Everything You Need to Know to Start Making Fireworks Rockets

Everything You Need to Know to Start Making Fireworks Rockets

Written by Harry Gilliam

Topics: How to Make Fireworks

by Ned Gorski


Pyro audience
This is Your Audience

A big fireworks rocket
This is a Big Honkin’ Fireworks Rocket

Audience watching fireworks rocket fly
This is Your Audience on Fireworks Rockets!


Obviously, in this introduction to rockets, we won’t be discussing military rockets, which have a long and rich history. Neither will we be discussing rockets designed for space exploration, which we’ll leave to NASA.

But leaving those aside, there is a wide variety of rocketry that folks can and do explore for purely recreational purposes. Such rockets include model rockets, amateur rockets, high-powered rockets, and fireworks rockets. The purpose of this article is to discuss fireworks rockets. However, in order to distinguish fireworks rockets from the other types, we will briefly mention and define each of these.

The following rocketry classifications and descriptions come from Wikipedia:

  • Model rocketry: “A model rocket is a small rocket capable of being launched by anybody, to generally low altitudes (usually to around 100-500 m (300-1500 ft) for a 30 g (1 oz.) model) and recovered by a variety of means.”

Estes® rockets are an example of the types of rockets launched in model rocketry. Typically, only commercially manufactured rocket motors are used in model rocketry. However, one Skylighter project highlights the hobbyist manufacture of rocket motors for Estes® rockets.

Estes model rocket leaving launch pad
Model Rocket

  • Amateur rocketry, sometimes known as amateur experimental rocketry or experimental rocketry is a hobby in which participants experiment with fuels and make their own rocket motors, launching a wide variety of types and sizes of rockets. Amateur rocketeers have been responsible for significant research into hybrid rocket motors, and have built and flown a variety of solid, liquid, and hybrid propellant motors.”

Skylighter sells many of the chemicals which are used in the manufacture of motors for amateur rockets.

Amateur rocket smoke trail.
Launch of an Amateur Rocket

  • High-power rocketry is a hobby similar to model rocketry, with the major difference being that higher impulse range (i.e., more powerful) motors are used. The National Fire Protection Association (NFPA) definition of a high-power rocket is one which has a total weight of more than 1500 grams and contains a motor or motors containing more than 62.5 grams of propellant or more than 160 Newton-seconds.”

Commercially manufactured motors are most frequently used in high-powered rocketry.

High powered rocket on lauch pad.
A High-Power Rocket Being Readied for Launch

  • Fireworks Rockets
    In his 1947 book Pyrotechnics, George Weingart uses the term “Sky Rockets” to refer to fireworks rockets.

    From Wikipedia: “A skyrocket is a type of firework that uses a solid (fuel) rocket motor to rise quickly into the sky. At the apex of its ascent, it is usual for a variety of effects (stars, bangs, crackles, etc.) to be emitted. Skyrockets use various stabilization techniques to ensure the flight follows a predictable course, often a long stick attached to the side of the motor, but also including spin-stabilization or fins.”

Some fireworks rockets, which employ high-powered fuels such as whistle, strobe, or hybrid fuels, blur the distinction between fireworks rocketry and other types of recreational rocketry. In general, though, the presence of pyrotechnic effects intended for entertainment is the distinguishing characteristic of fireworks rockets.

Large whistle rocket with 10-inch heading.
Launch of a Large Fireworks Rocket by Dan Thames,
2-Inch Whistle Motor, 10-Inch Ball Shell Heading

Photo by Mark Stallings


Except for the project on homemade Estes®-type rocket motors, mentioned above, the focus of this article and at Skylighter is on fireworks rockets. The description of fireworks rockets will be expanded upon in this section.

The purpose of fireworks rockets is entertainment. The rocket motor is often designed to provide an entertaining visual and/or audible effect, such as a long glittering or spark tail, or a loud ascending whistle.

