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Sunday, November 7, 2010

Last Day of the Season

Yesterday was the last launch opportunity for Tripoli Idaho for this year. Normally we don't launch on back-to-back weekends, but there were enough people interested in flying that we decided to take advantage of the last date we applied for in our FAA waiver.

We got out to the launch site and had overcast skies, though the clouds were higher than last week. Site set-up went well with many hands helping to get things done. Soon it was time to start thinking about flying rockets. I'd managed to acquire a reload for Flying Colors from one of the other TIR members who wasn't going to be at the launch. This was a Cesaroni 540I470-15A. As there was fog lurking in the Snake River canyon and obscuring some of the hills off to the North-West I was concerned that it was going to move down and sock us in, so I decided to get my flight off while I could, despite the grey skies. Once again assembly was very straightforward and I quickly had my rocket at the pad. I did have to borrow masking tape to secure the batteries in my tracker as my roll had been removed from my tool bag the previous week, Fail #1. In my haste to get the flight card to the LCO I forgot all about setting up my video camera, Fail #2. Consequently I have no video from this flight. Flying Colors made another brilliant flight, but once again I was unable to see the chute deploy. The winds carried it to the East, close to the same track as flight #2, but not as far out. I grabbed my GPS to get landing coordinates and couldn't get it  to work as apparently the battery was dead, Fail #3. I recovered the rocket and found it to be in excellent condition, with no evidence of any damage from this flight.

After grabbing a bite to eat I started prepping Dragon Fly for a flight. In preparation for going out to the site I'd trimmed down what I would carry out and only grabbed one of the two G76-10G reloads I had available. In the process I'd failed to grab the grease for lubricating the O-rings and threads, Fail #4. I had to borrow grease to assemble this motor. Assembly was straight forward, but as I started to head to the pad I glanced at my work table and saw the container of black powder used to deploy the recovery system still sitting in the plastic bag the motor shipped in, Fail #5. I would have discovered this when I got to the pad and didn't have the cap to secure the igniter in the motor, but was glad I saw it when I did. I quickly rectified this situation and headed out to the pad. One of the other rocketeers was also flying an Arreaux on a G76G and had his at the pad ready to go. I asked if he'd like to fly his in a drag race with mine and he agreed. When it was time to launch his rocket launched while mine spit out the igniter, Fail #6. My competitor had already had 2 or 3 such failures on previous launches of his rocket that day.


Video: Dragon Fly, Flight #4, Attempt #1

After my failed launch we were treated to a flight of Coldfire with automated flight commentary provided by "Kate".


Video: Coldfire, Flight 20

Once Coldfire had flown I serviced Dragon Fly at the pad. I had to borrow a replacement Copperhead igniter, having left my spares at home along with my grease, Fail #7. I got the igniter installed and made another attempted launch. Again the motor failed to start and the spent igniter was spit out, Fail #8.


Video: Dragon Fly, Flight 4, Attempt 2

One of the other attendees expressed the opinion that the Mojave Green propellant used in the G76G motors is hard to light under the colder conditions we were experiencing yesterday. Based on the number of failed ignitions I'm inclined to believe him.

After this failed launch attempt one of the other participants launched his rocket, Thumper on it's second flight on a "K" class motor. In the video you can hear the motor come up to pressure, with a sound like a bottle being filled with water. Warning, if you turn up your volume to hear this effect the noise at launch will be very loud. This phenomenon is also audible in the Coldfire launch presented earlier.


Video: Thumper, Flight 2

As you can hear this flight ended horribly. The chute failed to deploy and the rocket descended ballistically and impacted disturbingly close to the launch site, landing just East of the North-South road to our East. The nose cone was buried about 1.5' to 2' into the ground.

I borrowed another igniter, this time a "home brew" one and prepared the motor yet again. I had gotten lucky on the previous igniter installation and managed to feed it through the nozzle without having to disassemble the motor. The new igniter wouldn't feed through the nozzle, so I had to remove the rear closure and nozzle. When I pulled out the nozzle it pulled up the fuel grains as well. I was a bit concerned by this, but decided the forward insulator and O-ring were undisturbed, so proceeded with reassembly. This time the Dragon Fly flew when the LCO pressed the launch button, unfortunately, due to a misconfiguration of the launch controller so did another rocket sitting on the next pad.


Video: Dragon Fly, Flight 4, Attempt 3


Video: Dragon Fly. Flight 4, Attempt 3 (Slow Motion)

The Dragon Fly won this unintentional drag race, leaving the pads first, going higher, and landing last. This result was predictable however since the other rocket was a Level 2 certification attempt flying on a "J" motor. Bigger motors take longer to come up to pressure, so my little "G" motor launched quicker. The thrust-to-weight ratio also favored my rocket, consequently my higher altitude (expected: 2724.57995', actual:2863).

As can be seen in the videos, the skies improved during the day until we got a nice big blue patch above us. This allowed a Level 3 certification flight to launch on an "M" motor. The flight was awesome and successful, going at least 14,000'. I attempted to record this launch, but due to technical difficulties at the launch pad I ran out of battery power about 2 seconds before it flew.

After this flight there was a test flight on an "L" motor of a rocket that will be
flown in the spring for another rocketeer's Level 3 certification attempt. This flight also was very nice.


Photo Album: 2010-11-06, Last Launch Day of 2010

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