The Wings – Page 5
Time to start the ailerons. I
clamped some scrap flat boards to the bottom of the wing at ribs 3-6. This gave
me something to rest the plywood strip on while I traced the shape of the
mounting spar. I made sure the ply was vertical using a small square. Just to
be sure, I measured the “gap” on the underside (between the mounting spar and
the ply) at different places to make sure it was consistent. Marked and trimmed
to shape, I then marked the locations of the ribs and the hinges for the
stiffeners and doublers that will be mounted later.
After covering the workbench with
waxed paper, I laid the plywood flat and glued the top and bottom flanges to
the plywood spar face. I think adding the hinge doublers to the top flange
before gluing the flange to the plywood is the best sequence in this step. I
had done that with the mounting spar doublers but forgot to do it here. Thus, I
had to remove some T88 and sand the bottom edge of the doublers before I could
fit and glue them in. I also added the
rib stiffeners and the block for the aileron control bracket.
I decided to match the hinge holes and bevel the top
flange before adding the aft plywood to the aileron spar. This way I will be
able to see how the holes come thru the doublers and make sure I have plenty of
wood margin on the flange after the beveling. I mounted the hinges to the
mounting spar with temporary hardware making sure not to thread the screws far
enough into the nut plates to damage the Teflon but far enough for a tight fit.
A friend held the aileron in the appropriate position while I marked the holes
for the hinges. (Note: Earlier I had mentioned that I had drilled the holes for
the hinges in the mounting spar out of plans sequence because I thought the nut
plates on the backside of the mounting spar would be easier to add before the
mounting spar “c” was closed in. There was no major problem with this idea;
however, it does make the matching of the aileron side a bit trickier. I don’t
know if I would do this again as the nut plates are not THAT hidden.) After
drilling the holes for the hinges I mounted the aileron spar to the wing.
The top flange gets sloped to match the airfoil of
the wing. There is a good bit of wood that comes off here. Using the sanding bar with only half of the
bar covered with sand paper and the other half resting on the mounting spar
would work but I realized this would take A LOT of sanding. I could use a plane
but I was scared of cutting too deep on the aft side of the flange. My EAA
technical counselor recommended that I take a scrap board with a straight edge
and lay it on it’s straight edge on the slope and notch out for the high part
of the flange. Then I could mark on the aft side of the flange where the
straight edge resumes. As long as I stayed above this line with the plane I
would be fine. And, it worked. Thanks, Sam. I put the finishing touches on it
with the sanding bar as mentioned above.
The pictures below show some of the detail inside
the aileron spars and the aft face of the box spar just prior to closing the
box. Notice that the stiffener for the control brackets falls directly below
one of the hinge doublers. My spacing of the hinges is the same as called in
the plans. The only reason I mention this is that the diagram in the plans do
not show this stiffener below a hinge doubler.
After marking rib locations on the top and bottom of the aileron spar and sealing the inside, I closed the box spar and back drilled all the holes. I notched each end of the spar for the ply covers. I used the angle of the adjacent wing ribs to mark the angle for the top notch in the spar. I pulled out the shortened rib trailing edge sections that I had cut off ribs 3-6 (that seems so long ago) and adjusted them to the height needed to match the aileron spar. I added cap strips to each. With the workbench flat, level and covered with waxed paper I glued ribs 3-5 to the spars using corner blocking. I also glued the bottom ply to the inboard end of the aileron spars. Next was to add the sister ribs on top of the ply just installed. Pictures below show progress but not as much as you might think. I had set the box cover in place and forgot to remove it prior to the pictures. It will be permanently attached as soon as the second coat of sealer is dry inside the box.
I held off on adding rib #3 to the spar because I thought that it would make adding the tip bow easier. I decided that it really wouldn’t matter and added the #3 rib. Making sure the wing was level and lining up the aileron on the inboard side with the wing, I added the outboard end rib. Be careful here to make sure to position this outboard rib so that when covered with the 1/8” ply it lines up with the adjoining wing section. With the metal trailing edge held temporarily in place and the wooden trailing edge positioned to meet the metal, I marked where the ribs needed to be cut off. After cutting off the ribs I laid the aileron spar on its back and glued the wooden trailing edge to the ribs at the 3 locations. When the epoxy was dry I was able to fit and glue the sister rib into place at the outboard end. Because I had sanded a bit more on the tip bow after I had cut off the section for the aileron, I will have to do a little bit of touchup sanding to match the tip bow exactly.
I got the outboard sister rib box closed making sure the plywood covers matched the adjoining wing section. I then attached the metal trailing edge material after a good bit of adjusting with the sanding bar.
Both ailerons are now complete. I attached them to the wings and moved the wings to the hangar at the airport. Of course, the wings still lack the control system, leading edges, the most inboard rib and wing walk but these are done after fitting them to the fuse. The tail feathers are next.
Thoughts on Wings
*The wings have taken about 475 hours of shop time over a period of 2 years and 4 months, so far. I work slowly. This equates to about 4 hours of shop time per week.
*I would never be able to build a plane without some really good friends’ help - hands and minds.
*I would never be able to build a plane without being able to work on it at home.
*You can’t have too many clamps.
*New tools are half the fun.
*Order all oversized stock at one time to lessen shipping and crating costs.
*Measure, re-measure, and then measure again.
*When constructing the ribs, make sure the trailing edges come to a point. Mine didn’t. It worked out OK but it would have been easier if they had.
*The rib jig idea works well.
*Make sure the tabs on the compression struts are bent prior to welding them to the tubes. It’s difficult to bend them after the fact.
*Don’t cut the aileron section of the tip bow off prematurely. Make sure it is completely shaped the way you want it prior to cutting it off.
*The tip bows take a lot of sanding.
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General The Wings - Page 4 The Fuselage - Page 1
The Wings - Page 1 The Rudder The Fuselage - Page 2
The Wings - Page 2 The Stabilizers The Fuselage - Page 3