2014 Launch Reports
SLRA Spring High-Power Launch, March 22 2014, Elsberry MO
Several cold-blooded rocketeers came out to Elsberry to withstand the upper 30s / lower 40s temperatures and hold our first launch of the year. The cloud ceiling was solid between 2500 and 3000 feet, so the club started with some lower-altitude flights and test burns.
After 1:00 in the afternoon, the lower-level clouds began to break up and higher-altitude flights could take place. I loaded my Shapeshifter up with a CTI J285 motor for my Tripoli Level 2 certification attempt, which was also my first attempt at a dual deployment flight. My simulation showed a 4800 foot apogee with this motor, but since I had added the shroud for the Mobius camera and had no way to simulate its drag, I guessed that the actual apogee would be about 4500 feet. This turned out to be very close to the actual altitude.
Upon launch, the rocket weathercocked sharply to the east and passed into a cloud. I did not see it come down, and initially I could not hear the tracking beacon either, so I guessed that the battery connector had disconnected from the transmitter. However, since several people saw the rocket going east, I set off that direction to look, and Mike Walsh Sr. joined me.
After walking about a quarter mile to the east, we began to hear a faint signal from the tracker. We continued until we came to a creek too wide and deep to cross on foot, about half a mile from the pads. Since the tracker indicated the rocket was on the other side, we walked the half mile back to the pads and I took my car over to Highway 927 and came back from the other side. I eventually found the rocket among the cornstalks about 0.6 miles from the launch pad.
The rocket had separated at apogee, but the main parachute had not deployed. The nose cone was still fully seated and the shear pins were still in place. The nose cone was stuck in the ground about eight inches - the reason the tracking signal was weak was because most of the transmitting antenna was below ground (although I had turned the transmitter down from its maximum power, underestimating its range). One fin had come unglued, but it was still stuck in its slot in the airframe.
After bringing the rocket back to the launch area, I discovered that all of the ejection charges had blown. (Later, from the on-board video, I confirmed that the main charges had blown at the correct altitude, as well.) Despite the crash landing, none of the electronics were damaged, and there was no other apparent damage to the rocket apart from the one fin. However, this damage did mean my certification attempt was unsuccessful.
Weather conditions: Broken clouds around 3000 ft, windy (from NE approx. 15 mph), 42 F
Shape Shifter Jr. flight #3:
Motor: Cesaroni Pro38 648J285-15A
Altitude: 4484 feet AGL
Max velocity: 444 MPH (Mach 0.59)
Motor burn time: 2.0 sec
Peak acceleration: 12.6 G
Descent rate: approx. 66 MPH vertical, unknown lateral
Flight duration: 67.3 sec
Result: Landed in field; streamer deployed at apogee but main did not deploy; successful recovery, moderate damage (one fin dislodged); certification attempt unsuccessful
Flight data file (viewable with the Featherweight Interface Program)
(TODO: images & videos)
LDRS 33, July 17-20 2014, Kansasville WI
We had near-perfect flying conditions for LDRS (Large Dangerous Rocket Ships) 33 at the Bong State Recreational Area near Kenosha, Wisconsin. LDRS is the largest annual launch for the Tripoli Rocketry Association and its location varies from year to year. When it was announced that this year's event would be held in the midwest, I immediately started making plans to attend, as it may not be so close for several more years.
I had two main goals for this launch. The first was to complete my level 2 certification with a flight of my new rocket “Home Alone” on a J motor, and the second was to make my first flight of more than a mile in altitude. Everything went very smoothly for me and I achieved both of these goals.
Day 1
The event began on Thursday, but to save a vacation day and a hotel night, I drove up to Kenosha on Thursday afternoon and didn't go to the range until Friday. The predicted weather was very similar throughout the event: mid- to upper 70s, clear and calm. A breeze might have made it a little more comfortable, but all things considered, we couldn't have asked for better conditions to fly rockets.
I prepped Home Alone according the detailed checklist I had been obsessing over for the past several weeks and loaded up my certification motor, a Cesaroni J430. This was the smallest motor I was comfortable flying; being a fast-burning 2-grain motor, it would only lift the 9-pound rocket to around 3000 feet. At that altitude I expected that my certification observer and I would both be able to see the rocket's entire trajectory and make sure everything worked properly.
