2015 Launch Reports
Mini-Midwest Power 3, May 23-24 2015, Princeton IL
Since my local club, SLRA, is still working on nailing down a high-power launch site, we were unable to hold a launch this spring. So I loaded up the car with my “winter project” (actually only finished about a week before the Memorial Day launch weekend) and headed up the road to QCRS' excellent field north of Princeton, Illinois.
My primary goal for this launch was to get Ursa Major off the ground with a low-altitude, single-deploy flight. I eventually plan to fly this rocket with a cable cutter for dual deployment, but I need to do some additional ground testing with it before I'm ready to use it. I started off with flight simulations using a CTI J430, the same motor I used for my level 2 certification flight last year, but the rocket ended up being heavier than expected, and I changed my plans to use a J760 for higher liftoff speed.
With that project seemingly under control, I decided just a couple of weeks before the launch to set myself another goal that I wasn't planning to try until later this year at AIRFest - namely, to push for a supersonic flight with Home Alone. Its third flight last November on a K660 had reached Mach 0.98, so I was certain that just a little more motor would get it past Mach 1. I made a list of my options for that flight and brought it with me to the launch.
Not everything went perfectly, but I was successful in both of these goals, and learned a few things when my plans didn't quite work out.
Weather conditions at launch time: Clear, winds west-southwest @ 6 mph, 78 F, 26% RH
Ursa Major, J760
Since Ursa Major's flight had far less prep time than Home Alone's, I did it first. I used both the motor ejection charge and electronically-activated apogee charges for a) redundancy, b) testing purposes, and c) why not. I set the motor delay to 11 seconds, which should have been within a second of the expected apogee, and loaded the rocket up on the pad. It was one of the first “big” flights of the day, as most of the bigger rockets required more prep time. The motor ignited on the first try, and Ursa Major boosted away on a really nice-looking, solid trajectory. Its tracking smoke was still easily visible as it arced over into the wind at apogee, and the dark red parachute was visible all the way back down to the ground. It landed just a few hundred feet north of the pads, so radio tracking was not necessary.
Unfortunately, when I picked up the rocket, I found that the external fillets on two of the fins had cracked. Apparently, this rocket needs a softer landing than the 60 inch parachute included with the kit can give it, due to the increased weight from fiberglassing the tube. The external breaks should be repairable, and hopefully there is no internal damage. When it flies again, it will have both a drogue and a larger main parachute (possibly the 78“ Crossfire chute from Top Flight Recovery).
Ursa Major flight #1:
Motor: Cesaroni Pro54 1266-J-760 White Thunder
Altitude: 2,477 feet AGL (2710 feet MSL)
Max velocity: 351 MPH (Mach 0.46 @ 1000 feet MSL)
Motor burn time: 1.8 sec
Peak acceleration: 13 G
Descent rate: 23 ft/s (16 mph) under main chute
Flight duration: 117 sec
Result: Landed 500 ft N of launch pad (downwind); deployment nominal; successful recovery, external fillets on two fins cracked upon landing, not known whether there's internal damage
Flight data file (viewable with the Featherweight Interface Program)
(TODO: images & video)
Home Alone, L805
With that flight done and mostly successful by only 10:30 am, I started prepping Home Alone. Tim from Wildman Rocketry had his trailer full of rocket motors open for business, and I picked up a CTI L805 - my second choice on the list I had made from my simulations, but still a really good motor for my rocket. I rigged everything for dual deployment with redundant apogee and main charges (a total of four 1.5g charges).
However, when I put the rocket on the launch pad and turned on the computer, the startup beeps indicated that only three of the four charges had continuity - one of them had either come loose or not been connected securely in the first place. Since both the apogee and main deployment events had both a primary and a backup charge, it should have still worked in this configuration, and I considered going ahead with the launch, but then thought better of it and took the rocket back down off the pad. I carried it back to my prep area to take it apart and fix the loose connection.
