Q&A for How to Make Sugar Rockets

You don't. It's just that most PVC pipes with suitable sizes for rockets are for electrical wiring and thus are not designed to withstand a great deal of pressure. These pipes also tend to be low in quality and have a tendency to fissure. Adding the second pipe inside the first serves to help with distributing the force of the pressure. I have been using 25 mm electrical tubing for my rocket motors for years and I can tell you that if it doesn't crack during the powder packing, then it won't burst in flight either, as the heat generated softens the plastic and makes it more malleable. The motor will slightly expand from the heat and pressure, but it should not burst.

Yes. If you want larger quantities, multiply every ingredient by the same ratio.

I am doing a sugar rocket for my independent study in science class, so personally I think it's completely acceptable

Soak yarn in a mixture of potassium nitrate, sugar, and water and then bake it dry. Check YouTube for further instructions.

Durham's Rock Hard Water putty is easier to use and relatively inexpensive.

Amazon - Spectricide Stump Remover is 100% potassium nitrate and is around $7.00 for 1 lb. These are graduals and need to be ground; an old coffee grinder works well.

They will mess up the rocket so please don't do it.

You cannot, since the walls are way too thin and it would burn right through.

You're confusing potassium nitrate with ammonium nitrate, the fertilizer, (AN) 34-0-0. Not interchangeable.

You could use spray paint or any other art materials to decorate your rocket however you'd like.

No. You only need a license if you're making them with the intention of selling them.

Just increase the potassium nitrate and sugar ratio by the same amount, and use a longer pipe.

No, sugar rockets are not illegal in the USA.

The rocket will fly with the stick because it needs the stick to fly properly. Since the center of mass needs to be behind the center of thrust for it to fly straight, then the stick is necessary to stop it from spiraling out of control.

No, you cannot. It will catch on fire and/or explode soon after ignition.

Yes, as long as your parents and school are okay with it.

Which chemical? Sugar or KNO3 alone will not damage the pipe. Mixed - even if dry-mixed (not cooked) - the pipe could explode, though that is unlikely.

No. Potassium nitrate is one of the main ingredients in simple explosives. This mixture is actually a simplified form of black powder. You can substitute the other ingredients, but not the oxidizer (potassium nitrate).

Yes, adding fins will increase stability on your rocket. However, avoid putting the fins too close to the nozzle.

The propellant will work exactly the same no matter its temperature. So long as you leave the finished rocket in a safe and appropriate place it should still work no matter how long ago you made it.

This depends on the rocket's weight and thrust. You can calculate that with simple high school physics.

You could use a vise, which can be gotten at any hardware store. You could also just tape the rocket down to something heavy with duct tape.

Shorter flight times can be achieved by using less propellant. The converse is also true: more propellant will allow you to achieve a longer flight time.

If you don't mind ever seeing it again. If the heat doesn't destroy it, the fall will.

No, they are not legal in Romania.

Only about two feet, with this ratio. You must use a great deal of fuel to achieve any significant height.

Yes, it helps to cook the mixture in order to bind the ingredients together properly. However, dry packing works just as well, if not better.

Sugar rockets are likely to be considered illegal in the UK. Under the Explosives Act 1875, manufacturing solid rocket motors (defined as mixing the solid compounds necessary to make the solid propellant for a solid rocket motor) is illegal.

Yes, but they are limited to 63.5 grams of propellant. The Australian Civil Aviation Authority has rules around them, as does the Department of Mines. If you go over 63g of propellant per engine, you need a fireworks licence. The law is silent on daisy chain engines, that could be interesting.

When dealing with pyrotechnics compounds, never use PVC. In the event of a malfunction, PVC creates shrapnel. Paper/cardboard is a far safer material to work with. If you don’t want to make your own, you can find cardboard tubes at pyrotechnics suppliers and they are fairly cheap.