compound curves in plywood

"Rich S." wrote in message
...

The end result was a smooth, compound-curved, thin, light, streamlined
shell of a body.

Hah! I thought I had one - just one - picture around here someplace. You can
see it at http://tinyurl.com/4xqyw

Rich S.

In article ,
"Rich S." wrote:

"Rich S." wrote in message
...

The end result was a smooth, compound-curved, thin, light, streamlined
shell of a body.

Hah! I thought I had one - just one - picture around here someplace. You can
see it at http://tinyurl.com/4xqyw

Rich S.

Forget that. I want the four-foot long micrometer secret!

--
Alan Baker
Vancouver, British Columbia
"If you raise the ceiling 4 feet, move the fireplace from that wall
to that wall, you'll still only get the full stereophonic effect
if you sit in the bottom of that cupboard."

BA-100 wrote:

Does the cedar strip technique you mention use multiple layers of veneer?
Presumably you need a form to wrap this around. Does it have to be solid
or can you just use formers, say, every 9 inches or so? How do you clamp
to get a good bond between layers?


http://www.oneoceankayaks.com/Kayaks.htm

The web site I was looking at for a kayak.

Yes to your question of formers Their plans give you full size former
layouts that you cut out put on the plywood and cut the formers from there.
They then attach the formers to a central beam and proceed to lay up the
wood strips using whatever wood to get the design they want mostly cedar
with mahogany for designs. after they do the top half they cover with
fiberglass and epoxy. They then remove from the formers (you did use
waxpaper on the formers right?) and fiberglass and epoxy the inside.
They then repeat with the bottom side. Then you fit the two sides together
and apply fiberglass tape and epoxy to both inside and outside of the
joint.
Basically instead of using foam for a core they use wood strips.

As soon as I finish this KR-2 in my garage (about another 10 years) I'm
going to start on my Cape Ann Double Kayak!

John

Question: Does the cedar strip technique you mention use multiple layers of
veneer? Presumably you need a form to wrap this around. Does it have to be
solid or can you just use formers, say, every 9 inches or so? How do you
clamp to get a good bond between layers?

Response: Some of the cedar strip boats that I built were made from 1" x 6"
cedar planks, which means they were about 3/4" thick. Then I ripped those
planks on a saw (table saw, band saw or radial arm saw - whatever is handy).
This will give you long strips that are about 3/4" wide and 1/4" thick.
Cedar is used because it bends easily, looks good and is light. Stations
are built conforming to the curved shape you want. Each station is about
12" to 16" apart. Wax paper or tape are put over the plywood forms. The
first strip is installed, and following strips are glued adjacent to the
first step. The strips are stapled onto each form. Alignment between
stations can be assured by clamps over the strips you are gluing. The glue
does not matter, becase no strength comes from it. You can butt joint each
piece. Although some perfectionists angle the edges of the strips going
around a curve, it is not necessary. If there is a slight opening, epoxy
will seep in and make the structure stronger. The cedar simply replaces
foam, and the strength comes from the layers of cloth and epoxy resin.
Carbon fiber is stronger and lighter, but would cover up the beautiful cedar
strip finish, but could be used on the inside. Obviously, the application
and strength of the epoxy will control the strength of the overall
structure, but it can be quite high. The strength requirements for the
fuselage of something like a Bowlus would be quite low - but there would
obviously need to be some method of attaching the wings to the fuselage and
spreading out the stress of the lifting point.

However, the pod itself could be created similar to a cedar strip kayak. My
17 foot cedar strip kayak weighs about 50 pounds and I made no effort to
save weight.

One other process, which could be used is a process developed for the HK-1
Hughes "Spruce Goose" It is built of laminated birch. As I understand the
process, the it was plywood made in the shape required for the aircraft and
known as Duramold. The aircraft companies made a number of small boats
using the same process to perfect it. The Evergreen museum no doubt has
some information on the process.

The inventive can replace the Molt Taylor Aerocar of yesteryear with a
Glider/kayak. When making an outlanding, simply land by a lake ro river,
remove and store the wings and tail, and paddle home.

Colin N12HS

COLIN LAMB wrote:

Question: Does the cedar strip technique you mention use multiple layers of
veneer? Presumably you need a form to wrap this around. Does it have to be
solid or can you just use formers, say, every 9 inches or so? How do you
clamp to get a good bond between layers?

Response: Some of the cedar strip boats that I built were made from 1" x 6"
cedar planks, which means they were about 3/4" thick. Then I ripped those
planks on a saw (table saw, band saw or radial arm saw - whatever is handy).
This will give you long strips that are about 3/4" wide and 1/4" thick.
Cedar is used because it bends easily, looks good and is light. Stations
are built conforming to the curved shape you want. Each station is about
12" to 16" apart. Wax paper or tape are put over the plywood forms. The
first strip is installed, and following strips are glued adjacent to the
first step. The strips are stapled onto each form. Alignment between
stations can be assured by clamps over the strips you are gluing. The glue
does not matter, becase no strength comes from it. You can butt joint each
piece. Although some perfectionists angle the edges of the strips going
around a curve, it is not necessary. If there is a slight opening, epoxy
will seep in and make the structure stronger. The cedar simply replaces
foam, and the strength comes from the layers of cloth and epoxy resin.
Carbon fiber is stronger and lighter, but would cover up the beautiful cedar
strip finish, but could be used on the inside. Obviously, the application
and strength of the epoxy will control the strength of the overall
structure, but it can be quite high. The strength requirements for the
fuselage of something like a Bowlus would be quite low - but there would
obviously need to be some method of attaching the wings to the fuselage and
spreading out the stress of the lifting point.