Additionally, often the rocket motor is fitted with a “heading,” which creates a traditional fireworks display–for example, a loud report, a shell burst of stars, or a display of other types of fireworks inserts–at the end of the rocket’s powered flight.

Fireworks rocket innerds diagram.
Cross Section of a Typical Fireworks Rocket

The diagram above shows the elements of a typical fireworks rocket. The top of the rocket is on the right, and the bottom of the rocket is on the left.

This rocket has three main components.

Continue Reading: Everything You Need to Know to Start Making Fireworks Rockets…

36 Comments For This Post I'd Love to Hear Yours!

  1. Maurizio says:

    Hi All,

    These wonderful projects by the masters are tools for enriching us all, whether we are old hands, or novices in the discipline. If I may, I would like to add my small contribution.

    One of the things that has always puzzled me about black powder rocket makers, was their trial and error approach to designing a spindle for a core-burning rocket. A very well known and respected (by myself also) maker of black powder rocket spindles once confided in me about an instance in which he and another pyrotechnics master were trying different spindle length and nozzle throat combinations for a specific fuel they had developed. The trial and error they went through might have been avoided, or at least reduced, if they’d had a concrete way of quantifying such parameters. Well, I bring glad tidings; such a way exists.

    High powered rocket motor manufacturers use a very important variable dubbed “Kn” in the manufacture of their rocket motors. Kn is a very simple, but critical value, and it represents the ratio of two very important surface areas; Kn = (surface area of burning fuel, divided by the rocket nozzle throat area). Kn becomes a very important value in determining a rocket motor’s internal working pressure, and subsequently, propellant burn rate, thrust, and even exhaust temperature. In order to determine Kn, we must obviously be able to calculate the surface area of the burning fuel, to a reasonable approximation (you usually won’t have to be accurate to sub-millimeter dimensions). As this area changes in step with the burning of fuel, it may be convenient to calculate a minimum, and a maximum value for Kn. To calculate the minimum Kn, at the start of burning, we can use the average diameter of the spindle, assuming that it has a reasonably linear taper to it, and to calculate maximum Kn, we will use the inside diameter of the rocket motor tube. The equation to calculate a reasonable approximation of the surface area of the burning propellant assumes that this area is in the form of a burning cylinder with only one side capped; Surface area at start = (Pi * the average spindle diameter * Core length) + 2 * Pi * (one half the spindle’s tip diameter, squared). This value is then divided by the nozzle throat area, which is; Nozzle Throat Area = Pi * (one half the throat diameter, squared). Surface area at the end of the burn, yielding the maximum Kn, will have the exact same formulas, but slightly different variables; Surface area at end = (Pi * inside motor tube diameter * Core Length) + 2 * Pi * (one half the motor tube’s inside diameter, squared).

    Let’s do the following example:

    Let’s say we have a motor with an internal tube diameter of 1.5 inches, a nozzle throat diameter of .625 inches, and a spindle length of 14 inches. The spindle’s average diameter is .469 inches (the average of its maximum and minimum diameters), and the tip of the spindle is machined into a round tip, rather than a flat one. First, we calculate the throat area, as this does not change appreciably – unless the nozzle is made of marginal materials, or is specifically designed to erode; Throat area = 3.141 * (.3125)2 = .307 square inches. Next, starting (minimum) burning area: Amin = (3.141 * .469 * 14) + (2 * 3.141 * (.3125)2), = 20.63 square inches, plus .61 square inches, for a total of 21.24 square inches. We can now calculate the starting, or minimum, Kn;
    Min Kn = 21.24/.307 = 69.2

    We now calculate the maximum burning surface area, and thus the maximum Kn ;
    Amax = (3.141 * 1.5 * 14) + (2 * 3.141 * (.75)2) = 66 square inches, plus 3.5 square inches, for a total of 69.5 square inches. We can now calculate the final, or maximum Kn:
    Max Kn = 69.2/.307 = 225.4.

