P-51C Mustang Firewall - The Thought Process

Since finishing my Mustang's engine, I haven't had much time to work on my model because I have been studying for my General exam to get my Airframe and Powerplant license and I've been waiting for my sister to have her baby. So its been busy. But while I'm sitting here eating a terrible TV dinner before work, I decided to throw up a quick blog that doesn't show how things are detailed, instead I give new modelers or perhaps people who are new to superdetailing an insight into one modelers thought process when I first look at the kits parts. The oil tank and firewall provide a simple, yet good opportunity for this.

At first glance the Tamiya kit provides a good amount of details, much more than some Mustang kits I've seen. Just a bit of paint, maybe some dry brushing and weathering and it should be pretty good, right? Sure if you want to take the easy way out. The firewall has a lot of potential for detailing, if you know where to look. This is where research comes in. Luckily the P-51 Mustang is a well documented aircraft and you can find dozens of books and websites with pictures of almost every part of the airplane.

The first thing that has to come off is that ugly tab with the hole on the bottom of the firewall. In the kit this is where the engine mounts via a screw to the firewall. On the real Mustang, the engine was on mounts and so it shall be on the model. Why Tamiya decided to do this is beyond me, unless the plastic engine mounts don't have enough strength to support the engine, in which case they will have to be reinforced later. So I'll have to keep that in mind.


Around the upper edge of the firewall are these little blocks to represent the Dzus fastener mounts. One look at a picture and it is clear that these also have to go. I'm thinking soda can aluminum cut into thin strips and bent into the right shape. I will create the hole for the Dzus fastener by gently poking the aluminum with the needle on my dividers. This will create the hole and the dimple all in one motion. There is also a bracket that holds the Dzus fastener mounts in place which is not shown on the kit piece. This can also be made with soda can aluminum. This picture also shows the molded weld bead on the two oil tank halves. Unfortunately if this was a real Mustang, I'd fire my welder cause the beads are way too big. In this scale, the bead would be very subtle. So these molded welds will come off too, and I will trust that the glue bead that will ultimately hold the parts together will simulate a more accurate weld. Now before I remove any of these parts, especially the Dzus fasteners mounts, I will measure their width and mark their locations on the firewall so the new details go back in the same place.


The metal straps that hold the oil tank to the firewall are fairly accurate, except the turnbuckles used to tighten them down. They are very flat on the kit piece, but if you look at the real one, they actually stick out quite a bit. I will leave the metal straps on the kit pieces, but will have to carefully scrape off these turnbuckles. They can also be recreated with soda can aluminum and thin wire. Now the reason I'm going to keep the molded straps on the pieces is because the real Mustang's oil tank straps have a thin cushion between the tank and the strap. I will create new straps from soda can aluminum and will round off the corners just slightly on these molded straps to make it look like the metal straps are sitting on the cushions. Then I will install the new turnbuckles.

The area on the firewall that holds the oil tank is shiny chrome in every picture I have ever seen of the real Mustang. Luckily the kit makes this area quite promiment. I'm think about using the shiny side of aluminum foil to create this. And since the oil tank will be covered most of the compound curves in this area, I only need to foil over the flat areas that will be seen. Sometimes modelers have to think like movie set designers. If it won't be seen there's no point in creating extra headaches. There is a material called Bare Metal foil that has an adhesive backing which could also be used, but it can get rather expensive depending on where you buy it. Aluminum foil is cheap, easy to work with, and can be glued down with white glue, super glue, epoxy. Just scuff the plastic surface with some light sandpaper before gluing.

The bolts on the firewall are not painted, but instead are a natural silver steel color. After the firewall is painted green zinc chromate, the bolts will be painted silver using the tip of my X-Acto knife the same way I painted the bolts on the engine.


The oil return line looks OK, but the thing with molded round tubes is that they don't come out round. There is always some little mold seem visible even on the best kits. Sanding them down can be a pain because that often leaves little flat spots which become even more visible when you paint it. There is nothing more distracting than to see flat spots on your round lines. I'm thinking that this line will be replaced with a metal rod of the same diameter bend in the same orientation. This is one of those often missed little details that can make a world of difference. Besides seeing a real metal line will always look better than painted plastic. The rubber hose clamp will be simulated with a thick layer of black paint. I'll mask off the area with two or three layers of tape and then apply 3-4 coats of flat black paint. I want there to be a definate lip on the paint, which is usually a painting no-no. This time it will work in my favor.

