David Schaefer – My Balls Report, Part 1
| October 24, 2012 | 4:02 pm | Launch Report | Comments closed

For those of you that missed lunch the last few weeks, here’s a summary of our trip to Balls this year. Ken Overton, Robert Turner and I made the expedition out to Black Rock. Passing thru Beatty NV, we caught up with Bobbie Neubert. We met up with Paul Holmes at the launch. The trip out went very well and we arrived on the playa Wednesday afternoon and to our surprise there was just one other car out there. It’s hard to describe just what it’s like stepping out on the playa for the first time. Now I have flown off a dry lakebed before, but there’s nothing like Black Rock. It’s an unimaginable expanse of wide-open space with mountains way off in the distance. It absolutely takes your breath away. If you ever wanted to launch high, this is the best place on the planet to do it! Shortly after we arrived, more people started to show up. Our plan was to set up our camp and our pad on Wednesday but this didn’t happen because of the possibility of moving 4 miles north to accommodate a 475,000 foot waver.

Thursday was off to a slow start, as we waited for the launch organizers to show up. As it turned out, they were busy rescuing a guy from Florida that rolled his car. In the end we were in the right spot and started to set up camp around 10:00. It took some time to set everything up, including the pad, and test Marks’s wireless launch controller. Our plan for Friday was to fly 3 rockets, first Ken’s magnificent N to M two stage, then Robert’s L-3 attempt, then if we still had time my ½ scale EAC Hyperion.

So late in the afternoon on Thursday, we started to prep our birds. It seems like we all ran into problems. I discovered that my #1 altimeter wouldn’t shut off with the arming pin installed. I had thoroughly tested this before and had no issues, but now despite my best efforts to resolve the problem, I wasn’t making much progress.

During dinner, I had an epiphany; I was working to hard to get my arming system to work in its original form, as it turned out a very simple modification solved the problem. So into the night, we continued to work on our rockets. Next it was time to pack the chutes and again I ran into issues. I deliberately had chosen a long scale model to give me plenty of packing space, but trying to pack all of the stuff into a minimum diameter 3-inch rocket proved to be quite a challenge. With both Ken’s and Robert’s help and after trying several different packing configurations, we finally shoehorned all the crap in my rocket. It was an extremely tight fit. By 11:00 at night, we all seemed ready to fly in the morning.

On Friday, I woke up early with the anticipation of a kid on Christmas morning.

The weather was great for flying rockets but it was a little hazy. As the morning progressed, the haze burned off a bit to giving us good vertical visibility and you could see the rockets go a long way up. It took a while on Friday morning to get the launch started, as the AHPRA folk were still recovering from the rescue the day before. It was about 11:00 by the time we got Ken’s two stage racked and ready to fly.

There were lots of huge rockets going off all around us, as we got Ken’s rocket on the pad with Paul’s help. Paul worked the range tirelessly all day long, making sure things ran smoothly. I bet he walked 15 miles that day. After waiting more than a year, it was great seeing the splendid 2 stage ready to go. At ignition, Ken’s rocket had a very majestic liftoff. Clearing the rail, it tilted just a few degrees to the southwest but wasted no time accelerating to Mach. After the First Stage burned out, the rocket coasted upwards for quite a while and then the upper stage lit way up in the sky, boosting the sustainer to some serious altitude. I lost sight of it shortly after motor burnout and then I could see the chute on the booster and even that was very high up. Ken had a tracking beacon on the booster and GPS in the upper stage. We monitored the sustainer data until the readout showed it on the ground.

We hopped in Paul’s car and took off across the playa to recover the rocket. We recovered the bottom stage first and it looked great. Finding the upper stage was very easy with the GPS locked onto its position. As we approached the rocket, it became obvious that the main chute didn’t come out. Apparently the drogue deployed at high speed, the shock cord had zippered the fiberglass tube and it jammed the shock cord in place preventing the main from deploying. In addition to the zipper, there was some damage to the upper stage, but what an incredible flight!

Seeing this flight alone was worth the trip to Black Rock. Unfortunately, the avionics battery got knocked loose on landing, so I’m still waiting to find out just how high it went.


Next it was Robert Turn’s turn to fly with his L-3 attempt, a 10-foot tall 4-inch in diameter bright yellow rocket on a CTI M-1810. Unfortunately, when we got out to the pad, we could not get Robert’s rocket on the rail, as he had used fasteners on the rail guides that stood too tall. So we went back to camp. Being it was going to take some time to resolve this issue, we removed my GPS from his nosecone and reinstalled it in mine. So Ken and I drove my 1/2 scale EAC Hyperion out to the pad. It didn’t take us very long to set it up. I had it pointed slightly to the north to keep it away from the flight line. At Paul’s suggestion, this rocket was flying on a Gorilla M-745. The 7.7 second burn of the M-745 started out with plenty of thrust to get my 28-pound model accelerating fast, and at ignition the Hyperion moved smartly off the pad. Leaving the pad, the rocket flew straight and true. On Ken’s video of the launch, you can even hear me make a comment to that effect. The Hyperion climbed high into the desert sky and an impressive column of white smoke made it possible to track the rocket all the way thru apogee. The rocket had simulated to over 17,000 feet and it looked at the very least, every bit of that. I could make out a tiny speck in the sky but not any more than that. I tracked it for a while, as it drifted to the Northwest under drogue, and then I lost sight of it. Ken tracked it with the GPS for what seemed like quite some time (actually 5 ½ minutes) until the rocket was on the ground 2.4 miles away. We got in Paul’s car and I drove across the playa, as Ken occasionally corrected my heading and counted down the distance to my rocket.

