This week ended with more work being done on the fuselage. We trimmed the bevels that we made on the aft end of the main fuselage. We also continued to work on the area on the inside of the main fuselage where the spar goes through the skin and where the main landing gear will be attached. Chuck drilled and tapped brake lines in each main gear. Next week we will continue to add extra glass to the spar and landing gear mounting area and, hopefully, attach the landing gear brackets! Here are pictures from yesterday:

Here is a view of the hanger showing large pieces of our airplane. The wings are on the left and the fuselage halves are on the right. The aft fuselage is sitting on the work table towards the back while the main fuselage is on it's right side sitting on sawhorses. The curved sills, between the seat back and the instrument panel were given extra unidirectional glass this week to make them extra stiff.



This view is of the right inside skin where the main spar intersects. I will be adding a little spacer in the corner area.


Here is one spacer (1/4" last-a-foam with 1 ply bi-directional glass on each side) cut to fit. Next step will be to "flox" into place.
 


Here is the spacer on the opposite (port) side, floxed in place. I have added a single ply of fiberglass cloth which goes over the inside spar cap, spacer and bottom skin.





Here are the main landing gear mounting brackets with their clamps bolted on. The steel mounting brackets will get bolted to the inside of the fuselage and the landing gear legs will get clamped in place.

Well, it was just a couple of weeks ago that we attached the aft lower fuselage to the main fuselage and yesterday we cut them apart! However, in the meantime we made the mounting plates and the strong pads that they bolt to. We can now re-attach the two halves whenever we want to. Below are "before" and "after" pictures.


The joined fuselage's aft portion is sitting on the edge of our work table. The main fuselage is to the right and is supported by a sawhorse (not shown). The light areas are where last-a-foam panels are embedded between the inner and outer fiberglass layers (these add stiffness to the fuselage). The dark green band between the front and back fuselage sections is the front edge of the aft fuselage. We have added extra glass to stiffen this area. In addition, the little rectangle with 3 holes in it, sticking out to the right is an extra thick pad where a fuselage attachment tab will be bolted.


We have cut apart the two fuselage halves. Note that we cut the  pad in half as well. We will bolt the the fuselage attachment tab onto that side with two bolts. Then when we are ready to re-attach the aft fuselage, we will screw it on by putting a machine screw through the aft skin and into a hole on the attachment tab.


After separating the two fuselage halves, we cut a 45 degree bevel on the main fuselage's back edge and sealed the edge with flox and fiberglass. This is called a "flox corner" or "flox edge".



In this picture, the main fuselage is sitting right-side-up and we are looking at the bottom port-side corner. The glass and foam has been cut back at 45 degrees to form a bevel and the foam has been cleaned away from the edges of the glass with a Dremel wire wheel. Next we will wet the glass and foam with resin and then cover with a mixture of cotton fiber and resin (flox) followed by two layers of fiberglass (see the picture below).



Chuck is adding two plys of fiberglass over the beveled and floxed area. Once the resin cures, we will trim off the excess glass and we will have a nice strong beveled edge.

The last thing we did today was the addition of 3 layers of unidirectional  (UNI) glass on the inside and bottom of the sill, and inside surface of the fuselage side, between the seatback bulkhead and the instrument panel. This gives that area extra compression strength.  I don't have a picture of this yet, but will post one tomorrow.

We are continuing to make steady progress on the airplane. Last week we attached the center spar to the main fuselage.


This is a picture of our fuselage siting upside-down. The spar
is seen protruding from the side of the fuselage.


Here the fuselage is shown right-side-up. We could not resist inserting the landing-
gear to see how cool it will look!


Here we have the main fuselage and the aft fuselage joined together and we are
test-fitting two bulkheads to their positions on the aft fuselage. The larger bulkhead
on the left is part of the main fuselage. 


Yesterday, we fitted 8 of the 9 fuselage mounting tabs onto the fuselage. These aluminum tabs will eventually allow us to be able to attach and detach the aft fuselage from the rest of the airplane.

Over the next couple of weeks will will continue to work on the aft fuselage, adding the bulkheads and bonding the skins together. We will begin making the new horizontal stabilizer and new elevators in the next week or two as well. Here are some pictures of the mounting tabs:



This is a view looking at the area where the aft fuselage joins the main fuselage. The plane is laying on its side, so the bottom tab is actually on the port side and the one on the left of the photo is a bottom tab. We used some flox (cotton fiber mixed with epoxy resin) to "bed" the plate and then used bolts and nuts to tighten and hold the plates in position until the resin hardens. Eventually, we will remove the plates and then cut apart the aft fuselage and main fuselage. Then we will permanently re-attach the plates to the main fuselage with the two sets of bolts and nuts. More about this in future posts.


Here are two fuselage mounting tabs bolted into place on the top fuselage skins. The aft fuselage is on the left and on the right is the area that will eventually become part of the main fuselage (the turtle deck behind our seatbacks).