I'm sure there will be more things to detail once I actually start working on it, but I have to get through this test first. So there may not be any blogs for a while, but thats how life works. Business before pleasure. But I hope this offered a little insight into how to look at kit parts and see bigger and better things. Once the process begins, you'll see more.

P-51C Mustang Rolls Royce Merlin Engine Completed

Finally after several months of work, the engine to my 1/32 Tamiya P-51C Mustang is completed. I had some pictures taken on a good camera to get a decent all around view of the engine. Next I'll be doing the firewall and oil tank as soon as I get the time. Until then, enjoy the engine pictures.

P-51C Mustang Engine - Fuel lines and Atomizers

I almost missed some really cool details on top of the engine. I found them while trying to figure out where, what I thought was, the last fuel line actually ran. On the top of the engine are 6 fuel atomizers connected with a very thin fuel line that leads back to a splitter connecter, can't think of the actual name for it, but since I'm still in the process of building that it will be mentioned in the next blog.

Each Atomizer was made with a piece of .040: plastic rod and a thin wire that was folded into a "U" shape. I used the side edge of a razor blade to fold the wire. It was then very carefully glued in place on the wire. At this point the wire legs were longer than what you see in the picture below. This made it so much easier to handle while gluing it in place. Once the glue was dry I used fingernail clippers to snip them to the proper length.

As you can see in the picture above, there are three colors on this tiny little thing. The outside of the rod is black, the top face of the rod is gold, and the prongs of the wire are silver. Once the paint tried, I carefully cut the end of the rod off leaving the thinnest sliver behind. Forgive the blurriness of the photo. My camera can't focus on things this small, but for size reference, the atomizer is sitting on a piece of college rule notebook paper.

The atomizers were glued in place on top of the engine.



The fuel lines that connect the atomizers have a neat joggle in them which proved to be quite the pain until I made a jig to bend them on. I used the placement of each atomizer to make this jig out of a popsicle stick. I bend the wire over it and test fit it on the engine, tweaking the jig as necessary.


I used a very thin .007" wire for the fuel line. It bends very easy, but is very finicky. You have to be careful when handling wire this thin cause you can spend 10 minutes bending the perfect joggle then accidentally knock it totally out of shape. The fuel line runs underneath the ignition wires already in place. The two lines are mirror images of each other. The picture below shows the two lines in place on the atomizers.


Only a few more things and the engine will be complete...

P-51C Mustang Engine and Supercharger Details

The left side of the engine has a few less details than the right side, but this doesn't mean that you can't add a few little things to spice it up. One of the lines on this side is connected to the intercooler with a rubber hose held in place with metal clamps. I first cut and bent a paperclip to simulate the line. Then I carefully masked it off and painted the end with a few layers of gray paint to simulate the rubber hose.

I cut a thin strip of soda can aluminum and bent it around another piece of paperclip to create the curved shape. Once the pieces were glued in place, they look very much like metal clamps holding the rubber tube in place. I'll admit, they could have looked a little tighter, but sometimes you just have to live with what you got.

Another paperclip was used to make the second main line on this side. I couldn't see where the top of this line connected on the real engine, so it won't be seen on the model either. That's one of the benefits of model building. Its all an illusion sometimes.

The details on the supercharger can be a little confusing to look at since there are a bunch of black rods that seem to wind all over it, but really its quite simple. First a little surgery was necessary. I'm not sure what this rod assembly is called (Its part E13 in the kit) but its placed too low to be accurate.

So I had to carefully cut it off and raise it up. The red arrow shows the original location and how much it had to be moved up.

This little stub here was also not the correct shape and was removed.

The replacement was made using .030" plastic rod and a blob of JB Weld that was filed to shape. The finished part is seen painted and installed in a later picture.

On both sides of the carburetor duct is a simple round pivot point that is missing on the kit. This was added by drilling a small hole and inserting a .030" plastic rod that was cut to length and painted black. A thin aluminum wire was fastened to the center of the completed pivot point.

The connecting rod was fairly simple to make. A blob of JB Weld was used to create the connection down at the carburetor sanded in a similar fashion as several other lines on the engine.

With the new piece painted and added to the top of the supercharger, the little connecting rod could be added.

