Just back from the Leonard Oklahoma Spaceport. We went out to support a friend of ours who was launching today and decided that as long as we were there, wed go ahead and launch too. Since we were just there for fun, we launched with some moderate engines. For the first time, we used a JL-II altimeter/accelerometer, to provide empirical data on altitude and speed. Graces rocket went up 2655 feet at a maximum velocity of around 325mph and a maximum g-force of about 9. My rocket went up 2300 feet at about 311mph and maximum g-force of about 15. This illustrates the difference between a high thrust short duration motor and a lower thrust longer duration motor. Graces motor burned about twice as long as mine and had a higher total impulse, but only accelerated at about half the g-force of mine. However, that long burn gave her a higher peak velocity an altitude. Our friend, Stewart, had the highest flight of the day at over 6700 feet. He had another rocket on hand that would have gone over 10,000 feet, but the FAA waiver set a ceiling of 9000 feet for the launch so he wasnt able to launch his big rocket. A team of engineering students from OSU, along with their professor, launched what should have been the highest flight of the day, however, their parachute failed to deploy and their rocket came down ballistic. Since it was not a successful flight, its altitude was not recorded. Their rocket buried its nosecone three or four feet in the ground with wreckage scattered over a wide area. Just goes to show that things can and do go wrong, even with people that are supposed to know what they are doing. In this case, the failure was due to their students using igniters for the ejection charge instead of electric matches. I suspect that they thought they were being wise, using hotter burning igniters to ensure that the explosive charge went off. But in fact, igniters require much higher current to work... higher than onboard batteries can usually provide. Which is why igniters are only used on the ground for launch, where large car batteries can be used to set them off. So, the OSU igniterd, powered by small onboard batteries did not ignite at all and the rocket nosed over and plowed in. About a thousand dollars worth of rocket destroyed by a 5 cent igniter. My heart goes out to the poor OSU students, it had to be very disheartening. Other than the OSU crash, it was a great day with many fine rockets and a beautiful day for shooting with minimal wind.
Posted on: Mon, 11 Nov 2013 02:38:15 +0000
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