Pyrotechnic Projects: Real Visco Rockets

Is it Rocketry or is it Pyrotechnics?

Initially developed as strictly a fire producing device, the intention was to use these devices in conjunction with KNSU rockets to produce a visible flame for aesthetic effect. It was then discovered that these devices produce enough thrust to fly “Micro Rockets” !

The housing is 2" long, and was fabricated from .375 (3/8") hydraulic line with a .020 wall thickness. It is an open end burner. One end is plugged with .25" Bentonite Clay. There is no nozzle restriction at this time. . . I reserve this for future experiments.

The propellant is 5, 1.5" lengths of 3mm Visco fuse. It has a 1.5" length of 2.5mm Fast Burning Yellow Vis-Quick fuse in the core. The Fast Burning Yellow Vis-Quick fuse seems to be the trick. This fast burning fuse burns at 3 sec per foot, so a 1.5" length will burn in less than 1/2 second. This ignites the 5 pieces of 3mm fuse from the core.

The result - a quiet whoosh (about .5 seconds) with a 3 ft flame and a small amount thrust. Enough to propell a 4 gram rocket (pictured above ) 50-75 feet !

WARNING - Though minimal thrust is produced, this device produces a 2-3 foot flame. This creates a burn hazard if improperly used. Launch pads will be scorched from this device. Build and use at your own risk.

Note : This procedure uses a 2" length of aluminum tube. The 2.5 mm Visco is cut longer for illustration purposes. This fast burning fuse may be cut to the same length as the 3 mm Visco.

1. Cut 5, 1.5 pieces of 3 mm Visco fuse (Pieces should be the same length).
2. Cut 1, 1.5" piece of 2.5 mm Fast Burning Visco fuse.
3. Slide the 5 pieces of 3 mm fuse into the aluminum tube.
4. The fuses should be in a pentagonal position.
5. These should slide in with little resistance if properly positioned. - Do not pack. Note the pentagonal pattern of the fuse sections.
6. Using a wooden dowel, shove the 3 mm fuse sections all of the way into the housing tube. Do Not Pack.
7. Using an awl or similar tool, turn and shove the rod through the core. (I use a # 30 drill rod with one end rounded off.)

Note: Do not “bore” a hole - This action should pack the 3 mm fuse sections against the housing wall while maintaining the pentagonal pattern. This should also open and expose a hollow core in the middle of the fuse sections. 8. Shove the 2.5 mm Fast Burning Visco all of the way into the hollow core. 9. A piece of visco fuse can now be added for ignition. (1.8 mm fuse works good).

WARNING: This device produces a 2-3 foot flame. Do not attempt to light this device without a delay fuse or electrical ignition. Do not attempt to light his device at the fast burning fuse. Burn injury will occur !