Tamiya P-51C Mustang Engine

The engine starts out as a basic kit build, but you have to keep a few things in mind. Like all kits, they tell you to paint the parts as you build them. Well, us modelers know that there are other things to worry about before paint is involved. Seams needs to be cleaned and filled, injection molding marks need to be filled, and parts need to be test fitted. Also, if you've ever tried to glue painted parts, I'm sure you've found that the paint tends to run and look bad. Therefore, I've decided to build the engine in sub assemblies and paint it all at once. The reason I didn't just slap the entire engine together and paint it as a whole (because all the parts are semi-gloss black) is because there would be some areas where my airbrush would not reach well. All the little nooks and crannies of the engine would be blocked by something else, resulting in an odd-looking paint job. Plus there are some things that will be easier to detail before they are attached to the engine. So here we go...

The crankcase and cylinders fit together nicely without much seam smoothing. Before you put the cylinder halves together, be sure to drill out the two holes needed to attach parts H2 and H3. I will leave H2 and H3 off until the engine is painted because I want to cover the 2 long bars with aluminum foil to give it a steel appearance.


I handed painted some areas that would be covered by another part so after I airbrush the engine, there aren't some areas deep inside that are still gray.


Good example as to why you assemble the engine before painting it. This pushrod should make contact with the bottom of cylinder. I believe this is the linkage between crankshaft and camshaft. I filled this gap with a piece of .010" plastic.


With the engine subassemblies built, there were a few components either missing or could be made better. This little beauty is the oil relief valve molded onto the side of the engine. Although it looks pretty detailed, a quick gaze at a real Rolls Royce Merlin and the Merlin Overhaul Manual shows that this is very inaccurate. So off it will come and a new relief valve will be constructed. These molded on details looks good if you are just starting out with models or if you're not too concerned with accuracy or a realistic looking appearance. But for those with a discerning eye, details like this look so much better when they are scratchbuilt. That is coming up next...

More P-51C Tailwheel pics

I forgot I took these pictures. These really show the comparison between the kit piece and my scratch built pieces.

This is the kit piece for the steering arms with the pushrods cut off. It could probably be modified to look better, but I found it more useful as a reference for scratch building a new one.



This is the result. The aluminum band sticking up is part of the tail gear locking mechanism. This piece would be rotated down if the gear was locked, meaning the pilot could steer with the rudder petals. But because my tailwheel is in the unlocked, fully castering position, this arm is raised. Haven't made the pushrods yet. Those will get added closer to installation....and because I'm lazy and don't want to do them yet.

P-51C Mustang Tail Wheel Continued

I cut apart the kit piece so I could scavenge the pulleys from them. When you don't have a punch set, cutting small circles is the biggest pain. This saved me a lot of work.

 

 

 

The pulleys are mounted on arms. My first attempt at making these arms sort of worked, but the final assembly ended up being too wide to be scale, so I had to scrap it.

 

 

For the second attempt, I cut the piece from .005" plastic and sandwiched them together. The best way to make these little pieces is just to assemble them from really small, really thin pieces of plastic unless you have a photo etching system. Maybe one day I'll get one and try it out. This picture shows all the remaining little pieces that had to be made. This makes me glad that I'm not detailing the entire strut.

 

 

The locking mechanism was made from thin plastic and a thin strip of soda can aluminum bend in a "U" shape and glued on with epoxy.

 

 

The pulley mounts needed to be raised higher for a scale look than the arms on the kit piece allow. This was accomplished by adding a little .040" shim and then filing it to shape.

 

 

 

All the pieces were then carefully glued into place. If your hands are shaky, you might want to wait until you can calm with down or you're going to want to pound your head on the wall after a while. I purposely did not glue the spring in position because it needs to keep its natural metal color. I will glue it down along with the cap that will hold it in place after the strut has been painted.

 



 



Another obstacle overcome. Time to start working on the engine

P-51C Mustang Tail Wheel

Time to tackle the tail wheel, which would be mostly hidden up inside the fuselage and is something most people wouldn't even look twice at if the model was sitting on a shelf. That isn't going to deter me from adding unnecessary features and details to it. Ok, I'll admit that I'm going to chest and use a movie set mindset. If it won't be seen, it shouldn't be built. The detail will be added to the lower part of the tail wheel because when the suspension pushes the wheel out of the aircraft, this detail will be seen. Yes, that's right, I said I was putting suspension on the tail wheel. Not only that, but the wheel itself will be fully castering. The real Mustang had two ways of operating the steering on the tail wheel. It could be locked so that movement in the rudder pedals would move the tail wheel of it could be unlocked and would faster freely on its own if the pilot tapped the brakes on the main gear. I could have made the wheel move with the rudder pedals, but I'm not that crazy. Fully castering is enough, I think.

