RV-7 vs RV-8 forward spar relief notch?

[floridawing]

I have just started building the front stabilizer spar, HS702, for my RV8. It is from a new kit. I was reviewing information from some RV7 web sites. The builder said to cut a relief notch in the web prior to bending the 6 degree angle. The question I have is I do not see this talked about in my RV8 plans at all. Any information about this would help alot. Thanks!

[Lemmingman]

For clarity, you are referring to the horizontal stabilizer spar?

[N355DW]

If you are referring to the forward spar in the horizontal stabilizer, I just did this on my -7. I also remember reading in my plans that it was not necessary to do this in the -8 as the spars are designed for the -8, but in the -7 the a bit of the flange on each of the forward spars had to be removed to fit correctly.

[hendrik]

No need to cut off the flange, but the notch is also in the RV-8 plans. Have a look at the drawings (drawing 3, view A-A). Besides that, there is no way to make a clean bend without the notch.

[Jaypratt]

Wing?? or Emp H/S?

[floridawing]

Thankyou, I do see the relief notch on DWG-3, View A-A, but no guidence in section 6. Is there any guidence on how to make the relief notch in section 6 for the RV7? Thanks!

[floridawing]

HS702 relief notch, I see that the relief notch is in the plans DWG3 but not talked about in section 6. After looking at DWG 3 for the RV7 it does talk about how to make the relief notch. It seems that if you are bending the flange the relief notch is required. This would be a good thing to mention in section 6 for the RV8.

[David-aviator]

Originally Posted by floridawing

I have just started building the front stabilizer spar, HS702, for my RV8. It is from a new kit. I was reviewing information from some RV7 web sites. The builder said to cut a relief notch in the web prior to bending the 6 degree angle. The question I have is I do not see this talked about in my RV8 plans at all. Any information about this would help alot. Thanks!

I am a bit ahead of you with the RV-8 HS, riveted the forward and aft spars together yesterday and am attaching skins today. If there is a reference to a notch in the section six or on DG-3 of the RV-8 plan, I do not find it.

Six degrees is not much of a bend and in looking at the final riveted assembly, I do not see a need for a relief notch in HS-702, HS-810 or HS-814. It all goes together very smoothly. Maybe that's why it is not mentioned in the RV-8 plan.

[hendrik]

Originally Posted by David-aviator

I am a bit ahead of you with the RV-8 HS, riveted the forward and aft spars yesterday and am attaching skins today. If there is a reference to a notch in the section six or on DG-3 of the RV-8 plan, I can not find it.

So far, I do not see a need for a notch and maybe that's why the plan does not mention it.

Here it is:



And without it the flange-web transition interferes with the bend you need to make (blue line on my second spar):

[David-aviator]

[quote=hendrik;620164]Here it is:
And without it the flange-web transition interferes with the bend you need to make.

Well, the drawing does show a notch if one looks closely. But in looking at the completed structure, I see no need for it, the bend is so gentle and it is all riveted together forming one solid piece. There won't be any bending or flexing in the that area and the bend itself places no stress on the piece. It is actually slightly outside the flange joint.

Perhaps Vans needs to clarify the matter. There have been plenty of 8's built and it is interesting there is no mention of a notch in section six.

I can't believe one as to review a drawing in such detail (a magnifying glass would help) with no written reference to it. If the drawing had a note "this notch is important, do not omit it" I would appreciate its importance. But there is no such note. The drawing also appears to show 810 and 814 notched, I don't like that as it would weaken those parts.