THE CENTER WING
 
Because of the big wing span of this model, 3.60 meters or app 11 feet, the wing will be made in 3 parts. The center wing which is connected to the fuselage and holds the engine nacelles and the landing gear and both outer wings.
 
I wanted to make the wings out of foam, covered in balsa and epoxy. I am sure that is faster than making all the ribs and stringers out of wood. So I found this guy in Holland who has a CNC foam cutting machine. I went there with all my drawings and measurements and expected a high tech set-up with robot arms and mainframe computers and technicians with white coats and wraparound glasses. It turned out to be a 1990's IBM laptop, luggable not portable, and some pipes, motors and a hot wire.
 
Again using the Ziroli drawings we tried to emulate the wing foil as near as possible which sounds easy. There are so many parameters, but finally we did come up with something we thought would fit the curvature of the wing in the fuse. Remember, this model is not meant to fly, so the lift or drag coefficients are not that important. The look is.
 
The week after I returned with my car loaded with 10 cm thick foam out of a building supply company. We cut it into manageable blocks and started the machine.
 
It worked like a charm. In no time I had all my wing and stabilizer parts. And when I returned home it did even fit the fuse!
I was in heaven.
 
I forgot to bring my camera on both occasions so I have no pics. Not of the next stage also. Covering the wing with balsa. Again I read the tutorials on the net and thought it to be simple. I was wrong.
 
First I made big sheets of balsa by glueing strips together with CA. Than I applied white woodworking glue to the foam and folded the balsa sheets on and around it. One side at the time of course. I almost immediately noticed that it wouldn't stick. I took the sheet of (tearing it in the process) and applied more glue. On with the sheets. They were now saturated with moisture and started to go their own way, which wasn't mine obviously. I got bubbles and a couple of tears but boldly decided to go on with the other side. After both sides were covered in balsa I cut notches where the glue still wasn't thick enough and used a syringe to get more glue in there. Thank god I put plastic covers on my workbench and in the cut offs of the wing sections that I used to weigh everything down. I looked like a little kid that played with a big can of white paint without parental supervision. The stuff was all over the place!
 
There was a little voice in the back of my head that kept my spirits up by continuously saying: "don't worry, you want a model that looks old and beaten and that's what you are getting". I used everything in my workshop to weigh it down and left it until the next morning. The result wasn't good, but wasn't bad either. With a little sanding and a little filler it would come out just right. Good enough for a static, not good for a flying model.
I routered in some grooves for the wiring of the landing lights and the electric motors to turn the props. I should have done that before covering but I forgot.
Still no pics.
 
With the fuselage came epoxy nacelles. I started to fit them and measure them and found out that these were absolutely wrong in every which way you looked at them. So again out came the Ziroli drawings. I immediately ordered the cowls and the dummy radials from them. The nacelles themselves I made out of balsa and light ply. First I cut pieces out of the wing and glued MDF blocks in the wing where the hind leg of the landing gear would come.
 
 
Next came the box-frame with the longitudinal stringers.
 
Than I did the top of the nacelle
Top covered, starting underside
Wheel well outlined.
Wheel well almost finished, gear fitted.
Aft wheel well formed.
Trial fitting of the cowls and on the fuselage.
 
Where the center wing attaches to the fuse on the forward side, there is a bulge that extends from the underside of the fuse onto the wing. That I made
out of blue foam. I glued a piece onto the wing and sanded that into shape.
.
 
When both nacelles were finished I covered the center wing and the nacelles with epoxy and a light mat. I did this even though I covered the vertical stab with litho without epoxying it first and that came out right. But I want this model to last a life time and I expect to schlepp it to a number of places in the future. So epoxy it was. That didn't prove too difficult. The light mat, 80 grams per m2, adjusted itself perfectly to the curves and gave me no bubbles at all.
 
Now I was able to fit the center onto the fuselage. I had already glued in some MDF blocks for the screws to go through and into the fuse. Because of the shape of the wing fairing on the fuselage I had to take away some material on the top of the wing. That way it would fit like a glove and I would have to use hardly any filler on the fairing. The center will stay on the fuselage for transport. That way it will have it's own legs to stand on and it's only 90 cm's or 3 feet wide.
Not dead center yet. Keith is on the controls, Gordon is in the back with Inga...
 
Around this time my static props came in. I ordered them from aerotech models. Not cheap but the best I have found. They will have to be assembled and painted, but I trial fitted them and was relieved that the clearance between the props and the fuse was as it should be.
That is a major problem with this project. I just started without any knowledge and with a fuselage which had a lot of wrong things on it and with it and no drawings, but luckily a scale (1:8) that has some stuff available. Anyway, on with the project.
 
I marked all the panel lines and and hatches etc. on the wing to get an idea of the scale and see if everything would fit.
 
Panel lines.
 
Now on with what I like most and that is the detailing. The nacelles and wheel wells are the most detailed part of the DC-3. It has an elaborate exhaust system, a highly detailed radial engine and the wheel well is full of pipes, wires, junction boxes and hoses.
 
I started with the exhaust system. The exhaust comes under an angle out of the nacelle. First I had to cut a hole in the nacelle.
This is where the exhaust comes out.
 
The edges I taped in aluminum tape. It will be very difficult to get the panels to fit exactly, so in case a small gap may be visible, you will see aluminum instead of balsa wood.
 
In the gap I fitted a heat shield out of litho.
 
The exhaust itself I made out of plastic sewage pipes in different diameters. The end of the exhaust is an oval. I made this by cutting a strip lengthwise from a sewage pipe and glueing them together. The bend which tapers from wide to narrow I made by cutting a triangle out of a sewage pipe, heating it and molding it to the desired shape. The burn scars actually look very good, but unfortunately I have to do some filling to get the right shape, so the burns will have to be sanded out.
 
Rough assembly
 
Next I made the pipes that stick out on the front of the exhaust. frankly I don't know what they are for, I just have to make them.
These I made out of copper water-pipe, which has the correct size. Later they will be epoxied on the main exhaust.
 
Next I used epoxy filler to model the ends. Sounds good huh.. epoxy filler. Try to sand the stuff in that "armpit"
 
Left rough filler, right sanded.
 
This is what it should look like.
 
Fitting the exhaust will have to wait until the nacelles are sheeted on the outside. But I started with the wheel wells first.
 
Here is an example of what's inside the real plane.
A big oil tank and lots of pipes and stuff
Side view, gear is on the right.
 
I started with all the different panels that go into the wheel well. Again using paper templates. I did not heat these panels to keep them straight.
Panels for one wheel well
 
These were sprayed matt green and I scratched and weathered them a little already while the paint was still wet. After the paint dried I used wire wool to both smoothen the surface and get the rivets out.
Trial fitting.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fitted the litho and started with the pipes and the oil-tank
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
This is it for the time being. The undercarriage has to be modified and everything will be fitted properly when the wing is coated with litho and fastened to the fuselage.
 
 
 
 
 
Please Email me at:
dc3@propellor.tv