I would like to start a project for the construction of rockets as a project for high school students. Starting with the development of a solid fuel (KNO3 + sugar) which is the safest method for the production? What additives can I use? I have seen from very simple elaborations, to more elaborate methods with the same components. Heat the mixture and manipulate it how dangerous it is? How do I estimate efficiency?
I would not recommend this project for high school students. Whatever you do it's unsafe for not trained people
Dear Professor Geletti,
Thank you for your response, in fact I consider your criteria correct. I believe that the students should not prepare the fuel, because it must be prepared by a Chemist in safe conditions of laboratory (my responsibility, and I will prepare the fuel).
Now, there are many status in the creation of rockets, from a homemade experiment where the mixture of potassium nitrate and sugar is not heated, until preparing a more elaborate fuel for a less playful rocket and a more responsible engineering character.
Our purpose is to prepare a solid fuel and a simple rocket; that's if having security as a priority, that's why my question is specific.
Best regards,
Ender Araujo
I think that the answer of Yurii V Geletii is reasonable.
I experienced a lot of rocket fuels when I was teenager (long long ago!) and I can tell you that it may be very dangerous. The mixtures tried included sugar or other combustible cpds + nitrates or chlorates (definitely avoid the later!!!), metal powders + sulfur, etc. I used also nitrocellulose (maybe the safest? difficult to obtain.) Often the rocket exploded because of the geometry of the tube (surface at which the combustion takes place) and exhaust size (nozzle). Firing/ignition is also tricky. The combustion rate of a solid fuel depends highly on the mode of preparation, particularly the granulometry, the degree of dryness, etc. These effects are spectacular with black powder.
How to get nitrates and other oxidants if you are not in a lab? "Fortunately" it is impossible in France, you may guess why.
Anyway I have a suggestion: when I was in USA, it was easy to get small rockets engines about 15 mm * 100 mm long, which were used as a basis to build rockets by adding "fins" and nose cone, or even putting them in a larger model rocket. They flied probably up to 100 m. As an additional demonstration you may make VERY SMALL AMOUNT of the sugar or charcoal etc + nitrate mixtures as a controlled demonstration, show how to ignite... Good luck with your class. J-F
Safest is the following. Take your choice of KNO3 in a paper bag (glassware may be dangerous when it breaks!). Place the bag in a centre of a large flat field and pour over the bag at least a cubic metre of clean white sand (pure SiO2). Then take your sugar and spill it in a cup of coffee (or in more if one dislikes coffee too sweet).
Well, well, this will not make any explosives, but it is VERY safe!
Matyi demonstration seems to be safe. Don't put the coffee, but the sugar quantity for a coffee ! (I don't use sugar or sweeteners either.. .) I suppose that the dry sugar is placed on the paper bag containing the nitrate (NaNO3 used in agriculture works well also) and that the system is ignited but approaching a flame to the paper ? All the systems I described don't explode when they burn in an open atmosphere, but some are dangerous when mixing.
Dear Professor Benoit,
It is possible to perform a safe procedure for the preparation of this type of reaction, in chemistry, since there are more risks and dangerous laboratory procedures than the mixture of sugar and nitrate. Potassium, under controlled conditions. I do not have the knowledge or the experience that it has, however, as I am a "chemistry principle", it is my responsibility to consult an expert, that does not drive me crazy.
In general, I agree that it's quite unsafe. But if you (not children) work with small quantities for a school rocket there should be no big risk. Have you tried to follow these instructions? https://www.jamesyawn.net/rcandy/safety.htm
The best information about this type of propellant and rockets are found on Nakka's homepage:
https://www.nakka-rocketry.net/sucrose.html
I would agree with most of the peer researchers. Plz do not let high school students be involved in making solid fuel for rockets. Rather you can ask them to do a project on trajectories and its calculations. In school level i suppose theoretical studies would be good. Its highly dangerous and not advised to do it so in school level.
IIRC (from my youth), newspaper paper (the dailies' type) soaked in a KNO3 solution (in water), then dried, gives a reasonable rocket propellant: once dried, simply form a roll with a hole at the center. Once ignited at the end/center, this will burn very much like standard solid fuel rockets.
KNO3/sugar and similar mixtures give good explosives but poor rocket propellants. OTOH, if you want to build a cannon...
have you already see a boy with a hand cut from a student rocket? I've seen!
KNO3 + paper is about the "safest" propellant: not too critical to laborate the paper, not too critical when handling the dried paper. Just 2 addons:
- avoid excess heat for drying
- make the outer shell of the rocket from cardboard. You won't risk metal fragments flying ...
For all potential explosives when firing: distance, distance, distance.
A cordial greeting,
We made a simple rocket, with the mixture (unheated) o 65% KNO3 (s) and 35% Sugar because safety is the priority in this type of projects, as Professor Rigo tried to comment.
We did small-scale tests to test the fuel efficiency and then we did two "mini" rocket launches, both on a small scale. Although it worked as we had calculated, I have decided to finish the project due to the inherent risks to work at larger scales, because we currently do not have the knowledge, the expertise and the technology; in fact our expectation was to make a rocket with an educational purpose.
I thank everyone who made suggestions and shared their experience on the subject. Finally, the Dominican Republic could participate in the Glabal Rocket Launch in celebration of the 50th anniversary of the launch of Apollo 11, and (as far as we have references) it is the first time that a solid fuel rocket has been built in this country; which we activate remotely with a robot.
Thank you all.
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