I started by carefully separating the wheel axle from its mount and filing a nice clean hole that a 1/16" plastic rod would move freely inside.

 

I drilled a small hole in the top of the axle and in the center of the  new shaft so the two parts could be glued together with more than a flat on flat surface. The little connecting rod is only .020" but it provides enough extra "bite" on the parts so I don't have to worry about them separating. Make the 1/16" shaft extra long so you can cut it down to the proper size later. Once the glue has dried between the two parts, trim down the connecting rod and file the area smooth.

 

 

Glue the two kit pieces together with plastic cement. Make sure that all mating surfaces get glue. This will be very critical in the next step. Once the glue dries, carefully cut away the plastic piston rods and clean out the cooresponding holes. These will be replaced with 1/16" aluminum rod. I also cut away the top of the main strut so it can be replaced with a plastic tube. You can tell by the photo that the aluminum rod already makes the part look better.

 

 

I tackled the details next using several photographs of the real Mustang and the P-51D maintenance manual that I purchased online. The only details that would be visible are the steering arms and locking mechanism. Thankfully these parts aren't to hard to make. The kit provides a basic representation of these parts, but they can be improved. I used them as dimensional reference to make new parts. My first attempt at making the steering arm plate was pretty good until I realized that I missed a critical piece.

 

This picture shows the difference between the first part and the second part I made with the added platform needed to mount the locking mechanism. See even experienced modelers make mistakes. Gotta pay attention to the reference material.

 

 

To make the spring that would normally push up the locking mechanism, I dissected a small piece of wire and pulled out an individual thread, straightened it, then wrapped it around one of my application needles so it made a spring shape. You have to be careful with these really thin wires because you can unshape the shape with too much pressure.

The center post that fits inside the spring is a smaller diameter than the shaft. I chose .030" rod for this. After sizing the 1/16" shaft and cutting it to length, I center drilled it to .030" and glued in the smaller shaft. I cut it to length using the height of the spring as a guide. Leave some room for another ring that will set on top of the spring to hold it down.
 

 

More details later...

 

P-51C Mustang Landing Gear - Torque Links Continued

The pivot mounts on the lower strut were similar in construction, but I added another strip of thin plastic top and bottom because unlike the mounts on the upper strut, these mounts are tapered. Dirty little buggers. All that means is there was the added step of cutting the tapered and filing it down to the proper shape and thickness.

To attach the mount on the outward side, I filed a flat area into the strut and glued the mount in place with plastic cement. This picture also shows the 7/32” tube covered in tape to protect it from stray file movements. The Oleo piston is always the shiniest part of the landing gear and I didn’t want it to get scratched. When you add this aluminum tube, you have to carefully drill and file a hole into the lower strut. Unfortunately I don’t have any pictures of this process, but you can see the end result in a few pictures below.

 

The inward side was much more fun (Fun being a very sarcastic, misunderstood word) only because you have to deal with two really small pieces and position them in just the right place so the torque links will move properly. Once I created the piece, I use the torque link assembly to make sure this piece was the right length and in the right position. It took several trial fittings as I filed off little bits at a time, just to make sure I didn’t file too much off and would have to remake the part. After about an hour I was satisfied with it and glued it down. The piece on the opposite side was fitted in a similar manner using a piece of .020” brass rod to help align the part. Also in this picture, you can see the piston tube mounted in the lower strut. On the real Mustang there this portion is indeed hollow, so by making the piston from a tube instead of a solid rod, you get two scale details for the price of one.

 





 



As a final check of the operation, I put everything together and made the first movements. I also checked to make sure the lower strut was perpendicular with the upper strut. The model would look weird if my wheels were pointed outward or inward. Everything has to be straight. On real aircraft with landing gear of this type they would use shims mounted between the torque links. On the model, you can do the same, although they would have to be really thin (I’ll probably use .005” plastic or pieces of paper) or you might have to file down the tube that joins the torque links together. I purposely made them a little long for this reason.

You can tell by the video that the parts worked well and the torque links behave exactly as they should. To make the suspension, there will be a spring installed inside the upper strut as well as a stopping mechanism. On really airplanes the lower strut is held to the upper strut by the torque links or by a stop ring installed inside the strut. Of course with this model, both methods are a little inpractical, but I have devised a way to make a stopping mechanism so the spring doesn't push the lower portion out of the upper. When the time comes to install the landing gear, I will describe this in detail.

But until then, enjoy the tail wheel construction coming up next.

P-51C Mustang - Torque Links Continued

I cut the the pivot tubes .1" long and glued them to the center of the piece. Epoxy works best for attaching the stainless steel tube to the plastic. The tube that has the eyebolt passing through it is a .040" rod with a .015" hole drilled through the center. Once the glue dried I very carefully filed the vertical sides down to a taper like the real torque link. The large axle will be .020" rod. I will make the actual axles when I get closer to installation, but the stand-ins work for now.

