Month: January 2015

Wing Tip Screw Blocks

Posted on Updated on

The wing tips are attached with screws into the plywood sheeting on the nose and between rib #10 and tip. The plywood is not really thick enough to hold screws, putting some blocks under the plywood seems necessary. Once I glue the plywood on the wing nose it will be impossible to add these blocks so I better do it now.

I grabbed some 1/4″ x 3/4″ RS-5 piece of scrap wood and cut four 3/4″ long squares. I put each on the side of the nose rib and tracef the rib contour onto them. Using the sander and some channel lock pliers I sanded this contour into the block.

image

Now each piece follows the contour of the rib.

image

Before gluing these on I weighed them, a whopping 0.144oz. I think I can live with this weight gain.

image

I used a small file to remove the varnish where these blocks are placed then glued them with epoxy.

image

Once the glue was dry I varnished the blocks except for the side that will be glued to the nose plywood.

image

Using a straight edge I ensured the blocks were not higher than the ribs and filled as necessary.

Advertisements

Installing Leading Edge Ribs

Posted on Updated on

Getting everything lined up properly took more time than expected on this step.

Those RS-1 that were glued to the nose ribs were made too long so I could use rubber bands to hold the nose ribs in place while I lineup everything.

image

I used the aircraft nails, slightly protruding out the back of the RS-1 to keep the rib from sliding around.

image

Next I cut a scrap of wood to help line up the ribs properly.

image

The wide part was placed against the main rib, the skinny part should be against the RS-1 on the nose rib.

image

I used some masonry string so I could locate the center of the RS-4 stringer at each rib. The small pin under the string was placed at the root and tip so the string is slightly raised from the stringer.

image

I moved the rib up or down until the string was in the center. The small pin and PVC clamp held the stringer to the proper depth.

image

The stringer depth was adjusted at each rib until the proper gap between stringer and string was obtained.

image

Once everything was lined up the nails were driven in further to create an index point between rib and spar. Then each rib was removed and glued in place ensuring to line up the nails and nail holes created previously.

image

The stringer was then glued into the ribs and depth adjusted to the string as noted above.

I was unable to get a good picture that shows how straight the stringer is but I think it’s near perfect.

image

Once this is dry I will cut off the excess RS-1 on each rib and round off the stringer using a small plane. Then varnish will be applied to all non glue areas to prepare for installation of the plywood wrap.

Nose Rib Preparation

Posted on Updated on

The nose ribs need to be prepared before they are glued onto the front spar.

Ribs 2,3,5,6,8, & 9 just need 1/4″ sticks glued  to the nose ribs.

image

The #4 & #7 ribs are made the same except they also need a 1/4″ doubler rib added. Had to cut 1/4″ of the back of a 1/4″ nose rib for proper fit.

image
#4 or #7 nose rib

The rib doubler at the root needed the top modified to make room for the gusset and carry through bracket.

image

The root and tip doublers were glued to the outer plywood skin. The other ribs were allowed to dry and will be glued on in the next operation.

Prebending the Leading Edge Plywood

Posted on Updated on

Prebending the leading edge plywood is a bit more difficult than the aileron. I started by cutting some plywood scrap into the leading edge contour.
image

The profile is a tad bit longer than the nose ribs since the plywood is also longer.
image

Once the first one was completed I used it as a template to make more with the flush cut router bit. Once completed I connected then with dowels and inserted the plywood I had soaking in water.
image

image

image

image

The profile looks great, should make the leading edge easier to complete.
image

Prebend Aileron Nose Plywood

Posted on Updated on

The aileron nose ribs are wrapped with plywood, a 3″ PVC pipe is the perfect outer diameter of 3.5″ to help prebend the plywood.
image

Using the same 3″ PVC pipe I cut some clamps by cutting off about 1″ of pipe then cutting a slit in it.
image

After soaking the RS-512 plywood in warm water I wrapped it around the pipe and held it in place with the clamps.
image

image

To ensure the plywood is straight I used the writing on the pipe as a straight edge.
image

After sitting overnight it looks great.
image

Now I just need to make five more to have enough for both wings.

Aileron nose ribs installed

Posted on Updated on

Now that the aileron spar glue is dry its time to install the aileron nose ribs. On ribs #4 and #7 the nose rib is made from two pieces of plywood.

image

The two ribs were glued together.

image

Then installed and held in place with clamps. These ribs are wider to provide enough glue area for two pieces of plywood that will be joined here.

image
Aileron nose rib at #4 and #7

I held rib #5A in place using a clamp.

image
Aileron nose rib #5A

The rest of the ribs were simply stapled in place.

image
Aileron nose rib

Wing nose ribs

Posted on Updated on

A friend of mine had offered to cut the nose ribs for me on his CNC router. Instead I opted to do it myself because I want to build this airplane not have some computer do it for me.

I copied the template from the plans and cut out the shape on a piece of scrap wood. Then mounted it into a piece of plywood.

image
Wing nose rib template

There are six screws that hold the template in place.

image

They are poking out the template just enough to help hold the workpiece in place.

image

On the template I drilled two small holes in the corner of the stringer cut out. As each rib is cut out I also drilled these holes so I can easily locate the cutout on each rib.

image

I used clamps to hold the 1/4″ plywood in place and staples on the 1/8″. Each nose rib was cut out using a flush cut router bit.

image

Here is what a single rib looks like after being routed and drilled using the template.

image
Wing nose rib

After all of the ribs were cut out I used the band saw to cut out the notch for the stringer.

image
24 wing nose ribs

Each rib is nearly identical to the others, when stacked side by side they look like a solid block of wood.

image

Completing the aileron spars

Posted on Updated on

At this point I am deviating from the manual. The next step in the manual says to glue the top plywood end caps between root & #1 and tip & #10 ribs. The problem here is that the trailing edge of the wing is not yet glued on and it goes under the end cap. I will not glue the plywood caps until after the aileron is separated from the wing.

To complete the aileron spar I need to flip the wing over with the bottom facing up so the bottom caps and diagonals can be installed.

image

This is just like the top so I will not go into details here on installing the caps and diagonals. Once all of the components were in place the wing was flipped back over and placed on the flat workbench to dry. The only deviation from flat is I had to use some scrap plywood pieces to raise the trailing edge to make room for the trailing edge gussets.

image

As you can see I used tape to hold the tiny RS-1 between the diagonals in place. Epoxy does not stick to scotch tape so no worries about taking it off.

The aileron is really taking shape now.

image

Aileron spar caps

Posted on Updated on

Once the aileron spar webbing was dry I started installing the RS-3 upper spar caps and RS-1 upper diagonals.

image

It took quite a bit of staples to hold the spar caps in place.

image

To make life easier I ran the RS-3 spar caps through the router to add a slight bevel so they match the angle of the ribs. While I had the router setup I also ran enough material through for the left wing. The angle is different for the top and bottom spar caps so I made a bundle of each.

image

This task was difficult only because my workbench is against the wall and tall. A consequence of limited room and designing the bench so it will fold down against the wall. If possible a bench you can walk around all sides would be much preferred, and a large workshop would be excellent.

Aileron Spar Webbing

Posted on Updated on

The aileron spar webbing was rather simple to cut out and glue in place.

One cut to size I slid them into position and used clamps to hold them in place while the glue dries.

image

image

At rib five where the two pieces meet it was a little difficult to position the clamps.

image

With the aileron spar webbing in place I glued the root and tip ribs in place. Sorry I forgot to get a picture on this.