|But the REAL experiment: I
am placing a FULL soft drink can under the nozzle.
Sometimes you gotta chuck the rules.
The Space Shuttle uses liquid for damping sound and making steam, so why not me!
The motor is loaded with 4 propellant grains of Pixy Stix propellant, total propellant mass is 762 grams.
But there is a fifth grain, an un-cored end-burner which is intended primarily to provide smoke after thrust ends. It is also KN/sucrose with a little bit of Ti and red iron oxide to help it keep burning when the propellant grains are spent. I assume that the first web-thickness of this grain will burn along with the propellant, adding 39 grams to the total propellant mass.
Ignitor is bridge wire wrapped with fuse paper, with a touch of black powder and Ti inside. BP to make sure it fires, Ti for more sparkly heat.
Launch weightt: 9.75 lbs
Anticipated thrust: 960Ns
Burntime: 1.4 seconds
Altitude at apogee: Different sims give different numbers, the lowest being 4800 feet, the highest 6000. I'm guessing it will be somewhere in between.
Click Here for a movie of the launch and subsequent adventure
(13 meg .wmv file, 67 seconds of video)
Click Here for a short movie of the launch to apogee
(5 meg .wmv file, 26 seconds of video)
Launch was good. A brief smoke (grains were damp) and off it went. Smoke all the way to apogee and then some. And then some more. And more. And.... where is the drogue? Come on Drogue!
|So I trudged across the fields for awhile, but came back to
the launch site to dump my big camera and tripod. Also to quiz the natives on where
they thought it might have landed. Bernie Lalime, our Giant Leap
distributor loaned me his binoculars, which helped the search
Scanning the ground on the fourth field over, I spotted something suspiciously pink. It was far pinker than anything a healthy cow might produce, and this one did not seem to be in great distress. I walked over to see the fragments, covering one eye so the shock would not overwhelm me...
|And there it was, whole and mostly well. Pig-headed optimisim is again rewarded. The main parachute was
shredded and the nose cone cracked, but the altimeter was still beeping: 5526 feet. It made the mile mark!
And the cows left me a little memento, a token of their esteem.
|The ARTS altimeter reported three different altitudes at
apogee. The beeping upon landing indicated 5526 feet.
The downloaded graph had two more, one from the barometric
altimeter which read 5326 feet, another from interpretation of the
accelerometer data, which read 5656 feet. Good news is that all
readings were over a mile, which was my target goal.
Click Here for a larger version of the graph (126k)
The altimeter offered some other interesting bits:
Max G: 26.341
Max Acceleration: 847.38 ft/s/s
Max velocity: 684.33 ft/sec
Drogue Deployment: 19.990 seconds
Descent Rate under Drogue: 259 ft/s
Main Deployment: 37.140 seconds
Descent Rate under Main: 219 Ft/second.