How To Make Tourbillion Spinning Fireworks
Tourbillions are an old form of spinning fireworks that used to be much more popular in public displays but today are never seen except as very small and simplified consumer fireworks. Also known as whirlwinds, geysers and table rockets, they are a large heavy wall tube arranged to briefly spin horizontally on the ground and then to lift off into the air by means of two side spin holes and two or more lift holes bored into the underside of the tube. A stick is attached at right angles to the tube to form a cross, the purpose of which is to insure that the tourbillion maintains a flat level spin as it rises into the air. The effect is a huge umbrella shaped display of sparks rising into the sky that terminates in a final burst of sparks which looks almost like a normal aerial shell at the apex of its flight. This final burst is a unique property of tourbillions and caused by the fact that the two spin nozzle holes and the two lift nozzle holes all share the same tube and use the same body of rammed powder. When the device first starts to burn there are several inches of powder between holes but as burning progresses this powder "wall" gets thinner and thinner. Just before burnout it becomes so thin that it suddenly breaks down and the powder is rapidly ejected out all four holes in a final blast of sparks.
Although this is an excellent project for the beginner, it is recommended that you have some previous experience with mixing pyrotechnic formulations and are familiar with standard safety procedures.
- Make a tube extender using a 2-1/2 " long section of the exact same tube which will be used for the tourbillion. First, cover the outside of the tube with a single layer of heavy paper (40 to 70#) and glue in place; this makes the outer diameter slightly larger. Masking tape can be substituted for the paper in a pinch. Next glue or tape a strip of heavy paper 1-1/2" wide x 8" long onto the tube such that roughly 1/2" extends past the end of the tube forming a "skirt" as the strip is rolled on the tube (should go around twice). Set aside to dry.
- Using a ramming block with a 3/16" high step or nipple, ram a clay plug 9/16" thick in the 3/4" I.D. x 7 1/2" tourbillion tube. The top level of the clay inside the tourbillion tube should be at least 3/4" from the end of the tube. This plug must be heavily rammed to prevent it from being blown out.
- In roughly 8 increments, ram the tourbillion formula to a height of 6-3/4" in the tube, leaving 3/4" of empty space at the top of the tourbillion tube.
- Use the tube extender made in step one to facilitate ramming the final clay plug. Place it over the end of the tourbillion tube. The paper skirt of the extender should telescope over the tourbillion tube, centering the extender and holding it in place on top of the tourbillion.
- Measure into the extender tube the same amount of clay as used in the initial clay plug (from step 2). In the un-rammed state, the clay fills a greater volume of space than is available (3/4") at the end of the tourbillion tube. By using the extender tube the clay is kept from overflowing and, when rammed, should pack down to form a nice neat plug that is recessed 3/16" from the lip of the tourbillion tube.
- Take the 7.5" x 3.92" wide strip of paper and fold it in half lengthwise, then fold in half lengthwise a second time; unfold. When open, the paper should have three parallel crease lines running along the length. Please note that the dimensions of the paper should be the same length as the tourbillion tube and the width should allow the paper to make exactly one turn around the tourbillion tube.
- Align the paper so that these lines run horizontally as the paper sits in front of you. Starting with the top crease, measure in from the left-hand edge of the paper 7/8" and make a small mark on the crease line; this is point "A". On the middle crease, measure and mark two points 2-3/4" from the left (point "B") and the right (point "C") edges. A third point "D" is added exactly halfway (3-3/4") from the left and right edges. Finally, on the bottom crease measure in 7/8" from the right (point "E"). Poke a small hole in the paper at each of these 5 points.
- Wrap the paper strip around the filled tourbillion tube and secure in place. The hole positions should be transferred to the tube with a pencil or awl. Points A & E are the spin holes, points B & C are the lifter holes, Point D is the "wing" or balance stick attachment location.
- At points A, B, C & E (NOT D), carefully drill a 1/4" diameter hole about 1/2" deep. Use a slow drill speed, and always do this in a remote, outdoor location. A full-face shield is recommended when attempting any type of drilling in tubes containing pyrotechnic compositions.
- Find the center of the 7-1/2" x 1/2" x 3/16" stick. [An excellent source for tourbillion sticks is wooden stir sticks obtained from paint stores. For this project one stir stick will make two balance sticks.] Rest stick on flat surface; apply hot melt at mid point (point D) of tourbillion tube. The tourbillion tube should rest on top of the stick and cross at right angles with the 2 lift holes (B and C) pointing straight down and the 2 spin holes (A & E) alternately aimed left and right. Alignment is critical to proper functioning of the tourbillion.
- Hot melt glue is not sufficient to keep the stick secured to the tourbillion tube when the spinning firework is in operation. Drill a 1/8" hole in the stick close to and on either side of the tourbillion tube. Take a 6" piece of soft iron or copper wire, form into an inverted "U" shape, place over top of tube with the legs of the "U" passing down through the holes in the stick. Twist ends of the wire tightly together on the underside of the stick. Trim back twisted portion to form a knob of wire not more than 3/16" high. This knob will act as a point for the tourbillion to spin on when placed on a smooth piece of Masonite. Try giving the tourbillion a spin to insure that it can do so easily.
