Building the Legal Eagle XL Wing
6/25/2010; Fabricating spars
The building tables were reconnected to provide a 2' x 16' working space so the spars can be constructed. A line was snapped and blocks screwed to the table to establish a straight reference. Additional blocks and wedges were added so the parts of the spars can be clamped together after gluing with T-88 structural epoxy. The 5" filler at the root of the spar was used to establish the spacing between the two spar caps.
Note: If sourcing wood per the XL materials list, one spar interstation 1/4" x 3/4" piece (these are where the ribs are attached to the spars) can be cut from a 36" length of spruce. This will leave sufficient length for the compression ribs and prevent cutting up and wasting full length strips. A total of 32 strips of 36" length are needed for both wings.
6/28/2010; spar construction continues
The top of the front spars need a bevel so they will mate properly with the ribs and leading edge skins. The table saw was used for cutting a ten degree bevel.
Drilling holes for root and strut fittings is easier before wing assembly begins. Rear spar can be seen in the jig blocks. 1/8" bearing pads were added after the pilot holes were drilled. It was easier to stack the spars for match-drilling without the pads.
6/30/2010; attached ribs to spar
One thing to watch out for--do not glue the doubler to the inside of the rear spar at the strut fitting until after the ribs are in place.
I had to put a bevel on the top of the rear spar, probably just a matter of how the dimensions stacked up with the wood stock I'm using.
7/5/2010; Compression ribs and diagonals installed
Detail of diagonal fitting at root of wing.
Detail of diagonal fitting against spar web and compression rib.
7/8/2010; aileron construction
The aileron end ribs and hinge blocks have been fabricated and attached to the wing. Shown is the aileron spar web being glued in place.
The hinge blocks include a length of 3/8" aluminum tubing left over from the emp construction. When lightly reamed, it is a perfect fit for the 5/16" bolts which serve as hinge pins.
7/9/2010; aileron leading edge
Invasion of the binder clips--fantastic tools for clamping leading edge sheeting. A staple is driven between clips.
7/10/2010; wing lifted from table
The wing was moved from the building fixture and reset for installation of nose ribs and leading edge skins.
Scrap ply from the fuse jig was cut to serve as a fixture that fits the main spar. These cradles are screwed to the 2 x 4's that served as the base of the wing fixture.
The two 2' x 4' tables have worked beautifully for building the Eagle. They were connected to form one 4' x 8' surface while building the tail surfaces, then reset into a 2' x 16' surface for the fuse and wings. When not needed they stack so little floor space is lost.
7/14/2010; assembly of left wing complete
The leading edge skins are 0.8mm ply (1/32") and were very "soft" between nose ribs. I added a 1/8" luan rib between each nose rib and this really firmed up the leading edge.
7/31/2010; second wing panel completed.
Both wings are now on the cart ready for varnish and fabric.
8/3/2010; wing end plates
It seems the flight characteristics of the Eagle are enhanced by the addition of wingtip plates.
No reason the plates shouldn't have lightning holes, so might as well make the holes into something useful........
8/24/2010; aileron pockets
The space in front of the ailerons could be left open but might prove to be inviting to birds, mice and other critters to enter the wings. Shields were formed from lightweight roof flashing from the aviation department of the local Lowes. Appropriate angles were bent with the metal brake, and the shields were epoxied and riveted to the wings.
The shields were riveted to each rib upright and where the shield pieces were joined. It was necessary to make each shield in three pieces since the metal brake is only 36" wide.
Clean, light, and attractive.
4/11/2011; The wings are light enough to easily lift single-handedly, but once they are covered it is difficult to move them due to lack of handholds. Here is the fixture I built to make it possible to safely move the wings without assistance. The lift strut fittings are close to the balance point of the wing to so it is easy to grab the handle with one hand and steady the wing with the other.