Miniature Aircraft Tug

I have recently started building up my own fleet of model aircraft, and so far I have a 3D printed A220 and A380. I hope to expand my fleet by making more models, but if you have model aircraft you also have to have something to move them. Now, I know you could just push them around or carry them where you want them to go, but there's no fun in that, so I decided to build an aircraft tug that is somewhat to scale with my airplanes.

NOTE: This is my first instructable, so please excuse any errors or unclear instructions. If you have any advice or questions, please let me know in the comments.

Tools:

• 3D printer (Not absolutely necessary, but definitely helpful)
• Sharp knife
• Scissors
• Pliers or clippers
• Tweezers (optional, but very useful)
• Pencil
• Fine-tip markers or sharpie
• Toothpicks (for fine detail painting)
• A needle (for VERY fine detail painting)
• Ruler

Materials:

• 3D printing filament (I used black and white PLA)
• Black, white, orange, yellow, red, and silver paint
• Eraser
• Thin wire (optional: it is just used for extra detail that isn't absolutely necessary)
• Toothpick (for axle and and top lights)
• Paper
• Super glue or equivalent

I based the design mainly on the TUG Alpha 5 in the first picture. I also added an oversized hitch on the back to make it easier to attach model aircraft to it.

Print the main body and the wheels. In the second picture the wheels are a bit different. Those were my first attempt, but I wasn't happy with how they looked, so I designed and printed the set in the last picture. The files are for the main body and the improved version of the wheels.

Once the pieces are printed, take a sharp knife or some clippers and remove all strands or things like that. I didn't sand any of the pieces, but you could if you wanted a smoother look. If you don't remove the strands they will show up a lot more when you paint it, so try to remove them all now.

Set the wheels aside for now while you work on the main body.

Take a sharp pencil, and carefully draw an outline where the windows go. Also mark the vents on the side of the vehicle. Then lightly fill in with the pencil. If you are happy with the placement of the windows and vents then take a black or dark grey marker and fill in the windows. In my case, the windows were pretty dark at first, but as the ink dried they lightened up a bit. If you prefer darker windows, just do a few layers with the marker or paint them black. Make sure to let the ink dry before touching the windows, and even then try to avoid toughing them because the ink smudges easily.

Once the windows and vents are colored, take a toothpick with as pointy a tip as you can find and carefully trace the outline of the windows and vents with black paint. You can also use a needle stuck through an eraser for better grip. I found this to be VERY useful for tiny details throughout the project.

After the paint and ink on the windows has dried, take your toothpick or needle and carefully paint wipers on the front and back windows. All of the front and back window windows have one wiper each. The side windows don't have any.

When the paint has dried, you can carefully trace the outline of the cab to make it stand out a bit. It is very easy to overdue this, and I wasn't extremely happy with how thick the lines turned out, but it's hard to make super fine lines in corners, so just try your best. I you make you line to thick, you can take your needle and carefully scrape away the excess paint. Don't paint white over it because the white paint is a different shade than the white filament, so it will show up.

Finally, I painted the small floor area in the back black to resemble a mat or something similar.

I didn't have the right shade of yellow to resemble those warning bumpers or signs, so I just mixed some orange and yellow paint to somewhat resemble it. Once you have your color mixed, paint the front and back bumper like in the pictures.

Once the paint is dry, take you fine tip tool, whether it be the needle or toothpick or something else, and carefully paint diagonal black lines on the bumpers. Try to get the lines to meet of in the center on the front bumper, and only stripe the sides of the back bumper; leave the very back orange for now.

I also painted the top of the back bumper black so that I can paint the hitch in the next step. You can also paint in the red lights by the back bumper like in the picture, or you can wait and paint them when you paint the front lights later on.

This step is very simple. Just paint the bottom all black. While you're at it, you can also paint the wheel indentions or whatever they're called. Just look at the pictures for reference.

To not have too many steps, I added the hitch painting now. I used silver metallic paint to paint the hitch, but just grey should work fine too.

Now its time to paint the lights. First, paint an oval-ish background with black paint to help the lights stand out more. Once the black paint has dried, use a toothpick or similar round object to put a drop of paint on the black background. I used red paint on the outside, yellow in the middle, and silver metallic in the inside. You could also use white instead of silver, but I didn't want the white lights to stand out too much, so I went with sliver. My red and yellow paints were very watery, so I first painted orange lights, and then added the red and yellow color. This made the red and yellow stand out more than if they would be painted just on the black background.

