My efforts described on this page utilize the first-generation hydrogen-power water-rocket launcher.
In the spirit of Halloween and in consideration of the surplus pumpkins that follow it...
I decided to construct a pumpkin rocket. I knew the pumpkin wouldn't be able to hold the air pressure that we who launch water rockets are accustomed to using. I also needed a boosting system that would be able to get 10 pounds (4.5kg) of pumpkin up to speed.
My solution was to use the top of one 2L bottle and the bottom of another 2L bottle of slightly smaller diameter. The top bottle-half is inserted into a hole on the bottom of the pumpkin. (I used my Dremel tool to make the hole--I wonder if I'm the first person to use a Dremel on a pumpkin? Probably not.) There is a thick foam disk between the top bottle-half and the pumpkin to help distribute the load. The bottom bottle-half is mounted on my hydrogen-powered launcher. The two bottle halves slide together in a piston-like fashion. Upon ignition, the rapid rise in internal pressure will push the top bottle half up and away, along with the pumpkin... at least that was the design. Click on the image to download a 426KB MPEG movie of the launch.
Needless to say, it didn't work. I was predicting a height of around 50 feet. My consolation was that a few chunks of pumpkin did go that high.
Umm, I guess pumpkins are better pushed from the outside rather than the inside. And it was interesting how the bottom bottle-half was partially turned inside-out around the launch tube. The rubber bands (in the photo) were originally between the two bottle halves to achieve a good seal.
My second effort to get a pumpkin in the air using water-rocket technology is here.