Q&A for How to Make Rocket Fuel

Some model rockets can reach altitudes of over 5 miles. A larger amateur rocket called the GoFast Rocket recently broke records by going as high as 72 miles!

It depends on the type of rocket. Model rocket engines need 2 main ingredients: a fuel and an oxidizer. Your average model rocket uses some form of sugar (such as sucrose) as the fuel, and potassium nitrate as the oxidizer (or propellant).

The laws may vary depending on where you live. In the U.S., it’s legal to make rocket fuel for model rockets. However, in some states, you may need a special permit to buy or use certain ingredients, or to build certain types of engines.

The rocket fuel works. Just make a fuse, and it really burns.

A small 6-inch rocket will go at least 500 meters up or two miles away, so it's pretty powerful!

Strictly speaking, Karo syrup isn't necessary--it just helps to bind the other ingredients and make the resulting paste smoother and easier to mold. You can easily make homemade rocket fuel using potassium nitrate, sugar, and water alone. Just let the sugar cook down a little more to ensure that it's melted enough to make it manageable.

It is very dangerous if not handled properly. Don't light it inside, and if it is in a rocket then point it skyward, light the fuse and get behind something.

No. KNO3 is your primary oxidizer and the most readily available one too. Look up "stump remover" in a horticultural store. Be sure it says that it contains 100% KNO3.

The recipe provided here produces about 100g of fuel, which will usually be enough for several flights, depending on the size of your model rocket.

Standard Karo Light Corn Syrup is recommended for this recipe. Avoid syrups with flavorings or other added ingredients.

The exact distance your rocket will travel will depend largely on how long your homemade fuel burns, as well as how efficiently. While it's possible that a well-built model rocket could reach elevations of 1,000 feet or higher, there are so many variable at play that it may not happen if the fuel hasn't been properly mixed (or even if it has).

Not necessarily--molding the fuel into a ball just makes it easier to load into the round engine compartments of most model rockets once it's time for takeoff.

No, absolutely not. You're going to need professional-grade rocket fuel and oxidizer to get even somewhat close to orbit.

This is the only model rocket fuel recipe safe for home preparation and use. Other types of rocket fuel contain highly combustible ingredients like kerosene and liquid hydrogen that burn incredibly hot and can easily cause accident or injury if not handled appropriately. For the safety of yourself and your home, it's best to stick to simple sugar fuels.

You will have to resort to light weight metal body with a constriction on the opening and a cylindrical exhaust, the constriction does not have to be too small as this poses an explosion risk. The cylindrical exhaust is there to stabilize the motion of the rocket in a straight forward trajectory.

Yes. What's important is that you include an oxidizer among your fuel ingredients. However, using an oxidizer other than potassium nitrate will require you to adjust the quantity included in your fuel recipe, and your finished fuel may not burn as efficiently if the proportions are off by even a marginal amount.

R-Candy-type fuels burn extremely hot, and are capable of melting many varieties of plastics. If you want to reuse your rocket, look for burn-resistant parts and materials at hobby stores, or order them online. Keep in mind that these materials may cost quite a bit more than standard kits.

A small amount of corn syrup helps bind the other ingredients during the cooking process and results in a smoother, creamier paste that's more easily molded and hold its shape longer. However, sugar fuels can be prepared using potassium nitrate, sugar, and water alone.

The amount of fuel you use will be limited by the size of your rocket's engine compartment. And before you get too gung-ho, remember that you're only launching models rockets--no rocket will travel as high as 2 miles, no matter how much homemade fuel it's stuffed with.