Wing rib holes, very confused

This is my first post. I am building an RV-10 and I started the wings (left) about a week ago. I think I have read everything about the wing rib holes for conduits and pressure tubes and I am still confused. Can you use any 1/4" OD tubing? Clear flexible plastic or opaque stiff plastic or lastly aluminum? Can you use tubing purchased at Home Depot or Lowes? Do you always need hard plastic snap bushings or can you use rubber grommets? Now about the holes; I need 2 tubing holes since I am putting in an AOA system. Can I just add another 7/16 hole for another SB437-4 snap bushing, about 1 inch below and aft of the factory hole, as marked in the photo. For the conduit, can I just enlarge the hole shown in the photo to 3/4" to allow for the ribbed conduit even though it will infringe on the stamped stiffener? There is so much written, but so many photos are no longer available through their links. here are my 2 photos.

saabman910 said:

This is my first post. I am building an RV-10 and I started the wings (left) about a week ago. I think I have read everything about the wing rib holes for conduits and pressure tubes and I am still confused. Can you use any 1/4" OD tubing? Clear flexible plastic or opaque stiff plastic or lastly aluminum? Can you use tubing purchased at Home Depot or Lowes? Do you always need hard plastic snap bushings or can you use rubber grommets? Now about the holes; I need 2 tubing holes since I am putting in an AOA system. Can I just add another 7/16 hole for another SB437-4 snap bushing, about 1 inch below and aft of the factory hole, as marked in the photo. For the conduit, can I just enlarge the hole shown in the photo to 3/4" to allow for the ribbed conduit even though it will infringe on the stamped stiffener? There is so much written, but so many photos are no longer available through their links. here are my 2 photos.

Click to expand...

I can't seem to get dropbox to let me post your images but here is the link to them: https://db.tt/bx0O0EjMqi
Now, on to your questions. The tubing you use depends on your system. Van's supplies aluminum but I'm using the SafeAir system, which is plastic. Because these are experimental aircraft, you can use anything you want - the burden is on you to make sure it is suitable - but I'd stick with the proven stuff, given a choice.

Use the snap bushings unless the opening is accessible or you have a need for the cushioning of the grommet. Rubber grommets will deteriorate much faster than plastic snap bushings, and it's a pain to replace them inside a finished wing.

I need to locate photos so I'll make another post about hole location.

Ok, here's a photo of one of my wings:
Notice I have three conduits. The forward one is trim and wingtip lighting. The middle one is strobe from central power supply. And the aft one, to stay clear of all the power wiring, is for my Garmin magnetometer. In each case, I was able to make the holes for the conduit without infringing on the raised stamping. Ignore the tooling hole and use a drill press to put the hole where you need it. No bushing is required for the conduit, so make the hole the minimum diameter of the conduit and it wont move once installed. This should also answer your question about drilling additional holes for the AOA. Van's does not endorse making additional holes but the reality of installing systems requires us to make careful deviations from Van's recommendation. Keep hole sizes and numbers to a minimum and avoid disturbing the stamping meant to stiffen the part. Others have fabricated stand-off clamp pad and run their conduit through the existing lightening holes, where possible without interfering with the control systems. I hope this helps.

just an observation

Quarter-inch nylon tubing (McMaster-Carr) for Pitot/AOA use nests nicely in the curved edge of the J-channel that runs spanwise down the wing. Might reduce the number of conduits "needed" for your application.

Bill, thanks for the suggestion. I will take a look at that as a possible solution. Patrick thanks for the photo. I will avoid the stamping. I plan on all LED lights and have been told they will not interfere with any other electrical. I will probably put the Magnetometer in the wing and there will also be the servo, heated pitot, stall warning wiring in the wing. I am hoping I can get it all in the ribbed conduit. I really don't want to start putting holes in the ribs until I am sure I know what I am doing. As far as the photos, I am obviously doing something wrong. What is the normal process for including photos? I don't have a web site and it looks like you can't imbed them on the VAF site, that is why I tried dropbox. Dropbox will not let you link to the individual photos only the folder they are in. Thanks

upload your photos to www.postimage.org It is a free hosting site.

Once uploaded, click on the image you want to share. Then click on the share icon. A number of links will appear.

Copy the one for "hotlink for forum". (highlight then ctrl/c or click on the little copy icon to the right)

Now in your post to this site, click on the little picture icon and paste the hotlink (ctrl/v)

it is done!

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LEOK, you are the man! Thanks a million.