DC-3 Display Project

Click Here for Construction Part 1 Click Here for Construction Part 2

1-17-2002
The winter months always seem to make good building months, since it is too chilly outside to enjoy flying as much. After sheeting the top of the wing center panel, I decided to start on the engine nacelles. They were not as complicated as I thought they were going to be, but I did notice a few interesting tricks. I knew from prior experience that balsa becomes temporarily flexible when exposed to amonia, mostly due to some type of chemical interraction with the wood fibers. When the amonia goes away, the wood returns to its original shape. On the center section I used this technique with window cleaner, which contains some amonia dissolved in water. I haven't sheeted many round objects before, but I learned that smaller planks make the job much easier. The parts aren't cylindrical, so the width of each plank varies along its length. I started out with three inch planks, which were too wide. Eventually I noticed the hint on the plans to use 1 inch planks, which work much better. I finished the top half of each nacelle, but I have not started on the bottom yet. I can't completely visualize how the lines come together in that section, especially around the faring for the retracted wheel, the air scoop, the cowl flaps, and the exhaust. I hope I'll be able to find a real DC-3 to go stand by and take some pictures, and I'm sure that such a visit would simplify the process.
I have also worked out the details of wing attachment to the fuselage. The bolts are 1/4 X 20 X 3, which are certainly a little bit of overkill. That is one size for which I already have a tap and drill for though, so it was an easy choice. I have secured the front of the wing with a dowel and the back with two bolts, which is a common setup on airworthy models. I used epoxy to harden the portion of the wing where the bolts go, so that I will be able to counter-sink them.
I started the finishing process on the wing tip sections, mostly as an experiment for required methods. I used a 50/50 mix of polyurethane wood finish and thinner in hopes of hardening the wood. That is as far as I have gotten so far, but the current plan is to put a few layers of polyurethane with sanding between, and then a coat or two of automotive primer to check out the surface quality and to continue to fill up the holes. i'm not sure how it will work, but that is why I am starting now. The polyurethane choice came from my emphasis on low cost and not on low weight, since this won't be a flying model.

3-29-2003

I've been so busy building here lately, that I haven't been updating the web page very much. First of all, here are the pictures that correspond with this update:

Since this is a low-budget project, I have to try and be creative when it comes to scale details. The undercarriage is one such example; I decided that I would make the main wheels out of wood. So, I made a wooden blank, and cut it into a circular shape. Since I don't have a lathe, I tried to use a drill press to turn the wheels to shape. If you are ever interested in trying this, let me be the first to tell you that it probably won't work. The wood grain was the wrong direction, and the pine was certainly not the best choice of wood types. So instead, you can see that I went with blue foam. This actually worked pretty well. In the case of the tailwheel bracket, I applied knowlege that I gained from a walkaround of an old Hawaiian Air comination DC-3 that Hankins Air Service uses as a scrap airplane in Jackson, MS. Along with my trusty scale drawings and a bandsaw, I generated a pretty decent likeness. The wheel is an airworthy 3" model airplane wheel, since I had a few extras around. Now it's just a matter of attaching the parts that I have to the aircraft, but that is a task for another day in the distant future.

I've also done considerable work with the wings. It is apparent that the workers of this DC-3 factory shift were under the influence of drugs, since the rivet lines are about as straight as... well, let's just say they're a little bit curvy. As I got a little bit better with the rivet wheel, things got better. As you can see from the pictures below, I've covered most of the fiberglass nose, and painted a black radar dome on the front. I'm not sure that it is very scale, but it certainly looks good. The flite-metal would be a challenge to bend around that front surface, so that is why I conveniently included the radome. I'm going to cut out the windows and include a clear plastic window material. The shiny substance that you see on the wings is almost entirely alluminum foil tape from the hardware store. I guess it serves me right for being cheap, since the wide roll that I found has red letters on it. When I bought the roll, I figured the letters where only on the first few inches of tape. Rubbing Alcohol takes them off fairly well, and when I use a paper towel for the task, it generates some nifty designs on the paper. As for preparation, I prepared the wood by applying two very thin coats of polyurethane. Don't do this to a flying model- it will be to heavy, and not very dent-resistant. But, for our little project, it beat the fiberglass method hands-down.

