Eustace the Dragon, a K'nex Dragon Puppet

There was a boy named Eustace Clarence Scrubb, and he almost deserved it.

This is not that boy, but I did name the final project after him because I love the Chronicles of Narnia series. This is a ventriloquism puppet I made a while back, left alone for a while, then came back and improved later. The current version includes a trigger-operated mouth, a three degree-of-freedom neck, two degree-of-freedom eye movement, and articulated opening wings. The entire system is designed so that it can be worn over the arm and so that all the moving parts can be operated simultaneously with one hand.

I hope you enjoy this.

Here is the parts list for this project.

Knex rods:

• 69 green
• 97 white
• 30 blue
• 13 yellow
• 14 red
• 2 gray
• 12 purple flex-rods

Knex connectors:

• 20 gray one-slot
• 12 gray two-slot
• 18 orange
• 21 red
• 51 green
• 13 yellow
• 3 white
• 36 purple 3D
• 14 blue 3D
• 6 tan clips
• 10 blue clips
• 4 ball clips
• 4 blue/black hinges

Other K'nex parts:

• 2 mini triangular panels (equivalent to a yellow connector with three green rods)
• 4 black disks (2 required, 2 optional)
• 2 green headlight domes
• 2 black headlight domes (optional)
• 10 silver spacers
• 20 blue spacers
• 42 Y-clips

Non-K'nex parts:

• Elastic String or Rubber Band

A lot of the parts, especially the clips, can be substituted with other parts during construction, so for anyone who wants to do this but doesn't think they have enough parts, I recommend reading through the steps and looking for places where they can use substitutes. That said, the ball clips and hinges are required for mechanical linkages.

Also, as usual for designs in which I use a lot of non-classic-colored K'nex parts, I'll be identifying non-classic parts with the following nomenclature: "classic color (color in image)". Feel free to use your own colors and to add whatever other details you want in order to customize it.

For a firm grasp of the project, we start with the handle.

1. The handle starts with two frames as shown here. The white rod needs some form of spacer, either a clip like I used or a pair of blue spacers.
2. The white rod fits on the two red connectors so that the frames are separated by the spacer.
3. A pair of yellow (dark gray) rods attach to the top of the yellow connectors on the grip frames. Note that the one on the back uses a pair of blue spacers to keep the frames apart.
4. This is a side view of the handle so far. You may choose to center it on the yellow (dark gray) rods or you may choose to push it to one side, depending on what is most comfortable. I keep mine pushed to the left so that it is easier to use with my right hand, but you can adjust the position as desired after the rest of the dragon is built.
5. These two parts will connect the handle to the rest of the frame.
6. They connect to the rods on top of the handle as shown.
7. Here is another view of the handle and frame so far.
8. These will form the trigger for operating the mouth. The Y-clip is for the finger to operate, so it can be replaced with whatever is most comfortable or left out, although it should remain short to keep from interfering with other parts later.
9. The trigger assembly attaches to the frame in front of the handle.
10. The yellow (dark gray) rod fits to the frame with one slot between it and the rod on the front of the handle.
11. Here is a side view of the handle with the trigger attached.

This is the lower section of the head, with the moving mouth and the attach point for the handle.