We linked the lower aft fuselage and the forward fuselage together last week. This week we are making the mounting pads and plates that will be used to hold them together and to take them apart for transport or to work on them.




Chuck standing behind the fuselage at Hanger 115. We set the vertical fin on the aft end of the fuselage because it looked much cooler that way! May 9, 2012.

I just wanted to show some pictures of some of the activities leading up to the wing test in September. I will be following up with our more recent work on the forward fuselage.

Seatback Bulkhead (August 2011)

One important first step in assembling the main fuselage was to put together the seatback bulkhead.
Here we are putting "flox corners" and glassing the inside edges of the two cutouts on the seatback. We will have access to our luggage area through these two holes.




Here we are attaching the lower seatback bulkhead to the upper bulkhead (which was illustrated in the first image above). The seatback is angled back for comfort.



Here Chuck is trimming the fiberglass after it has cured.





Here is another view of the seatback bulkhead. Notice the small cutouts on the lower bulkhead to allow the elevator pushrods to pass through.


Besides the seatback bulkhead, we also worked on finishing the rest of the bulkheads that will be used in the forward fuselage. 

Such as this one (Bulkhead128) which will be located a couple of feet behind the seatback bulkhead.


Here is the lower instrument panel bulkhead. It will be located ahead of the
seatback bulkhead (September 2011).

As mentioned in an earlier post, on September 19th we tested both wings and the center spar by placing 27 bags of concrete (1,620 lbs) on them to see if they would bend but not break. Great news, they both bent a little over 6 inches but they didn't break!

Next we begin building the forward fuselage!

It has been a long time since I have posted an update on our project. In a nutshell, we assembled both wings, and have finished making all the bulkheads and the panels for the center console. Our next phase is to begin making the main fuselage. But first we needed to load-test both wings!!!

The tests were performed with the wings upside down and and 1620 pounds of concrete bags were laid down along the length of the wing.

First we built two support frames, one to hold down the center spar on one end and the other to support the opposite end.  Next a wing was bolted to the end of the center main spar and the wing tip was supported by a jack on the other. We placed 27 bags of concrete, weighing 60 pounds each on a wing. After that we slowly lowered the jack until the wing tip was no longer supported. Both wings deflected down nearly 6 inches, but did not crack or break. They both passed the 4 G test!

Here are a couple of pictures from the test.


The two cars are holding down the far end of the center main spar.
This shows the right (starboard) wing, up-side-down with 11 bags
of concrete. 16 more bags to go!


The same wing now with all 27 bags of concrete. Chuck is measuring how far
the wing has deflected.


Here are some of our test observers (Gordon, Bob, Ed and Bruce). I am standing
in front and Chuck is on my left. Not shown is Walter and Renee (who
took the picture). To say that we were relieved is an understatement.

Now we are ready to begin building the fuselage.

We have completed the five bottom wing skins and are now ready to finish assembling the top wing skin mold's leading edge. Here is a picture of me (Darryl) standing in front of our hanger at Livermore Airport (LVK) and the 5 bottom wing skins laid out behind me.


You can begin to appreciate the size of the wing for our little airplane! Without the wingtips, the
wing is about 30 feet long.

This coming week Chuck and I will be finishing the top wing skin mold.

We have just finished our third bottom wing skin! We are now able to make one part a week.


Here are our first bottom skins for our wings. This is the outside (or bottom) surface. There are two layers of fiberglass on the outside, next is a 1/4" last-a-foam layer, followed by a layer of fiberglass on the inside surface, for a total of 3 layers of glass. All three parts have been post cured at 130+ degrees for two hours.

Next week we will make bottom skin number 4, that will become the first outboard half of the outer wing. It will differ from the first three because it will have a removable inspection cover/window for to allow visual inspection and removal of the aileron belcrank and linkage. The following week we will make wing skin number 5 that is a mirror image of number 4. After that we will finish the top skin mold and begin to make the 5 top skins.

Our First Wing Skin!



The picture above shows the first of 10 wing skin parts we will be making in order to build our wings. Here is what went into making this part....

Plugs, molds and wing skins

Since October, we have been working on making molds for our wing skins. We decided to create a "plug" of the wing cross section and use that to make an upper and a lower wing skin mold. The plug is about 6 feet long and is a very accurate representation of our wing's airfoil. We got help from our fellow EAA 663 member Jack Burke and his homemade CNC machine. His machine accurately cut 8 ribs matching Chuck's design. In early October, about the time we moved into the new hanger, we glued together the ribs and spars to form the plug's skeleton.