The main strut was going to have to be fabricated mostly because the kit part looked lame. Also in order to make the landing gear retractable, I would have to modify the axle point at the top of the strut. The kit piece is angled and I need it to be straight. However, the bottom portion of the strut was ok and I wasn't about to try to scratch built that awkward shape. Even my insanity has its limits. So I cut off the part I would use and then used the dimensions of upper strut to make a new one from aluminum tubing.
 

 

The main tube is 1/8" and the outer tube on the top is 9/32". The outer tube on the bottom is soda can aluminum cut into strips and wrapped around held in place with JB Weld. If you haven't used JB Weld it is used for gluing metal pieces and it works great and sets fast. You needed to scuff the mating surfaces before using this stuff, but once its on, it's really good stuff. The axle for making the gear retractable is solid 1/16" aluminum rod.

 



And now for the fun part. The torque links need a hinge point on the struts so that they will work properly. It needs to be thin, yet strong and unfortunately drilling into a thin piece of plastic didn't work. The material remaining after the hole is drilled is not strong enough to withstand the motion of the struts moving up and down, not that my model will be withstanding many hard landings, but still I'm over engineering this thing so I don't have to worry about it breaking later with no way to fix it. So to make this little hinge mounts, I took a strip of .020" plastic (remember the axles here are .020" diameter). Then I wrapped a thin strip of .010" thick plastic around one end end using a piece of .020" brass rod to preserve the hole. Sometimes it's better to built a hole than to drill one. I used my calipers as a vise to hold these parts together while the glue dried.

 

 =

 

 

As you can see the plastic needs a little filing to make it nice and flat. The overall thickness of this part is no more than .020", so it is quite a pain to file it down. I just pushed the part into my finger with the file and it worked fine. I left the "tail" on the part so I would have more material to grab while I positioned the mount on the strut. In this situation I found it easier to use a round file to make a divot in the plastic so it would fit around the strut. Use epoxy to glue these parts on. Once the glue was set, I carefully cut off the tail. I did each side one at a time. It took longer but it was the best way to assure the parts didn't shift while I was working with the other side. 

 

 

 

That finishes off the top part...the bottom part is to come...

 

 

 

 

P-51C Mustang Landing Gear - Functional Torgue Links

So in my quest for details that really make no sense but are really cool, I decided that my P-51 will have not only retractable landing gear, but also working suspension. This would require an entire rebuilt of most of the landing and after looking at the detail on the kit parts, I figured I was going to end up modifying it anyway. The torque links in the model are made of a single piece of plastic with a photo-etched detail piece glued over it. The photo etched part looks pretty good, but it is much too flat to be used by itself, plus there would be no way to make it move. Basically it served as a reference for dimensions to make new parts. I tried several different methods of making torque links from assembling small strips of plastic to actually carving the entire piece from a chunk of plastic. Both failed of course. Then I tried gluing together small pieces of metal. That also didn't work. I had seen other modelers make torque links by soldering pieces of metal or even by forging metal somehow. Well I haven't gotten to the point where I've installed a forge in my apartment so I had to think of another way. Plus all these other models make the two torque links into a single piece and mine needed to move. So I had to figure out how to make really small axle points as well. Not only that, it had to look like the Mustang's landing gear strut. Whew, did I get all that out! Yeah, many headaches to come. However, I had a moment of inspiration by looking in my bag of Evergreen styrene shapes. I happened to have I-beams that were the right width and these happened to be the best base for making torque links. Here's what I did:

First I had to do some math. I know, you said you'd never need math in life, but suck it up, you do, especially is model building. I knew what the link length was from measuring the kit piece and I knew I was going to need to make pivot tubes. I decided one tube would be made from what is called an application tip, basically an industrial syringe needle. These are available in many very small sizes and are made from steel so they are thin-walled, but really strong. The smaller axle was going to be the tricky one. I took a piece of .040" plastic rod and drilled a .015" hole down the length of the rod until I had enough to make a pivot.

 

After knowing what dimensions the pivots would be, I subtracted from the total length of the part and I knew how long the I-beam piece needed to be. In this picture, the short side is the required length. Note the longer side and the angle of the cut. This will come into play later.

 

After knowing what dimensions the pivots would be, I subtracted from the total length of the part and I knew how long the I-beam piece needed to be. In this picture, the short side is the required length. Note the longer side and the angle of the cut. This will come into play later. Making parts like this is where research comes into play. I was constantly checking and double checking the actual torque links on the Mustang to make sure I got this right. I drilled some small holes to corner out the cutaway and then carefully chipped out the hole with an X-Acto knife. It took me a couple tries to get the hole right. There is a fine balance between how much material is left between the hole and the vertical side wall and you have to be careful, but it can be done.

