Things Can Go Wrong
WARNING AND DISCLAIMER: If you are underage, then consult with your parents or guardians before attempting any of this. You are on your own - I'm not responsible for your actions or harm you may bring to others because of your actions. Making the items described below can result in injury or death to you or people in your vicinity. Some things mentioned here may be illegal to make in your city, county, state, or country so check the laws that apply to you before you attempt anything described here. These notes are not complete on purpose. If you are reading them and new to pyrotechnics, then you are making a mistake. Stop now - this page is not for you. Get a beginning book on fireworks (see Skylighter or American Fireworks News (very quick shipping) for a start) and read up. You can't make any of this work without more information so read up or join a club or ask someone to help you.
If you've read the other girandola pages (8-10-12 inchers and 24 inchers), you will remember that there are three main things that affect girandolas. The first is balance, the second is strength and the third is weight. However, that is just the construction phase - once you get the little tiger built, you will have a host of other variables to work with.
One key to a successful girandola launch is to make sure it is spinning fast enough to be stable when it leaves the launch stand. You can tell if your girandola is not spinning fast enough because it will tilt over and go sideways at you and your audience (;-}). You can also tell the girandola is not spinning fast enough by listening to it. If you hear a distinct whoosh-whoosh-whoosh as the motors whirl around, then it is likely the platform isn't spinning fast enough. Here is a 10" girandola launch that didn't have enough spin and went about a 1/4 mile off course. Lucky enough, it hit some trees and bounced out into a clearing - It was a still day and it was smoldering a bit so we could see it from a hundred yards away. I thought for sure it was a goner. It was reloaded and used to demonstrate a 'good' spin speed in the next movie on this page. Click on the image below and listen carefully to the talking motor:
Another problem with the above flight - the delay between the first motors ending and the second set firing was almost three seconds. Whew! Waaay too much time! That meant the girandola (which starts falling right after power shuts down) had been falling for three seconds and all that energy had to be absorbed by the second set of motors. The result was that the frame barely reversed itself before the second set of motors had burned out. Check it out in the last few seconds of the video.
To correct the spin problem, either install the motors at a sharper angle (sometimes problematic) or install lateral thrusters as in the following video. Click on the image below to see a girandola come right back to the launch stand.
However, there were still other things wrong with the above flight. Four 5/8 motors and two 3/8 side thrusters were used and, instead of sequencing (side thrusters for two seconds, two main motors for five seconds, 1 second delay, two auxiliary motors for five seconds), all six motors fired at once! Unfortunately, that meant the first two motors were burning from both ends and didn't contribute anything to the lift. The launch still looked successful - if a bit smoky and a tad short. It got a fraction of a second spin up before lift off - which you can see if you sequence through the movie.
Hmmm... This can't be good.... This is a 10" girandole (or what is left of one) that had been fired, broken, and repaired many times. On this ill-fated flight, a motor broke the wood hoop along an old repair and tore free of the frame on launch. The rest of the motors fired and it tore itself to shreds due to the imbalance. A curved piece of frame and a running motor make some really interesting moves in the sky! It looks like frame fatigue took this girandole to the grave.