Thursday 21 April 2011; Clark County Country --
This morning the Grand Mother and Grumpy left our motel early to arrive at Fort Bale in time for breakfast. Breakfast comprised something delicious that the Swede called "Swedish Pancakes" and eggs -- lots of eggs (do you suppose this was some sort of promotional deal, or what!?). To put on the Swedish Pancakes, there was a sauteed combination of zucchini, onions and almond bits, and rhubarb sauce. Does that sound yummy or what!? (It definitely was, and this old German ate three of those Swedish delicacies even though it was "out of sight" vis a vis his diet.)
After breakfast, Grumpy was prevailed upon to "suggest" a design improvement for a "bottle rocket" design that Bee-Boo was intending to demonstrate in a couple of weeks.

The basic design was modified to incorporate a "launch tube" (12" piece of 1/2" PVC pipe pointing straight up), with a 1/2" O-ring fitted into a groove around the lower part of the launch tube such that the friction between the O-ring and the neck of the 2-liter soda bottle would hold the bottle firmly in place until a certain air pressure was pumped into the interconnected PVC launch system and the empty volume inside the soda pop bottle.
The basic design used a threaded PVC fitting around which two or three layers of electrical tape was to be wound to provide friction to hold the bottle rocket until pressure, estimated to be around 30 psi had been pumped into the launch system. Upon "lift-off" from the basic design, the compressed air in the bottle would expel water from the bottle to "jet" the bottle to a height estimated at "about 30 feet".
Bee-Boo opined that the bottle should be filled about half full for maximum altitude. His goal was to exceed the 30-foot altitude professed for the basic design. "Stretch" (the Dad) appropriated his 12 volt electric-powered air pump for the first test. This device had dial pressure gauge incorporated at the outlet; this was a neat feature, allowing at least
some engineering data to be taken on this first test launch.
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| Chief Rocket Project Engineer |
Bee-Boo's modified design, with the 12 inch launch tube, prevented a large amount of water to be exhausted until the neck of the bottle cleared the top end of the launch tube. The theory behind this modification was that the bottle would be accelerated to some good velocity, primarily by the air pressure acting on the bottom of the bottle, until the neck cleared the launch tube, and then further accelerated by the expulsion of the water, "to reach unfathomable heights"! The first "dry run" was an outstanding success -- and anything but a dry run!!
Upon applying power to the little air pump, Stretch and Bee-Boo both moved away some 10 or 15 feet. Grumpy, ever the curious engineer warily stepped up to the "safe" end of the launch system (about 3 feet from the vertical launch tube) where he could observe the pressure readings. When the pressure rose above about 5o psi, Grumpy "lost interest" in further pursuit of test data; he estimates that, when the pressure inside the PVC pipe and vacant part of the bottle finally overcame the friction holding the bottle on the launch tube, the pressure was probably 55-60 psi! Needless to say, the bottle took off like a cannon shot, straight up in the air, spewing water on the surrounding area -- including Grumpy who was standing 10 or more feet back by this time. No data were taken on the apogee of the bottle, but various estimates placed the altitude as "more than 600 feet above sea level"!
The smile on Bee-Boo's face was priceless as he returned from recovering the empty soda pop bottle from a tree 100 or more feet "down range" from the launch site. No, Grumpy stupidly did not think to take photos of the launch nor of the proud owner's big grin. It will just remain a Great Grandpa's happy memory of one very happy Great Grandson.