Was doing some optimal water rocket calculations. Looked around for a good launcher design and found this fellow. He seems to have done everything I was doing and then some. I particularly like his boosted dart from a 2-liter bottle, although the prospect of a 60-gram missile coming in stable from 470 feet is... daunting. I suggest small water balloons as boosted darts :-)
This is fun stuff. Now have a spreadsheet that uses the Excel solver to optimize launch mass and fill ratio. Also discovered the viscosity of water declines rapidly with temperature. Spigot warm water sends rockets higher.
Say... anyone know the specific heat ratio of moist air? Dry air is 1.4, so I've been using 1.35. What's a geek to do?
Regards,
-Larry (Don't laugh. They can't regulate it!) C.