Worked on the F-757-S gussets - 2.5 hours

Wanting to take a break from the Aft are of the fuse. I decided to work on the F-757-S gussets. The instructions have you work on this area before you start work on the top skins so its as good as time as any.

I started rounding the outer edge of the gusset to help fit the inside radius of the longeron. This then allows the 4-#30 holes to align and cleco. 

 

I then drilled the #40 holes already in the longerons into the gusset. Next I drew center lines from those holes and extended them back to the aft part of the gusset. I also drew a red minimum edge distance line to help me ensure that I drill things correctly.

I marked out the required dimensions for the F-757-T detail on the longerons and then compared those lines with those made on the gusset and confirmed that I wouldn't have edge distance issues.

Riveting on the F-706 Bulkhead - 2.5 hours

 One of the items on the to-do list was to finish riveting the F-727/F-726 baggage ribs to the F-706 bulkhead. I really was dreading these rivets thinking it was going to be a super huge pain. (After all riveting the seat ribs to F-705 certainly was).

 

Fortunately the riveting went extremely well. I used my super long rivet set on the gun, and used the angled portion of the bucking bar (on a built up rest) which ended up being the perfect setup for setting the rivets closest to the skin.

Just super pleased with how all of them turned out.

 

Riveting the Aft Deck/F-709 Bulkhead and drilling Shoulder Harness Anchors - 4.5 hours

 Spent the morning riveting the aft deck to the fuselage. Used a combination of bucking and squeezing. Took some time but I eventually got there.

 Now I am ready to fit and rivet the F-709 bulkhead to the aft deck. Bit of head scratching to figure out how to place the factory rivet head to the aft so it looks good. I ended up using my super long rivet set which does and excellent job of riveting.

Now I am ready to start the initial fitment of the F-775 rear top skin. This allows me to mark the appropriate holes on the F-709 bulkhead enough to give me an idea of where I need to flute.

 

Still on a bit of a roll. I moved on to the F-636 Shoulder Harness Anchors. After careful marking and placement I drilled the holes slightly undersized and then finished with the reamer. 

 

Fitting/Drilling the aft deck spacers and started the side canopy deck - 4 hours

 I am ready to fit and drill the aft deck spacers. I bought some 3M poster hanger tabs to help secure the spacers. I then slipped and celco'd the aft deck onto the fuse. This would allow me to draw circles in the holes of the aft deck and ensure everything looks good before I drill.

Once happy with the fit, and yes it took a little time to make sure the pieces were sitting proper, I finally committed to drilling. At this point I wanted to get working on the F-824B coverplate area before I got the aft deck on. much easier to at least dimple for the #6 screws now rather than later. 

I am now ready to debur and prime all of the aft deck parts.

 

While waiting for the primer to dry, I decided to move over the the F-721B side rails. I need to make a slot in the rail to accommodate the F-757-S gusset plate. First I marked out the lines for the slot, clamped an oak guide block and used the cutting wheel on the dremel to allow a rough cut.

After rough cuts where made, a little time was spent cleaning up the cuts with a file and then a buff with 3M on the dremel. 

After some primer dry time on the nut plates, I riveted the nutplates to the side skins.

And some closeups of the Aft deck spacers. As you can see the two holes on the longeron adjacent the F-711 spacer are awfully close to minimum edge distance which raised my eyebrows, but there is excellent edge distances on the F-711D angle mounted under it.

 

 

 

 

More Aft Deck work - 2.5 hours

 After the initial fitting of the aft deck, I still need to cut/fit the F-710C spacer and the F-711E down elevator stop/spacer. I took my time with the fitting and I am very pleased with how it all turned out. 

Next item was to cleco and match drill the F-709 bulkhead to the F-714 aft deck. Easier to do it now rather than later I suppose.

 

Drilling and riveting the F-695 Gussets - 6 hours

 I called Vans Technical Support in the morning when I got up. After reviewing the pictures and some discussion, the best scenario for what I had going on was to clamp the weldment a bit. While it is true that edge distances are not as critical for steel as they are for aluminum, we really want to increase the possible edge distance were we can. It was agreed that too much pre-load was not great, but the consensus is to split the difference as best I could. Excellent...I can do that.

So later in the day, I got to work! I did some edge prep on the gussets to get them to fit a little better against the firewall. Using AutoCAD I re-spaced the rivets to give me good edge distances all round, I then transferred those onto the actual gusset using a #40 drill.

I then clamped all the pieces down. Notice that I have a brace against the firewall. That is to help push a little on the firewall to get it perfectly straight. It has a very slight bow so before I drill the gusset to the firewall I want to make sure everything is straight.

 Once happy with the fit, I drilled into the longerons with #40. I then used these pilot holes and used by drill guide from ATS to finish the holes.

Using a reamer, I upsized the holes to #30. 

Edge distance is much improved on the left side. I confirmed 0.1875" which I am very happy with.

Feeling confident. I started riveting. (I decided I will rivet the holes along the firewall later. It was getting late).

 

 

Started fitting the F-695 Gussets - 6.5 hours

 Feeling confident dealing with all the anxiety of the Aft Deck fitting and drilling. I decided to tackle the F-695 gussets while the fuselage was all perfectly level. I had been tipped off that other builders had not paid much attention to edge distances on the steel weldment and it bit them. So I decided to get all the edge distances drawn out on the gussets.  This took a lot of time for such a small item, but its a critical item. 

My right side weldment is basically perfect fitment. 

However the left side is not perfect. This happens due to various reasons, welding is one of them as the heat generated by the weld can move pieces out of proper position. So how to make the left weldment work? Basically if I left things as-is I only have 0.16" edge distance if I follow Vans 7/16" dimension. I can get 0.240" clear if I move the holes out further to minimum edge distance on the longeron.

Now the tricky part. I can clamp the weldment...but by clamping it I notice I introduce a considerable amount of tension on the firewall and firewall angles. Im not sure that I sould be putting these parts under such pre-load. The gap does tighen...but I have to really squeeze that clamp tight. I will call Vans tech support in the morning and double check with them what to do.

Another item that many builders talk about is the fit of the gusset against the firewall. I will double check my rivet spacing and try to lessen this gap as best I can by removing a little bit of material from the gusset.

 Another item to factor in is the rivet spacing if using the dimensions on the plans vs. how that will actually hit the weldment. Using AutoCAD, I drew out the dimensions of the gusset and the rivet holes and printed it out. This paper template would easily let me do my checks. I can see that Van's stock rivet placement dimensions will cause a little grief if I am not careful. Looks like I will need to make some adjustments on the spacing.