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Auxiliary Longerons

July 22, 2013

This weekend I spent on what I thought was going to be fairly straight forward and relatively easy tasks.  In fact it turned out to be one of those days where you don’t see much progress, but you sure did a lot of work.

100_1478 100_1479The six cross members that you see here are the auxiliary longerons.  Each one has its own idiosyncrasies to overcome.  I decided, for this post, to show you how fabricating a part takes.  In the top picture you’ll see a triangular piece that is in the upper right corner.  This is a gusset and you get to make two of them.  It starts out with the aluminum stock that Vans provides you with the part.

Notice all the dimensions in  the drawing to the left?

Notice all the dimensions in the drawing to the left?

So the drawing now tells you everything you need to know about this part.  There are holes to drill, shaped areas that need to be removed and two bend lines.  Woot!  The tri-fecta.  Out come the rulers and straight edges and 1/4″ drill bits.  You transfer what you are seeing on the diagram to the part in the form of blue Sharpie lines.

Hope I got them all.

Hope I got them all.

Now I know what I am doing, its off to the saw to start trimming this out.  I used a #40 drill bit to mark the holes.  These will eventually get final drilled to #30 once I have it in place on the plane.

Roughed in.

Roughed in.

From here I have to clean it up, get it de-burred and then the seemingly endless cycle of fitting.  Fitting means, put it in place see whats wrong, go nibble some more metal away or bend it a tiny bit more.  Bending is really tricky.  You only want to bend this stuff one direction.  Because of that you have to sneak up on the final bend.  You dont want to go over if you can avoid it.  Now that its right, here’s what it looks like in place.

100_1475Now it isn’t completely finished, of course.  It still needs lots clean up and priming, but the part is ready.

So that was two days of good work.




From → Build Log, Fuselage

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