Spar tube / carry through not centered

[Tree top pilot 13]

Assembled the wings to the fuse and all the wing building chores can be finished now. The thing is that the carry through tube in the front do not center up inside the spar tubes. It appears that they are about 5/16 OC off of the centerline of the spar tube. Is this a common thing? I would tend to think that the rear spar has more lift load than the front...may not be critical. I just wondered if any others have noticed this on their plane....normal or not. You can see in the pic that I did mark the center of the spar tube...and the ending results.

Edited 18 Feb 2012 by Tree top pilot

[horsepower 24]

Assembled the wings to the fuse and all the wing building chores can be finished now. The thing is that the carry through tube in the front do not center up inside the spar tubes. It appears that they are about 5/16 OC off of the centerline of the spar tube. Is this a common thing? I would tend to think that the rear spar has more lift load than the front...may not be critical. I just wondered if any others have noticed this on their plane....normal or not. You can see in the pic that I did mark the center of the spar tube...and the ending results.

I believe my Skyraider is like that,Its in storage right now but I will look next time Im out at my shop.I think it is so you dont have to notch as much out of spar for the wing fold.Dont go by what I say though because the factory had already done mine.Randy

[dholly 718]

Each fuse will have some weld creep in the front and rear pin bushings, unless it's crazy stupid I'm not sure it matters all that much. FWIW, my Avid+ fronts were spot on, pics show how the rears played out. My wing tips are still level when folded.

[Tree top pilot 13]

This is a shot of a drill through the tube. The other wing is a bit worse as far as the offset to the rear of the tube. The edge of the hole on the other wing is almost 1/8" behind the centerline mark ! The only way to remedy this is to rework the carry through tube on the fuse I guess...or leave it as is. I am just pissed that there was not a better fit...and better parts than I was supplied. I would lose a small amount of span.....and a crap load of work to re-do to make this correct to me. I know these are not type certified aircraft, but please make an attempt to fit things though design before you send it out. Then again it was my fault for not checking this before hand. I could have shortened the ribs to get this right. The guy that has an online Kitfox build log...http://tropicaltuba.com/Kitfox%20Project/images/387.jpg This shot appears to have the support plates well behind the tube center line. I am uncertain as what to do with my situation. My instructions were to drill the rear spar tube top hole first. Then the wings would be mounted and the front holes drilled after setting them in correct relation to the fuse centerline. This has been a nightmare so far. Oh the joy.

Edited 19 Feb 2012 by Tree top pilot

[dholly 718]

Hmm, I think I see now. That almost looks like the distance between carry thru tubes was jigged short or the ribs are a bit long, as opposed to only the spar pin bushing being out of vertical. Kinda hard to tell in a pic without the level fuse in front of you as a reference. Is the center to center measure between your F/R spar carry thru tubes correct?

[edit] I would add that the left rear top hole was already drilled by the 1st owner of my kit after installing the drag tubes and gluing only (4) ribs. Grrr, RTFM stoopid! Also, I did not have ribs #1 thru #4 glued to my spars when I drilled the rest of the spar pin holes, although I did make a temporary spacer to keep the spars positioned correctly at the root while drilling. IIRC, the C/L to C/L between F/R spar carry thru tubes on my Avid+ was 27-1/2", same as my Mk-IV.

Edited 20 Feb 2012 by dholly

[SuberAvid 617]

On our Avid+ fusalages both Jack and I found that the F/R carry through tube spacing was off by about 3/16 to 1/4". Since both of us were using wings that were already built we had to modify the front carry through tube to get it to line up with the wing spars by heating and bending the ends of the carrythrough tube. I built an alignment jig off of my Avid MK4 fusalage and notched a piece of pipe that slipped over the carrythrough and the notches fit around the pin tube to use as a bending arm; then heated the carry through until it was just red and bent it a little at a time until the jig slipped into the pin tubes in the F/R carrythroughs. After they all fit I welded tabs in to add some strenght in case it weakened the carrythrough.

Attached are some pics of he finished "bent" front carrythrough tube.

[Tree top pilot 13]

So what to do now? Re- work the wings and bend the carry-through tube? Leave it as is and make bigger supports for the wing tube? Wished I had not baught into their kit now...as I have had to replace most everything. Now this. Shame on these guys for not getting this a bit closer! Shame on me for not catching it before drilling. I can't simply cut the tubes off and restart because the spar attach fittings will be into the ribs...and I am not re-making the lift struts. And not looking to shorten the brackets. Looks like I kicked myself square in the teeth. You guys have had a look at the Kitfox I mentioned earlier? Looks like the same deal. Just stuck now with this seemingly endless issue. Spar hole center to center is 27.25".....a bit short.

Edited 20 Feb 2012 by Tree top pilot

[saskavid 47]

So what to do now? Re- work the wings and bend the carry-through tube? Leave it as is and make bigger supports for the wing tube? Wished I had not baught into their kit now...as I have had to replace most everything. Now this. Shame on these guys for not getting this a bit closer! Shame on me for not catching it before drilling. I can't simply cut the tubes off and restart because the spar attach fittings will be into the ribs...and I am not re-making the lift struts. And not looking to shorten the brackets. Looks like I kicked myself square in the teeth. You guys have had a look at the Kitfox I mentioned earlier? Looks like the same deal. Just stuck now with this seemingly endless issue. Spar hole center to center is 27.25".....a bit short.

I measured the front spar holes on my avid c hh, and the worst one is off centre .343, the other is .225.I didn't build the plane.Over 300 hrs flight time there has been no issues detected.the wings are supposed to be exactly 30.00 inches outside edge of spar to outside edge of spar according to my outdated assembly manual.Little bigger here a little shorter there, and this is the result.

[tcj 150]

tree top, my kitfox kit turned out like your photos show. One front spar attach hole is about 1/4 inch behind the center line. I fold and trailer for each flight and it doens't seem to be a problem. I had to run a reamer through it with the spar in place over the carry through tube lug to get the pin to slide in, because the hole in the reinforcement was drilled before installation and perpindicular to the attach fotting. Did that make any since?

The lugs on the carry through tube were spaced exactly to the correct distance ao I called the factory...the old skystar now defunct factory not the current one...and the guy told me to drill the spar where it is. That was bad information. After I drilled the first front spar I measured the spar ends and they were spaced a 1/4 inch to wide.

Then I placed the number one rid in position and it was a 1/4 too short. I could easily hold the spars tight to the ends of that rib with very little pressure. I checked the other wing and it did the same thing so I Put the number one rib in place and put a bungee around the spars to hold them tight to the rib before I drilled that one.

Just make sure when you epoxy the number one rib to the spars that you force a solid bead of epoxy into the space between the rib and spar. If there is any in your case that is. I epoxied the number one ribs to the spars with the wings installed on the fuselage and let them set up before removing them so as not to force the spars out of alignment with the fuselage lugs.

Edited 20 Feb 2012 by tcj