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Tools + Tips

PIETENPOL

CORVAIR

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What are these things? They are clamps made from back plastic drain pipe. The smaller one is 3" pipe and the larger is 4" pipe. On the larger one, at the top, you can see a black line. This is were the pipe was cut across.
The handles make them easy to use one handed. I came across these years ago in Fine Woodworking magazine and now have bucketfulls of the things. You can see them in use in the Pietenpol pages. A
small, flat head nail through the plastic into the end
of the dowel holds it in place.

A page for tools I have found usefull that you cannot buy, and information not readily available.

Have you ever tried to drill a hole through a wide board and have it come out the other side exactly were it is supposed to? And just how successful were you? This thing is a drill guide that lines up the exit point using a pin, with the entry point of the drill bit. The two shown at the right are 1/8" and 3/16" tools.
In the left picture you see the pin on the left, then the body, made from soldered copper water pipe. The long drill bit is on top. There are many ways of making this tool.
I found 12" long stainless steel tubing in my local hobbyshop. This I ran through the copper from one end of the tool to the other with a little bit sticking out both ends.
Then I worked up some epoxy putty, the kind that comes in sticks as shown in the right picture at the bottom. This was then stuffed into the copper pipe around the stainless tubing and allowed to set. The next order of business was to determine the width the plank to be drilled and cut out a section of the tubing accordingly. Now the drill bit will be guided absolutely straight to the exact point it has to hit on the other side of the plank. No guesswork involved.

And what do we have here?

A wooden cam clamp

Some scrap 2" X 6" or pieces of 2" x 4"and 1/2" thick hardwood, some cutting, drilling and glueing and there you are.The drawing on the right gives the process for making the spiral face of the cam. First you draw a series of lines radiating out from a point 20° apart. then, at some point down the first line you draw a line perpendicular that crosses the next line. Use that crossing point to draw the next line the same way. Keep going and your lines spiral outwards. Join them all with a curve and voila!

The dimensions of the clamp parts are not critical. You can make this thing in any size you need. Using the materials I have suggested just makes it easier. Just make sure the long bar is tightly glued into the bottom jaw and the sliding jaw should be loose enough to slide easily. I glue some cork to each face for cushioning against the work. The cam pin is a short piece of 1/2" hardwood dowel. The drilled hole you see at the end of the slot in the sliding jaw is necessary to prevent the wood splitting.

The diagram here represents the pressure exerted on a wing as it flies through the air. On the left is the point where it attaches to the body, or fuselage. The wing this is for is the same width at both ends. The pressure is not the same all across the panel as you would expect. It becomes less and less the closer you get to the outer tip. At the left end of the chart is seen the words " aspect ratio" . The numbers 6, 10, 20 represent the length of the entire wing ( both sides, or panels) relative to the width. A wing with an aspect ratio of 10 is ten times longer than it is wide. On the chart we see that the numbers are different for the three wing shapes represented. The wing on my Pietenpol Aircamper is very close to a 6.
Why would you want to know such a thing? Well, to start with, it helps in designing a wing that is strong enough to hold you up in the air and at the same time is not so heavy that you can't get off the ground.

This template is for the standard lettering used in  the 30's and 40's. This page is from a maintenance manual from 1940. Almost all the letters and
numbers can be produced with this template.
Some, like " K "for instance, you'll have to figure out yourself.

In the diagram at left we are concerned with glueing a
crossmember to the floor of a large " box ". How is it to
be clamped down for the glue to have a good contact
with both parts? In fig.2 the crossmember A is in place
and we see another crosspiece B at the top crossing .under the sidebars at the top of the sides. This is a piece
of scrap material. The piece C is the clamping bar. It is
a thin piece of scrap cut a little longer than the distance
from A to B. When bent into place it applies pressure
to the crossmember A. The more pressure desired, the
heavier or longer piece C is made. Fig. 3 is a side view
of the whole thing.

In fig. 4 there is no sidebar as a part of the box so a C
clamp holds a piece of wood for the B piece to sit against.

Another way would be to run C all the way up to the
ceiling if necessary.

Whatever is at hand to do the job.

FIG. 1

FIG. 2

FIG. 3

How do you measure from one side of a "box" to the other? Or the inside of a cabinet for shelves? Anywhere you need an accurate inside measurement. A tape measure my come close but is hardly accurate.
The answer is at left. This technique was used by our ancestors to build entire rooms full of counters and cabinets.
Two sticks, each longer than 1/2 the distance to be measured are held together and the ends run out to contact the sides of the box. A line "A" is drawn across both sticks. They are removed and placed on the material to be cut with the lines again matched. Now you can mark the the end to be cut off knowing that your material will fit exactly between the sides.

The second set of marks "B" have been added simply to showthat you can use the same two sticks to measure a number of dimensions, then cut out a number of different pieces for other locations. for instance a piece to fit across the bottom of the box where the two square blocks are.

Pencil line "A"

Pencil line "B"

Stick #1

Stick #2

Below are two tables concerning the strength of wood suitable for aircraft use. Spruce ( Old growth Sitka ) is now in short supply and is very expensive.
Most of the woods in this table have characteristics comparable to spruce. Some will have to be dimensioned differently due to their weight relative to spruce. For instance, Douglas fir is considerably stronger but also much heavier. This means that to replace a 1" X 1" spruce longeron will require using a smaller piece of fir. Possibly 1" X 3/4" or 7/8" X 7/8". You'll notice that Yellow Cedar( Alaska Cedar) is the same weight as spruce but much stronger. You could make pieces a little smaller to conserve weight but it would be easier to leave the dimensions alone and accept the increased strength as a plus.
Western Hemlock is very close to Sitka spruce in all catagories so you would not change any dimensions.

The second table grades various woods in simplified form. Use them together to determine what is suitable for your own situation of cost and availability.