Rocket candy

Rocket candy, or R-Candy, is a type of rocket propellant for model rockets made with a form of sugar as a fuel, and containing an oxidizer. The propellant can be divided into three groups of components: the fuel, the oxidizer, and the (optional) additive(s). In the past, sucrose was most commonly used as fuel. Modern formulations most commonly use sorbitol for its ease of production. The most common oxidizer is potassium nitrate (KNO₃). Potassium nitrate is most commonly found in tree stump remover. Additives can be many different substances, and either act as catalysts or enhance the aesthetics of the liftoff or flight. A traditional sugar propellant formulation is typically prepared in a 65:35 (13:7) oxidizer to fuel ratio.^[1]This ratio can vary from fuel to fuel based on the rate of burn, timing and use.

There are many different methods for preparation of a sugar-based rocket propellant. Dry compression does not require heating; it requires only grinding the components and then packing them into the motor. However, this method is not recommended for serious experimenting, this is because dry compression is less saturated, and can be dangerous if it falls out the rocket. Dry heating does not actually melt the KNO₃, but it melts the sugar and then the KNO₃ grains become suspended in the sugar. Alternatively, the method dissolving and heating involves both elements being dissolved in water and then combined by boiling the water off, creating a better mixture.^[2]

The specific impulse, total impulse, and thrust are generally lower for the same amount of fuel than other composite model rocket fuels, but rocket candy is significantly cheaper.

In the United States, rocket candy motors are legal to make, but illegal to transport without a low explosives users permit.^[3][4] Since they count as amateur motors, they are typically launched at sanctioned Tripoli Rocketry Association research launches which require users to hold a Tripoli Rocketry Association high power level 2 certification. Users may also launch using these motors by applying for an FAA flight waiver.