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5-1-2013 ~ Blog # 526 (David)
On Wednesday we had a recruitment fun launch where we invited 6th and 7th graders who are interested in joining IHM's Rocket Team next year. We had a good turn out, nice weather and a lot of fun. Thanks to Svea, rockets ejected, marshmallows, glitter and stuffed animals.
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3-24-2013 ~ Blog # 513 (David)
We spent over six hours at the
launch site today; it was a windy day and we had a rough time.
The winds were around 15 MPH and were blowing in from the East
and not the West as usual. Although we launched from the
far East edge of our area, we lost two of our first four rockets
that we sent up. Both of these were the primary rockets of
each team. An hour was lost looking for these two rockets.
We then moved our launch pad 1300 feet East of our regular
launch location to the edge of a muddy, plowed corn field.
We didn't lose any more rockets but it was a long muddy walk to
the barn between launches. I think we had more fuse
failures than actual launches; this ate up loads of time.
Svea's team flew both of their rockets; one flew 45' low, the
other 175' too high. They cut down the air-brake streamers
on the low one, and called a qualification shot. Their score
would have been around 21, but their egg broke. On their
second and final qualification shot the ejection charge failed
and the rocket was destroyed. By this point 10 of our 12
shots of the year, from all four teams, had been used and no
scores were close. One team had two qualification shots
left, but it was late and the wind was picking up. On
their first shot their egg broke and their altitude was low due
underperforming Cesaroni motor. One ran back for a new egg
and they reloaded in the field. Then, on the last launch,
16.48. That number is not a shoe-in, but it stands a
reasonable chance of getting in the top 100. Our NAR
official pointed out that with a higher four point penalty on
the time window (48 to 50 seconds), we will likely see higher
scores for the top 100 cut-off. Our fingers are crossed. Click here to see a short HD movie of eight launches.
This is the one: 16.48
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Wednesday was cold and a bit windy, but we launched anyway. We didn't loose any rockets! One team attempted a qualifying launch, but their score was way beyond what might qualify. Svea's team has two flyable rockets, so the four members split into two teams of two. Svea sewed a hemispherical parachute that is effective enough to get their time in the right window. Flat 15" parachutes are just too small for a heavy hard body payload section, egg and altimeter. Their latest concept is to eject a soft payload section out of the main body tube. This is just a sock with minimal padding, under a 15 inch flat parachute. The lightness of the payload section also appears to be producing reasonable times. They had two altimeter failures, so we are not too sure if the altitude is right. Sunday is it. Two team need to take their two shots and two teams need to take their last remaining shots. Stay tuned.
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Rockets: Nice day but no numbers 3-16-2013 ~ Blog # 511 (David)
Today we had the least wind that we've had on a launch day in a month and for the first time in quite awhile we didn't lose half a rocket or more to trees. Svea's team, however, has a new rocket that returns to Earth in three pieces; with the nose cone falling with a streamer. They did manage to tangle their nose cone and streamer in a tree, but that's a pretty minor loss. Only one team called an official qualifying launch attempt; their score will not make it to nationals. Other teams tend to be flying a bit high and the times are a bit short.
This baby took a nice core sample.
Our NAR official launched his rocket. Look closely at the flame; notice the two inch pulse loops. Close up: 100% crop, 1/8000 sec, f2.8
Svea listening to the audible altitude code emitting from her rocket's altimeter.
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We are running out of time and things are not going so well. I seriously doubt if Cesaroni motors have a consistent thrust output. It's not uncommon for a single rocket to fly with the same motor, loaded exactly the same, under the same flight conditions and have altitudes vary by over 100 feet. On the up side, all four teams have two or three complete rockets, we have plenty of motors and two qualification launches left per team. Also, two teams out of four seem to be flying in the ball park. On the downside; we have eight days left. Qualify or die! We flew last Wednesday after school. In the two hours on site we had winds of just under 10 mph and clear skies, followed by 25mph winds mixed with near white out snow. We lost one half of a rocket when a 12mph wind launch picked up into a 20 plus mph gust as the last flight of the day hit apogee.
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3-10-2013 ~ Blog # 509 (David)
We launched today and were lucky that we only lost half a rocket to a tall tree; it was very windy. We called it quits early due to the wind. Svea's team managed to recover the tail section of their original rocket; it has been stuck in a tree for the past three weeks. I'm still loving the new/old 80-200mm f2.8 AF.
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We launched this Sunday but called it quits as the wind picked up.
Normally our teams tape the nose cones to the payload section. Taping the payload section to the body tube, however, turns a rocket into an expensive lawn dart.