However, the pod itself could be created similar to a cedar strip kayak. My
17 foot cedar strip kayak weighs about 50 pounds and I made no effort to
save weight.

One other process, which could be used is a process developed for the HK-1
Hughes "Spruce Goose" It is built of laminated birch. As I understand the
process, the it was plywood made in the shape required for the aircraft and
known as Duramold. The aircraft companies made a number of small boats
using the same process to perfect it. The Evergreen museum no doubt has
some information on the process.

The inventive can replace the Molt Taylor Aerocar of yesteryear with a
Glider/kayak. When making an outlanding, simply land by a lake ro river,
remove and store the wings and tail, and paddle home.

Colin N12HS


Sounds like some of the early Curtis flying boats. I think they'd be fun.

Dan, U.S. Air Force, retired

"COLIN LAMB"
thlink.net:

Question: Does the cedar strip technique you mention use multiple
layers of veneer? Presumably you need a form to wrap this around. Does
it have to be solid or can you just use formers, say, every 9 inches
or so? How do you clamp to get a good bond between layers?

Response: Some of the cedar strip boats that I built were made from
1" x 6" cedar planks, which means they were about 3/4" thick. Then I
ripped those planks on a saw (table saw, band saw or radial arm saw -
whatever is handy). This will give you long strips that are about 3/4"
wide and 1/4" thick. Cedar is used because it bends easily, looks good
and is light. Stations are built conforming to the curved shape you
want. Each station is about 12" to 16" apart. Wax paper or tape are
put over the plywood forms. The first strip is installed, and
following strips are glued adjacent to the first step. The strips are
stapled onto each form. Alignment between stations can be assured by
clamps over the strips you are gluing. The glue does not matter,
becase no strength comes from it. You can butt joint each piece.
Although some perfectionists angle the edges of the strips going
around a curve, it is not necessary. If there is a slight opening,
epoxy will seep in and make the structure stronger. The cedar simply
replaces foam, and the strength comes from the layers of cloth and
epoxy resin. Carbon fiber is stronger and lighter, but would cover up
the beautiful cedar strip finish, but could be used on the inside.
Obviously, the application and strength of the epoxy will control the
strength of the overall structure, but it can be quite high. The
strength requirements for the fuselage of something like a Bowlus
would be quite low - but there would obviously need to be some method
of attaching the wings to the fuselage and spreading out the stress of
the lifting point.

However, the pod itself could be created similar to a cedar strip
kayak. My 17 foot cedar strip kayak weighs about 50 pounds and I made
no effort to save weight.

I'm pretty sure that the process would be to heavy for the strength it
would provide, unless it were modified to provide several very thin
crossing layers, all of which woul have to be tightly glued to each other
to have any real strenght.
But an idea has just popped into my so-called mind..
If I were to make three mold of each side freehand over a male mold, each
90 deg to the last, and then take them and stack them over the same mold
and vacuum bag the whole lot together....

Hmm.


One other process, which could be used is a process developed for the
HK-1 Hughes "Spruce Goose" It is built of laminated birch. As I
understand the process, the it was plywood made in the shape required
for the aircraft and known as Duramold. The aircraft companies made a
number of small boats using the same process to perfect it. The
Evergreen museum no doubt has some information on the process.

This isn't to far off the original method of manufacture for the Baby as i
understand it.


The inventive can replace the Molt Taylor Aerocar of yesteryear with a
Glider/kayak. When making an outlanding, simply land by a lake ro
river, remove and store the wings and tail, and paddle home.


Would have come in handy at least once in my gliding career when I left a
waterline on a 2-33!

I'm pretty sure that the process would be to heavy for the strength it
would provide, unless it were modified to provide several very thin
crossing layers, all of which woul have to be tightly glued to each other

I'm no expert in (or any field) but several people have mentioned about the
lack of strength a single layer plywood would have and you'd need several
layers (ad various angles) etc etc. Yet the most common new "core"
constructions uses styrofoam for a core, I'd think the plywood at almost
any thickness would be stronger. The reason for use the plywood would be for
the looks (at least that's my guess).
John

In article . net,
"COLIN LAMB" wrote:

I just looked at the fueslage of the Bowlus and it would be easily
duplicated using cedar strip techniques. Assembly is very quick with almost
no tools required, except for a saw to cut the wood strips. I did use some
mahogany in one of my canoes, just to try it, and it works fine. Because
the inside of the fuselage does not require the transparancy that the
outside does, you could even use one of the lighter and stronger cloths
(such as carbon fiber). This would result in increased strength and lighter
weight.

Now I may have to build one. The tube from front to rear could be
constructed easily using carbon fiber cloth rolled into a tube, or a
commercial tube purchased.

Colin

You might want to explore this site:

http://single-handedskiffs.com/pages/453349/index.htm

That is a sailboat constructed along the lines being discussed. What's
interesting and germane to note is the *loads* on such a boat created by
the rigging. Typical standing rigging (that which holds up the mast) is
tensioned to hundreds of pounds, so you can get some idea of the loads
created between the rigging pulling upward and the mast pushing down.

There are some notes about the resin system used (from West, IIRC) and
some strength testing done on sample panels.

--
Alan Baker
Vancouver, British Columbia
"If you raise the ceiling 4 feet, move the fireplace from that wall
to that wall, you'll still only get the full stereophonic effect
if you sit in the bottom of that cupboard."