P-47 Thunderbolt

Ziroli 1/5 scale 92" span

 

 
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Motor mount and cowl

        
Since the firewall, is glued in to the front of the fuse, flat against a lip. I figure it would be easier to build the actual engine box outside of the fuse, then glue it all in once complete. I'm using a 3W-75 rear carb, so I had to make clearance in the firewall to accommodate the carb.
  
Now that the basic firewall is built, I decided to glue it into the fuse. I also mounted the motor to see how it would line up with the cowl.

After looking at the cowl, and looking at some different options. I decided to glue in some points that would hold the cowl in place. The cowl on the P-47 sits somewhat suspended, leaving an open ring around the circumference of the cowl, thus allowing for airflow to cool the motor.
  
Here is a pic of the cowl mounted to the fuse. The 3W-75 fits in rather nicely.

Switch Hatch
       
In order to conceal my switches and such so that they are not visible. I made an actual working hatch in the scale location. I unfortunately don't have a picture of the lay up, but prior to cutting the access panel, I laid up some glass cloth over the panel location. This way I would have a formed hatch door that could be cut to fit the cut out, perfectly. Once the hole was cut out, I used some 1/64th ply to form a lip that the door could rest on. I then used Sonictronic offset hinges to hinge the door, followed by a BVM hatch latch to hold the door in place.

Wing
  
There are still more things to do on the fuse, but I've decided to start work on the main wing. The wing builds flat, but utilizes 1/4 X 1/2" shims to purposely build in wash out.

I ran into my first problem in that I wasn't sure of how the tip rib is constructed. According to the plan, the trailing edges of the ribs are to sit on top of the shims when lined up on the plan. Although due to the small size of the tip rib, it just floats, and can't rest on top of the shim. By just floating, there is no definite angle at which is should sit while gluing. I posed this question on RCU, although I didn't get any responses to the problem. So I basically decided to leave the tip rib loose, pull the wing off the board, and sight the rib in line with the other ribs. I think this will work and give me a pretty close angle for the washout required.
       
The next set of pictures shows the construction of the gear supports. I was actually a little confused on how they fit together. The plan only showed a top view, and it was a little confusing with the parts that were included in my wing kit. Regardless, in the end I decided to do it my own way, and how I figured the gear would hold best.
  
Here is a picture of the Robart Gear and Glennis scale wheel I will be using.
  
Now that the basic structure of the wing is done, the next steps are to sheet the lower part of the wing. The wing is sheeted with 3/32" balsa. (I use to always build my sheeting with white glue, although lately I've found that I can do just as good a job with CA. A little more expensive, but a lot quicker to put together.) Once I had enough sheeting built to cover the wing structure, I used the wing plan to draw the outline of the wings trailing edge.
  
Now that I had my shape, the next step was to glue on the sheet. I used the original shims that were against the plan to keep the proper twist in the wing, as I was gluing. It seemed to work out fairly well.

Now that I had a "basic" right  wing, I decided to start framing up the left side.
     
Since the left side was a carbon copy of the right side, I decided to just get it to the same stage as the right, without taking so many pictures. I'm now have a left and right panel, that are framed and sheeted on the bottom.
  
According to the instruction sheet I got with the Ziroli kit, the next step is to sheet the top of the wings. Although I decided that it would be easier to do all the internal work (i.e. retracts, doors, lights, controls, etc) prior to closing up the wing. Before cutting out the shape of the wheel well, I wanted to lay up some fiberglass in the general area of the well, so the glass will form to the contour or the wing. I basically taped a piece of wax paper over the wing, then laid 4 layers of 6oz cloth over the wax paper. (For those who are wondering, I used West System epoxy to lay up the glass)
  
Once the glass had cured, I then removed the fiberglass skin, and cut out the shape of the wheel well.

Once I had the shape of the wheel well. I then took my formed glass sheet, and cut out the doors. I purposely over sized them by about an 1/8" of an inch, so as to create a lip that will sit on top of the wing skin. (After speaking with others and looking at this further, I have now decided to recess the doors into the wing.)
        
To give the doors a little scale realism, I added some 1/4" balsa to the inside of them. This will give the doors some rigidity, as well as a scale look. My next hurdle was to make them functional. I used some Dubro 1/4 scale plastic hinges with removable hinge pins, so I can easily remove the doors if need be. After looking at various pictures of the scale P-47, and how the inner door was actuated, it soon became apparent that with the air pistons I had it wouldn't be easy, as I wouldn't have enough throw to move the door correctly. So I scraped the scale location, and decided to go with a bell crank system that would give me the necessary throw to make the door work properly. Basically I just used a 1" cylinder from Ultra Precision, mounted to the rib, then connected to a Dubro 90 degree bell crank. The ball crank is then connected to the door, and after a little tweaking it seemed to work relatively well.
  
Now that I had the inner door working, I started to work on the upper doors. that are connected to the actual strut. I began by first recessing the retract cover into the wing. I used some BVM flush mounted screws to hold the hatch cover in place. These seem to work rather nicely. Once the hatch was installed, I then fitted a small Dubro hinge to the hatch plate and the upper door.
  
My next challenge was to figure out how to attach the door to the strut. So I got some scrap 1/4" 6160 aluminum, and made a pinch collar that would fit onto the strut. I then tapped in two 2-56 ball links, that would eventually be connected to a U shaped 2-56 rod, connected to the door.
     
Here are a few pics of the mock up, in motion. It seemed to work rather nicely. Now that I know it works, I will make a more permanent installation. 

Construction Page 1

Construction Page 2

Construction Page 3

Construction Page 4
 

 

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Last Updated 03/01/2007