For the last week Jacob and I have been building and rebuilding an Air Rocket Launcher Prototype. The body of this launcher is made from 4 inch schedule 80 PVC. I couldn’t find any 4 inch fittings at the local hardware stores, so I used ABS instead. The "professional plumbing dude" @ Home Depot said that Christie's Red Hot Blue Glue would seal them quite nicely. I asked if he was sure, because this launcher was to hold well in excess of 100 psig around little 2 year olds. If it failed, that would be a bloody mess and we would be left with all that cake. He assured me and I was on my way. I assembled the parts, and after a day of curing; I pressure tested the unit. Right around 90 pounds, the fittings failed and the unit turned into a rocket of its own. I did this test in the backyard with no one around. I was pissed. Somehow I knew it wouldn't work. $20 in really nice PVC fittings and I rebuilt the unit. Once again, after curing for a day, Keline and I did a pressure decay integrity test. We pumped the unit up to 100 psig and let it sit for an hour. It didn’t leak at all, when we returned, the gauge read 99 psi. Jacob and I then built an assortment of paper rockets to test. We conned mom into building one also. Some fly really well, others… not so much. (With a Mexican accent…. Not so much…). We have lost 2 rockets into Freddie’s monstrous tree. I picked up some foam board for the fins, we are tearing through Keline’s expensive scrapbooking paper for the rocket body tubes (they are pretty rockets), and we use tape as the nose cone.
Last night we finalized the “perfect rocket”. It is easy to build, very robust, and a good flyer. We launched the first model version over 25 times, some @ 20 psi, others launches @ 105 psi. I can gage the wind and have the rocket launched and recovered within about 10 feet of the launching pad. We used a stop watch to time the flight from launch to landing and some are as long as 7 seconds. I got out my old physics equations and calculated that the rockets are reaching around 150 ft. We then went for distance. I put the launcher in the street and launched it down our road. Pacing off the recover distance, it was 100 paces, or a football field in length. NOT BAD for $26 in parts….. Next is water rocketry, then solid state fuel rockets. But Jake is only turning 2, so we will have to wait a little bit.
