Dimensions for cut on front spar flanges

Hi, folks, just starting the emp kit and am facing my first head-scratcher. Vans' HS instructions appear to include the work required by SB 14-01-31, including drilling the relief holes into HS-702 and cutting an angle out of the corner of the front spar flanges. The drawings show the cut, with a note to maintain edge distance to a hole, but the referred-to hole is not pre-punched on new kits, so I'm not sure what else I can use to guide my cut.





I thought I'd be clever and check SB 14-01-31, and lo and behold the dimensions of the cut are not specified there either, just the same note to maintain the right distance from that hole.

I assume this hole may be drilled at some point later in the HS fabrication, at which point I have the right reference for this cut. Should I just wait until then to make this cut?

I am trying to remember that part - sorry, but I cant remember! I will be heading to the hangar tomorrow afternoon and I will look and see if I can get a picture or at least look at it. Somebody should chime in sooner with the answer! Good luck. Have fun with your build.

Edit - I just looked and realized you are talking about the SB. I checked mine and found no problems. I should be able to get a picture tomorrow. Mine is the 9, so not exactly the same but still an area of concern.

Holes

If I remember correctly, I waited till the hole positions were marked then made the relief cut.
Watch edge distance on that relief notch. Some drill that hole from the web when it really should be started right at the vertex of the web and flange so the final 1/4" hole is only about 1/8" into the web.

Thanks--I think I will just wait until I get the holes marked, and continue on for now. It's not getting in the way of anything just yet.

I am in roughly the same exact spot as you on the tail kit, maybe a little bit ahead of you.

I ended up just cutting a very very short relief on that flange to give some clearance. Then I left it until I had the HS-00006 and HS-00005 pieces fit together with the skin clecoed to the skeleton of the horizontal stabilizers. There is a point where they have you mark the locations with sharpie. What I did was actually mark the locations along the first 12 inches or so of the front spar flange to the skin with a sharpie. There are a few holes in the front spar flange that are not drilled. I marked my centerline on the spar, and then marked the holes using the skin once I had it all clecoed together.

Then, there is a step later on where you have to dissassemble the stabilizer to prepare it for priming/deburring/etc. Thats when I used my the sharpie mark I transfered earlier to measure the edge distance for that relief cut.

Then I just marked the proper edge distance around where the hole should be, and drew a line up up to towards the centerline (where the left and right front spars meet). Just be sure you don't trim the flange all the way, you need to stop your cut with about half the flange remaining, which should put you right near that bend line. Cut it leaving yourself some extra room just in case. You can always trim away the excess little at a time, but once its gone, theres no getting it back

Heres the photos of my build, feel free to dig in and find something that might help:

https://goo.gl/photos/fhxxvuRSBfKsqeSe9

EDIT: I haven't riveted my stabs together yet, and all my parts are disassembled ready to be dimpled, so if you need me to I can take some better photos of that front spar relief section and do some measuring for reference. Just let me know.

Lynn, wow, you take a lot of pictures, I'll be visiting that site often for reference I think. All I have at the moment is here: Empennage pictures You're a lot farther along than me, since I just started yesterday

Yeah, I figure might as well snap as many as I can while I am working on it, so I can have a good reference later on down the road if I need it.

I picked up a cheap Cannon Elph camera that has Wi-fi, so I keep the camera in the basement with my tools and build, then just upload the photos using the wifi connection after each build session.

Right now, I have been sticking them in that album I linked you to. It does a pretty good job, and I will keep sticking more photos in there as I progress.

But, I also have a "build thread" started on the forums here: http://www.vansairforce.com/community/showthread.php?t=143331

And I am playing around with writing some WordPress plugins on my site: www.theskunkwerx.com The website isn't in its final version yet, and I have been tinkering around with Wordpress templates and such, but I do keep that VAF thread updated with my hours and progress, and always link to a relevant album for the photos.

I'll go down to the basement tomorrow morning and take some photos of my front spars for you. I'll also measure that distance to give you an idea of what my "final" cut was for that relief. I wouldn't let that relief cut hold you up on progress though. Just make a note in your plans to re-visit it before you do final assembly and then you can double check.

Centerline

You will find parts like this throughout the build. Make it a habit to draw centerlines on flanges before first assembly. When a part might be close, draw an edge distance line. Look for the line. It will save you potentially drilling a hole with an edge distance problem.

Keep building and eventually you will be fitting the skin. Once you fit the skin you will line up the center line Larry talks about in the last post with the row of holes on the skin and match drill them. Once you match drill you will be able to make a determination where that cut goes.

See this post from my build thread http://www.vansairforce.com/community/showpost.php?p=919815&postcount=14

In the sixth photo down you will see where the flange of the inboard rib will interfere with the spar flange if it is not trimmed enough. I would just cleco the spar to the skin using the available holes and mark the hole position before trimming. If I recall there is quite a bit of margin available, a luxury you cannot count on moving forward

wirejock said:

You will find parts like this throughout the build. Make it a habit to draw centerlines on flanges before first assembly. When a part might be close, draw an edge distance line. Look for the line. It will save you potentially drilling a hole with an edge distance problem.

Click to expand...

Buy a C-Thru ruler like this and it makes drawing those center-lines a snap.



6 inch one shown, the 18 inch one is also vey useful.

You can also measure and scale dimensions for feature locations from the drawings. This has worked well for some feature locations in question and can be a valuable reference or at least a check and balance. Good Luck.

N329JR said:

You can also measure and scale dimensions for feature locations from the drawings.

Click to expand...

I ended up doing just that--measured the actual drawing and applied to the scale of the actual part.

I was going to cut off the spar flange for the SB 14-01-31 and decided to check the interference before making the cut.
I fail to see how the flange interfere. There is also good access to set the rivet.

The below picture shows how my modified HS-405. Trimming the spar flange seems completely unnecessary when using the HS-405 modification instead of the new HS-00005.

What am I missing ?