Motorized Jet Engine Model

This project is a model of how millions of people get across the globe. And fast. One of the fastest things many people will see is a plane. This Instructable tells you how to make a clean and professional looking engine model mounted on a base. It includes a speed controller for the motor and is powered by AA batteries with no external power source. This makes it completely independent of anything else and is very simple to set up.

I originally got the files from Makerworld. The Creator is CATIAV5FTW. (link) There is a public copyright on this piece by them, so I am free to modify the files so long as I credit them.

This project is a way to introduce someone to a host of new skills. It includes woodworking, soldering, circuitry, 3D printing, and 3D design if you so choose.

This took me about 4-5 days to print everything (with plenty of break between prints.) and about 8 hours to assemble and complete. So set some days aside and get ready to make a good-looking model.

Hardware

M2.5 10mm Screws (100) ~$4.50

M2.5 Hex Nuts (100) ~$3.25

M2.5 Washers (100) ~$1.25

6204 Bearings (2) ~$7.25

6003 Bearings (2) ~$4.00

PWM Adjustable Speed Controller ~$2.00

4 AA Battery Holder ~$1.50

GA12-N20 6V 60RPM ~$3.50

18" x 11 1/4" x 3/4" Wooden Board ~$3.00

Polyacrylic (To protect wood) ~$0.50

Small Gauge Wire (~1 ft.)

Solder

Superglue / Hotglue

Small Screws (3/4 in. max length)

3D Printing Filament

White PLA (575g) ~$10.50

Blue PLA (275g) ~$4.40

Black PLA (200g) ~$3.60

Tan PLA (225g) ~$3.60

Silver PETG (100g) ~$1.40

(Just the colors and types of filament I had on hand, it doesn't really matter what color or type of plastic you use.)

Tools

Soldering Gun

3D Printer

2mm Alan Key

Needlenose Pliers

Sandpaper (depending on your printer's capabilities, tolerances can be tight.)

Hot Glue Gun

I got almost all the hardware from AliExpress, but you could get most of it for this project from Bambu Lab, which sells it as a kit.

This is a step I had to take so that all the blades would spin together. Originally, the blades were not connected by a central shaft. The big fan in the front and the fans in the back would spin together, but the fans in the middle would not. So I had to modify the files so that they could all be connected by one main shaft. I did this by connecting them with hexagon connector pieces. I made the negative of one part a hexagon shape and the positive a hexagon too.

I made many more adjustments, one of which is a motor holder inside the model. I made a disc with a negative space for the motor that fits into the back of one of the casing parts.

I also made the stand into two pieces that connect with a dovetail joint. The stand was too big for me to print with my printer, and I made it a dovetail joint, as I know it is strong and sturdy.

I did change one other part of this model, and that was the nose cone. My printer had trouble printing the main white stripe, so I completely remodeled it without the main stripe.

I also made two additional parts. I made an electrical housing box to hide the circuitry. I made a hole in the housing to have the knob stick through. I also made a small nameplate to fill in space. I felt that it was empty in that area, so I made this to fill it and also label it.

Here are all of the parts I made or redid.

This is by far the largest and hardest step in my opinion. I had a lot of trouble with this step because it requires tight tolerances. Some printers may have problems with this. Sandpaper, glue and needle nose pliers are heavily recommended.

First thing when printing is to make sure you have the right settings. Some of the parts have very small lines that are easy to mess up. I printed this PLA parts with PETG settings and did it at about 25mm/s. The pieces I am talking about are the stator fans and the main fans. The most important thing with these is that the first couple of layers go down cleanly and without trouble.

I also had tree support enabled as there are many parts with complex geometries that need support. Orientation is also very important as many parts are almost impossible to print in some orientations. It is important to make sure that the side facing down has the most contact area. Since these parts will not be under much pressure I would not be worried about possible layer line separation and cracking.

I did have some problems with stringing in these parts and I simply used a heat gun, but a hair dryer might work just as well.

After all of the parts are printed and post-processed, I would simply test fit all of the pieces to make sure all of the pieces are correct before gluing. Another reason I used PLA with this project is because super glue chemically bonds PLA. When attaching the stator fans (silver fans) and the normal fans it is critical that they are attached squarely and straight. Any deviation in the spacing can introduce wobble and extra friction into the parts which can be detrimental.

One other thing is to make sure the fan blades are facing the correct way when spacing. The internal holes in the parts have a slight taper to them and sometimes will not fit correctly unless they are facing the correct orientation. They also want to face the correct direction for realism.

The pieces normally fit very well with a friction fit, but I did have to use sandpaper and lubricant on some places due to either me or my 3D printer being inaccurate.

