Chapter 7 - Step 2

Step 2 involves contouring the bottom corners of the fuselage, making a lip around the landing brake and F-22, making a reinforcement for the step, and putting the antenna in the belly.

Cutting Foam May 17, 2000. Here I am cutting the foam corners. I have already made the 45° cut and I am now making the next pass. The two black lines visible were drawn about 4.5" from each edge. This marks the end of the curve. These lines go from F-22 to the aft end of the landing brake. From there I just did what looked right to transition to the landing gear bulkhead.

Aft Shape May 20, 2000. Here is the aft end all sanded to shape. The darker band forward of the forward landing gear bulkhead is a gap at the lower longeron. I need to fill this in with some foam.

Contoured Edge May 20, 2000. Here is the completed shaping of the bottom, right edge of the fuselage.

May 23, 2000. Here is a close-up of the foam gap I have on both sides of the fuselage. Chapter 5 has you place the lower longeron in place based on the dimensions shown on figure 5-5. To do this I needed to have the longeron over hang the foam edge a bit. This turned out to be a problem in the aft section. This will be fixable by gluing a strip of foam in place and sanding to shape. The gap is a bit too big to fill with micro or flox and would add a bunch of weight.

Completed Contour May 23, 2000. The fuselage bottom edges are all rounded to shape. The long, box shaped tool in the fore ground is a Perma Grit sanding tool. This was the best spent money so far. I highly recommend the Perma Grit tools for this sort of thing. It easily allows you to sand the micro between two layers of foam without forming the dreaded "double valley".

Brake Lip May 31, 2000. Here is the 1/16" lip made around the landing brake. I rounded the edge so the glass will go into the depression without a problem.

F-22 Lip May 31, 2000. Here is the 1/16" lip made around the F-22. I rounded the edge so the glass will go into the depression without a problem. So far the lip is along the bottom and the corners. I will do the sides later.

Step Cutout May 31, 2000. This shows the foam cut away for the step reinforcement. Cutting the wood for this is going to be a pain.

Landing Brake Duct Tape June 3, 2000. Here I have applied the 1" of duct tape around the landing brake. The sides required 5 layers and the aft edge required 6 layers to make it flush. The difference seems to be due to sanding the depression. You can also see that I applied duct tape around the lip of the cutout as well. Some people have had trouble with epoxy getting under the landing brake while glassing the bottom. The result is the landing brake is glued to the bottom and this obviously creates of bunch of extra work.

Foam Hole Patch June 3, 2000. There was a big ding in the foam where the cutout is. I layed a piece of scrap over the ding and cut through both the scrap and the bottom so they were the same size and shape. I then chiseled the old foam away. This is what you see here. I simply microed the scrap into place. After a speck of sanding you will never know there was a patch here. One the great aspects of composite construction.

Patch Work June 4, 2000. Here are three different patch jobs.

In the bottom left and just left of the hammer head you can see some blue foam nailed in place. I cut too deep in these spots with the hacksaw so I am gluing these pieces back so I can sand it smooth. This will save on a lot of filler later.

I had to remove part of the NACA scoop to fill a void. The hammer is holding a small board to weight down some of the foam after being glued back in place.

You can barely see the foam that was added to the gap in the fuselage bottom/side corner (center to upper right of picture).

June 4, 2000. Here is the birch plywood step reinforcement floxed into place. You can see part of the marker beacon antenna cable channel at the top of the picture.

Coax and Antenna Joint June 7, 2000. Here is a close-up of the marker beacon antenna and coax cable join. The cable is RG-58/U (solid center). Belden #8240. I got it at Radio Shack for $0.22 per foot. It is Radio Shack catalog number 910-1582.

You can clearly see the three baluns on the cable. I soldered an extra piece of wire from the braid to one of the copper antennas.

Marker Beacon Cable Channel June 7, 2000. I made a channel for the marker beacon antenna. This channel goes down to the micro. The idea is that I will micro the cable in the bottom of the channel and then cover the cable and fill in the top of the channel with a piece of foam. Once this foam is sanded flush you will barely be able to tell where the cable is.

Marker Beacom Antenna June 7, 2000. The marker beacon is running down the passenger side of the fuselage. The cable crosses the fuselage between the landing brake and landing light. It then enters the cabin just forward of the IP near the right side.