On the right side of the supercharger were a few more aluminum lines as well.  These were made like the others...with pain and aggravation.

At the bottom is a small arm (seen above) made of thin plastic. To make the connecting rod here, I bent the wire and then flattened the ends by squeezing them with pliers to simulate the appearance of the actual part.

Here is the arm in place on the engine.

Only a few more details to go and the engine will be finished.....finally.

P-51C Engine Ignition Harness continued

I finished installing the ignition wires on the other side of the top of the engine in the same manner as discussed in the previous blog. Here's what it looks like.

For the ignition wires on the sides of the cylinders, I had to use a different approach. I cut short lengths of the metallic string and glued a short piece of .020" plastic rod to the end and painted the rod silver.

To prepare the harness for attachment to the engine, I cut a very thin strip of .010" thick and formed them into J-shaped clips that were glued in the proper position on the harness.

I painted the new pieces silver and glued the harness in place. With the wires I cut the plastic rod a little shorter so it matched a scale length and test fit and cut the string so it was the correct length to reach from the harness to the spark plugs, which are nothing more that .020" plastic rod glued in the appropriate locations on the cylinders.

 

I glued the end of the string to the harness first and then glued the rod to the spark plugs at a slight angle. Use a picture of the actual Merlin as reference to get this right. Don't run the wires straight to the spark plugs. The real wires had a little bend and slack in them. The wires on the Merlin were attached to the plugs with spherical joints which is easy to create using some thick adhesive. I tried using super glue first, but it shrinks when it sets so it didn't create the right shape. But I had some JB Weld laying around, so I mixed some up and dabbed a little blob in the joint and it formed the perfect shape. 

After a little silver paint, the ignition wires look extremely similar to the ones on the real Mustang.

The first side of the engine is done.

P-51C Mustang Engine Ignition Harness

So there was a slight change from the last post, but if you read the introduction to this project, you know I said I would admit my mistakes. Well this wasn't really a mistake, more of a "oops that won't work" thing, which happens in projects like this. You have to be prepared to have these moments. Nothing is perfect the first time. That's how you learn.

So for the ignition harness wires, I first tried to take metallic string and coat them in super glue so the strands would stay together, but this made the string too stiff and it was a pain to try to glue in place. I wanted them to be stiff, but not that stiff. So I scrapped that idea, cut off all those pieces of string and went in another direction. Instead of coating the entire string with super glue, I coated only the tip to keep the strands together. Then I glued the tip of the string in place on the engine, coated a small portion of the string in glue in the area where I would be cutting it, let it dry, cut the string to length with a set of nail clippers, and then carefully glued the end to the harness.

The uncoated string bends more easily and looks more like the real thing. You don't want to have any sharp bends or obvious straight areas in these wires or it will look really fake and weird.

Half way done. I'd say it looks pretty good for being plastic and string

P-51C Mustang Engine Ignition Harness and Oil and Fuel Lines

Finally after having way too much time away from my Mustang I could finally get back into it. So I left off working on the ignition harness. The wires on the real Merlin were silver braided cables which is odd to scale down. At first I tried using elastic, strangely enough, from an old pair of underwear. Just a side note: Sometimes as a scratchbuilder you have to explore some pretty strange options to find materials. The elastic didn't have the right pattern and once it was painted it become too stiff and the paint cracked off. So scratch that idea. I found a roll of metallic thread buried away in my work bench, but it had a slight problem. Once I cut it, the three strands that made up the thread separated. To fix this, I coated the thread in CA to bond the strands and could then cut some pieces that would stay together. Now, the pattern on this thread isn't quite the same as the real Merlin, but it is quite similar. And the natural color of the thread means it doesn't have to be painted.

I'll install the harness soon, but for now here are a few more pictures of the the oil and fuel lines going into place. Before you start a task like this, let me assure you that it is indeed a tremendous pain in the stabilizer, but well worth the effort. If you didn't read my last post, the lines are made from two sizes of Ook hanging wire available at any hardware store and for just a couple of bucks. The really big line in the picture below is made from a jumbo paper clip.

The little nubs representing the fitting on the ends of the lines, as seen below, were created with a blob of JB weld that, once hardened, was sanded flat on two sides. Silver Testors paint matches the natural aluminum color of the wire, which makes it great for hiding any mistakes or glue that may have leaked out of the joints.