   
Three views of the framework for the wing plug. The 8 ribs were cut on Jack Burke's CNC machine. We then glued and nailed wood spars onto the notches in the ribs. The plug is now ready for us to glue on a plywood skin. (October 19-21, 2009)

Next we glued a thin birch plywood skin over the framework. In order to get the plywood to bend around the leading edge without cracking, we soaked about 12 inches of the plywood in an ammonia and water mixture to soften the wood fibers. Other than a small mishap in which Darryl's wood, cardboard and polyethylene sheet trough decided to come apart, the set up worked pretty well.

    
 Our makeshift water trough        Getting ready to glue the plywood onto the plug frame. (Oct. 22, 2009)
containing ammonia and water.
(Oct 21, 2009)



Part way there! (October 22, 2009).



The plug with top plywood skin drying with strap clamps keeping it on tight (October 22, 2009).


Bottom plywood skin glued in place (October 29, 2009).


 
Here is the plug after we have put a layer of
fiberglass over the plywood skin. February 2-10, 2010)

After fiberglassing the plywood skins on the plug, we found that the surface was not nearly as perfect as we had hoped! There were lots of peaks and valleys which we needed to fixed. We first tried a plaster-like product called "ProForm". We figured that it would be easy to apply and sand down. Unfortunately, the plaster did not stick to the fiberglass. When we started sanding, the plaster just chipped off. So we removed all of the ProForm and went to "plan B" which was to cover the entire plug with epoxy and glass microspheres (also known as "micro").

 
Chuck squeegeeing on ProForm plaster and Darryl inspecting the dried plaster (February 10-11, 2010).


Because of the cold weather and other outside activities (like the holidays and Darryl and Renee buying a new house) we did not accomplish a lot on the plug between November and February. We did, however make the seat back bulkhead for the fuselage (see below).

 
Seat back bulkhead, forward facing side.              Seat back bulkhead, aft facing side.


Completed seat back bulkhead with cutouts (November
24, 2009).


Completed seat back bulkhead with one luggage cover
in place (November 30, 2009).

Getting back to the wing skin plug, we spent most of the month of February coating the plug with micro and carefully sanding to get as smooth a surface as possible.



Here is the plug after we have covered it with a slurry of micro. We spay painted
the micro surface with green paint so that we could see where the low spots
were as we sanded it down. Note the 7 foot long aluminum extrusion that we
used to sand the surface.

We did several coats of micro, followed by a lot of sanding. After a few cycles of this, we got smarter and began to use bondo get the final low spots filled in. By the middle of March we were pretty happy with the overall shape of the plug, so we began applying a "high fill" primer on the surface and carefully sanded to get the final surface we wanted. This did this step several times for both the top and the bottom sides of the plug.  Here is what the plug looked like at this stage:
 
Plug with surface primed and sanded (Mar 18, 2010).   Plug ready to be waxed (Mar 26, 2010).


Here is Chuck looking pretty pleased with the wing plug. We are
now ready to make the top and bottom molds for the wing skins
(March 29, 2010).

On March 29th, we made the bottom mold. First we clamped  a very straight piece of wood onto the leading edge of the plug. The wood allowed us to create a flange on the leading edge of the bottom mold. When we make the top wing skin mold we will make a matching flange on it so that the two skins will mate precisely when we put the wings together. I will go into this later on in more detail.



Wood strip clamped to the leading edge. This will create a flange on the mold.


In order to make the bottom wing skin mold, we started by covering the bottom surface of the plug with a gel coat layer, which is made up of resin, Cab-O-Sil (a powdered glass material) and pigment. The Cab-O-Sil makes the gel coat layer very stiff, so that it doesn't drip or flow. We let the gel coat cure for about 2.5 hours and then covered it with seven layers of fiberglass.


Chuck spreading the gel coat layer with a squegee (March 29, 2010).



Bottom wing skin mold after the seven layers of fiberglass had
been applied on top of the gel coat. Note that we used a straight
piece of wood to create a flange on the leading edge. The flange
will be important later on when we make the upper wing skin
mold March 29, 2010).



Here is a picture of the mold after it has been trimmed and placed
back onto the plug (March 31, 2010).

The next step took some thought on our part. Basically we needed to put a backing on the flange and also make sure that the flange edge had a clean and sharp corner with no gaps or pockets. To do this we attached the mold to the plug by inserting screws all around the side and back edges to make sure it would not shift. We then applied strips of fiberglass onto the back side of the leading edge flange.


Next we clamped the wood backing on top of the wet fiberglass and then filled in the gaps with a mixture of cotton fibers and resin (also known as flox)..
 
Wood backing clamped onto back of      Adding more flox to fill in the gaps on
flange.                                                 the wood backing.


Since the mold was still pretty flexible, the next step was to make it as rigid as possible. We did this by adding foam stiffeners going lengthwise and chordwise while the mold was still attached to the plug. We fiberglassed over the foam which resulted in a very stiff and inflexible mold. Here are a couple of pictures of this process:

 

At this point, we were able to start making the top wing skin mold. Basically, leaving the bottom wing skin mold attached to the plug, we turned over the plug and then fabricated the top wing skin mold the same way we did the bottom.



