phill,I am not an engineer but have some real life experience with this idea. (construction & structural steel) Typically a small hole in the centerline of the web is not an issue. The futher the hole needs to be up or down from center determines if it would need reinforcement. Also the distance from the end of the span is a factor. I think that I have a picture somewere out there of what you describe. I have a 3/8" fuel line run through the main spar on centerline and very near the point that the spar is supported at the fuselage side. I also have (2) 1/4" extension tubes for fuel shut off's through the spar so that the fuel shut off's are right between my legs on the front side of the spar. But i stopped there with holes and ran wiring around or over the spar I am sure there is math that can be done to show the maximum size that could be put through and the reinforcing would most likely be an additional layer on each face fully bonded. The holes must be neat and without tearout or splintering of the web material. Edges need to be sealed. Personally I concider a 3/8" hole in the center line to be minor. A hole for something the size of a torque tube i think is major. The box spars as shown for a KR2S (fully enclosed) are incredably strong.Hope this helps,Joe Horton . ---------- Forwarded Message ---------- From: phill.h...@gmail.com To: KR List <kr...@mylist.net> Subject: KR> Drilling through the spar List-Post: krnet@list.krnet.org Date: Thu, 09 Feb 2012 14:43:17 +0000
Recently I ran across a picture of a KR that had what looked like a 3/8" metal tube, like a fuel line, or similar, running through the main spar just inside the cabin, then farther inboard, a hole with a control rod running through it. This was the main spar, not the aft spar. It didn't look like the shear web was reinforced in anyway. I was just wondering if that's a good idea or not. If the area was reinforced, I could go along with it but it looked like they just drilled through. I went back trying to find this picture so I could provide you all with a link but I couldn't find it again, now I feel stupid. But in theory, you shouldn't pass anything through the spars unless it's properly reinforced, right? If someone did go through the spar, what would the reinforcement look like, a doubling of the sheer web, application of some CF or BID to the area, what? I wish I could find that picture again. Phill _______________________________________ Search the KRnet Archives at http://mylist.net/private/krnet/ to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html ____________________________________________________________ 60-Year-Old Mom Looks 27 Mom Reveals Free Wrinkle Trick That Has Angered Doctors! http://thirdpartyoffers.juno.com/TGL3141/4f33ec79324f7f9ab0cst04duc
