53-10-00.00 Wing Box Assembly


53-10-00.00 Wing Box Assembly Overview

Builders Data Base Link to Wing Box Assembly
Builders Data Base Link to Welding Fixtures

Jig Components required to manufacture 53-10-00.00 Wing Box Welding Fixture.

53-10-00.01 Wing Box Base(1)
53-10-00.02 Wing Box Side (2)
53-10-00.03 Wing Box Center Spacer (1)
53-10-00.05 Wing Box Alignment Block (4)
53-10-00.06 Wing Box Lower Leg Spacer (4)
53-10-00.08 Wing Box Upright Spacer (4)
53-10-00.09 Wing Box Spar Alignment Block (2)
53-10-00.12 Wing Box Lower Cross Tube Spacer (6)
53-10-00.15 Wing Box Boom Attach Spacer (2)

If you haven’t watched the video on cutting and using the templates for the EMG-6 may want to take some time now to us to review that so that it’s a little bit easier for you to follow along with the building instructions.

53-10-0 0.00 Wing Box Welding Fixture Assembly

The 1st component of the fuselage frame that will be assembled is the wing box assembly. The wing box assembly consists of the main spar attach tube positioned within the welding fixture in relationship to the fuselage boom assembly attach points. And the interconnecting tubes that Orient the fuselage main spar attach tube to the boom attach fittings. The orientation of the fuselage boom in relationship to the fuselage frame is critical and therefore the use of the welding fixture aids in ensuring that this alignment is correct during the welding process.

Complete an inventory of the required components to assemble the welding fixture for the wing box. Reference drawing 53-10-00.00 wing box welding fixture.


Downloading a free copy of E-Drawings will allow you to open up E drawing files that we provide with the drawing package. These E drawing files will allow you to explore each one of the individual fixtures and components for a more complete view and orientation during the assembly process. The E drawings viewer will allow you to rotate the part in any 3-D orientation and zoom in and out until you have a clear understanding of the relationship of each part.

E-Drawings Web Site

Understanding the coloration of the frame.

In the drawings and pictures of the welding fixtures the surface of each tube is shown in relationship to its proper positioning.

Green: the Green tubes are tubes that will be welded while the tubes are held within the fixture. (Note that these tubes will only be tack welded while in the fixtures to prevent burning and damaging the wooden fixtures)

Red: the red tubes are shown for orientation purposes and will be welded onto the assembly but only after the assembly has been removed from the welding fixture.

Assembly of the Wing Box Tunnel Welding Fixture

1st Begin the assembly of the wing box, by predrilling the wing box sides part number 53-10-00.08 reference drawing 53-10-0 0.02-1 (wing box side)  by pre-drilling the wing box sides with an 1/8” or #30 drill bit.

Clamp and screw together the wing box sides with the wing box upright spacers part number 53-10-0 0.08.

1 of the 4 upright spacers is used at the aft location at the bottom of the wing box. There is one additional spacer part number 53-10-00.03 Wing Box Ctr. spacer that is also located to orient the wing box sides parallel with each other and also aligns the wing box sides to the wing box base. This particular assembly will be screwed to the wing box base using screws. To extract the wing box frame from the welding fixture this box will have to be unscrewed from the base in order to lift out the tact frame assembly.
Taking extra time to ensure that these parts are oriented properly will assist in ensuring that the mating of the fuselage boom assembly to the frame is oriented correctly.

Assembly of the Wing Box (Base) Welding Fixture

Assemble the wing box base welding fixture by placing each one of the 8 Wing box alignment blocks part number 53-10-0 0.05 in the locations depicted on the base. Secure the 1st alignment block with wood screws ensuring that the screws have been flush or just below the surface of the alignment block. This will ensure that the next block being screwed down on top of this block is not interfere with previous screws that were installed.
Each one of these alignment blocks have alignment holes predrilled that correspond with the predrilled holes in the base. Simply place the block into place on the base insert 2 alignment bolts into each one of the alignment holes and secure the block in place using screws.
Caution the use of cheap sheet rock screws have a tendency to pop the heads off when over tightening. If the heads pop off it becomes very difficult to disassemble the templates without damaging both part being screwed down as well as the base part. The use of the gold plated structural screws or high quality sheet rock screws are a better alternative.
Ref:53-10-00.00-2 Fuselage Assembly procedures.

To make this process easier manufacturer to alignment bolts by cutting the threads off of a 1/2 inch diameter bolt. This will allow the alignment bolts to be inserted and removed easily without the threads hanging up on the material that it is aligned with. This will also prevent damage to the individual fixture pieces as well as ensure a more accurate alignment.