Here is a picture of the top wing skin mold. The leading edge is towards the
left and the trailing edge is on the right side of the photo. There is a flange
on the leading edge that was created by presence of the flange on the lower
wing skin mold which we left in place when we made the top mold. Notice the
bottom wing skin mold in the background (April 28, 2010).

After finishing the layup of the top skin mold. we removed both molds from the plug. We now concentrated on the finishing of the bottom wing skin mold. First we needed to attach a wood extension to the leading edge flange. This would allow the fiberglass of the leading edge to be supported. We would then trim most of that away. Here is what the extension looks like:

Here is the mold with the wooden extension screwed into place. The mold has been coated
with 3 layers of wax.


Before we tried to make our first lower wing skin, we made two test parts that were only 10" wide. From the tests, we concluded that we would do the skin in two separate vacuum bagged layups. The first would consist of the two outer layers of fiberglass and the 1/4 foam core. After curing, we would then do a second layup in which we apply the single inside layer of glass. It would be a bit more work and would use more materials (peel-ply, release/cauls and polyester fiberfill bleeder), but would give us more consistant results.



Vacuum bagging the first bottom wing skin. This was actually the second lay-up
where we have applied the inside glass layer over the foam. The wet fiber glass
is then covered with Dacron polyester cloth (peel-ply) followed by perforated butcher
paper ("release/caul"). Polyester fiberfill ("bleeder") is then added on top in order to
absorb the excess resin. The entire mold was then enclosed in a polyethylene bag
and vacuum applied. You can see some of the resin being squeesed out along the
edge nearest you in this picture.



The first look at our wing skin!  The release/caul and polyester fiberfill bleeder have been
peeled back to expose the peel-ply and inner skin. The peel-ply is fairly easy to remove
leaving a nice clean surface which is ready to be bonded to the ribs and spars (June 8, 2010).



Here is the first lower wing skin sitting on its mold. It is starting to look like a wing!
(June 8, 2010)

All moved into the Hangar and building our airplane!
Since the mid-October we have been in our new Hanger at Livermore Airport (KLVK). Our first order of business was to get everything stowed away and organized. Here is a picture of our hanger now that we are all moved in.


Our hanger is located on the extreme northeast corner of the airport. Right
now it is pretty noisy since there is a lot of construction going on with the
building of a new freeway on ramp for Hwy 84!

As you can see above, we have done a pretty good job of filling the hanger. It is hard to believe that most of that stuff was in my garage. The big work table is set up on the left side of the picture just behind the Harley. The hangar came with a nice loft which we are using to store our completed parts, foam blocks and molds.

Now we are working on making the wings. We completed the main wing spars earlier this year (see the July 31st entry below) and last month our friend and fellow EAA 663 member Jack Burke used his home made computer controlled mill to cut out a bunch of wooden ribs for making a wing section plug. Chuck designed the parts and sent the drawing files to Jack. He then used the drawings to program his mill. Here is a picture of the mill in action:
(need pic of mill IMG_4774)

Within a day or two of moving in we got to work gluing the plug's ribs and longerons together.
 

The plug is glued together and ready to have thin plywood skins added.

On October 22 we took the plywood skin for the top surface and soaked a 10" wide leading edge in water and ammonia to make it soft enough to bend around the leading edge. Other than a small mishap where the trough had a major leak, the technique worked out pretty well. Here is a picture of the plywood soaking in the water/ammonia trough.


Top plywood skin for the plug soaking overnight in water and ammonia to
make it bend better for the leading edge.

The next day we bonded the top plywood skin to the plug frame.


Straps holding wooden top skin in place while the epoxy sets.

We discovered afterward that we might have been better off if we had done the top skin in two stages. Trying to bend the leading edge and entire top surface was a handful, and there were some small bulges in the top surface. We ended up making two length-wise cuts in the top skin so that we could re glue the high spots.


Reworking the top skin. We turned the plug over and added 3/4 x 3/4 strips
of wood to the underside skin and clamped the skin down well.

By November 12th we had finished reworking and sanding the top skin and were now ready to glue on the bottom skin.


The plug is upside-down with the bottom skin glued into place.

The next step on the plug will be to add one or two layers of fiberglass. We will need to sand the skin to a very smooth surface so that we can make molds for the top and bottom wing skins.

In the meantime, we fabricated the seatback bulkhead this week. Here are a couple of pictures of that assembly.



Seatback bulkhead foam. Two areas have been machined down and will
be where openings will be cut out for access to the luggage area.


The front surface had been wetted with resin and micro and the first layer
of bi-directional fiberglass is being applied.


The second layer of bi-directional fiberglass has been applied and squeegeed.