    So, here we are; we’ve come up with these two values, but what good are they for us? Is there any way they can help us in the real world? Fortunately, the answer is a resounding “YES”. A specific fuel can be used in many different sized rockets, as long as the Kn value is respected (with the exception of very TINY motors). A rocket maker can adjust a very wide range of diameters, spindle length needs, and thrust needs for any fuel he wishes, so long as he knows the Kn range in which that fuel operates. If one knows that a particular formula worked well in, say, a 1” diameter rocket with a spindle length and diameter that gave a Kn of 125, he can design his spindle, throat, and tube to adhere to this criteria, for any size rocket motor he wishes to make. In the case of a nozzleless rocket, recently covered in an article by Skylighter, one uses the inside diameter of the fuel grain for both the nozzle diameter, and the spindle diameter. For an end burner, one uses the following values: Amin = Pi * (one half the motor tube’s inside diameter, squared), and Amax = 2 * Pi * (one half the motor tube’s inside diameter, squared). Maximum and minimum Kn will then be solved accordingly. As a side note, BP works very poorly in end burners with a Kn of less than 35 – 40, even in a very fine grain size. At minimum Kn = 45, things start picking up, and by min Kn = 55, performance becomes acceptable. I have seen end burner kits marketed by several companies with Kns in the low to middle 20s, and the people who try to make end burner rockets with them, tend to be very disappointed, unless they resort to adding exotic, or very high energy fuels to the BP. Another note about Kn involves the use of very small nozzle throat sizes. While using a very small nozzle will, in fact, raise the Kn and the motor’s internal pressure to high levels, such designs are best avoided because smaller nozzles are far less efficient than their larger brothers, mainly owing to the turbulence created when the hot exhaust gases go supersonic through the throat. Further, in the internal pressure versus thrust balance, a nozzle throat area is reduced by the inverse square of the ratio of a smaller vs. a larger nozzle, reducing thrust accordingly, while increasing internal pressure, and efficiency, only in a linear fashion. Hence the preference for larger nozzle throats. Last but not least, if one is making a spindle from scratch, by all means, don’t omit the expansion bell at the base of the spindle! Popularly known as the “15-degree taper”, this controlled expansion of the motor’s exhaust gasses improves thrust significantly, especially in motors with high internal pressures, where the proper shaping of an expansion bell can increase motor impulse by as much as 20%!!!! I hope that some folks have found this little note of interest, and please feel free to ask away; I will be happy to drop in regularly and answer any questions that I can. : )

    Maurizio

  2. mark harris says:

    would you post a detailed description of how to construct a strobe rocket similar to the one in the video. mabey add; stars, flying fish,
    or a big bang to the finish. That was totally amazing. Thanks.

    • Rich Trimble says:

      Great plans for whistle and strobes in project plans section on the skylighter site. These rockets take off hard and fast, and reach heights over 1500ft. I have been using red rubber stars and or crysantamum stars in BP rockets with excellent results. The whisltle and strobes seen to work well with titanium mixed in with fuel above the spindle, and a report. At the end of all their screeching a nice POP is a perfect finish. These rockets really seem to be the ‘Drag racers”, compared to the “woosh” of BP rockets.
      Rich

      • Harry Gilliam says:

        Rich, now try some of our cheap or free Titanium Dihydride and see how well they work. Tell us all what you find out! –Harry

  3. Rich Trimble says:

    Thanks Ned for your incredibly detailed project plans. I was a closet pyro for years. Started with my Gilbert 4 chemistry set in the late 60s…. Started reading your project plans this past fall. Bought the turbo pyro kit and just got sucked into the rockets with 1 oz, then 4 oz( excellent tutorial on 4oz rockets) , currently 1lb. Got a hydraulic press from Greg Smith Equipment with gauge, and made my first whistle and strobe rockets this past weekend. WOW , resounding successful flights X3. I have not found any online author/website that comes anywhere near the details of compounding pyrotechnics or construction of vehicles that you provide. I have a day off today and think I’ll try the blue strobe.

