Tinkering with the floor stiffners - 1 hour

Very short build session in the garage tonight. I fiddled with the fit of the 2 centre floor stiffeners. Tried to get that joggle bend sorted so the skin sits nicer.

I then drilled the remaining holes in the stiffener.

Next I need to drill the #30 holes in the vertical portions of the stiffeners, but the area is too tight for my cheap 90deg drill kit. I will see if I can borrow my buddy Mike's 90deg pneumatic drill to finish this portion.

More work on the F-796B angles - 9 hours

Big long day in the garage. I'm motivated to get these F-796B angles done. They are not easy to knock off. Long story short I believe I made about 6 or 7 angles total in the end. And only 2 are needed. That goes to tell you that these are a bit tricky to get perfect.

I'll try my best to explain the pitfalls so you only need to make two.

When cutting the angles initially...Be sure to start trimming the 45deg cuts before you do final trimming and shape the ends to fit the inside radius of the longerons/stiffners. This is due to the fact that the longerons/stiffners have a twist in them and they need to be a tad longer once they sit back inside of the longerons. I cut 2 angle just a tad too short because of this.


No question that edge distance is horrible in this area. And ultimately you will not make proper edge distance on those 3/16" holes...as everyone talks about (and Van's tech support confirms) in this particular case, its ok. I drilled one angle with the F-902 bulkhead in place, but the holes do not end up in the right location as per plans I have smaller edge distances than I would prefer. New parts....Again.

I tried my very best to maximize edge distance wherever I could. I want to follow dimensions on the plans as much as possible. So to drill the first hole, I now removed the F-902 bulkhead. Using the lines drawn on the back of the angle I was able to located the first #30 pilot hole.

Then I was able to align the angle and drill the second #30 pilot hole. Perfect! But when I reinstalled the F-902 bulkhead and then went to install the F-796 angle...The fit is really tight and the web of F-907 interferes with the angle.

A bit of head scratching here. But I figure it is best to remove the portion of the angle that interferes with the web of the bulkhead. I still can maintain decent edge distance around the 3/16" holes. So I went to work with the file to take down some of the interference.

In the end, this is all I needed to do to get a really nice fit.

To complete the #40 holes in the F-796 shims, I simply followed the instructions and used the center line drawn on the shims. I used keeper rivets to help keep it all aligned while fitting and drilling. I find they are more accurate than cleco's


Once the shims were in place....I was then ready to install the Angle and complete the remaining #40 holes.

The final fit is excellent

Working on the F-796 parts - 2 hours

Not a big build day. Very unmotivated today to spend all day in the garage. I did manage to cut the F-796B angles to fit inside the longeron/stiffeners.


I didn't reference Van's dimensions on the plans...I just cut them according to the fit. Also, I did my homework last night on the F-796C&D shims and it appears that everyone seems to have issues with the fit. So I decided to shape them to the curve in the bulkhead rather than cut them down. A little time on the sanding station and they fit well. An important note...its only the top half of the shim that begins to interfere with the bulkhead....so trim the spacers according to the fit, and not the entire length of the shim.
Unfortunately I didn't take a picture of the finished product, but you get the idea.  

Worked on the F-772 bottom skin and F-796C&D spacers - 4 hours

I started the days build session by cleaning up the F-772 bottom skin. I feared that I was scratching the aluminum too much by taking the bottom skin on/off all the time. I broke all of the edges with a file, and then used a 3M wheel to smooth them out.



Next I used the edge forming tool and rolled the edge on the aft potion of the skin.


Next step that I wanted to do was to locate the hole on the upper tabs of the F-902 bulkhead to the longeron. They is virtually no room to work with here so before I did anything I marked minimum edge distance on the longeron.

On the tabs. I installed them temporarily, marked where the tab overhangs the longeron. and then started to mark minimum edge distance on all 4 sides.


I then drilled the #30 hole and confirmed proper edge distance. Next I Installed the bulkheads in the fuse and very carefully marked a pilot hole in the longeron with my 90deg drill set. I have just enough edge distance to work with. My drill set is too bulky to drill these holes, I will just need to finish drilling these when I take the longerons off to countersink them.
 
Next I turned my attention to the F-796C&D spacers. I had cut these out some time ago, but now I need to drill the top 3/32" hole. So I got creative.

Now when fitting the shims to the bulkhead, you will notice that you will need to make some adjustments.

Reading Mike Bullocks RV-7 build log, he notes that he had to trim about 1/16" off the bottom shim, and 1/32" off the top shim.. I'm going to do a bit more research on this.

Installed the F-902 bulkheads (Round 3) - 3 hours

I'm tired of talking about how I installed the F-902 bulkheads. I've done it twice already, Always messing up the holes to the F-7101 gear attachment web. (It is a bit tricky to get the fit right).

I'll be brief. I did everything as I did before, Ensured the F-7101 web was tight against the longeron. I used 0.040" scrap to simulate the bottom skin (yes it matters). I used a few clamps on the assemble to hole it all tight. After drilling, I installed the floor skin to double check all of the alignment. The result is excellent. Finally a F-902 bulkhead with correct holes drilled to the gear web. Sheesh!




I then removed the floor skin so that I can work on the lower tabs (upper in the picture.....remember the fuse is upside down). I marked the edge of the longeron on the tab (in red) and then I marked out lines offset from the edges by about 0.245". This gave me an idea of where I want to place the #30 hole.

I then re assembled and then transferred the hole to the lower longeron.
The fit is really good.

Began drilling the F-772B floor stiffeners - 2 hours

A while ago, I had already cut and notched the center two stiffeners for the correct fit. Now it's time to install and drill the F-772B floor stiffeners. Before drilling, I test fit the F-782C center cabin cover since the holes do not appear that the sit at the center of the angle. In the end this is not a concern as the cover nests inside the angle very well.

 I began drilling a pilot hole at the center of the stiffener and worked outwards. I began to notice an inward bow as I cleco'd.


I also checked the bow in the side skin where the F-719 stiffeners are.

Yup, there is no doubt that the joggle (z-bend) in these angle parts result in the fit from needing a bit of attention. I do recall a time when I was talking with Vans tech support and they had recommended a small shim in these areas. I am going to ask the question to the build group on-line and see what others have done to smooth these out.

I have posed the question on-line but have not got a whole lot of responses. A couple of people say that it will be fine once riveted, and one suggested cutting the joggle off and riveting on an offset extension with shims. Nobody mentioned shims as Van's indicated. I don't know what I am going to do with this just yet

More F-719 work (Round 2) - 4 hours

I had ordered another F-719-L stiffener from Van's and went to work re-drilling and fitting the whole piece. I am now becoming a master a doing these...This is my third left stiffener.

Long story short. It came out perfect. Holes for the side skins and rudder pedals all drilled and are excellent.

I'm still concerned with a bit of an inward bow where the joggle is.