This past weekend I got some big lessons handed to me. This rocket had been flying well on I and J motors, but had not gone out of sight, recovery typically involved walking between 50' and maybe 500' at the furthest. I wanted to see the tracking systems at work. I had adapted this rocket to accept a 54mm 6GXL motor by using a 'donut' av bay. I had done some ground testing of deployment charges in this configuration, and the charge requirements were definitely different. I did not write down the charge amounts for when the 6GXL motor was in. At the launch, I flew this on an L935. It was a great 'up' flight, straight as an arrow. But, with no event until a distant and powerful boom was heard.
I used the Garmin 320 handheld to walk to the last known position, which I am not sure of what altitude that would have been at, or when still going up, or on the way down. OR sims showed this flight barely over mach 1, to an altitude around 8700'. The last known position was at the edge of 'sections' of 4' tall corn fields and rolling hills, and there was nothing there. I returned to the car to get the Marshall RF tracker and started walking. An hour or so later, just as I was about to give up and surrender to the reality that the RF tracker was likely destroyed, I heard a beep, and located the rocket. There was no nosecone at the bottom of the hole, no evidence of anything above the upper bulkhead. After returning with a shovel, I found the nose cone, unscathed and suspended in a sage bush, no digging necessary. The boom was almost certainly the main chute exploding. There was obviously no separation at apogee. The charges were too small, and I now suspect that I forgot the correct charge sizes, as I did not write it down when testing at home, and the backup charge was too small, regardless. The backup charge should have been the saving grace. The electronics worked fine, both drogue charges fired. The 1/2 tubular nylon main harness was 'blown up' about 6" above where it met the kevlar bridal, frayed and not cut, and the 'leg' off of the main harness that led to the deployment bag was broken off at the knot which joined it to the main recovery harness. I did not see any evidence of the main chute.
2 of the fins were laying on the ground next to the rocket, unscathed, the third was partially buried with the rocket, and also unscathed. These will fly again. The RF tracker was packed in to the mess like a trash compactor, but looks exactly as when it was loaded in. The chute and shock cord provided padding for it, and from what I understand, the internals are epoxy potted. I was unable to get to it until after I cut the rocket apart at home, and the transmitter was still sending, the next day. Marshall makes a great tracking system! Gold... I have great appreciation for this tool, now. The nose cone is undamaged, and will fly again. The LiPo batteries combusted inside the av bay, and the switches are the only thing inside there that survived. These are the Fingertech switches, and they are fine, but with a smoky residue on them. These seem like a no-brainer after seeing how well they survived. Everything else was a complete loss. Many of the surface mount components were gone from the boards.
I maybe should have been more upset about the whole thing, but I was not. I knew the risks, and my number came up. There were some intensely valuable lessons that came with this, and a feeling that they would have not come any other way. In all the reading I have done,and people I have spoken with, over and over I hear people saying that '**** happens', and to expect it, that it happens to everyone. In deep reflection on this, I think that yes, things do happen, but always for a reason, and rooted in the decisions leading up to, and level of understanding of all aspects of causality in regards to the particular situation. I made a gross error, or more than one. Hindsight is 20/20 they say. I wish I knew then, what I now know.
Another really important lesson learned... Build a rocket that the motor actually fits in. Seems obvious, right? It was a poor decision to adapt the rocket design to fly what was arguably too long of a motor for that rocket, and that decision left the concept of simplicity behind. Yes, it can be done, but that does not mean that it should be done.
I am cleaning the remaining epoxy from the fin tabs, and rebuilding them into a similar rocket that is built around a 75mm 3G motor, like this one should have been in the first place.
When I finally heard the first beep from the tracker, it was a great feeling. I knew the rocket was likely a complete loss, there was no way for it to be otherwise. The descent was not quite as fast as the ascent, but the boom came from about a half mile away, and it was powerful. I had 'tested' the Marshall tracker previously, and was kind of unimpressed, possibly because I knew where the beacon was, in testing. After walking through the hills of corn as far as I did, and finally locating the landing site, quickly, once the signal was heard, I am fully impressed.
The Garmin dog collar system is awesome.
I got to see the tracking systems work.
I used the Garmin 320 handheld to walk to the last known position, which I am not sure of what altitude that would have been at, or when still going up, or on the way down. OR sims showed this flight barely over mach 1, to an altitude around 8700'. The last known position was at the edge of 'sections' of 4' tall corn fields and rolling hills, and there was nothing there. I returned to the car to get the Marshall RF tracker and started walking. An hour or so later, just as I was about to give up and surrender to the reality that the RF tracker was likely destroyed, I heard a beep, and located the rocket. There was no nosecone at the bottom of the hole, no evidence of anything above the upper bulkhead. After returning with a shovel, I found the nose cone, unscathed and suspended in a sage bush, no digging necessary. The boom was almost certainly the main chute exploding. There was obviously no separation at apogee. The charges were too small, and I now suspect that I forgot the correct charge sizes, as I did not write it down when testing at home, and the backup charge was too small, regardless. The backup charge should have been the saving grace. The electronics worked fine, both drogue charges fired. The 1/2 tubular nylon main harness was 'blown up' about 6" above where it met the kevlar bridal, frayed and not cut, and the 'leg' off of the main harness that led to the deployment bag was broken off at the knot which joined it to the main recovery harness. I did not see any evidence of the main chute.
2 of the fins were laying on the ground next to the rocket, unscathed, the third was partially buried with the rocket, and also unscathed. These will fly again. The RF tracker was packed in to the mess like a trash compactor, but looks exactly as when it was loaded in. The chute and shock cord provided padding for it, and from what I understand, the internals are epoxy potted. I was unable to get to it until after I cut the rocket apart at home, and the transmitter was still sending, the next day. Marshall makes a great tracking system! Gold... I have great appreciation for this tool, now. The nose cone is undamaged, and will fly again. The LiPo batteries combusted inside the av bay, and the switches are the only thing inside there that survived. These are the Fingertech switches, and they are fine, but with a smoky residue on them. These seem like a no-brainer after seeing how well they survived. Everything else was a complete loss. Many of the surface mount components were gone from the boards.
I maybe should have been more upset about the whole thing, but I was not. I knew the risks, and my number came up. There were some intensely valuable lessons that came with this, and a feeling that they would have not come any other way. In all the reading I have done,and people I have spoken with, over and over I hear people saying that '**** happens', and to expect it, that it happens to everyone. In deep reflection on this, I think that yes, things do happen, but always for a reason, and rooted in the decisions leading up to, and level of understanding of all aspects of causality in regards to the particular situation. I made a gross error, or more than one. Hindsight is 20/20 they say. I wish I knew then, what I now know.
Another really important lesson learned... Build a rocket that the motor actually fits in. Seems obvious, right? It was a poor decision to adapt the rocket design to fly what was arguably too long of a motor for that rocket, and that decision left the concept of simplicity behind. Yes, it can be done, but that does not mean that it should be done.
I am cleaning the remaining epoxy from the fin tabs, and rebuilding them into a similar rocket that is built around a 75mm 3G motor, like this one should have been in the first place.
When I finally heard the first beep from the tracker, it was a great feeling. I knew the rocket was likely a complete loss, there was no way for it to be otherwise. The descent was not quite as fast as the ascent, but the boom came from about a half mile away, and it was powerful. I had 'tested' the Marshall tracker previously, and was kind of unimpressed, possibly because I knew where the beacon was, in testing. After walking through the hills of corn as far as I did, and finally locating the landing site, quickly, once the signal was heard, I am fully impressed.
The Garmin dog collar system is awesome.
I got to see the tracking systems work.
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