    Rich

  4. jim says:

    great site and good instruction but no mention of bp mix? 60.30.10 or 75.15.10? thanks once again for the post

  5. tm says:

    Just a quick question…..

    On the stick stabilization — do you have a favorite material? What length do you use?

  6. Bruce Hildreth says:

    Sucks that I can’t watch videos on phone. As iPhone refuses to use flash player.

  7. Alessandro says:

    Can I modify a normal rocket firework to remove the stick. I’m asking it because the stick always goes down and if you launch a lot (like 60) it’s a stick rain.
    I’m thinking in something to stabilize the flight and for the direction use a PVC tube. Maybe a 120cm PVC tube to “guide” the rocket but it need to stay in the correct direction (and that’s the stabilizer magic).

    Thanks a lot!

  8. Robert says:

    I see the 1/2″ ID rocket has the same green plastic faux-bamboo gardening stake stick as I used. What’s the Al foil on it for? To prevent the exhaust from burning/melting away the stick?

  9. bob says:

    what is the point of the rocket stick?
    thanks bob

    • Bob, the rocket stick acts like the tail on a kite. Keeps it moving straight. –Harry

      • Rich Trimble says:

        Do you need to change the length of the stick if you make the rocket top heavy with a ball shell header? Have been making 1 lb rockets with 1 1/2 inch can shells which fly well with standard 3 foot sticks. I would to make a 6lb rocket with a 6-8 inch ball shell , standard stick would be a 5 footer 3/4 inch, would that work?

  10. Nice rockets, you made something good :)

  11. Randy says:

    Topic: ‘dialing in” BP

    I bought the tools and have had mixed success; its related to the strength of my black powder certainly. I have weighed carefully (digital scale) , coffee grinder the ingredients to dust, (sulfur and charcoal was already there) mixed in water slurry and whipped it for a while and set the mud in the sun. Re sieve again until I had dust.

    What is my error, I get puny thrust, adding oxidizer and re blend does not improve it.

    I backed off adding the larger grain charcoal to my mix, thinking I am short on oxidizer not fuel. When I did do so for the ‘tail’, my results were worse.

    What is the secret, to getting a ‘hot’ powder?

    Randy

    • PopPopH says:

      Randy, I am new at this also but I have perfect results every time using the Red Gum BP ball milled for 8 hours and then screened through 20 mesh. For the 10 oz. batch of BP I kick the Potassium Nitrate up to 7.90 oz. That would be:

      Potassium Nitrate: 7.90 oz
      Charcoal 1.5 oz
      Sulphur 1.0 oz

      You can get the Ball Mill for $39.00 (Rock Tumbler) at HarborFreight.com and modify it the same way (easy) described in here.

      • bob leigh says:

        Hi,

        I can’t see the link to how to modify the harborfreight ball mill.
        I’m new at this too and any info on the bar mill will be great

        appreciate it.

        Can you send the link or any info please?

        Bob

      • Bruce Hildreth says:

        Load it with 5 pounds of lead balls and see how long it lasts. But can’t beat a deal

    • PopPopH says:

      Randy I forgot to mention that the instructions for making Red Gum BP is at Skylighters. Also it sounds like your BP mix in a slurry had way too much water and the water leeched out the Nitrate. The Red Gum Powder uses Denatured Alcohol to disolve the 3 grams of Red Gum (for a 10 oz batch) and the Powder should be more like a Putty and not too wet and screened while it is wet and rescreened when it dries. I use this powder in my Stingers and 1/2 id BP rockets. You know whn these take off cause it sounds like an F-16 launching off of a Carrier Deck…….Scaled down of course to hobby level.

  12. Dick Mertins says:

    Another one was a steam engine ( which was common in those days ). The engine appeared first then the tracks. Once that was completed the wheels turned and what appeared to be smoke came out of the stack.

    I didn’t know LSD was available in the ’40′s.. Just kidding. Looking forward to more info.

  13. Dale Burrows says:

    Addendum to above, Im have eliminated the clay nozzle and they still blow up.