- Run a piece of quickmatch from spin hole "A" diagonally over the top of the tourbillion tube body and into spin hole "E" on the opposite side. The paper piping will need to be cut back 1/2" at either end of the quickmatch to expose a portion of the black match inside. This exposed portion is threaded into the spin holes. A piece of bare black match is run from inside lift hole "B" up to spin hole "A", cut and taped down next to the match going in hole "A". Repeat on the opposite end with a piece going from lift hole "C" to spin hole "E". Neatly tape everything in place. Tape should cover all bare match completely.
- In the section of quickmatch running over the top of the tourbillion (from A to E), find the exact center and insert a 2-1/2" piece of green visco fuse through the piping of the quickmatch. Secure in place.
- Select a test-firing site. Set down the Masonite sheet on a section of level ground and place tourbillion at the center of the sheet. Give a final hand test spin. The tourbillion should spin freely by itself for 2 or 3 revolutions before stopping. Light fuse, and stand back.
This tourbillion formula is one recommended by Lancaster ("Fireworks Principles & Practice") from his section on tourbillions. Results will vary depending on the quality of your meal powder. Try using with 80-mesh charcoal, or additional 5-10% titanium to increase the spark trail.
FREQUENTLY ASKED QUESTIONS
Q. I've read several books containing descriptions of tourbillions and they all use a curved hoop for a balance stick or a twisted stick like a propeller. How come you use a straight stick?
A. The only purpose of the curved stick was to allow the tourbillion to more easily spin on the ground without the ends digging into the ground. A straight stick with a center pivot point (like a top) is much easier to make and actually gives a more stable spin. Propeller shaped sticks provides little or no additional lift. Efficient propeller design is no trivial matter, on top of which the spin rate of a tourbillion is way too low to make a propeller effective.
Q. Most descriptions of tourbillions have the spin holes located more in toward the center. How come you place them right near the clay end plugs?
A. With the holes located closer to the center the spin rate will be increased due to the increased burning surface available (there is powder inside the tube, left and right of the spin hole). However, the total burn time is reduced due to closer hole spacing, limiting the height that the tourbillion will attain. Since the device spins in a stable fashion using my hole layout, the added burn time is a desirable feature.
- Increased tourbillion tube length for additional burn time to improves flying height. The balance stick should be lengthened also to maintain stability (normally the stick length is the same the tourbillion tube length). New hole spacing must be used to reflect the increased length of powder in the tourbillion tube. Follow this rule:
- Divide the total length of powder in the tourbillion tube into thirds. Locate the lift holes at the 1/3 mark and at the 2/3 mark, with the spin holes located near the clay end plugs as usual.
- Use a Gold Glitter Saxon Mix or a color driver mix to power the spin holes. If you are using the 6" of rammed powder as in this article, the first 1" would be gold glitter then 4" of tourbillion mix, then 1" of gold glitter mix. If you are using a longer tourbillion tube, each spin hole (for the glitter formula) uses 1/6 of the total powder column.
- Increase tourbillion tube I.D. and length for more impressive takeoffs, ascent, and final burst.
- Preventing the lift holes from enlarging will greatly increase flight altitude.
- On large tourbillions a 6-hole arrangement can be utilized to improve launch stability and reliability. Placement of the first 4 holes (A, B, C and E) is identical. Two additional holes (F and G; they can be smaller, 1/8") are added on the underside of the tourbillion tube in line with lift holes, and are located 1/8" further in from each end of the tourbillion tube than the spin holes. Matching is slightly different. Instead of running match from the lift holes to the spin holes, the match now goes from the 1/4" lift holes (B and E) to these smaller lift holes and is not connected at all to the spin holes. What this does is allow the tourbillion to build up its stabilizing spin velocity first. Since the additional 1/8" holes are located very near the spin holes, approximately 1or 2 seconds later flame will issue from these holes, ignite the match which travels over and ignites the main lift holes. Erratic flights are greatly reduced by having a delayed lift hole ignition.
- Aluminum rammer, 3/4" x 10" (TL1008)
- Bentonite clay (CH8078)
- Black match
- Black powder, Meal D
- Charcoal (CH8062)
- Drill bits, 1/4" and 1/8" and drill motor
- Funnel, small
- Hot melt glue gun and glue
- Kraft or typing paper 7.50" x 3.92"
- Masking tape
- Masonite board, 2' to 3' square sheet
- Potassium Nitrate (CH5300)
- Powder scoops, small
- Quickmatch (GN3001)
- Ramming block
- Ramming mallet
- Sulfur (CH8315)
- Tube, 3/4" I.D., 7-1/2" long, 1/4 wall thickness (TU1068)
- Tube, 3/4" I.D., 2-1/2" long, 1/4" wall thickness (TU1065)
- Visco fuse, green (GN1000)
- Wooden stick, 7-1/2" x 1/2" x 3/16"
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