1. These components will form the trigger linkage, which will connect the trigger to the mouth.
2. Here is the assembled linkage. The white (silver) rod that doesn't have a blue rod attached to it will connect to the mouth.
3. The linkage attaches to the head via an axle on a pair of gray two-slot connectors. The Y-clips on the connectors face away from mouth attach point.
4. Here is the linkage with the assembled axle.
5. Here is a front view of the linkage. As mentioned before, note that the gray connectors have Y-clips facing away from the front.
6. This U-shape will form the lower jaw of the mouth.
7. The Y-clips on the lower jaw attach to the ends of the blue rod. Normally, this type of connection is weak, but the other parts will hold it in place.
8. The white (silver) rod connects between the two green connectors.
9. Here is the top side of the lower jaw.
10. The jaws will attach to an H-shaped frame made from two blue-purple (blue-silver) 3D connectors and seven white (two white, four silver, and a black) rods. The ones that are white in the photo will connect to the nose.
11. The middle white (black) rod attaches between the purple (silver) connectors, and a yellow (dark gray) rod will connect opposite the two white rods.
12. Here is the frame with all the parts attached.
13. The Y-clips on the back of the axle will attach to the yellow (dark gray) rod on the frame. Both parts are shown upside-down.
14. Here are the frame and lower jaw connected.
15. Turn the assembly right-side-up to attach the upper jaw.
16. The upper jaw is a U-shape similar to the lower one, but with a white (silver) rod already attached. The spacers shown are left over from earlier design experiments and are not necessary for this project.
17. Here is the assembled mouth.
18. This assembly will form the nose of the dragon.
19. Here is a side view of the nose, to show how the green connectors attach.
20. The green connectors will attach to the white rods on the frame.
21. Here is the nose attached to the jaws.
22. Here is a back view of the mouth and nose so far.
23. A green connector with a Y-clip and a green rod will give the nose a bit more shape.
24. Stick the Y-clip right in the center of the schnoz.
25. The rods on the back of the jaw frame will attach to the frame on the handle, and the blue rod attaches to the trigger.
26. Here is the mouth and nose connected to the handle.
27. These connectors will attach the head to the neck later.
28. The white (silver) rods on them will attach to the top of the rear frame connector on the handle as shown here.
29. These two connectors will be needed for attaching the eyes in the next step.
30. The green connectors slide onto the same rod that is used to attach the jaw axle.
31. Rotating them up behind the fixed green connectors will temporarily hold them in place, but the connection is weak. It will be made stronger when the eyes are attached.
32. Use a rubber band or an elastic string to hold the mouth closed. The best attach point I could find was the place where the mouth linkage attaches to the mouth, as this is fairly hidden once the design is complete, and it provides plenty of potential fixed points on the frame to anchor the rubber band or elastic string.
33. This is the mouth and handle at the end of the step.

This step includes the eyes and the rigid sections of the top of the head. These sections form the controller that allows you to manipulate the eyes.

1. This square frame will become the controller for the eyes.
2. The two white rods form a socket in which you can put your thumb to manipulate the eyes.
3. The green connectors here will be used to help hold the connectors for the eyes. The white (silver) rods will slip through the holes in the green connectors on the frame.
4. Another pair of green connectors will attach to the other side of the white (silver) rods.
5. Note the way the green connectors face relative to each other.
6. Here is another view of the connection, showing the angles of the connectors relative to each other.
7. These parts will become part of the top of the head.
8. They assemble as shown, with the white (silver) rod in the Y-clips and the blue rod in the slot next to them.
9. The white (silver) rod will fit into the center of the control frame.
10. The side with the blue rod faces away from the 3D connector when attached to the frame.
11. Three green connectors and three white rods will form the rest of the top of the head.
12. Here they are assembled.
13. The assembly will connect to the green connectors from steps 7-10.
14. Here it is attached to the rest of the top of the head.
15. A pair of green connectors with Y-clips will attach to the blue rod.
16. The Y-clips attach to the rod so that the green connectors fit alongside the white rods.
17. These parts will form the back of the head.
18. They assemble as shown here.
19. Attach the part from step 18 to the back of the 3D connector to hide your thumb, and add a couple gray one-slot connectors with green rods.
20. They connect as shown here. Notice that the holes in the gray connectors fit over the white rods.
21. Finally, we begin the assembly for an eye.
22. Here is one eye assembled.
23. A pair of green connectors and a white rod will hold the eye in place.
24. This assembly will allow the eye to move up and down.
25. The red (dark gray) connector with the white rod attaches to the Y-clips on the eye holder.
26. The white (silver) rod on the bottom is the axle on which the eye moves side to side.
27. You will need two of these eye assemblies (of course). They are structurally identical, but you can play with the colors to give them a bit of variety.
28. The ball clips on the backs of the eyes attach to the Y-clips on the sides of the top of the head.
29. Here is a closeup of how the back of the eye connects to the head.
30. Adding the "ears" here is optional. I just included this image to show when I put them on my model.
31. Add a silver spacer to each post on the bottom of the eye holders.
32. The posts slip into the single-slot gray connectors from the lower part of the head.
33. Here is the two sections of the head connected two each other.
34. This is the beginning of the part that will hold the two sections together.
35. The blue rod and spacers will form a hinge for the last part.
36. Here is the assembled hinge. It will simultaneously hold down the top of the head and hold up the trigger for the wings.
37. These parts form the wing trigger. Modify them as desired to make it easier to operate.
38. The trigger attaches between the two red (dark gray) connectors on the hinge.
39. A pair of green connectors attach to the blue rod on the end. These will link the trigger to the wings.
40. The red (dark gray) connectors on the ends of the hinge attach to the posts at the bottom of the eye holders.
41. Here is the hinge attached to the eye holders. The step is now complete, and the remaining pictures are the current state of the project.

