Homemade Multi-Launch Model Rocket

Easy-make Homemade Multi-Launch Rocket

Bought Materials

• Estes D12-3 Rocket Engine & Igniters
• Estes Shock Cord
• Estes 18 in. Parachute
• 2 in. Diameter Cardboard Tube + Tight Covers (1 for each opening, 2 in total)
• Estes Wadding Paper
• Estes Launch Pad and Launch Controller/Remote

Materials Around the House

• Cardboard
• Duct Tape
• Acrylic and/or Spray Paint
• T-Pins
• Paper Towel/Toilet Paper Roll
• Plastic Straw

Tools

• Hot Glue Gun + Hot Glue Sticks
• Sharp Edge (scissors, blade)
• 3D Printer (availability)
• Ruler
• Markers

Before building the rocket, it is important to understand how it works.

Firstly, the rocket is to be mounted on a standarized Estes rocket launch pad (supplies) or any suitable launch pad with a launch rod. Once mounted, the igniter should be clipped to the remote. Make sure the clips do not touch each other. Once full connected, you may step back and initiate the launch.

During flight, the rocket will have a certain amount of thrust and burn for a certain amuont of time. The engine used in this model is the D12-3 engine (supplies). The name D12-3 is based upon its statistics. "D" is the typing of the engine in which it produces 2x as much thrust as a "C" engine. D engines produce roughly 7.4 lbs of thrust. The "12" is the amount of propellant inside. This should not matter as all D engines have the same amount of propellant therefore they will burn for the same amount of time. Finally, the "-3" is the delay until the ejection charge.

The ejection charge is what starts the next phase of launch. Given the engine for this rocket, the D12-3, the "-3" is the amount of time in seconds until the ejection charge burns. The ejection charge is basically one final burst of propellant that shoots out the other side of the engine which will stage the rocket and deploy the parachute. So, the "-3" means that after the main propellant burns out, the engine will burn for rougly 3 seconds before the ejection charge ignites and stages the rocket.

Finally, the parachute should be deployed and safely bring the rocket to the ground. If the parachute cords do get tangled then what is able to expand should slow the rocket down enough for very minimum damage that can be ignored for the next launch.

Supplies Required: Cardboard tube, Sharp Edge, Ruler, Marker

To start, simply measure a segment of the tube from one edge and up 10 inches and mark that point. Then, cut around that mark so that you end with a 10 inch long tube.

Tip: wrap tape around the marked position to get an accurate cut.

Supplies Required: Cardboard Tube, 3D printer (PLA), Sharpedge, Cardboard Tube Cover, Hot Glue, Ruler

Firstly, take the remaining section of the tube and cut an even cylinder with a height of about 1.5 inches, measurements don't have to be exact.

The hardest part of this step is gluing the tube cover to the stage. Before gluing, make sure that the "hump" of the cover is facing outside so that the flat side/the side that concaves in is the part that is glued to the stage. Idealy, glue the cover to the side you find to be the flattest. Sanding edges won't help much but it is a plausable solution.

Finally, the nose cone. 3D print the gcode file below and it should be a perfect fit. You may glue the nose cone in if it is not desired to put anything inside the first stage's empty space/"cargo bay"

Supplies Required: Cardboard, Hot Glue, Scissors/sharpedge, Ruler, Plastic Straw

Cut out four identical triangles in the cardboard with the bottom leg at 3 inches and the height at 4.5 inches.

Once cut out, these may be painted before attachment if wanted.

When it comes to attaching the fins, they do not need to be placed exactly 90 degrees from each other can can be eyeballed. The first fin is the easiest, especially if the rocket does not have a design yet. Using hot glue and a ruler if wanted, attach the fin as straight up as possible as that is what's most important. The easiest way to attach the other fins is by turning the rocket so that the bottom of the rocket is facing you. Eyeballing still works but to be more exact, you can use a ruler as a diameter and find where to hot glue the next fin. The other two fins can also be eyeballed as long as they are generally about 90 degrees in between the first two fins and that they are also pointed straight up.

Now that the stabilizers are attached, using hot glue, securely glue a plastic straw in between two of the fins and make sure that the straw is pointed straight up, parallel to the rocket body. This straw will be what the launch pad's launch rod will be placed through before launch.

Supplies Required: Cardboard Tube Cover, Paper Towel/Toilet Paper Roll, Hot Glue, T-Pins

Starting with the bottom, take a cover of the tube and try to center the D12 engine in the middle. It does not need to be exact as long as it is generally centered. Once the engine is centered, using a sharpie, trace a circle around the engine. Once traced, the area inside the circle must be cut out and will be used at the main opening for the engine. Leaving some messy lines is fine as imperfections also keep the engine steady.

Next, using a paper towel roll, rip the spiralled folds off so that it can be wrapped around the engine. Once wrapped, securely tighten the roll around the engine and put hot glue over the folds until the roll can hold itself. Once dried, before taking the engine out of the roll, make sure the flat edge of the roll is lined up with one of the engine's ends and start to feel where the other side of the engine reaches on the roll and mark it. About half an inch above that point, cut the roll so that its total length is the length of the engine + 0.5 inches.

Above the marked line, push 4 T-Pins through but make sure that they are pushed through near the edges so that they create a square or any sort of relatively-large opening in the middle. This opening is for the engine's ejection charge (Ejection Charge; Step 1)

Once the roll has been made and the engine fits inside it securely, place the flat end (the side without the pins) around the opening of the cover (on the "humped" side/the side that's placed inside the rocket body) and hot glue in place. Make sure the engine can be placed inside and outside the mount but is secure enough that it take some effort to the engine out of. If the engine can easily be taken out, wrap a small amount of duct tape around the engine until the tape makes the engine just thick enough so that it take effort to remove from the engine mount.

Materials for this step: Parachute, Shock cord, Hot Glue, First and Second Stages

Unfold the parachute and follow the strings to see that they end in loops. Using the loops, place the shock cord through the loops and make sure the parachute is closer to one side of the cord than the other. After tying the strings to the shock cord, hot glue the farther end of the shock cord inside the first stage near the top opening which should be about 1-2 inches from the opening. the other side of the cord has to be hot glued to the bottom of the second stage, atop the cover that goes inside the first stage.

You may fold the parachute in and place it inside the first stage for more workspace however you will have to take it out once again.

Completely optional

Paint!

Tip: Use tape for any straight lines you want to create as it is hard to do on a curved surface free-handedly

Starting with the rocket fully disassembled, start with the engine mount. Place the engine mount inside the rocket (the cardboard roll goes on the inside) and hot glue the cover to the bottom. Next, using one sheet of wadding paper, push it to the bottom of the rocket until it touches the engine mount and then you may fold the parachute and shock cord and place them inside the rocket body. Then, close the rocket with the second stage. Now, the rocket is ready for launch.

Finally, the rocket should be ready for launch!

This was built in the state of California where there are strict laws against model rocketry. You will have to do research to find what areas and when you can launch based on your state.