Sometimes because of the misalignment the amount of torque required to move the blades was too great for my motors, so I had to introduce more space for the fan blades to decrease friction. I simply put some washers or some nuts in between parts. They simply act as spaces and still allow for it to be fully tightened.

When assembling make note that you don't need some of the bearings since the model spins together now. The ones you don't need are shown in the image above in the red. It is okay to keep them in there but it does add weight, meaning you may need more torque to turn the model.

I recommend that you make the model in three large sections and then attach the sections together when you are ready to. This makes it so if you were to make a mistake that it only affects a smaller region. The sections are of the individual fan sections. For instance, the big fan is its own section, and the larger fan in the back are another section.

When I started thinking about this project, I knew since there were multiple components, that I would need to mount it to something. The easiest thing I could think of to mount it to was wood. I then went to my garage where I have a lot of scrap wood, and I rifled through everything until I found a larger piece of wood. It is a pine board that was originally 20" x 11 1/4" x 3/4". Even though it might seem thin, it still is plenty strong. I made it slightly shorter because I though it looked a little too large for the model. I also chose this size because the entire model now fits inside of this bottom plate. Nothing comes out of the boundary of the wooden base, making it simple to store.

After I had found my piece of wood, I sanded it first with 60 grit sandpaper, all the way up to 220 grit, it jumps of 20 - 30 grit. The stain I used for this project works best when it is sanded to 220 grit. I then added a chamfer to the edges to make it look nicer and more refined using a router with a 45 degree router bit.

I then stained the light pine with Minwax's Golden Oak stain. I did a deep soak of the stain for 10 minutes and then wiped it off and let it dry. Then repeated to the other sides and edges. I tried to make it look as uniform as possible to make it look professional.

Since pine is a soft wood and it has no protection, I decided to coat it with polyacrylic to protect it. I did 5 coats on every side. I applied it gently to not make bubbles, let it dry for 2 hours, sanded it lightly with 220 grit, and then added another coat. I made it 5 coats thick as it makes a nice, thick, and glassy finish for the wood.

Sorry for the lack of photos, this is a process I went through quickly.

I planned to make this a very simple electrical circuit to introduce myself to electronics and circuitry. It has only 3 components. A speed controller, an electric motor, and a battery pack.

There are also only 6 connections, and 4 of them are screw connections.

First, I got the outgoing wire to the motor. I used brown 14-gauge wire as I had it on hand, and I chose brown because it looked more on theme with the wood. Then I attached the wires to the connection points on the speed controller after putting them through the hole. The connections were already marked on the board, so it was easy to do. I then put the speed controller in the housing. I made it so the off position was directly at the bottom. I then set the battery pack in the housing, too. Now that the housing is complete, I was ready to attach it to the board. I put it 1/2 inch away from all the edges and then predrilled a hole to thread the screws into. I then tightened the screws into the wood to keep it stable.

To give the wire access to the motors, I had to drill 1/8 inch holes into a nose cone and a casing. I made sure the holes lined up and that the wire could go through. I then put the wires through the holes. After stripping the wire, I soldered it using 60/40 solder. First, soldering the wire and then remelting it to the motor's terminals. Whenever I did this, I made sure to have the positive and negative connections in the right place, making sure that the fan pushed out into the engine model. To make the connection stronger, I also reinforced it with hot glue. I then attached the nose cone to the model and screwed the casing to the model, too.

To make my wiring look more professional, I hot glued everything down to the wood. I made sure to make the lines straight and to make the turn look square.

I used a 6V system for this because it uses easily available batteries while still having a decent voltage. It also makes the battery box smaller than, say, a 12V system. I chose a 60rpm motor because it is the fastest motor I could find (At this small size) that would consistently turn the fans. That is one of the problems I had with this project: finding a motor with enough torque to turn the fans, but still be relatively fast.

I wanted to make sure that this project would not come apart unless you want it to. To do this, I double-checked that every screw and bolt was tightened. To attach the base to the board, I predrilled four small holes into both the plastic and the wood board, only as deep as my screws. I am using four screws because it is overkill, but not by much.

To attach the model to the plastic base, I used hot glue. I put a thick line on the base and then put the model on it and pressed down firmly, and let it cool. I also put it in an orientation that I think looks the best to the viewer. Even though hot glue is not the sturdiest material, it is still enough for this application. I am able to pick up the entire thing by the engine, and it holds very well.

To attach the nameplate I used hot glue again as anything else would be overkill.

Now you have created a working model of a jet engine. It not only looks cool, but it spins and is built sturdily. Throughout this process, you have learned more skills, including soldering, circuitry, woodworking, and complex 3D printing. I doubt anyone can get through a project like this without some sort of hiccup, so it doesn't matter how long it took you or how many things you had to do again.