CFTC2 - Clear FTC #2
Using the experiences of the past backgliding rockets, the next one should be built more by calculated design than by trial and error. A neighbour's friend brought me some 31 mm diameter clear FTCs and a 21.3 mm white PVC pipe as an ideal launch tube from USA. Thanks, Markus Schäufele, for all the trouble you had!
I built 2 Water rockets from it: CFTC1 with a payload compartment for an altimeter in the future and CFTC2, a plain rocket, described here.
Getting the BCP far back of the CG is no problem with this skinny rockets.
Using my CLA calculator, I tried at first to calculate a position of the finned sleeve, where the rocket would backglide without weight in the back, by moving the sleeve forward. I could not find a position with theoretical backglide stability this way: the CG did move forward as well as the CLA, the distance CG-CLA was never sufficient. Since FTCs are so rare here in Germany, I do believe in my calculations and did no test launch with this attractive weightless method. However, this could eventually work with 3 fins only and less and/or lighter fin glue.
Next, I adjusted fin size and back weight. The distance CG-CLA was attuned to 45 mm on CFTC1 and 50 mm on CFTC2 = ca. 1,5 calibers.
Then came the great moment:
Stand / Last Revision: 19.10.02
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