On the right a picture of my tri-pod cable-tie launcher.
The cable-tie hold and release mechanism is an idea I found on the web and is used many times by water rocket enthusiast. If I'am correct it was invented by a Australian named Ian Clark & Mc Naughton
The tripod bars are made out of aluminum U-profiles of 10mmx10mm. In the center a PVC electrical pipe can slide over a copper 12 mm pipe. So the the launcher legs can be folded.
On the copper pipe a brass joint is soldered with a slot for a O-ring. This O-ring acts as a seal.
The cable ties are clamped to the copper pipe with tube-clamps. A 40 mm PVC drainage connector straight piece is used as a slider. If it is pushed up, the bottle is clamped on the launcher. A rod mechanism and some rubber bands will pull the PVC connector down on release, this will allow the cable-ties to move outward and the water rocket is released.
I used the valve of a bicycle tire on the bottom part of the copper tube for easy connect with the tube for pressurization.
The release mechanism is triggered with a rope, ->a word of WARNING here<--, make this mechanism so that it triggers easily, if you have to pull it to hard, chance is that the launcher will fall over and releases the rocket straight in your face. And that, of course, is not a thing you want to happen.
On the net I once saw a construction that used a syringe and a tube connected to a bicycle pump to pull the sleeve down, this I think is an much safer release, I will add this construction to the launcher in time.
The top end odf the copper pipe can easily be extended with a PVC electrical tube, so depending on the size of the rocket I want to launch I can adjust in this way the length of the launchtube. See the launch reports section for the launchtube in action.