    • Paul Cloyd says:

      Dale, you probably have a hot powder that is too loose in the motor casing, too loose could either be large bp grains or not pressed tightly. You can mill your powder down to a finer grade and if hammering it in the motor, use smaller increments of powder per press. I think if you are comfortable with the density of the powder you can add 2-5% charcoal and slow the burn rate down. Hope this helps.

  14. Adam Lachance says:

    what do you use to ignite a bp rocket? Is it illegal to make fp in the us?

  15. Well I have had some interesting situations ,when a friend of mine and I launch my
    home made rockets. Mainly because I live in town and can not test them until I go way way out to his place. Consiquently we have been lucky to have to have rockets cato and headings go off shooting stars and such all around us. But the other day we
    had one of my whistle rockets cato. It was a 3 LB . And my friend was laughing at the same time saying OWWWWWWWWW. He must have got hit with a piece of unburnt
    fuel. It hit him hard enough to cause and instant bruse the size of a quarter. He was
    busting up laughing at the same time saying wow that realy hurt.. We will probably
    start wearing safty glasses from now on. So I can see how the on your back wondering what the F__just happend could happen. But never let them make you stop.
    We must continue to blow up our back yard and be FREE FREE to blow up ourselfe if we want to. Keep on thinking free.

  16. Dave Gilliam says:

    I would just like to say that I think your website is great! I really enjoy reading the newsletters and articles in your archives. This may sound dumb, but one of these days I am going to order from Skylighter!!! Just got some things to get first.

  17. Nick Johansen says:

    Brilliant Harry. Thanks.

  18. Frank says:

    Years ago, back in the 40′s I had seen some beautiful fire works one year and had never seen them again. The fire works that I had seen was awesome. When the rocket burst open a scene appeared. I recall one that was a wicker basket that was brown in color unfold. When the basket was formed green vines with leaves grew. After the leaves roses of different colors blossomed. The entire picture lasted tor a long time.

    Another one was a steam engine ( which was common in those days ). The engine appeared first then the tracks. Once that was completed the wheels turned and what appeared to be smoke came out of the stack.

    The last one that I can recall was the USA flag. It started with the flag pole then the flag unfolded with the 48 stars with the red stripes on it. Seems like there may have been a second rocket that was fired at the same time or seconds later where a bald headed eagle was shown as flying, meaning the wings were or appeared to be moving as a bird in flight.

    Since then I have yet to see any of the fire works display up to this day.

    How was any of this done ? I imagine that it cost a small fortune at that time period and a far great cost to make that today. Sure would love to see that again also, would love to learn how to make them myself.

    If it’s of any interest or importance I had seen this as a child in Vandergrift, Pennsylvania in the mid 40′s.
    Frank

    • Irish buck says:

      At the worlds fair in spokane (4th of july) 1974 I think .The displays showed the moon landing, old Abraham and George quite cool.

      • Frank says:

        Hi Irish Buck,

        That must have been an awesome site to see. I’m sure glad that that skill wasn’t lost through out the years. I sure would love to learn how to make those types of rocket displays.

      • Frank says:

        Hi Buck,

        Do you have any ideas as to how they made those types of rocket displays ? I would think that they must have had several rockets bundled together then separated to make the displays come alive. Just a guess.

        Anyone have any ideas ? It sure would be a challenge to make with great expense as well but, really worth the effort.

        Frank

    • Robert says:

      Assuming your description is accurate as to the effect, it is conceivable the wicker basket with flowers was an aerial display, but to make a brown colored basket, it would’ve had to be a smoke effect in a daylight display.

      The other descriptions could not have been aerial displays. The most sophisticated shell or skyrocket stabilization techniques could not produce an effect of such detail. You must’ve conflated an aerial display of shells and/or rockets with some ground works that were part of the same show. You’re describing transforming set pieces, wherein lances (colored fire sticks) attached to an erected framework are fused to fire partly simultaneously and partly sequentially to “paint” moving pictures in the dark.

