Thorp Air Command - T18.net

I am considering installing a Dynon AOA pitot tube. In order to have the AOA portion work, you have to run a second tube from the pitot up to the Dynon box in the cockpit. My center section wing ribs do not have any lightening holes. I could not run another tube through existing holes.

What would be the easiest method to drill a new hole in the existing center section ribs in order to run the new AOA tube? I have already conceded that I will not be able to install rubber grommets on the new interior rib holes, but I'll just have to live with that.

Ryan,

If you're going to drill holes, maybe you make them big enough for small rigid PVC and run your tubing inside. You could always check it or replace the tubing as needed a little easier that way? PVC might offer enough protection anyway. I think a lot of folks do that. I'm close to that point in building, but don't know if I need it - already have holes for grommets.

Les Krumel,
Albuquerque

You can also run auto loom thru that area . That's what I did . Very light weight and offers plenty of protection . It also gives you a little wiggle room if you don't line up the holes perfectly . As far as drilling the holes , I can't remember what I used ? Maybe an extra jobber drill bit ?

RB

I like the idea of PVC or something similar, but my concern is getting access to the interior ribs on the center section. I would like to leave the center section attached to the plane if I can, so that will mean drilling with a REALLY long drill bit, or with a REALLY long extension with a unibit. Im not even sure I could get bit or an extension that would reach from the outmost end of the center section all the way to the fuse. That's about 4 feet I think.

I welded a 3/8" x 4ft. rod on a 1/2" drill..................

You might be able to rent a bit that will reach ?

RB

Hi Ryan, I'm in the same dilemma with 66WT. However, I've got the Sunderland folding wing and it has 2 inspection panels on either side of the center aft rib. The inspection holes are big enough to get an air drill inside with a hole cutting bit. Once I have the holes in place, I've run 1/2" irrigation flexible pipe through the wing. It gets anchored at both ends and the wire loom slides in real nice. Let us know how it turns out.

T

Could you go aft thru the aileron push/pull holes?
Cubes

hmmm. you think I could have any issues of AOA tube and aileron linkages getting caught up on one another? My initial reaction is that this would be an OK route, but what do others think about that route?

What kind of tube is it ? Aluminum or poly ? You might be able to run a short piece of ridged aluminum tube thru the push pull tube hole at some point and securely attach it with Adel clamps on the inboard and out board ribs ? You could do a test run to see if there are any clearance problems . I would go with Bill's idea and have a drill bit welded to the end of a ridged rod ! I have the S-18 wing and it was not a problem drilling an addition hole in the center wing at a later time to run the strobe/position and pitot line .

RB