johnnypyro Posted June 14 Posted June 14 Hummers are one of my favourite commercial fireworks. So trying to get them to work myself is an obvious challenge. The goal is to eventually launch one from a 0.5inch tube with a time fuse, but first I need to get the hummer humming. The tubes are made on a 8mm rod with the paper wetted with water glass before rolling. Cut to 30mm length, a bit of clay is rammed at one end, 3mm tangential hole drilled for 2mm visco. Then composition rammed: Meal D 0.93 Al bright (#300) 0.03 Ti flake (#50) 0.04 Water glass is painted around the hole. I'm currently getting about 70% success - here's a good one hummer1.mp4
Mumbles Posted June 15 Posted June 15 At first glance this all seems like a good plan. The functional one you shared looks great. When you get them working close to 100%, those will also make some great shell inserts if you were ever interested. To maybe be able to provide some suggestions, when they don't work like you want, what happens? A lot of hummer issues revolve around the vent hole. This is generally related to the hole not being located consistently or quite in the right spot/angle, or the fuel being a little bit too hot and blowing up before the pressure can be released. A drilling jig and consistent tubes help with the first issue. Slightly taming the fuel, or experimenting with the size/location/number of vent holes on larger hummers helps with the second. Given the size of your tubes, I could see there being less margin for error on the vent location and angle.
johnnypyro Posted June 15 Author Posted June 15 Made another 10 this weekend with 100% success in that they span at high speed, just some faster than others. Part of this improvement is that I'm getting my eye in with spotting those that probably won't work and rejecting them. I'm also getting a bit more practiced at making the tubes. Yes, the hole is the hardest part to make. I'm using a bit of angle to hold the hummer whilst I drill as close to the vertical metal as possible. I'm going to use a drill press next time instead of handheld. hummer2.mp4 The gopro doesn't capture the high frequency sound very well. But you can hear my wife hooting with surprise when she came out to see what I was doing. I told her exactly what was going to happen.
Uarbor Posted June 24 Posted June 24 This bit of information might help but I have used water glass to reinforce the hole in the tube whenever I was making helicopters to stop the hole for me eroding due to fire
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