Cozy Construction Chapters.
Chapter 7 - Contouring foam sides/bottom, NACA scoop, Marker beacon antenna, Glassing sides and bottom
Started 5/27/2004 finished 8/29/2004 Total chapter hours worked :63.5
Started by building up foam for the NACA scoop.
Next the plywood and foam for the landing gear and firewall areas.
Working on the 3/8" PVC foam between the firewall and landing gear.
The foam is now ready for contouring. I used a home made sanding board made out of 3/4 MDF that I sprayed glued 36 grit paper to and the perm-a-grit tool set about $65 from Wicks.
Taking your time on this step is key. Work the length front to back and back to front. This will help you get the feel for how much to sand and where.
This picture shows the 1/4" Alum. hard points for the landing gear cover after they have been floxed in.
The bottom contouring is complete, here you can see all the contours are smooth and feathered. You will find that each type of material sands a little differently, the wood being the hardest along with the macro, that's where the perma-grit sanding tools make it a lot easer.
Now is the time to build the marker beacon antenna, the materials I purchased from RST Jim Weir. The co-ax RG-58 cable is cut into the foam along with the three Ferrite Triodes that slip over the co-ax and then floxed in place. The copper foil has a sticky back that hold it in place until the bottom is glassed. Make sure that you are comfortable with soldering the co-ax to the copper foil, a bad connection here will make the antenna no good. The co-ax enters in front of the IP bulk head. Also in these pictures you can see the tape around the air brake making it possible to have a smooth surface once the final air brake steps are completed in chapter 9.
Glassing the NACA scoop is a tough one. The plastic wrap is there to hold down the glass into the 1/8" joggle for the landing gear cover. Knife trim flush with the top of the scoop. After cure I carved out the foam along the scoop top edge, applied flox corners to reinforce the sharp edge of the NACA scoop.
This picture shows the bottom glassing complete and the air brake. I cut through some of the glass around the landing brake while the glass was still curing. This idea I got from other builders web sites, I hope it will make finishing the brake easer when the time comes.
Here's a picture from the front with the peel & ply still on.
Engine and Landing Gear mount reinforcement lay-up.
These pictures show some of the engine mount reinforcements on the bottom.
Here you can see the cut out for the canard, which will be built in chapters 10,11,12.
In this shot you can see the template line that I drew to give me an idea as to how much foam and wood would be removed.
These three picture show the completed contouring of the top. Just like the bottom take your time and work the entire length, do NOT try to contour just one area; like the book says work the length and check with the templates often. It was very satisfying to see the completed contours come out, not knowing what it was really going to look like.
The fuel sight gage windows will be cover with the fuel sight gages from Vance Atkinson.
These five pictures show the two sides being glassed with there reinforcements. I built two three legged support systems that allowed me to rotate the fuselage along the longitudinal axes. To keep the finished bottom and the inside clean I cut garbage bags bottoms off and made long sheets to protect the other parts, cheep and worked really nicely.
During the process of glassing the side you also have to added the engine mount reinforcing lay-ups of 3 plies of UND and 2 plies of BID all of which gets peel & plied.
On to Chapter 8.
This site was last updated 09/22/11