It was then that I had an extremely lucky break, although for a moment it seemed like bad luck. While I was rotating the rocket on my prep rack, removing the plastic rivets to access the forward section where the loose connection was, I pushed lightly on the side of the shroud holding the on-board video camera, and it came off in my hand. After a moment, it occurred to me that if the deployment charge hadn't had a loose connection, or if I had decided to go ahead and fly it despite the loose connection, the camera would have been hanging on by a thread and would surely have shed itself somewhere in the first second or two of the flight. If that had happened, I would have lost not only the camera and the shroud, but the on-board video of Ursa Major's first flight, which I had not yet downloaded from the camera. It was actually extremely lucky that it came off when it did. Upon inspection, all of the epoxy I had used to bond the shroud to the rocket was still stuck firmly to the airframe, but had come cleanly and completely unstuck from the camera shroud, which had been made on a 3D printer. Before Home Alone flies again, I'll refasten this shroud with machine screws, but I may have to be slightly clever about how I do it since I can't have anything protruding into the inside of the rocket which will snag the recovery gear.
After that, the flight was quite routine. With all four deployment charges connected correctly, I returned Home Alone to the pad and it took off on its supersonic journey. It was so quick, in fact, that I utterly failed to keep it in the frame of my video camera, which is why there is no video of the flight here at all. (There was a semi-pro videographer there, so I might eventually get access to his video.) It disappeared into the sky, and, as usual, I had no idea which direction it went after apogee and didn't see the deployment occur. However, I had a good signal from the radio tracker, indicating that it had come down to the northeast. After walking a few hundred yards in that direction, I finally saw the chute blowing around on the ground in the distance, and judged it worth doubling back to my car and driving around the perimeter of the field to reach it. Home Alone had come down about a half mile north-northeast of the launch pads.
Besides fixing the camera mount, I will also need to sand the rocket down completely and repaint it. The Dupli-color paint that I used on Home Alone, whether due to user error or not, never cured properly and still had a sticky, tacky feel even a year later. This makes it not only difficult to handle, but it also looks grubby all the time because it picks up sooty fingerprints every time you touch it. On top of that, after landing in a muddy cornfield, it is now absolutely filthy. Time for a fresh start. I'll keep the same design and color scheme, and can reprint all of the decals, so it should end up looking similar to the way it did originally (except possibly for a slightly brighter blue color).
Home Alone flight #4:
Motor: Cesaroni Pro54 2833-L-805 White
Altitude: 12,786 feet / 2.4 miles AGL (13,152 feet MSL)
Max velocity: 843 MPH (Mach 1.12 @ 2000 feet MSL)
Motor burn time: 3.0 sec
Peak acceleration: 18.3 G
Descent rate: 74 ft/s (51 mph) under drogue streamer, 22 ft/s (15 mph) under main chute
Flight duration: 217 sec
Result: Landed 1/2 mile NNE of launch pad (downwind); did not see deployment but assumed nominal; successful recovery with use of radio tracker, no damage
Flight data file (viewable with the Featherweight Interface Program)
GPS track of descent (.kml file viewable with Google Earth)
(TODO: images & videos)
AirFest 21, September 4-7 2015, Argonia KS
I made my first trip to Argonia, Kansas this year for AirFest XXI. This is a great event put on every Labor Day by the KloudBusters Tripoli prefecture. I had a good time, but the weather was so hot that I limited my activity to early mornings and retreated to the motel in the afternoons.
I did have two good flights - Home Alone flew on a Loki Research L1040, which, at 3700 Ns, is the highest-impulse motor that will physically fit in the motor mount, and my new Nike Smoke flew on a little CTI G80. The Nike Smoke flew with no electronics, so there is no data section for it here.
Weather conditions at launch time: Partly cloudy, winds south @ 16 mph, 82 F, 58% RH
Home Alone, L1040
Home Alone flight #5:
Motor: Loki Research L1040 Red
Altitude: 14,815 ft AGL (GPS), 13,769 ft AGL (barometric)
Max velocity: 929 mph (1363 fps)
Motor burn time: 3.37 sec
Peak acceleration: 18.7 G
Descent rate: 53 mph (77 fps) under drogue streamer, 17 mph (25 fps) under main parachute
Flight duration: 228 sec
Result: Deployments nominal except that the backup charge for the main parachute did not fire. Landed in an area of tall weeds just south of the parking area. Easy recovery.