 

Carefully cut away the long vertical side and file down any raised area. This might interfere with placement when you re-glue it on later. I used my Vernier caliper to hold the piece in place while I cut the angle.

Carefully re-glue the cutoff side piece so that it is centered on the horizontal flange. Use plastic cement for this instead of CA as it will give you the ability to move the piece around to make sure it is aligned properly. Also, this joint will need to be strong as you will be filing it down later. Plastic cement melts the plastic together while CA just sticks them together.

As you can see, the torgue link is coming along.

Tamiya 1/32 P-51 Mustang Introduction

For the past few years, I have continually challenged myself to something better with each model I built. I have wanted to add something to it, some detail or feature that would push my skills to the limit and beyond so that I can gain some sort of knowledge from it. My last project was a heavily-modified 1/350 USS Missouri with hundreds of photo-etched parts, added details, and modifications that ultimately led to my first "Best in Show" trophy at a local model building contest. Not much, but hey, a win is a win. This time around I wanted to return to my airplane roots and try something I have never done before. And something I had never seen before in any model of this scale. This project would stretch my model building and engineering skills to their max, but if I could pull it off, it would be something that would turn heads and drop jaws for years to come. Ok, so maybe I'm being a little grandiose, but it will certainly be impressive.

The model I chose for this endeavor is the new Tamiya P-51D Mustang that came out last year. Now before you click the back button because everybody and their brother has built a P-51 model, let me encourage you to keep reading. I chose this kit because it was set up beautifully for what I want to do with it. A full list of goals for this model will be listed below. I'm not going to post a review of this kit because there are already a dozen posted online. I'm also not going to do a standard build walk through because those are also online. Basically this kit is going to be used to show you how to make extremely fine details and how to modify existing kit parts to improve them. This build will also contain several features that you probably have not seen before in a plastic model, especially one in 1/32 scale. Perhaps you have seen things like this on Radio Control models or models built by professional companies who have access to CAD programs, computer controlled machining, or fancy molding techniques. Well I'm just a ordinary guy with ordinary things. So since I don't have access to fancy, schmancy tooling, and I'm sure most people don't either, I'll show you how to do detailing with regular off the shelf products and tools you can find at any hobby store or hardware store. All it will take is a lot of time and a lot of patience and a lot of ingenuity. And I'd rather spend that than a lot of money.

 

The biggest modification to this kit will be the conversion of the D-model Mustang to an earlier B/C variant, specifically the P-51C flown by Tuskegee Airman Captain Charles Bailey. That alone should be a project in itself, but I like taking things well beyond the realm of comprehension. Here are a few other details and features this model will contain:

Detailed engine and accessory area

Detailed Landing Gear well with hydraulic lines
Detailed gun bays, machine guns, and ammo belts
Redo gun bay doors to open on piano hinges
Detailed cockpit redone in C-model configuration
Detailed tail wheel well
Detailed landing gear struts and torque links
All landing gear will have suspension and will be retractable
All gear doors will function properly
All control surfaces will operate with movement of stick or pedals
Flaps will be linked and make moveable
Rudder and elevators will be redone and covered with simulated fabric
Canopy pieces will be hinged

This is just a small amount of what will actually be done to this model and the list above doesn't detail out exactly how much work will go into them. That is what the walk through will be for.  I will cover all the methods and show pictures of as many steps as possible. I will also try to show as many attempted steps as possible, meaning you will see all the projects that didn't quite work the first time and how I changed them so they will work. You might as well learn from my mistake too.

 
I hope this project gives you some ideas to detail your own models and will teach you techniques that will make modeling a satisfying and fun hobby. Enjoy!!

More USS Missouri Details

I found some pictures on my memory card of the details of my Tamiya 1/350 USS Missouri that shows off the photo etched parts.


Some people have suggested that when you use photo etched pieces, its easier to paint them on the fret (the tree that holds the parts) and then assemble the model. I think thats a little strange. Glue as many parts to the model and then paint them. That way the paint can cover the glue.

While adding the photo etched parts, I built the superstructure in sections and test fitted them in place. This gave me a good idea of how to mask and paint each section. It would have been a strategic nightmare to paint all the vertical surfaces gray and most of the horizontal sections navy blue once the entire model had been glued together, so keeping the boat divided into small sections made life a lot easier.

The pictures below show the world of difference photo etched parts can make especially on very small parts. The plastic parts provided with the kit were way too thick and I know the Missouri had some armor plates around her guns, but the kit parts would have made those plates almost a foot thick. Thin brass looks much better