fuselage dimensional problem

[Nical]

Good day, Eaglers. I am nearly finished with my XL fuselage and have run into an interesting problem:
 On page six of the XL plans the dimension between centers of the vertical tubes (cockpit aft and cockpit forward) has a dimension of 29".
   Installing the wing mounts  (pg 7a) at the tube centers gives a centerline of 29". Fine except the centerline of the wing spars is 28 7/16".  So to weld the mounts to the tube centers   screws up the spar clearancing .
   What have you guys done  here?  I am guessing just correcting the welded mounts to conform to the 28 7/16" centerlines. No longer a perfect load path but given the reinforcement plates perhaps OK.
   If any builders out there want to offer a bit. Of feedback on this I'd sure be grateful. I am jigged up now to do the 28 7/16" dimension but will wait to read what you guys think first.
     Thanks for your consideration
     Nick L.   XL-E-20

[CHARLES DEBOER]

There is a note on pg. 7a which refers to the dimension for a 3/8" bushing that goes into the wing mount weldment.  "FIT TO THE WING FITTINGS"  I welded the mounts to the inside of the vertical 5/8" tubes.  That reduces the 29" center line dimension by 5/8".  The remaining adjustment is accomplished by ADJUSTING THE LENGTH OF THE  3/8" BUSHINGS.  CHECK THE DIMENSIONS OF EACH WING ATTACH FITTING.  There may be a slight difference between the two wings.  Clamp and tac-weld the mount and check to be sure the mounts are square to the fuse.  Use a lot of tac-welds because the 1/16" plate can warp easily.

[scottiniowa]

Good day, Eaglers. I am nearly finished with my XL fuselage and have run into an interesting problem:
 On page six of the XL plans the dimension between centers of the vertical tubes (cockpit aft and cockpit forward) has a dimension of 29".
   Installing the wing mounts  (pg 7a) at the tube centers gives a centerline of 29". Fine except the centerline of the wing spars is 28 7/16".  So to weld the mounts to the tube centers   screws up the spar clearancing .
   What have you guys done  here?  I am guessing just correcting the welded mounts to conform to the 28 7/16" centerlines. No longer a perfect load path but given the reinforcement plates perhaps OK.
   If any builders out there want to offer a bit. Of feedback on this I'd sure be grateful. I am jigged up now to do the 28 7/16" dimension but will wait to read what you guys think first.
     Thanks for your consideration
     Nick L.   XL-E-20

     Nick, I am guessing your past this by now…but for others following, This is certainly one of those areas where if  you build the wings first and then the fuselage, or build the  fuselage without the wing attach points. Then you can install the wing attach part/piece to the wings (front and back) and then position this to your frame. By doing so, you can assure yourself by measuring from tail post to one of the end ribs that you have things right on the money. 

    You can concentrate on having the front attach. point right where it needs to be, and the rear one is where it is at that point it doesn’t matter if your off a bit either way, because it has to be able to hold your wing-accordingly that YOU built and not what the plans said.  

    With the double wing strut, there is little to worry about if your ahead or behind a few in measurement.   This of course is based on the fact that your wing is built close to specs.  Off a tiny bit doesn’t matter now.

     We do larger planes the same way, that is to say, we make a square jig that would hold or bolt up to the wings.  This jig is then set upon the aircraft without the wings and squared up, just like above.  If the jig is square and previously held the wings, things will fit.

   Best of success.
Scott