Spruce strips for Jurca Replica

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marianmadalin32

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People, can you look on that PDF file of mr. Jurca and tell me how many spruce strips do I need? Are all 25 mm wide? They are all 19 mm thickness? Many thanks.
 

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Shayde

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The material list is in the bottom left of your PDF; there are 25 x 19, 38 x 19, 19 x 19, and 12 x 19 strips required.
 

Shayde

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Dang that's a lot of wood.

It's a very woody plane. :D

Many thanks. But how many of each size do I need? 19 mm is the thickness? The rest is the width?

Again, it's all right there in the PDF. For instance, it says you require 180 feet of 25mm x 19mm spruce, 40 feet of 38mm x 19mm spruce, etc. Do the same for the next two lengths of spruce, and the four lengths of ash. As @ToddK says, it's a lot of wood.

Out of interest, where did you get this PDF from?
 

marianmadalin32

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It's a very woody plane. :D



Again, it's all right there in the PDF. For instance, it says you require 180 feet of 25mm x 19mm spruce, 40 feet of 38mm x 19mm spruce, etc. Do the same for the next two lengths of spruce, and the four lengths of ash. As @ToddK says, it's a lot of wood.

Out of interest, where did you get this PDF from?
From a friend. Why? And why do you mention ash? All of the strips are made of spruce.
 

Shayde

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And why do you mention ash? All of the strips are made of spruce.

Not according to the plans. It's mostly spruce with some ash, along with mahogany and birch ply. It's all there in the PDF's material list.

From a friend. Why?

Okay. I was curious if it was downloadable from somewhere, as I wanted to read the rest of the plans.
 

marianmadalin32

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No one answered my question. I need someone who already built a Gnatsum. How many spruce strips do I need ? How many strips of 12 mm wide ? How many of 19 mm wide ? How many of 25 ? And how many of 38 ??? Many thanks.
 

Tiger Tim

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No one answered my question. I need someone who already built a Gnatsum. How many spruce strips do I need ? How many strips of 12 mm wide ? How many of 19 mm wide ? How many of 25 ? And how many of 38 ??? Many thanks.
You will have to figure that out. The plans say how many total feet of each but unless there’s a cut list somewhere, or you can get a single 180 foot strip, it’s up to you how to cut them from available material to minimize waste.
 

cvairwerks

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Seems a little bit of a confusion, I see only 4 strips of 25 mm wide on top and 4 on bottom. So a total of 8 strips ???
That's only for one side, you have to build a mirror image for the other side, so 16 pieces, of varying lengths. The easiest way for you to figure it out, is make multiple copies of the prints and color in each piece of the various sizes and from there, build up a cut list.
 

Shayde

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...the foam is used to form fiberglass skins and then the foam is dissolved away. So no weight penalty.

I saw that in the plans - I thought it was quite clever, though the plans say it was a well-known technique. It does seem to be a quick way of creating a non-stressed skin for a plane.
 

Dana

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Can you explain the difficulty you’re having reading the plans? Is it a language issue, a file format issue, or something else?
Working from a pdf "from a friend", I suspect a pirate copy that may not be complete and.or up to date, and no support. Add the language barrier (he's from Romania) and not many homebuilders for local support. A Jurca is a big project, there's one at a local airport that's been stalled for a long time.
I saw that in the plans - I thought it was quite clever, though the plans say it was a well-known technique. It does seem to be a quick way of creating a non-stressed skin for a plane.
We used to make model airplane fuel tanks that way back in the 1970s.
 

marianmadalin32

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Working from a pdf "from a friend", I suspect a pirate copy that may not be complete and.or up to date, and no support. Add the language barrier (he's from Romania) and not many homebuilders for local support. A Jurca is a big project, there's one at a local airport that's been stalled for a long time.

We used to make model airplane fuel tanks that way back in the 1970s.
A local airport where? It' s location???
 

Jay Kempf

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Granted these plans aren't clear but they were probably state of the art in homebuilding when they were produced.

Material purchasing is something you have to figure out up front. You don't need to buy strips. You need to buy planks and cut strips from the planks. If you don't have the ability to cut strips and accurately size them for the material list in the plans you are going to have to go work on that capability before moving into the build. Building an airplane is not a close enough sort of thing. Rounding down the inch dimensions to MM is not a good way to start interpreting the plans.
 
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