to have settled on what could be
termed
a
light, single seat, ELSA which should need roughly 30 to 45 HP. The VW
should be ideal for the purpose.

No matter what he builds from Home Depot lumber it isn't ever going to be
an
ELSA.


Perhaps, and perhaps not.

At the moment, they appear to still be pretty busy working on kit
certification. However, it appeared (by reading between the lines in an
interview with Marion Blakely) that plans built ELSA is in the future. It
would then be "out of character" for custom built aircraft and/or small
designers of plans to be specifically excluded.

Besides, I think you know what I meant in terms of performance--even if Fred
chooses to apply only for the traditional amateur built experimental
category.

Peter

On Thu, 10 Aug 2006 18:33:37 -0400, "Peter Dohm" wrote:

No matter what he builds from Home Depot lumber it isn't ever going to be
an ELSA.

Perhaps, and perhaps not.

At the moment, they appear to still be pretty busy working on kit
certification. However, it appeared (by reading between the lines in an
interview with Marion Blakely) that plans built ELSA is in the future. It
would then be "out of character" for custom built aircraft and/or small
designers of plans to be specifically excluded.

I think the basic problem would lie in the certification process. Ignoring the
grandfathered aircraft, ELSA certification requires two things: That an example
of the aircraft be built and certified as an SLSA, and that the ELSA builder
strictly conform to the materials, processes, and design of that example SLSA.
You can't change the engine, you can't change the radio, you can't make a single
deviation from the manufacturer's construction manual UNTIL your plane receives
its ELSA certification.

Thus, the plans must specify the materials to be used. The structural wood
elements will have to be spelled out. Conceivably, the designer could just
specify "Hemlock with XXX rings per inch, with the grain slope no more than
X:Y," etc, which means you *will* be able to go to Home Depot Aerospace and hunt
and pick for conforming wood.

However...remember, the designer has to certify the aircraft as a
production-type LSA. It's going to be a lot easier for him to specify "Spruce
conforming to XXXX standard."

Either way, there can be problems afoot for the plans builders. In both cases,
a hard-nosed FAA inspector could demand proof that the wood on the aircraft
meets the standard specified by the designer. If the designer specifies a
particular grade of spruce, you can probably show the appropriate receipts. But
if the designer merely states the qualification criteria for wood selection,
this might be a bit more difficult to provide sufficient proof.

ELSA is NOT Experimental-Amateur Built. There are some significant differences.
If you're building, the only advantage you get with an ELSA certification is
that a later owner can receive an LS-I certificate that lets them do their own
annuals. Otherwise, you're much better off as Exp-Am.

Ron Wanttaja

"Peter Dohm" wrote in message
...
"Gig 601XL Builder" wrDOTgiaconaATcox.net wrote in message
...

"Peter Dohm" wrote in message
...
I must dissagree. "Fred" appears to have settled on what could be
termed
a
light, single seat, ELSA which should need roughly 30 to 45 HP. The VW
should be ideal for the purpose.

No matter what he builds from Home Depot lumber it isn't ever going to be
an
ELSA.


Perhaps, and perhaps not.

At the moment, they appear to still be pretty busy working on kit
certification. However, it appeared (by reading between the lines in an
interview with Marion Blakely) that plans built ELSA is in the future. It
would then be "out of character" for custom built aircraft and/or small
designers of plans to be specifically excluded.

Besides, I think you know what I meant in terms of performance--even if
Fred
chooses to apply only for the traditional amateur built experimental
category.

Peter


The entire basis of the E-LSA is that it is built exactly to "factory"
standards with no deviation. Otherwise it is a Exp-Amateur that just happens
to be legal to fly by an LSA.

There is nothing to be gained by builders, manufacturers, pilots or the FAA
by a change such as you describe and many things to lost so where is the
motivation for such a move?

Bret Ludwig wrote:
...

Direct drive VW made sense in 1965. Not today. Use a liquid cooled car
engine and a redrive, perhaps a Honda since they are attractively
priced as JDM pulls.

Have you seen many airplanes flying with liquid cooled car
engines and a redrives?

How many with Honda engines?

Is the CVCC engine better (or worse) for flying than other
auto engines?

--

FF