When we got to the rocket, I could see that all of the chutes had deployed and the Hyperion looked perfect, I was thrilled. I put the arming pin back into the number 2 altimeter, so I could make out the altitude from the beeps from the number 1. It indicated that the rocket went to 17,923 feet, my new personal best. Ken drove back to camp, so that we could fly Robert’s L-3 before it got too late in the day.

At camp, Robert congratulated me on the flight and showed me his rocket with the rail guide issue resolved. So now it’s his turn to fly. Once again we took his rocket to the pad. Once set up and ready to go, we carefully went thru his checklist to make sure everything was good. The large yellow rocket certainly looked up to the task and it was set to go on a CTI M-1810. When the motor lit, the rocket looked like the Starship Enterprise going into warp, as it hurdled off the pad. One moment the rocket was flying straight and true and the next….. well it’s hard for me to find the words to describe the totality of the event, but I’ll try… disintegration comes to mind. Small bits of yellow rocket started to flutter down everywhere. I watched the payload section (with my GPS tracker in it) hit the playa with a resounding thud.

Robert and I walked around picking up pieces of rocket for several minutes. We never did find the altimeters.

From our vantage point, it was hard to tell what happened. Several people on the flight line said it look like the body tube had folded. Thinking about this, one of Roberts’s altimeters was an outdated Adept. I’m thinking it probably deployed when the rocket hit Mach. By the time we collected all of the pieces we could find, the range had closed. We headed back to camp to make dinner. Next door they were have quite a party with a fire. Ken decided to take a large bucket of discarded propellant over to liven things up. He made a lot of new friends with the semi coherent group from Minnesota , as he tossed large chunks of propellant into the fire. On occasion the burning propellant would shoot flames 15 feet high! After all the excitement, I was exhausted but still looking forward to the morning, as Paul Holmes was going to fly his very impressive rocket. An “N” powered bird with two “L” strap on boosters that would fall away after they burned out. Ken was starting to prepare the boosted dart that he and Tony Huet had worked on. He was estimating the dart would travel to 44,000 feet! I was considering flying my Me-163 Komet, but only after Paul and Ken got their fights off, as I could fly the Komet anywhere. It didn’t take me long to fall asleep that night.

PerfectFlite Altimeters
| October 12, 2012 | 12:31 pm | Reviews | Comments closed

So back in 2004\2005 I needed a new altimeter to replace an aging Olsen altimeter that was really no longer being supported.  I wanted one as a backup to my G-Wiz MC for the flight of my 14x upscale of the Estes NASA Pegasus.  I had read about the Perfectflite altimeters for a while and decided to give them a chance.

PerfectFlite Altimeters

 The one that I received was the MiniAlt WD (MAWD) and I have flown it on many rockets over the last 6 to 7 years.  I have flown it in single stage and dual stage rockets on anything from Js to Os.  So a year or so back I damaged it due to my own error and was not sure how it was going to to work.  It tested OK but the next time I flew it in a rocket the only reason the rocket did not come back in hot was due to motor ejection.  It did not fire either of the two charges off, but I was still not sure if it was something I did or the altimeter.  It still tested like there were no problems with the unit.

So, it was time to replace the altimeter and since I had such good luck with the MAWD I went back to the PerfectFlite web site to see what they were up to.  As luck would have it, they were still making altimeters. But there were a few changes in them.  They were still right around the same size but the new unit, now called the StratoLogger, was bigger.  It’s still a small altimeter though, it’s 2.75″L x 0.9″W x 0.5″H and will fit into a 29mm tube.

This new altimeter is a great little unit.  Besides having to outputs for apogee and main chute deployment it also measures the temperature, and the battery voltage.  There is also an audio out port where the user can add either LEDs or an external speaker.  There is also telemetry data being outputted so you could connect it to a radio and transmit your altitudes in real time.  It has enough memory on the unit to store 31 nine minute flights.

The altimeter has more options and abilities than most altimeters of the same size.  And the best part is the retail price is just $71.96, but if you buy two of them the price drops to $67.96.  You just can’t beat being able to get an altimeter for that price with all the features this one has.

You can get the full specs of the altimeter at their web site, http://www.perfectflite.com.


A sample post for Math
| October 10, 2012 | 11:54 pm | Site Info | Comments closed

So we have a few guys in the club that will love being able to edit and post messages that contain advanced math problems.

We can do special symbols too.

\aleph \nsubseteqq \sum \lbrace \rbrace


A_\infty + \pi A_0\sim \mathbf{A}_{\boldsymbol{\infty}} \boldsymbol{+}\boldsymbol{\pi} \mathbf{A}_{\boldsymbol{0}}\sim\pmb{A}_{\pmb{\infty}} \pmb{+}\pmb{\pi} \pmb{A}_{\pmb{0}}


\begin{pmatrix}\alpha& \beta^{*}\\\gamma^{*}& \delta\end{pmatrix}


You can get more information at this site, http://en.support.wordpress.com/latex/.  But I actually think the best resource I have found so far has been this page.  ftp://ftp.ams.org/pub/tex/doc/amsmath/short-math-guide.pdf