Friday I felt like I needed to do something that could be construed as actual work toward creating the plane. To preface this I will try to explain my parts fabrication ideas. Sorry about the long-windedness.
I have seen here and other places that while builders are making parts they have damaged them in some way or have had to remake the part for some reason. In thinking about this I decided that I need some way to be able to remake the part without having to spend any more time than necessary.
I started thinking about the steps needed to create each part and it seems to me that there are three major steps in creating these parts.
First it will have to be drawn on the material in order to be rough cut to shape. This, I think, should include any locations where holes will be needed for tooling purposes, a bending relief radius or any other reason a holes would be required. Next it would have to be cut to its final size as a blank ready for bending or whatever other work will be required. I have seen where a router with a flush trim bit can be used to shape thin sheet aluminum to make creating the blanks easier and in less time that doing it with hand held metal shears. Then lastly will come the bending of the flanges or, there again, whatever is required to finalize the part.
In order to accomplish these steps, and hopefully make it easier to remake a part if necessary, I am going to make not only a forming block, as the plans suggest, but what I call a tracing block and a routing block for the parts. This will hopefully also allow me to more quickly make multiple copies of parts that require more than one of each.
The attached photos show the tracing blocks I made this past weekend for some of the parts for the 650’s rudder. If you look close you can see small holes (7/64”) drilled in the blocks that will be used with a center punch to locate the holes needed for the tooling blocks (routing and forming) along with holes to be drilled for the corner relief holes called out in the plans.
The way I arrived at these tracing blocks was to draw (in AutoCAD) the forming block shown in the plans. Then from that develop the shape of the blank prior to it being formed. This shape will become my routing block made out of ¾” MDF. From this routing block shape I offset the perimeter by 3mm larger and simplified the shape. That became my tracing block. I then plotted them full size on paper and used spray adhesive to glue them to the 1/8” hardboard. Now I can use them to make it easy to trace, center punch hole locations and cut out each part from the aluminum sheet stock where they will be ready to be routed to size.