Building a 1/2 Scale Cap 232
By James Goss
Here it is mid summer now of 2001 and I have just got started on a half scale project. This kit has absolutely no written instructions at all. What it does have is two small sheets of drawings to work from. This kit is definitely for the experienced giant scale builder and is something really different for me to build. I enjoy working with a kit that has a challenge and I think I have found the mother of all challenges in this kit. Big planes require large work areas and I am lucky that I have such a shop for this project. The wingspan will be 147 inches and the fuse will be about 10 feet long, when completed the plane will weigh about 70 lbs. It requires a 210 -140 cc engine for power and many high torque servos. The designer of this plane uses 330 inch-ounce servos in his plane operating on 6 volts. It will require a 36-inch prop if I can find one, large props are hard to come by sometimes. The fuselage is made of fiberglass and the wings and tail sections are sheeted foam. The wing uses a wood spar instead of an aluminum pipe, as do most other giant scale planes. The spar in each wing is 80 inches long and measures 4 5/8 high and 3/8 thick. It will be made from some type of hardwood; I am not sure at this time which wood I will use.
At first I thought the fuselage would be really quick to build, by it being made of fiberglass. Making the large formers and firewall and getting them to fit the structure is going to take some time. It takes me all day to make one or two formers and install them with epoxy. This is how I do it: I make a pattern of the formers from paper and transfer it to cardboard. I make sure the cardboard has a good fit in the fuselage before I actually cut the former. The formers are built from ¼, 3/8, and 1/2 inch plywood. At this time I have already installed the firewall and tail wheel backing. I built these from ½ inch maple that has 9-ply structure. I have had a lot of trouble with tail wheel assemblies in the past on large planes so I wanted to be sure that this would not be the case with this plane. I am using a Heigh style tail wheel and I have installed a bronze bushing for it to seat into. This should never allow the hole in the plywood to wallow out. Just getting the formers in position is a problem because of the access to the fuselage. The fuselage is in two pieces and will be joined in the center. I will keep you updated on this project each month until it is time to test fly it. I will try to have some pictures of the progress next time.
Update
December 2, 2001
Well here it is December already and I am back on track with the Cap 232. I had gotten off on several other projects during the last few months and let the Cap sit idle. This time I started with the tail sections and got them sheeted with 1/16-inch balsa. The horizontal stabs are very thick but relative small in size. The elevators are huge and occupy most of the area for the tail section. Same design for the vertical stab, small stab with huge rudder. The rudder servo will be mounted in the vertical stab and the elevator servo will be installed in the horizontal stab. The horizontal stab is in two pieces and will be a plug-in design with a 7/8-inch round aluminum spar. Getting the holes drilled for the aluminum spar turned out to be quite a chore. The pipe must run true and level as it goes through the tail section so the horizontal stab will be parallel to the wings. With this accomplished I began construction of the vertical stab and rudder. I had purchased all the balsa and ply for this project and had it put aside until I needed it. Scratch building several planes in the mean time I dipped into my earmarked supply of balsa and now I was out of 1/16-inch sheeting. Placed a call to Balsa USA and got some on the way. Not being able to finish the rudder I decided to start the wings.
Let me say first that these wings are really big, I mean huge! Each wing panel is in four separate sections with a large spruce spar running the length of the wing. I am using thinned epoxy to sheet the wings with 3/32 balsa. I thin the epoxy with a 50/50 mix of epoxy and alcohol. This is the first time that 48 inch balsa was not long enough to sheet a wing panel. Each panel is 67 inches long and the fuselage is 13 inches wide, this adds up to the 147-inch wingspan. I have just finished cutting the slots in the fuselage for the wing spars to enter. They are 4 5/8-inch high and 3/8 wide. The wooden spars will go through these slots and overlap each other inside the fuselage. A wooden box built from ¼-inch plywood and enforced with carbon fiber will house the spars. This is where I am in construction at this time.
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