Launch report: Clear FTCs 1 and 2 as Backgliders
Here you find the construction of the CFTC2 rocket.
|
|
My nephew Nicolai with CFTC1, a 3-finner. The payload compartment on the very left with an inner bulkhead. |
|
Video CFTC2, 3741 downloads |
On an almost windless day, we launched the 4-finned CFTC2. It did not rock up and down as the Backmaxes did, but it spinned quickly around its longitudinal axis. Half by reckoning, half by chance, the little wind we had blew the backgliding rocket exactly to the launch crew. It was caught repeatedly and safely by hand, which was great fun! See the video on the left. |
Comparison: plain bottle cap vs. selfmade
ogive nose cone
Preliminary Results
On the same day we compared the performance of a
plain bottle cap as a nose cone vs. selfmade ogive nose cone.
We filled the CFTC2 rocket with 200ml water and 6 bar air. The rocket was shot with both nosecones 3 times each. Altitude measurement was done with one stop watch and the SEAM method.
|
|
HSEAM |
H rel |
tapogee |
tdown |
| plain bottle cap as nosecone |
84 m |
100 % |
3.7 s |
15.1 s |
| styrodur nose cone on cap |
90 m |
107 % |
3.85 s |
17 s |
The result is not very safe: these values are averages from the 2 closest values in each group - one outlier per group was left out, because of the somewhat high variations. Eventually I redo these measurements with higher pressures and more samples.