This is where the head connects to the rest of the body. The neck is essentially a universal joint mounted on top of a pinned hinge. The top of it attaches to the back of the head to form the upper body. The bottom will connect to the lower frame of the body.

1. The upper universal joint is made from a blue and purple (blue and silver) 3D connector surrounded by 4 white rods. The red (dark gray) connector is needed for stability.
2. The center of the joint is a white connector surrounded by 4 green rods.
3. The center plate is placed under the center of the 3D connector, and the two side connectors are slid over the green rods.
4. Two silver spacers are used to keep the connectors from sliding back off the center plate. They are held in place by the frame, which starts with four 3D connectors and two blue rods.
5. The connectors form an hourglass-shaped frame.
6. A blue rod fits on the side opposite the red (dark gray) connector with a pair of orange (brown) connectors on it.
7. A pair of gray two-slot connectors with green rods on them connect to the back of the frame.
8. Just like the ears earlier, these black domes are optional and can be skipped.
9. The open end on the front of the frame connect to the blue rods on the back of the head.
10. Another blue rod slides through the holes in the gray connectors on the back of the top of the head.
11. This rod attaches to the frame to complete the square.
12. This is a gray one-slot connector and a gray two-slot connector attached to a couple green connectors by a pair of white rods.
13. The white (silver) rod on the back of this assembly attaches to the 3D connector in the center of the frame.
14. A total of five purple (green) flex-rods will add texture to the back of the head.
15. Two of the flex-rods attach to the green connectors behind the eyes.
16. The other end of those connectors attaches to the gray connectors on the back.
17. This is the back with those two flex rods attached.
18. Two more flex-rods attach to the green connectors on top of the head.
19. These attach to the orange (brown) connectors on the back.
20. The last flex-rod attaches between the green connector on the nose and the gray connector in the center of the back.
21. Turn the model upside-down for this next step.
22. The red (dark gray) connector with white (silver and black) rods will stabilize the universal joint.
23. Attach the stabilizer to the frame as shown.
24. This is the other side of the universal joint for the neck. A blue or tan clip could be used in place of the black disk, but the disk works much better.
25. The silver spacers and tan clips will hold the universal joint together on this end.
26. Here is the joint with the spacers and clips attached.
27. The frame here will attach to the lower part of the body.
28. The blue spacer fits over the rod on the bottom of the universal joint.
29. The frame fits over the blue spacer. This will sit directly on top of your arm, so you will want to use a black disk here instead of a clip.
30. Here is what the project will look like at the end of this stage. The eyes and mouth should be usable at this point.

Here is the body, legs, and tail.

