Homemade Rocket Engine

Try creating your own model rocket engine.

Model rocketry is a very popular hobby, and the technology has advanced considerably as the number and type of model rockets available has increased.
Several types of model rockets are available relatively inexpensively, including gas propulsion and liquid fuel, but by far the most popular model rocket is the solid-fuel propellant rocket. This type of rocket uses a fuel similar to gunpowder to propel the rocket as high as half a mile into the atmosphere.

Things You'll Need

• Saltpeter (potassium nitrate)
• Sulfur (flower of sulfur)
• Confectioner's sugar
• Brown paper
• Glue
• 1/2 inch diameter wood dowel (8-12 inches long)
• Gypsum-based water putty

Instructions

1. Measure 113.2 grams of saltpeter, 48.5 grams of sugar and 8 grams of sulfur.
   You can increase or decrease the amount of the ingredients as long as you maintain the same percent ratios (saltpeter 63 percent, sugar 27 percent and sulfur 10 percent). The closer you get to the ideal percentages of the fuel mixture, the more powerful the propulsion will be when it is ignited.

2. Mix the saltpeter, sugar and sulfur thoroughly. A mortar and pestle or another non-friction mixing method is ideal, but do NOT mix the ingredients in a blender or any other metal mixing device that might generate enough friction or heat to ignite the mixture. Store in a completely airtight container.

3. Wrap the paper around the dowel once or twice and glue to produce the casing. Create a nozzle at one end of the casing using the water putty. The nozzle thickness should be about 1/4 inch. Let the putty dry overnight and then use a 3/32 inch or 7/64 inch drill bit to drill a hole through the center of the nozzle.

4. Pack the propellant material around a 3/32 inch wire rod from the level of the nozzle to a total fill length of 3 inches including nozzle. Moisten slightly, pack again, then remove the wire rod and let dry overnight.

Tips & Warnings

• These homemade rocket engines are approximately equivalent to Estes Class B rocket engines.

• The propellant mix is highly flammable and even explosive under pressure. Handle with extreme caution.

References

• Rustic Girls: Model Rocket Engines
• Teleflite Corporation: The Incredible Five Cent Sugar Rocket
• Pyronfo: Rocketry
• Mad Cow Rocketry