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January 20, 2006:
(1.0 hrs.) The first thing that needs to be done on the
longerons is to measure and cut them to length. Make sure you
measure twice and cut once! It would be an expensive proposition
to have Vans send out a new set of longerons given they are over a 187"
long. Once the are cut to length, the aft
ends needs to be trimmed. I used the aft top section of skin as a
template for where the cuts need to be made.
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Here are the finished aft longeron cuts.
I made these with a combination of hacksaw, file, and die grinder with a
2" ScotchBrite wheel. |
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January 21, 2006:
(2.0 hrs.) A shallow curve needs to be made in the forward
portion of the longerons. Bending a curve into aluminum angle is
not something I was looking forward to. However, I proceeded as
per the plans.
After marking the starting and ending points for the curve, I clamped
the first longeron in a bench top vise using hardwood to protect the
longeron from the vise jaws. The longeron gets positioned about 1
" aft of the forward curve starting point. |
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Next I made a series of lines 1" apart
between the start and ending point of the curve. I will use these
to help me position the longeron in the vise for each bend.
The idea is that I will position the mark right on the outside of the
vise jaws, pull down on the forward end of the longeron while hitting
the bend mark with a 1.5 lb soft mallet (the kind filled with sand).
The longeron is then repositioned in the vise at the next bend mark and
the same procedure follows. This is done until I reach the
position marking the end of the curve. |
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Here is another shot of the longeron in
the vise. You can already see the curve forming by the fact the
right end of the longeron is dipping. I think I took this picture
after I made the first couple of hits on my bend marks.
The angle was pretty easy to bend using this method. It does
tend to bend out of plane, but that is easily fixed by flipping the
angle 90 degrees and bending it. |
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I cut out the paper template for the curve
and taped it to a piece of plywood. I then used this to check the
accuracy of my bends. The paper template is flipped over for
checking the opposite longeron. I found that it was easiest to
slightly over bend the curve and then slowly take the bend out until it
matched the template.
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January 27, 2006:
(2.0 hrs.) The F-721B canopy deck left and right pieces
require a simple modification for the slider canopy. A portion of
the rear tab needs to be removed and a slot needs to created.
Here is a picture of the F-721 marked for trimming. I used my
band-saw to make the initial cuts and then finished it off with a
cut-off wheel in a die grinder. |
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Here the F-721B is clamped in place on a
longeron. It needs to overhang the longeron side by 1/32", so I
clamped a piece of 1/32" aluminum sheet to the longeron to give me an
edge to match the F-721B up to.
Once it was clamped in place I match drilled it to the longeron with
a #40 bit. |
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Next I made the downward bend in the
forward end of the longerons. Again, I used my vise and a soft
mallet.
Here you can see my SmartTool digital protractor giving me the
precise angle reading. |
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Next I moved on to some assembly of the
aft section. First I used the step drill to make the hole for the
aft tie-down eye bolt in the tail cone. Once that was done, I
cleco'd the F-712 and F-711 bulkheads into the tail cone. The tail
cone skin is thick, and so not very flexible. It makes assembly go
a bit easier if you bend the flanges of the bulkheads to match angle of
the tail cone. |
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Once the tail cone is assembled, the rest
of the aft section is easy to put together. Here you can see the
aft bottom skin and side skins cleco'd to the bulkheads. |
