Countersink Problem

So here is something that you might be interested in. I am required to countersink the inside edge of the bottom flange of the F704 forward bulkhead. This is a problem because the forward edge is pretty narrow where the countersink cage will not fit.

Here is a shot of the area where i need this done. Fuzzy picture but i need the last 5 holes done.



And here is  shot of the huge countersink cage. It will never fit as the holes are to close to the perpendicular edge. The countersink cage normally gets chucked up in a drill. There is no room for this either.



I didn't think this could be done by hand but lets give it a shot. I removed the guts and had nothing left but the center shaft. Took some doing, but eventually I got the result I was looking for.





Rivet test fit



Hour or so later, 10 holes complete.

Question For VANs

Sorry for waiting so long to post the answer to the question to VANs. Much like the rest of the questions I have asked. Don't over think the design. Just build according to the instructions. They said it is just fine. It is how all of them look.

For the last week or so I have been doing nothing but deburring, dimpling and scuffing. I find this very boring and tedious. I don't think anyone would be entertained by this so I didn't take any pictures. I will post a pic of a pile of completed parts once I am ready to prime. Until then, I'll be sitting here rubbing and sanding.

Center Section Forward Assembly Prep

Today was a long day. I spent most of the day in the shop working on the center section. I have match drilled all of the frame. Most of the time was spent cleaning up items I have been putting off until I understood them better.

I finished the fabrication of the F-704 Main Bulkhead spacer blocks. These are wooden Blocks which are exactly 1 7/16 inch which is the same size as the wing spar. I have to thank my friend Ernie from Lakeland EAA Chapter 454 for making the block of wood to exacting specs. I cut the block down to size and drilled the 4 holes for the spar bolts. Perfect fit. Thanks Ernie.



With the block in place I can now install the front half of the F-704 spar.





Also the spacer bushings and AN3 bolts are installed.



With everything in place, final drilling of the spar is completed. This includes countersinking 4 locations in the bottom skin called out in the plans.



And finally the F-704H side panels are installed and drilled.



Now to spend the next two weeks deburring and dimpling. Oh Joy . . .

Another Question to VANS support

So this morning after I had finished the cutouts for the step kit, I have some heartburn about what I have done.  The cut is an arch in both sides of the F-623 Corner Ribs on both sides of the baggage compartment floor. The plans call out a cut which covers the entire height of the side wall. After doing this, I realize that this cut takes away 100% of the rigidity of the part lengthwise. Questioning this I sent an email to VAN's tech support to confirm that this is what they intended.

Here are the plans calling out the cut.



 And here is the cut I made.



We will see what they come back with. Might be buying a new part.

Center Section

Now assembling the Center section. This is where the pilot and passenger seats are located. I have attached the seat ribs to the F-704 and F-705 bulkheads.



Next the baggage ribs are attached.





Then the structure is turned upside down and the bottom skin is attached.



In order to attach the pilot and passenger steps, a hole must be drilled in the F-726 baggage rib. I used a hole saw mounted in the drill press to get the exact location.






The corner ribs required to be modified as they were originally designed for the RV-6. Both ends needed to be trimmed. Then all holes were match drilled using the skin as a guide.



This section is cut away in order make room for the steps which will be installed much later.

Starting the Seat Ribs

Today I am on to the seat ribs. First task is to cut out 4 spacers. Used a hack saw and filed to final size.



Next the center two seat ribs must be cut to make room for the control stick linkage.

So I draw the shape I will remove and use a cutoff wheel to make quick work of it.



The cut out the notch so that the controls can be installed. Repeat the same thing again in mirror image and these parts are complete.

Aft Fuse Finished

BLAM!! Aft Fuse is primed and riveted.