Cozy

Chapter 4 - The Bulkheads

The Shop

This is where I hope to build most of my airplane. Well in half of it, my wife still wants the other half of the carport. I've got an 3 x 12 table to do the layups on, and other stuff of course. A box on the wall to store rolls of fiberglass. Another that is heated is to keep the epoxy warm. Also to the left is a utility room to store all the goodies, ie. spare 13b Madza for parts.( see Chapter 23 for more on my engine choice.)

The Plan

In this chapter we will manufacture the seven bulkheads that are installed in the Cozy Mk IV fuselage. From fore to aft in order, these are F-22 and F-28 (named for their fuselage stations), which mount the canard, then the instrument panel, then the front seatback, then the forward and aft landing gear bulkheads, and lastly the firewall. In addition, you will make a temperary firewall for assembly purposes. There are many short jobs in this chapter with cure times in between, so you will want to make several bulkheads at the same time.

Seatback

First and foremost "FOLLOW THE PLANS". Don't try to get creative and do steps before they are called for. I put some of the notches in the foam to save time later, WRONG. There is a reason they say to do it this way. They have more experience than you. This piece is the back of the Pilot/co-pilots seat. It is the first layup you do because it is probably the simplist. All others layups will build on the skill you develop here. The layups went ok, but I had one edge that didn't want to laydown. Easy to fix! If yours isn't throw it away and start over, it doesn't cost that much. When you feel confident, procede. When you cut the BID, don't pick it up!!! It will deform!!! Roll up the fiberglass, then place it on the part and unroll it. Also, when you remove the BID from the roll, don't pull it off the roll. It will deform!!! Place your hands on the roll, and unroll a pile of glass. Then put both arms under the glass and extend the pile out. This part gets 2 plys of UNI (unidirectional - most of the fiber run in the same direction) on one side. The other gets 1 BID. The lighter areas on the sides are peeled plied. This is a layer of Dacron squeeged on top to form a surface that is ready for later layups. It is removed as soon as the epoxy is dry.

F28, F22 and Doubler

These layups are fairly straight forward. The F-22 is the forward bulkhead in the aircraft. It is the attach point for the canard (the little wing in front). The smallest bulkhead is the F-28 (called that because it is 28 inches from the nose of the aircraft when done). If you are careful you can use the BID that is removed from the leg cutouts to build the 8 x 12 layup for the hardpoints in the landing gear bulkheads combine these with the insrtument panel cutouts you can save alot of glass later. Lay the sheet of BID over the whole panel so it sticks into place, the use your Dritz sissors to cut out the holes. You can see them on the board. Then you can apply the epoxy. The F-22 gets 2 BID and 1 UNI per side. The F-28 gets the same but then adds a foam doubler and 9 layers of UNI and BID alternated on each side. You can see these by the greener areas of the sides. So you can see how the layups are getting more complex as you go. The doubler goes from the sides across the top. The board and weights are keeping it in place while curing. It adds additional strength for the canard attach points.

Instrument panel

This is the instrument panel, it will hold all the flight instruments, radios, engine monitoring equipment etc. It sits just in front of the pilot, with their legs fitting thru the large holes. It has channels on the back to carry all the wiring and stiff'n it so it doesn't flex for and aft. The holes for the instruments are cut into the panel later. This panel adds to the complexity by adding the stiffeners and wire channels.

The landing gear bulkheads

John Slade says "the hardpoints are interesting." I think that is an understatement. No where does it mention that you can get all the hardpoints from one 8 x 12. But you do, so don't waste glass making four of these layups. Guess how I know, oh well another trip to Aircraft Spruce for more supplies. This portion of the plane holds the landing gear in place. The four darker areas of the bulkheads are the hardpoints. They are the point where the landing gear bolts into the plane. The hardpoints are made by laying up 22 layers of BID then forming them into the foam core. 2 BID and 1 UNI are then placed on each side.

The firewall

You can see the temperary firewall leaning against the table. The real one isn't needed until a later chapter. The temp is used after the next chapter to align the sides when you start putting it together.
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