I admit my hands were shaking as I hooked the rocket up on the launch pad. My jitters soon subsided, though, as the fast-moving launch crew started my countdown almost before I could get back to the spectator area and start my camera. Home Alone flew perfectly straight up to its predicted altitude of 3000 feet, remaining just under the scattered clouds, and arced over towards the spectator area as its apogee event fired and it deployed its streamer. Descending under streamer, the rocket continued to drift over the spectators and towards the parking area, causing the LCO (launch control officer) to call for a “heads up.” When I could no longer see the rocket, I packed up my camera and radio tracker and headed back towards the parking area as the LCO (also my certification observer) congratulated me on a successful certification flight.
I went back to my car and dropped off my camera and tripod, and debated whether I should take the tracker with me. I had just decided that I probably wouldn't need it, and stowed it in the back of my car, when I turned around and saw my rocket lying on the ground next to another rocketeer's EZ-up tent across the aisle. My first thought was that he must have found my rocket and brought it back to his tent already, but when I approached it became apparent that it had landed right where it was, with the shock cords and parachute strewn around three sides of the tent. My neighbor didn't seem to be too put out by the near miss, and I had a very short walk back to my car.
Weather conditions: Scattered clouds around 3000 ft, winds calm, 73 F, 59% RH
Home Alone flight #1:
Motor: Cesaroni Pro54 821J430-18A White Thunder
Altitude: 3034 feet AGL
Max velocity: 318 MPH (Mach 0.42)
Motor burn time: 1.84 sec
Peak acceleration: 10.3 G
Descent rate: 59.47 ft/s (40 mph) under drogue streamer, 18.39 ft/s (13 mph) under main chute
Flight duration: 91.5 sec
Result: Landed in parking area; apogee and main recovery deployment nominal; successful recovery, no damage; certification attempt successful
Flight data file (viewable with the Featherweight Interface Program)
(TODO: images & videos)
Day 2
My goal for my second flight was to exceed a mile in altitude. From my first flight I found that my actual altitude differed from my simulation by about 5%, which was about what I expected due to the extra drag of the camera shroud (which my simulator can't simulate easily). I had originally planned to fly either a 4 grain sparky or a 4 grain smoky motor, either of which should have put me at around 6000 feet and met my goal with a little bit of a cushion. However, since the first flight had gone so well, I decided to push my luck a little more and reach for another (completely arbitrary) milestone - exceeding 500 mph. This would require a slightly higher-impulse motor, and after running some more simulations I settled on a 4 grain motor with Cesaroni's red propellant, “Red Lightning.”
I purchased the motor at the Wildman Rocketry trailer and returned to my workspace to get things ready to go. While I was working, another SLRA member, Craig, stopped by. He and his wife had decided to come up for the weekend to spectate and take photos, and he helped me get the rocket hooked up at the pad.
Again, I barely had time to get back and start my camera before the LCO called for my countdown. Home Alone shot off the pad on the red motor and quickly disappeared from view completely. I was starting to worry about finding it, and was still scanning the sky overhead, when people to my left started shouting for a heads-up and I saw my rocket drifting down under parachute only about 150 feet up. It came down in the grass just across the road from the spectator area, about fifty feet from where I was standing with my camera and tripod. I wish I had caught sight of it earlier and been able to watch the deployment, because from the altimeter data and the on-board video, it appeared that the main parachute didn't fully inflate until the rocket was at around 300 feet altitude (after the ejection which should have occurred at 800 feet), which meant it must have come out somewhat tangled.
Without actually seeing it, I think the way in which I folded the main chute may have led to the tangling. For future reference, I'll note here that it was folded according to the Top Flight instructions (in half to form an L, then in half again to form a long rectangle with a point at the end, then in half lengthwise, then the point folded inwards, then rolled). The gores were then wound around the bundle per the instructions, but then, to make a more compact bundle, I folded the roll in half again before packing it in the tube. I think that folding it again after the gores were already rolled on the outside was a Bad Idea and caused the two halves to get tangled with each other. The next time I pack, I should try either folding the bundle in half before winding the gores around it (so they're only going one direction) or coming up with another way to fold it so the gores are on the inside.