Once the alignment block has been secured using an appropriate number of screws the use of a pry-bar or claw hammer can be inserted under the head of the alignment bolt and removed easily.
Caution: Do not pound the alignment bolt all the way flush with the material as it will make it more difficult to get a prybar under the bolt head to assist in the removal.
Refer to drawing 53-10-00.00-2 fixture assembly procedures for an example.

These are the procedures that will be used to align all of the fixtures within the frame welding fixture assembly.
Caution: do not glue the parts together unless you have purchased the welding fixtures. Disassembly will be required to fit all of the parts back into the shipping container.

Forward Spar Installation

Lay out the 1st part for the wing box assembly the Forward Spar P/N 53-10-10.
Once the part has been cut, drilled, and marked insert the forward spar into the base of the welding fixture.
Then insert the wing box tunnel assembly on top of the forward spar, positioned correctly and using 4 to 6 screws screw the tunnel assembly to the base.

Now insert the  wing spar alignment spacer (part of the fixture assembly) part number 53-10-00.09 as shown in the picture and insert a 1/4 inch bolt or shaft through the main spar and align with the alignment fixture. This will ensure proper alignment of the main wing spar and all of the other tube intersection markings that you placed on it during the manual factoring process.

Boom Attach Spacers

Attach the 2 wing box boom attach spacers part number 53-10-00.15 to either side of the wing box sides. Use a 1/4 inch diameter bolt or pin to align the plates with the quarter inch holes in the sides then secure the plates to the sides with screws in the 4 holes provided. The spacer serves 2 purposes, the 1st is to protect the fixture during the tack welding process and the other is to provide some additional space for the boom attach fittings. (During the welding process the frame will contract slightly making it more difficult to install the fuselage boom assembly onto the frame)

Boom Mounts

Next we need to manufacture (4) of the boom mounts manufactured from a 1/8 inch thick 4130 steel washer P/N 53-10-16.1 boom mount washer alternate and P/N 53-10-15 boom mount.
Caution: ensure 100% penetration on these welds around the boom mount assembly. These are critical mounting locations.
Weld these components as shown in the drawings and install them onto the side of the welding fixture tunnel on the outside of the boom mounts spacers.
These can be installed with regular grade 2 or grade 5 1/4 inch diameter bolts, washers, and nuts. The hardware that is used to install these will be considered unusable after the welding process. Even the tack welding can get hot enough that it will destroy the plating on any hardware and therefore should not be used for anything other than fixturing.

Interconnecting Frame Members

The next step is to manufacture each of the interconnecting tubes using the templates in the drawing section.
53-10-11 Wing Box Lower Tubes
53-10-12 Wing Box Forward Top Tubes
53-10-13 Wing Box Vertical Tubes
53-10-14 Wing Box Aft Diagonal Tubes
53-10-17 Wing Box Aft BRS Mount
53-10-18 Wing Box Forward BRS Mount
53-10-27 Wing Box Aft Crossmember

The tubes should be cut and fit before the welding begins.

Remember that each tube intersection may need to have a hole drilled to allow the expanding gases during the welding process to escape. Failure to provide a vent for each tube may result in the tube blowing out in the area where you are closing out the final section of weld.

It’s much easier to put a hole in the tubing prior to the welding process that it is after the frame has already been tack welded together.
There will need to be a few vent holes left in the tubing until all of the welds have been completed on the frame and then during the final closeout each one of those holes will be welded closed.
There should be no holes to the interior of the main structure whatsoever. This means that tubes that are open at the ends should never be drilled as an intersection vent for the closed tubes.  All vent holes need to be welded closed.

With proper planning you can provide a vent path for most of the tubes where they intersect leaving only a few holes that need to be welded in the end.
It is also a good idea just before closeout that you pressure test the frame assembly to ensure that the last hole that’s been welded up does not allow air to leak out any of the other welds or vent holes.

Tack Welding the Frame

Once the basic wing box frame has been tack welded on the top side the center tunnel may be unscrewed to have access to the bottom welds. Each of these areas should be tack welded as well.

More emphasis may be placed on the welds that are not next to the wooden welding fixture, whereas the welds that are next to the wooden fixture should only be tack welded until it is removed from the frame fixture itself.

Once the basic structure has been welded the frame may be removed from the welding fixture and each of the welds around each joint can now be completed. These weld should be completed before the additional tubes are added to the frame.

Keep in mind that is much easier to weld around a tube intersection that doesn’t have a lot of other stuff attached to it.

By building the fuselage frame in sections allows us to work with very small components that have easy access to all sides of the weld.

Once the frame becomes a completed frame it becomes rather difficult to manipulate and maneuver and hold it in place while your welding.

We have found that a vice mounted to our welding table that has a swiveling head that swivel 360° as well as a base that swivel 360° allows us virtually any position we want during the welding process. For the small components it’s very simple to hold the part in the vice and position it so that welding is much less of a chore.

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