  19. Very good article. I just wish you had some video’s like youtube video or something

  20. Bob Gross says:

    Safety 101 (How not to test fire a black powder engine)
    My first accident in 63 years.
    It was getting late, and I decided to static test fire one of my 4oz rocket engines in the back yard. I had a stand made for it, so the engine would be strapped onto the stand with the nozzle pointing up. I decided to fire it from my workshop, using an old battery powered ignition controller. I would observe the ignition standing behind the workshop door. So far, all was going well.

    I dug out some old igniters, but they were so old, that when I pre-tested one, it fell apart, including the ignition switch on the old controller. Not wanting to give up, I decided to use a piece of (old fuse) I had. The fuse is suppose to burn at a rate of 2 feet per minute. I cut off 15 seconds worth, to give myself enough time to get up the steps, and into my workshop before ignition. Even though it had rained all day, and enerything was soaked, I had the garden hose ready, just in case, and positioned the test stand about 5 feet from the steps to my workshop door. So far, so good.

    Things start going down hill quickly. As soon as I lit the fuse, it started burning reeeeeal fast. I thought “Oh shi**”!

    I turned and made a dash for my workshop door. The last thing I remembered was lying on my back, looking at the ceiling of the porch over the door to my workshop. I tried to get up, and crawl to safety behind the workshop door, but was in so much pain, all I could do was lay there, (about 6 feet from the untested engine), hoping the engine wouldn’t malfunction. While I was struggling to get to my feet, the engine ignited. It made one hell’ve racket, that got the attention of my wife, who was in the kitchen fixing dinner. She looked out the kitchen window and saw me rolling around on the workshop porch (trying to get up), and thought I had been hurt by the rocket engine. By the time she made it out to my workshop, I had managed to get to my feet. That’s when I realized what had happened. I was in such a hurry to escape the rapid burning fuse, the sole of one of my aging house slippers came loose, and caught on the lip of the bottom rung of the (3) wooden steps to my workshop. I apparently made a grab for the railing as I fell.
    About that time the pain set in. My left shoulder hurt like a son-of-a- *&^%$#$. When I looked at it, I noticed I had dislocated the arm bone(it was sticking out where it wasn’t supposed to). I popped it back in place with the palm of my right hand. That smarted a bit too! Then my wife said “what happened to your knee”? It was bleeding profusely. I apparently laid it open when it hit the steps, as the rest of me was on it’s way to meet up with the porch floor. When I decided to go inside and clean my knee, I noticed my right foot didn’t work so well. Four of my five toes were looking straight up at me as if to say, “what did you do that for”? When I fell up the steps, besides dislocating my shoulder, gashing my knee, I bent my toes backwards on my right foot. I was apparently in so much pain form my other acrobatics, I didn’t notice the toes had been rearranged.

    I managed to hobble in to work the following day, but was sorer than a 10 cent call girl. There was something good that came out of all the chaos. My experimental engine worked great. Unfortunately, all I got to see was the ceiling of my workshop porch!

    Moral of the story:
    Don’t wear old house slippers with a loose sole while testing a new rocket engine.
    Never use old fuse to ignite an experimental engine.
    Never use an old ignition controller to test fire an experimental engine.
    Never attempt to use an old igniter to test fire an experimental engine.
    Never try to out run an old fuse.

    • Frank says:

      Thanks for the great tips my friend. I’m not laughing at your pain but, your creative ability to put your story into humor that makes it interesting to read.

      Just a suggestion; next time try wearing safety shoes and a fire retardant fireman’s clothes. A heat protective helmet would be in order as well.

      Good luck on the next testing of a rocket motor.

      Frank

      • Bob Gross says:

        Frank, I’m pleased that you enjoyed the true story. I couldn’t help but laugh myself when I looked down, and saw my toes pointing straight up.
        The accident shows what can happen during a moment of stupidity. I have been sucessfully building black powder rockets since I was 12 years old. I still love the smell of the burnt powder.
        Be safe…
        Bob Gross

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