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2-18-2013 ~ Blog # 504 (David)
Today is the deadline for submitting TARC round one qualification scores. Yesterday all four of our teams made qualification attempt flights; it was a cold, snowing and windy day. The elements wrecked havoc on our flight performance and we lost 37.5% of our rockets to the Rocket Eating Tree Demons. All teams made two or three practice launches before calling an official qualification launch; each team has only three official qualification launches for the season. While three teams had four members show up for the launch, poor Svea was on her own. On her first flight Svea's rocket failed to eject it's parachute and it lawn-darted a good six inches into the earth. The nose cone, altimeter, and fin section survived and we managed to rebuild the rocket with spare parts. The rebuilt rocket flew well on its second flight, but the main section parachute failed to open and a fin snapped loose on impact with the ground. Her qualification attempt flight was a Hail-Mary shot. The nose cone separated from the payload section when the parachute deployed and the expensive altimeter fell into a deep, snowy, forested ravine. The nose and tail parachute sections drifted into trees about 700 feet from the launch pad. The altimeters emit a beeping code that indicates the rocket's altitude at apogee. At the end of the day, while looking for a rocket section that was lost last week, a team member found Svea's altimeter. Our girl's team lost their nose section to a tree 40 feet up and 1500 feet from the launch pad; the wind carried it nearly twice as far horizontally as it flew vertically. The other two teams managed respectable scores, but scores that really don't stand a realistic chance of qualifying.
That yellow speck in the center of this photo is the parachute of the girl's team's rocket nose section.
Svea's official attempt. That yellow speck in the left of this photo is the parachute of her nose section.
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2-10-2013 ~ Blog # 502 (David)
We launched some rockets today and left the top half of one about 79 feet up in a tree. Three of our four teams stand a reasonable chance of getting a qualifying launch next week. Svea' team has been the only team to use the "Smokey Sam" motors; they have not worked out well. They've been unpredictable and often underpowered. They will be trying another motor next week, but won't have as much of a chance to tune it in before calling a qualification attempt launch.
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1-13-2013 ~ Blog # 497 (David)
We had our third launch yesterday. Svea's team had a rough day. They had multiple fuse failures. On their first actual ignition the ejection charge went off on lift off; the rocket received some internal burn damage and their parachute shock cord was destroyed. We fabricated a field quick fix and got the rocket flyable. The bottom half of the rocket ended up in a tree on the third launch.
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Yesterday we had our second TARC launch of the school year. We are still plagued by launch wire and fuse reliability. All four IHM teams showed up and had multiple launches. Almost every flight was at least 100 feet over the target altitude of 750'. The wind picked up and carried a few rockets pretty far and two managed land in trees, but were recovered. The challenge this year is hitting this altitude with a fairly light rocket (650 grams loaded). Traditionally TARC rockets' altitude are tuned with ballast, but a light rocket limit doesn't leave much room for much ballast. We've begun experimenting with controlling altitude with aerodynamic spoilers. The most delightful discovery of the day was actually hearing the crackly sound of streamers at 150 MPH. Once the motor burns out after 1.1 seconds the streamers made a beautiful and quite audible crackly noise. Svea's team rocket hit 745 feet on its fourth and last launch of the day. There's a lot of luck involved in hitting a desired altitude because the motor thrust performance can vary 10% or more, but still: 745 feet is a good number. I think the altimeter was armed at about 15 feet higher uphill than the launch pad, but still: 745 feet is a good number. We had some wind, which can really affect altitude, but still: 745 feet is a good number. Finally the payload hit a bit hard and broke their egg, which would have disqualified the flight in competition, but still: 745 feet is a good number for December.
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11-17-2012 ~ Blog #486 (David)
Today Svea and I drove up to Amherst to meet most of the rest of the IHM Rocket Teams for our first launch of the year. We are months ahead of where we were last year, but not really close to having rockets perform where we want them. We had bad luck with fuses and had quite a few no-fires. Thanks to our government overreacting to presumed terrorist everywhere, model rocket motors can only be sold with one fuse per motor. I am baffled that the idiots at the Bureau of Alcohol, Tobacco, Firearms and Explosives have such little understanding bombs, weapons, explosives, etc. that think that making model rocket fuse harder to get will stop or even deter a terrorist. There are hundreds of way to make fuses for bombs. Model rocket fuses, however, are relatively weak, very unreliable, and are really only good at igniting model rocket motors. Our motors cost $20 each. I believe we had five defective fuses today which means that we are sitting on about $100 worth of motors that can't be used because we can't buy spare fuses. This is just one more way that the Patriot Act and Homeland Security are trampling the rights of Americans, in this case law abiding hobbyists and students, while doing nothing to deter terrorists.
The Team America Rocketry Challenges rules for 2013 include: a target altitude of 750 feet, flight duration between 48-50 seconds, one egg laying sideways, a 15 inch diameter parachute and a weight limit of 650 grams. Today's flights were hitting 840-980 feet, so we need to bring them down with: smaller motors, more weight or air brakes/drag.
In the photos below, our rockets are short and white with unpainted wood fins. The other rockets pictured belong to NAR members who also attended the meet.
This NAR member rocket was just full of bad news. I'm guessing a bad O ring allowed the propellant gasses past the ejection delay.
This is my experimental finless rocket. It flew straight, but was very underpowered.
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