At any rate, it was a beautiful second flight and another very short recovery walk. Once I downloaded my altimeter data, I found that my altitude and speed had both exceeded my simulations, even without taking into account the 5% I expected to lose due to the camera. I have to assume that there is just that much variation in impulse between one motor and the next, and I happened to end up with an “overachiever.”
Weather conditions: Scattered clouds around 5000 ft, winds calm, 73 F, 55% RH
Home Alone flight #2:
Motor: Cesaroni Pro54 1596K500-18A Red Lightning
Altitude: 7394 feet AGL
Max velocity: 573 MPH (Mach 0.76)
Motor burn time: 2.44 sec
Peak acceleration: 13.8 G
Descent rate: 74.90 ft/s (51 mph) under drogue streamer, 21.81 ft/s (15 mph) under main chute
Flight duration: 133 sec
Result: Landed in field very close to spectator area; apogee and main recovery deployment nominal except main seemed to be tangled until ~300 feet AGL; successful recovery, no damage
Flight data file (viewable with the Featherweight Interface Program)
(TODO: images & videos)
Day 3
I didn't think I could top the flights I'd done Friday and Saturday, and didn't want to push my luck too much further since I planned to drive home this afternoon. I went to the range for a couple of hours to take photos and pick up a couple more motors to use for SLRA launches, since buying them at the launch saves me the cost of shipping and hazmat fees. I selected a K530 (4 grain smoky) which should power a flight to about 6000 feet, and a K600 (5 grain white) which should fly above 9000 feet. With these two, I should have options for a fairly wide variety of weather conditions.
SLRA August Park Launch, August 23 2014, Valley Park MO
We had a park launch on Saturday morning, but due to the high heat and humidity, I didn't stay long. I flew my Estes Flutterby for the first time and successfully recovered it. SLRA September Park Launch, September 20 2014, Valley Park MO
The September park launch was met with much more pleasant weather than last month. We were joined by members of a local Boy Scout troop who flew model rockets (mostly Estes Alphas). I flew my SpaceX Falcon 9 (second flight) and also made a test flight with the unfinished egg-lofter that I'm building for the October Fly contest. Flight data for the egg-lofter:
Over Easy (Scratch-built egg-lofter), flight #1:
Motor: Estes C6-3
Altitude: 212 feet AGL
Max velocity: 52 MPH
Motor burn time: 2.0 sec
Peak acceleration: 5.2 G
Average Acceleration: 1.2 G
Coast time to apogee: 3.0 sec
Apogee to ejection time: -0.1 sec
Ejection altitude: 208 feet
Descent rate: 10 MPH
Flight duration: 17.7 sec
Result: Landed in field; successful recovery, no damage
I am redoing the tail-cone and will seal the balsa parts, sand and paint the entire rocket, which hopefully will improve performance a bit.
October Fly NAR Regional Competition, October 11 2014, Valley Park MO
I flew my egg-lofter for the competiton to an altitude of 186 feet. John Buckley, the contest organizer, just squeaked past me with an altitude of 746 feet.
I hadn't had time to paint the rocket, but I sealed and sanded all of the wood parts. I also replaced the tail-cone with a new one cut to fit cleanly inside the end of the airframe. However, I underestimated how stripped-down a real competition egg-lofter is. John's design was a very minimal capsule around the egg with a minimum-diameter airframe.
My first flight did not record good flight data because I think I had the packed parachute blocking the port holes in the airframe. Data below is for the second flight (which was clearly higher anyway, as the first flight launched at a significant angle from vertical). After the contest, I measured the mass of my egg at 62.5 grams, almost exactly the same weight of the dummy egg I used for my test flight.
