This idea was born out of a frustration from last year. I was a Scout Master on a National Youth Leadership Training course and I felt that it took to long to launch multiple 2 liter soda bottle water rockets. So I started to look for launchers that could launch several rockets at once but I did not find what I wanted. After searching the internet I found inspiration from several sources and designed the RPL (Rocket Propulsion Laboratory) a multiple rocket launch control center. Not only can you launch water rockets but paper and solid engine rockets as well.
I designed it with lots of lights and switches that get the boys intrigued and relay involved. The launcher I use is located here http://www.instructables.com/id/paper-and-pop-bottle-rocket-launcher/
Here is a video of 4 rockets launching at the same time
Here is a Video from this years Timberline NYLT course with our final launch