Saturday, August 21, 2010

On Hold...

Everything has to go on hold while I attend a 10 week class for work.  I'll return to work on the bulkheads in November.


Sunday, August 15, 2010

Instrument Panel

The IP is made from multiple pieces of foam and pieced together before glassing.  I used the full size plans I bought as a template and a seamstress pattern marker to transfer the template to the foam.  I did run into one small problem...

As I mentioned before, the plans kit comes with a set of drawings but some of the bulkheads templates are only half drawings and you have to make the mirror image.  That's not that big a deal but I thought it would be easier just to have the full sized drawings.  The full size set was provided by a former builder.  Just in case there could be differences between the two, my process involved checking the full sized drawings against the plans drawings to make sure any changes had been picked up.  In the process of checking the IP, I noticed a 1/4" difference in the height of the two sets of drawings.  Which one was correct? 

After consulting with the Cozy mailing list I decided to go with the larger dimension as I could always trim excess if needed.  After a little more checking of different drawings and actually measuring the distance between WL marks, I actually found that it was the plans drawings that were distorted in the vertical axis...presumably from the copying process.  This may explain why several builders report having IPs that were 1/4" short when they went to install. I've decided to stick first with dimensions as called out in the instructions and second, with the full size plans for any measurements I need to take from the drawings.



Here We Go...The Seatback Bulkhead

Well, at long last, it's time to start building real aircraft parts.  The long journey ahead starts with the fairly straight forward building of the front seat back.  It's made out of 3/4" medium density foam, glassed on both sides, and becomes one of several structural bulkheads running from one end to another in the fuselage.  At this point I went ahead and purchased a small 10" table saw from Lowes.  It was perfect for cutting the 45 degree beveled edges at the top and bottom of the seat.  I'm sure it will come in handy more.  The beveled edges are necessary because the seat reclines 45 degrees when installed in the aircraft making for a relaxed seating position while flying.
Glassing the front went very well.  I am peel plying everything.  Peel ply is a process of applying a dacron fabric over the completed wet glass until it cures.  When you pull it off, it leaves a surface that doesn't need any sanding or other prep to be able to bond another piece to it.  Otherwise, fiberglass parts that must be bonded to other parts must be sanded with very course sandpaper to eliminate any smooth areas that won't adhere well.  The sanding process will cut fibers in the glass--not the best situation.  With the peel ply process, I don't have to worry about where I might have to bond something in the future, it will already be prepared.  The peel ply also works really well to hide transition areas between two layers of glass.

Seatback, glassed on both sides now and
 positioned approx like it will sit in the Cozy

The back side of the seat back didn't go as well.  I ended up with several lean (dry) spots under the surface as well as a few bubble type voids.  At first I was pretty dissapointed. I can only guess that I got in a hurry and didn't do an adequate job of wetting the glass cloth and moving the air out of it.  After a close inspection and a review of the inspection criteria in the plans, I decided that none if it, even taken as a whole, was severe enough to force rejection or repair.  I couldn't just leave it though, everytime I saw it I would be reminded that I could have done much better.  Besides, this would be a good opportunity to practice some of the repair techniques. In order to fill the voids, I puchased a couple of the largest syringes CVS pharmacy had in stock and carefully injected expoxy into the voids.  This worked great !  Then I thought...this might work on the lean areas?  Sure enough it did.  The trick was to poke an air relief hole on one side of the dry patch, then inject from the other side.  A little heat from a heat gun made this process a breeze.  I was able to cure most of the larger lean areas and make I then felt much better about the part.  Next time I won't let myself get rushed.


Monday, August 2, 2010

Tools for Composite Building

Chapter 3 introduces the builder to a number of items that are needed to build with composites, provides an education on fiberglass techniques and the different terms and processes you will use, and walks you through some exercises to practice those techniques before you start on real parts.  First the tools and equipment.

1.  You will need a flat top workbench that is at least 11ft x 3ft.  The length is to support the lenght of a wing or canard when you perform the assembly and layups.  These are obviously parts that need to be built true, without twist or curve, so the top must be extremely flat.  I built mine to be 12 x 4 like many others.  I followed the recommendation of a few other builders and purchased I Level TJI Engineered Floor Joist to use as beams for the workbench. There happend to be a millwork place about an hour from me that carried them. They are very solid and will keep your bench from twisting. I used 4x4s for legs and installed levelers to aid in leveling the entire table. The biggest problem I had was getting the tops of the beams all lined up to make a flat top. One of the beams was not as flat at the others on top so I had to shim under it until I got the partical board I used on top nice and flat. I worked for a few hours but finally got the top within .1% of level no matter where I checked it. Then I placed masonite over the top to provide a clean surface that would be easy and cheap to replace when needed.

Epoxy pump and insulated
heated cabinet
2.  An epoxy pump will make your mixing much quicker and easier.  Like most builders, I also built a heated epoxy cabinet to keep the epoxy at a good working temperature.  I used an old shelf cabinet I already had, installed foam insulation inside, and outfitted it with a light for a heat source and a dimmer to make the temps adjustable.

3.  You also need to keep your fiberglass cloth from getting dust or any contaminant on it.  I used the same idea that other builders used and constructed a wall mounted cabinet that folds up from the bottom to protect the cloth.  It has two sections that unfold into an approx. 6ft cutting table. Although it works well, it's probably not the design I would use if I did it again as I've pinched my fingers twice now by holding it in the wrong place when I unfold it.  I've now marked the end of the table with "NO GRIP" markings to remind me to hold it on the sides when unfolding the table so the outside legs don't catch my fingers when they fall into position.

Glass cabinet closed to keep cloth clean

Glass cloth cabinet open for cutting

4. One other tool I'll need is a foam cutter.  Chapter 3 shows you how to make one but I've decided to wait on building it since I won't need it for a while anyway.

Chapter 3 gives you a full list of recommended tools, both hand tools and things like a band saw, table saw, and drill press which will make some things easier.  I purchased the tools package from Wicks Aircraft Supply as well as their special package of Cozy Girrls tools.


Sunday, August 1, 2010

The CAF Emerges

Since the end of May, I've been focused on converting the garage into what I call the Cozy Aircraft Factory (CAF).

New lighting...I replaced the poor lights with 2 sets of 4-bulb, 48" floresent lights giving me much more light for which to see the Cozy.

I insulated the garage door with Prodex Total Reflective Insulation.  My garage gets the direct sun until 1100am and can really warm up the CAF fast in the summer mornings. 

 To make the CAF a more year round fabrication facility, I insulated the attic above and 2 exterior walls with lose fill insulation.  In the pic below you can see the holes drilled to pour in the insulation.  Then I purchased a portable air conditioner/ heater/dehumidifier which I'm sure will help make things much more tolerable in the extreme seasons.  Working well with epoxy and fiberglass is very temperature dependant.  You need a warm place, warm parts, and warm epoxy, perferably 80 degrees or more, to give you good results.

I had to install utility shelving high on the back wall to get much of my storage up and out of the way and completely reorganized the place to make as floor space as I could. 

Here is what it looked like after I finished. In this picture you can see the overhead utility shelves on the back wall.  Note this picture was taken after I had also built the required 12ft long work bench and other items you need to fabricate the larger parts.  I'll discuss those more in Ch. 3.

The Cozy Aircraft Factory Ready for Action