What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

HS-702 Flange

Rockologist

I'm New Here
Happy Easter everyone. Like many my first post here is a call for help. I just finished the HS-702 relief holes and was pleased with how they turned out, BUT I forgot to flatten the flanges you cut back leaving a slight rise in the surface of the HS-702 tab next to the relief holes. I cut the flange down so far I am no longer left with anything to bite onto to bend them flat. I used my die grinder to grind one down flat and the HS-00001 Does indeed lay flat now, but I fear I have thinned the metal flatter than probably desired. Possible maybe to just trim the tabs back past the flange? Should I order new 702s and try again?
thanks!

2wu9wTm.jpg

You can see the rise of the leftover flange on the right of the relief notch.

P12QAls.jpg

702-profile

VZ7TyIL.jpg

Doubler wont lie flat

WnIfGiE.jpg

So I ground down the protruding flange.

8X0RrU8.jpg

Doubler now lies flat, but did I make the 702 too thin in the process?
 
Last edited:
Rivet gun

That is pretty thin. Question for Vans.
If you replace it...
The pilot hole for the relief notch is drilled right in the vertex of flange/web. I used a 45° wedge to drill in the bend. The final 1/4 hole takes 1/8 off the web and flange.
Lay the part down on the back rivet plate and use the flush set and gun to massage it flat. Seems like the manual says something similar. Dial down the pressure to maybe 10 psi to start. You can use a piece of scrap to practice.
 
Last edited:
That is pretty thin. Question for Vans.
If you replace it...
The pilot hole for the relief notch is drilled right in the vertex of flange/web.
.

I have to disagree with Larry on this one. My plans show the center of that relief hole squarely on the web of the HS-702 spar, not in the vertex of the flange bend. I remember debating this for a long time if that made sense. Even after I drilled the hole, I was concerned I messed it up and showed Vans a picture and their reply was "notch looks great!". For the record, it looked just like what you've got now. I too had a small burr that I did my best to pound flat. In the end, that part is sandwiched between the doubler plate and the upper and lower angles. I think you're OK even if you polished the burr away. Some other builders took the same approach if you look around.

Its never a bad idea to call Vans, but I say good to go.
 
I too think it looks good. Just be sure the inside of that relief is shiny for fatigue resistance. Vans did a good bit of FEA on that section for the SB, so their opinion on the hole location is golden.
 
Relief notch

I have to disagree with Larry on this one. My plans show the center of that relief hole squarely on the web of the HS-702 spar, not in the vertex of the flange bend. I remember debating this for a long time if that made sense. Even after I drilled the hole, I was concerned I messed it up and showed Vans a picture and their reply was "notch looks great!". For the record, it looked just like what you've got now. I too had a small burr that I did my best to pound flat. In the end, that part is sandwiched between the doubler plate and the upper and lower angles. I think you're OK even if you polished the burr away. Some other builders took the same approach if you look around.

Its never a bad idea to call Vans, but I say good to go.

You are correct Kenny.
The center of the hole is 1/32" from the flange. The reason for my suggestion is any bit larger than 1/16" is going to hit the flange as it cuts and possibly walk making the notch more than the 5/32" called out in the detail. Just me being OCD!
 
Last edited:
Thanks for the response guys! I got the rest flattened out using the flush set and ground back a bit the "thin" i made and still have ample edge distance so I feel I am good.

For the notches I used a round file to file down 5/16", my sharpie lines in the OP, from the edge which the plans called out

dhBHPP2.jpg
 
Congratulations

Congratulations. Now I feel bad. My old plans show it totally different. I was giving bad advise. Don't listen to me.:eek:
 
Congratulations. Now I feel bad. My old plans show it totally different. I was giving bad advise. Don't listen to me.:eek:

I never saw the old plans, but I figured they changed the guidance when they released the service bulletin. When I was researching build logs (pre Service bulletin), I noticed the notch was much shallower and there was more shaping/blending. Basically it looked VERY different from what I was interpreting the directions to be and I wasn't sure if it was because I was mis-reading the plans or if Vans has in fact modified the instructions. Turns out it was the latter!
 
Hi Rockologist,

I've just started my RV-7 empennage as well and I'm at the same point that you are.

I'm curious as to how you trimmed the angle shown in section F-F, given that the hole that needs edge clearance isn't there until later when the skin is match drilled.

-Ted
 
Hi Rockologist,

I'm curious as to how you trimmed the angle shown in section F-F, given that the hole that needs edge clearance isn't there until later when the skin is match drilled.

-Ted

You didn't ask me, but I'll tell you anyway. I left those angles untrimmed until I match drilled the skin to the spar. You just have to deal with a little binding/interference with the root rib until you trim it off.
 
You didn't ask me, but I'll tell you anyway. I left those angles untrimmed until I match drilled the skin to the spar. You just have to deal with a little binding/interference with the root rib until you trim it off.
Thanks for answering even though I didn't ask you :).

I was thinking of marking the hole position with the skin on, removing the skin, then trimming the angle. Your solution sounds more efficient assuming I can get the HS-00005 rib in place with the interference.
 
By the time you have the skin on the structure to mark the hole, your probably match drilling anyway. The fit is snug but i didn't have any problem with it.
 
You didn't ask me, but I'll tell you anyway. I left those angles untrimmed until I match drilled the skin to the spar. You just have to deal with a little binding/interference with the root rib until you trim it off.

Already got your answer but i just trimmed the angle very conservatively and plan on coming back and trimming it to the proper angle once I have match drilled the hole. I hope what I considered to be conservative turns out to be once I start drilling!
 
Last edited:
Drill-bit walked on aft flange of HS-00006

Since we're on the topic of HS-702, may I hijack your thread with a related question?

When drilling the aft flange of HS-00006, my bit walked and moved the hole closer to the web.

WC51YOAl.jpg


Is this going to be a problem? It won't cause an issue with edge clearance but it will move the rivet pretty close to the bend of the flange.

Thanks
-Ted
 
Hole

I don't think it's a problem but I've been wrong on this thread before so take it for what it's worth.:D
 
I don't think it's a problem but I've been wrong on this thread before so take it for what it's worth.:D
Nice one!

As long as you can either form the shop head or get the manufactured head to sit flat, its probably fine. Might even be able to grind a little flat spot on the manufactured head if you choose to put it on the fwd side of that assembly. That's a very UNofficial suggestion.
 
Last edited:
Nice one!

As long as you can either form the shop head or get the manufactured head to sit flat, its probably fine. Might even be able to grind a little flat spot on the manufactured head if you choose to put it on the fwd side of that assembly. That's a very UNofficial suggestion.
Thanks Larry and Kenny,

There's plenty of room for a shop head, so I won't worry about it.
 
Me too kind of

Hello and thanks for all the great info. I am just starting the empennage and have come upon the dilemma with the relief notches on HS-702. After reading your thread, it appears I have plans that show the new notch and my instructions that describe the old method of drilling into the bend radius of the flange. I have looked at the drawing and read the instructions so many times I'm cross-eyed. I will call Vans and make sure I'm not being stupid but sounds like I should follow the dwg and not the instructions.

Thanks again,

Eric
 
I have looked at the drawing and read the instructions so many times I'm cross-eyed. I will call Vans and make sure I'm not being stupid but sounds like I should follow the dwg and not the instructions.

Eric

I believe Vans updated the drawings but not the instructions. I just went back and re-read them and sure enough they say to center that hole in the center of the bend radius which is how it was done prior to the service bulletin.
 
Back
Top