For this step, take a toothpick and cut it into 12mm lengths. These will be your axles. You may need to thin down your toothpick a bit for it to fit into the hole in the wheel. To do this just take a sharp knife and carefully shave of small amounts from the tip of the toothpick, checking constantly to see if it fits. Once it fits, glue one wheel onto the axle, then place the axle through the hole in the vehicle and glue on the second wheel. Do this for the front and back.

Make sure not to use too much glue or else the wheels may stick to the vehicle, which would keep them from turning. For me it doesn't matter that much if the wheels turn or not, but I modelled it so that I have the option to have them turn. It just makes it more realistic.

If you printed the wheels black, you won't need to paint them black. If you do need to paint them black, do so before gluing them together. Now, take your silver or grey paint, and paint all of the side of the wheel, leaving just a rim of black. The design of the wheel should make this easier because the area around the hub is recessed. Then, take you fine-tip tool and put 8 black dots on the hub to resemble bolts. I did this in a later step, so you will only see it in pictures later on. I would recommend doing it now though.

Now is the time to choose what you want to call you vehicle. I just stayed simple and called mine AC TUG, which stands for AirCraft Tug. Go to Microsoft Word or something similar, and type your chosen name. If the name is long, you will need a smaller font. I just typed out the name twice for every font (one for each side of the vehicle) and then repeated that in 6 different sizes. For me, 5pt font worked perfectly.

Once you have printed the name, measure the area on the side of the vehicle below the vents, and cut the paper with the name on it to fit that area. Carefully glue it on, and to get rid of the sharp corners, I painted a thin black outline to give it a more rounded appearance.

On the second image, you can also see the bolts painted on the hub of the wheels.

For the warning lights on the roof of the vehicle, I cut one end of a toothpick flat and then dunked it in some orange and yellow paint. Let this dry, and if necessary repeat the dunking to get a brighter color. For the smaller light at the back of the vehicle, just use a flattened tip of a toothpick. When the paint is dry, carefully cut the painted tip off of the toothpick, and glue it onto the roof.

While I waited for the paint on the toothpick to dry, I also added some detail to generator thing beside the cab in the back. I painted the sides of the top part black, and then painted the sides and the very top part of it white. I also drew a vent on the side of it with a pencil.

You can also paint some tiny door handles on the doors now if you haven't done so already.

TIP: It's a lot easier to draw fine details with a pencil if you first paint the plastic object. In this case, I painted the generator thing white, and adding details like vents and hatches and handles was a lot easier and showed up way better.

Technically, all the details so far are optional, but the following details weren't referenced from actual Tugs, I just added them to try to add some realism and fill in empty areas.

First, I used some very thin wire and painted it white to resemble railings on the roof. I didn't take very many pictures while I was adding these details, so you'll just have to look at the pictures of the completed thing.

I also took an eraser and cut very thin slices and glued them on the room over the wheels, giving the roof a more 3D look. I then took a tooth pick, split it in half, and painted the halves white. The halves were used in the front and back of the roof to give a rounded transition from the main body to the roof. Please look at the pictures for reference.

Another thing you can do is take your black or dark grey marker and color over the silver metallic paint on the wheels. I did this at this stage because the silver metallic paint was a bit too shiny for my liking, so I left the small hub shiny, and colored around it with the dark marker. This significantly reduced the sheen of the paint while at the same time darkening it a bit and making it look much better.

You can also paint a mini license plate on the back of the back bumper. I just painted a black square for now. Maybe I'll paint something different on it later on.

One of the last details was a ladder. I don't know if Tugs actually have ladders on them, but it did add a cool touch. So first, I took the same thin wire and cut two longer strips. It helps to draw the ladder on a piece of paper and then glue the pieces onto the paper with stick so that they stay where they need to be while you superglue the pieces together. Paint the ladder white, and glue it onto the roof.

The last thing that I added was the front mirrors. For these, I carefully cut the shape out of thin slices of an eraser. I realize now that it would have been easier to add them to the model in the software and print them already attached, but it worked out all right. Just make sure that you have a sharp knife. Finally I painted the inside of the mirrors with metallic silver paint, and painted a black trim on the sides of the mirrors.

Congratulations! Hopefully you now have a finished Aircraft Tug model in front of you, or you learned something new while reading this.

I hope you enjoyed it, and if you have any questions or suggestions, feel free to let me know in the comments.