Over Easy (Scratch-built egg-lofter), flight #3:
Motor: Estes C6-3
Altitude: 186 feet AGL
Max velocity: 48 MPH
Motor burn time: 2.0 sec
Peak acceleration: 4.2 G
Average Acceleration: 1.1 G
Coast time to apogee: 2.9 sec
Apogee to ejection time: -0.3 sec
Ejection altitude: 175 feet
Descent rate: 9 MPH
Flight duration: 16.5 sec
Result: Landed in field; successful recovery, no damage
Midwest Power 12, October 31-November 2 2014, Princeton IL
Since our local high-power field in Elsberry was not yet available, I drove up to Princeton, IL for a day at Midwest Power 12. Quad Cities Rocket Society has a 16,000 foot standing waiver at their launch site in Princeton, so this seemed like a good opportunity to try a high-altitude flight with my newest high-power rocket, “Home Alone.” I considered trying an L motor, but eventually decided that this would have been a bigger step than I wanted to take, and settled on a K-660. This is the highest-impulse motor available for the largest motor case I have (an L motor would have required me to buy a bigger case).
I drove up to Princeton on Friday night and did as much of my preparation as possible in my hotel room, since the weather was going to be brisk. However, Friday was extremely windy and Sunday was expected to be overcast, so Saturday was definitely the prime day for rocket launches. I took my time getting to the range on Saturday morning, so it was a balmy 40 degrees when I arrived about 10:30am. I registered, picked up my motor from the Wildman Rocketry trailer, and finished prepping my rocket. I got on the launch pad about 1:30pm.
The launch appeared to be picture perfect - the rocket flew arrow-straight into the cloudless sky. As usual, I lost sight of the rocket at apogee and didn't see the deployment events. However, unlike the previous flight, the rocket did not land right next to me out of pure dumb luck. I could hear the radio transmitter throughout the flight, so I didn't expect the rocket to have traveled too far; I returned to my car and hooked up the directional antenna and started looking around.
I quickly got a strong signal to the southwest, and it did not take long to establish that the rocket had landed in one of the few surrounding fields that had not yet been harvested. I started wading between the 10-foot-tall cornstalks, stopping every so often to get a new bearing on the radio beacon. After close to an hour, I finally located the rocket about 500 feet from both the northern and eastern edges of the cornfield. It was here that I learned the most important rule of traversing cornfields: walk in the direction of the rows as much as possible; walk perpendicular to the rows as little as possible. Thanks to my GPS data, I can pinpoint the moment at which I learned this lesson (2:21 pm). However, more significant in the long run was that this recovery was a HUGE confidence booster in my ability to use the radio tracker. I was limited to a line of sight of about five yards while wandering through the cornstalks, but the radio tracker led me directly to the rocket.
The recovery was successful, but there were a couple of casualties. One was my excellent hat, crocheted for me by my wife, Colleen. I stuffed it into my sweatshirt while I was reassembling the rocket, and somewhere along the way out I dropped it and didn't notice. Similarly, I had the bright idea of disassembling my radio tracker antenna for the trek out of the corn to make the walk less awkward (as I was trying to balance the rocket on my shoulder); along the way, four of the five crosspieces fell out of my pockets and were lost. Fortunately, though, I held onto the most expensive of the pieces and have already ordered replacements for the lost pieces. And Colleen is in the planning stages of making me a new hat.
I had made one addition to the rocket since LDRS that I was eager to try out - I installed a Canmore GPS logger in the nose compartment, hoping to be able to be able to generate 3D plots of the rocket's trajectory, like this. However, on this initial flight, the GPS did not appear to capture altitude correctly. I will continue to look through the data and see if the information can be salvaged, and I will definitely try flying this logger again, but initial indications are that it may not work well for rocketry.
Weather conditions: Clear, winds east @ 5 mph, 45 F, 50% RH
Home Alone flight #3:
Motor: Cesaroni Pro54 2437-K-660 Classic
Altitude: 11,632 feet AGL (11,846 feet MSL)
Max velocity: 740 MPH (Mach 0.98 @ 2000 feet MSL)
Motor burn time: 3.7 sec
Peak acceleration: 25.6 G (momentary)
Descent rate: 105 ft/s (72 mph) under drogue streamer (tangled), 26.6 ft/s (18 mph) under main chute
Flight duration: 163 sec
Result: Landed 500 feet into cornfield south of launch area; apogee streamer tangled but main parachute deployment nominal; successful recovery with use of radio tracker, no damage; lost hat
Flight data file (viewable with the Featherweight Interface Program)
(TODO: images & videos)