Flight data file (viewable with the Featherweight Interface Program)
(TODO: images & videos)
SLRA Fall Launch, October 17 2015, Elsberry MO
Due to an unexpected combination of events (dry weather and an early harvest), our club found itself with an opportunity to use the Elsberry launch field in mid-October. I was excited to fly Home Alone at this launch, since I had not had a chance to show it off to the local club - it had flown in Wisconsin, Illinois and Kansas, but never in Missouri. I had the CTI L990 Blue Streak motor that I had bought with my Wildman Rocketry coupon at AirFest, which would be good for my first “window” flight at Elsberry.
Home Alone, L990
Unfortunately, my streak of bad luck at Elsberry appeared to continue. Home Alone's main parachute failed to deploy, and it landed in the creek, and it hit a rock under the surface of the water. Any one of these three by itself would probably not have been catastrophic, but the combination was.
Both radio trackers stopped transmitting when the rocket hit the water, but we were watching and listening to the live telemetry on my mobile phone, provided by the TeleGPS unit. From this, it appeared that the rocket had in fact landed in the creek, and gave the distance to it. Unfortunately, after I got in my car and drove to that area, the TeleGPS software on the phone was no longer showing the landing location - it was showing the rocket as being back on the launch pad. I attempted to find the rocket by searching areas of the creek at approximately the distance I recalled the telemetry calling out at the time the rocket disappeared, which was between 1800 and 1900 meters. After about five hours of searching, I was unable to find it.
After returning home and looking at the map in some more detail, I realized that the 1800-1900 meters to the landing location was being measured from where I was standing, behind the LCO table, and not from the launch pad - and the measurement I was using to guide my search was probably leading me to an area at least a few hundred feet too far south. I planned to go back and look again, but before I could do so, my friend Mike Walsh went to the area I described and found the rocket, almost dead center in the creek and completely submerged. After fishing it out, he found that both main deployment charges had fired, but the nose cone had not separated and the main parachute did not deploy. The only reason for this that I can guess at is that one of the shear pins had broken as I was putting it in; I did not see how this could affect the deployment, but apparently it did.
After picking up the rocket from Mike and getting it home, I had a great deal of difficulty getting the nose cone separated from the forward compartment, even after drilling out the shear pins. I am assuming that this was because mud had seeped in between the body tube and nose cone shoulder and hardened, and that it was not jammed like this at launch time. I put all of the electronics in tupperware containers full of rice to dry out (with the exception of the batteries, which I discarded), and found that everything at least powered on.
The TeleGPS appears to work fine, and retained good location data up to the moment of impact. The BigRedBee transmitter seems to likewise be fine. The Raven altimeter powered on, but the flight data in its memory was corrupt. Having no way to test its sensors, I plan to return it to Featherweight and see if they can check it out. The Mobius camera powered on and contained good video data up until the last point when it rolled over to a new file (which it does when the file size reaches 2GB, approximately every 20 minutes). By a stroke of luck, this happened when the rocket was coasting at about 9000 feet altitude, just a couple of minutes before the crash.
I thought repairing the rocket would be a simple matter of replacing the missing fin (which is why you see “Home Alone will fly again” a couple of times in the video), but after washing the mud away I found a crack about an inch long in the body tube extending from the rear of the slot where the fin broke off (see photo). After talking to a number of club members about this, I agreed that just epoxying over this was not sufficient to make the rocket safely flyable, and doing a tip-to-tip relamination would be more work than just building a new kit. So at this point, Home Alone is officially retired.
Weather conditions at launch time: Clear, winds north-northwest @ 9 mph gusting to 18mph, 51 F, 38% RH
Home Alone flight #6:
Motor: Cesaroni Pro54 2771L990-P Blue Streak
Altitude: 11,782 feet AGL
Max velocity: unknown
Motor burn time: unknown
Peak acceleration: unknown
Descent rate: 73mph under drogue streamer
Result: Good apogee deploy of drogue streamer; main parachute failed to deploy; rocket landed in creek and the tail end struck a rock underwater at approximately 73 mph. Both radio trackers failed upon contact with water. Rocket was not found until the afternoon of the following day and spent more than 24 hours submerged. One fin broke off and was lost, and there is a crack approximately an inch long in the body tube extending horizontally from the aft end of the slot where the fin broke out. Radios appear to function OK after being dried out; GPS contained good data up to the time of impact. Altimeter powered on but data was corrupted. Camera powered on and contained good video up to its last file rollover (which occurred during coast).
GPS track of flight (.kml file viewable with Google Earth)
(TODO: images & videos)