I was finally inspired for today's update because earlier this afternoon, I went to a hobby shop. It is almost a sin to call the store a hobby shop, because quite frankly, Frank Jackson's Advance Discount Hobbies is much more than that. My first visit was almost 4 years ago, and on my way through the door I realized that it was perhaps the best model shop I've ever been in (and I've been to quite a few in the South Eastern United States). One would not suspect that such a store would fit in Monticello Arkansas, but in fact that rural setting provides a very central location for the entire Mid-Southern United States. Perhaps the greatest thing about Advance Hobbies is Frank; he is an airplane fanatic to the core. While some shops focus on R/C, or limit inventory to the fads and "big sellers," Frank has successfully accumulated an unbelievable inventory of all things flying. He is an equal-opportunity model aviator! Whether it's free flight indoor rubber powered models, control line models, building supplies, kits, ARF airplanes, or even plastic static models, Frank has it. Even better than that, he knows a whole lot about all of it, and if you are interested in expanding to various aspects of the model aviation hobby, his store is the place to go. If you are ever in my part of the country I hope you will go visit with him. Don't be fooled... I'm not paid by him, or even encouraged to spread the word about his store; I'm just a very enthusiastic customer who is glad to see such an incredible business.

7-13-2003

Enough about that, and back to the progress. I've been able to get quite a bit done in the past four months, and I am finally starting to see an airplane appear in various rooms of the house. After applying the metal tape to the other wing tip panel, I sheeted the fuselage top back to the last former before the stabilizer. Since I want to make the stab semi-removable for the transport in the end, I wanted to take some time to get things worked out. I attached the center section of the wing so that I could be sure to line everything up, and set it up on a table.

I believe that the first builder incorrectly joined the aft fuselage and stabilizer saddle, since these sides came together just behind the stab trailing edge. According to my calculations, the tail should continue beyond this point another 6 inches or so, and the saddles should be separated by a former called F14. The end result was that the sides converged before they should, so that was going to be an obstacle. The tail of the DC-3 is one part that has been looming over me for a while. It is a fairly complicated intersection of curves, and it isn't too easy to visualize without seeing the completed parts. I decided to make this part out of foam, since foam is cheaper and more readily available than balsa for me. As you can see, I started by adding big chunks of foam to get the right converging angles of the fuselage sides. I made a stabilizer mounting system that was reliable enough that I could mount it in the same place every time, and did the same with the fin. The middle two pictures show this detail; you can see the two screw heads, and the light colored wood that they are holding on is actually attached to the stabilizer. You can also see that the foam is at a fairly crude stage at that point. By the way, if you click on a thumbnail you can see the "big fat super huge" version of a picture on this page. After a break to pick some flowers in the garden, and lots of head scratching, you can see the tail taking shape with the last picture on the row below. This simple way was how I should have done it in the first place, but that is beside the point.

I'm not sure why it was that I waited until now to shave the tips of the stab and elevator down, but I finally did that one afternoon. I also shaved down the tip of the fin and rudder, and added more material in the attachment for the stab and fin. I used a box from the crackers that I ate that weekend to make some templates and cut those curves that make it all come together; the elevator curves on both halves where it meets the fixed portion, and the rudder has a bit of a curve too. All of these come together at the tail position light. The last three pictures on the line below show this detail farily well.

I was lucky enough over the holiday to go to the Air and Space museum in DC, and I took a few pictures of the Eastern DC-3 there.

I've just about got the tail far enough along to start making the curved filletts that are another crucial step in the way the parts flow together, but before I do that, I want to have more sheeting done. I think I'm going to go ahead and sheet most of the aft section of the fuselage, and give the tail section a break for a while. I've got a bit of work cut out for getting the center section of the wing and the fuselage to mate harmoniously, which is the last big barrier to having the fuselage sheeted. Then it will be time to start sanding until I just can't stand sanding anymore; I still have to finish sand the fuslelage, center wing section, and the new areas in the junctions. Then I'll be on the home stretch; hardening, and metalizing.

I've also given some thought to the logistics of hanging this beast, and I think the best method is going to be to build a stooge out of lumber that has the same attach points and similar weight. This way, we can take care of the building's structural anchors and line lengths without worrying about damage to the model. Then, when it is time to hang, I'll be able to bring in the model and clip it to the three attach points and be done. I'm already hanging the plans on the wall for my next project, in hopes of extra motivation- it won't be too much longer I hope until the DC-3 is on display and out of the various rooms of the house.
Click Here for Construction Part 4

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