1. These components form the frame for the lower body.
2. The frames assemble as shown. Pay attention to the direction the 3D connectors face, as this will be important.
3. The red (metallic green) rod fits in the purple (silver) 3D connectors in the triangle opposite the blue connectors.
4. Attach the other frame to the same rod so that the frames mirror each other.
5. Add blue rods to the locations shown to stabilize the frames. Do not add a blue rod to the rearmost connector, as that will be added later.
6. You will need two front feet and two rear feet. The rear feet have a blue rod just behind the claws, and the front feet have a blue rod separated from the claws by one slot.
7. The rear feet attach to the blue 3D connectors as shown here.
8. Another blue rod attaches to the purple (silver) 3D connector beside the foot and slides through the holes in the top.
9. The front feet attach just like the rear feet, but the blue rod fits in the slot just in front of the vertical one.
10. Here is the body with all four feet attached.
11. You will need four legs like this. The only difference between the front and rear legs is the direction of the top part.
12. The front legs attach between the front feet and the Y-clips on the red (metallic green) rod.
13. The rear legs attach to the rear feet just like the front legs, but they stick straight up without attaching to anything else for now.
14. This red (metallic green) rod will stabilize the rear legs.
15. The Y-clips will attach to the legs so that the rod sits just under the rods on the frame.
16. Here is the frame with the legs attached at this point.
17. The three green connectors will be the first parts of a folding joint on the back.
18. Two green connectors slide onto the white (silver) rod, and a blue rod holds them together.
19. Two blue spacers slip onto each side of the rod, and a green connector slips on afterwards.
20. A yellow (dark gray) rod holds the green connectors together.
21. Two more blue spacers fit onto each side of the yellow (dark gray) rod, and red (dark gray) connectors clip over them.
22. The red (dark gray) connectors clip on facing the opposite direction from the green connectors.
23. The entire assembly clips to the red (metallic green) rod on the back.
24. Sliding the blue clips up beside the red (dark gray) connectors will give it a more stable fit for holding the legs in place.
25. We can now attach the head to the rest of the body, but this step isn't quite done yet. The square frame under the universal joint attaches to the 3D connectors above the front feet.
26. Here is the joint after attaching it to the rest of the body.
27. Here is what the model looks like so far.
28. These parts will connect the tail to the body.
29. Here they are assembled.
30. Slide the gray connectors over a blue rod, separated by two blue spacers and two silver spacers, as shown here.
31. The blue rod fits into the unused gap between the 3D connectors
32. A pair of purple (green) flex-rods will connect the tail holder to the head so that moving the head will move the tail as well. Another flex rod connects the gray two-slot connector on the back to the green joint above the rear legs.
33. The front ends of the flex-rods attach to the 3D connectors on the back of the neck. The other ends attach to the hinges on the tail connector.
34. Here is a closeup of the point where the central flex-rod attaches.
35. The tail itself is four flex-rods and a white rod connected to two yellow connectors and a two-slot gray connector.
36. The tail connects to the green connectors on the tail holder.
37. Eustace is almost complete. All that remains is adding the wings.

This is the step where our dragon finally takes flight.

1. We will start with the inner wings. The first part is this small truss and an extra white rod. One of the two Y-clips will connect to the midsection of the wing, and the other can be replaced with any clip.
2. Here is the assembly with the white rod attached. The Y-clip on the bottom is the necessary one, and the other can be replaced with a different clip or connector.
3. These four orange (brown) connectors will form the connecting link between the inner wing and the midsection.
4. Here is the assembled connection link.
5. The last part of the inner wing is a red (metallic green) rod with two tan clips and a gray one-slot connector. The tan clips are necessary to reduce twisting.
6. Here are all the parts needed to make the inner wing.
7. They assemble as shown. The tan clips slide all the way to the ends to lock the connectors.
8. Here is a closeup showing which Y-clip is used to attach the connecting link.
9. The wingtip begins with the parts shown here.
10. These parts will complete the wingtip. I used a red (metallic green) rod for the tip, but you can experiment with other lengths to find what looks best. If you do, be sure to test the mechanism after the wing is assembled to ensure that it does not interfere with the folding process.
11. Here is the fully assembled wingtip.
12. The midsection is simply a pair of red (metallic green) rods linking the wingtip to the inner wing.
13. Here is the assembled wing. You should be able to fold it back and forth by manipulating the front part of the inner wing.
14. The other wing is a mirror image of the one shown in the previous parts of this step. You will also need four white rods and four clips of almost any type.
15. The wings attach to the 3D connectors on the back of the neck. Note that the rear section attaches below the 3D connector and the forward section attaches above the 3D connector. This reduces the likelihood that parts might lock together while the wings fold and unfold. The other wing attaches to the other side in the same way.
16. These are the linking rods that will connect the wings to the control lever under the chin.
17. Here is an underside view of the wing with the linking rod connected.
18. This is a top view of the same wing. The Y-clip on the connecting rod attaches to the unused slot on the red (dark gray) connector.
19. Just as with everything else in this step, the connecting rods are mirror images of each other.
20. The Y-clips on the other end of the connecting rods attach to the lever under the chin as shown here.
21. Eustace the Dragon is now complete!

Here are what the different controls do and how to operate them.

1. Operating the mouth simply consists of pulling and releasing the trigger with the index finger.
2. To move the eyes, press your thumb into the back of the 3D connector above the handle. The eyes move in the opposite direction from the connector, so pulling it down moves the eyes up, pushing it to the left moves them to the right, etc. One flex-rod is removed in the video to make the thumb easier to see.
3. The wings are controlled by the lever under the chin. Pushing it forwards extends them, and pulling it back retracts them.

That's everything for how to build Eustace the Dragon Puppet. Feel free to customize the design to your liking and share your results. I hope you enjoy!