So, maybe I'll try a three-stager
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Sorry to here about that. Still quite a speed accomplishment. Kate was pretty calm and collected to the end it sounds like. Kurt
JimJarvis50
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I actually have quite a bit of data and video on this flight. You won't believe what actually happened.
Jim
blackbrandt
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Oh, you know we love data. 
Zebedee
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Premature deployment after sustainer motor burnout?
CoyoteNumber2
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JimJarvis50
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Yes, I suppose it is possible that Aliens snapped this pic of the booster fin can.
Jim
ChrisAttebery
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Killing me!
Jim,
that is a highly interesting camera angle. Where was that camera organized positioned and why did it end up side by side with the fin can?
Random Flying Object
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Well, that's interesting!
After a bit of thought, unless Jim manipulated the date/time in the bottom corner it appears that the section of the rocket that housed the camera is pointing in the right direction. I am pretty sure he has a camera in the third stage and that is definitely the booster fincan in the pic.
That being the case I agree with "premature deployment" but it appears to be before booster burnout.
UhClem
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What if the booster wasn't as draggy as expected (or the upper stage had too much) and passed the upper stage after separation but before upper stage ignition?
JimJarvis50
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Well, I don't mean to get everyone thinking too hard about this particular pic. It's just one aspect of maybe a half dozen interesting aspects about this flight. Here's another pic with another clue, but give me a while to work out the data so things make sense.
Jim
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IIRC...There was a pretty good hiccup in the booster motor burn. I wonder if that was mistaken for motor burn out?
Tony
Tony
That pic is bizarre...awesome, but bizarre.
JimJarvis50
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Very good. If you listen to the video very closely, Kate calls booster burnout at the chuff.
https://photos.google.com/share/AF1...?key=NEtfTnNkb2tQV0hQc190SXJSVFFVWlA3QldDbUt3
The Raven controlling the separation charge thought that too.
Jim
Well at least you likely set another record with that shot, closest exhaust pic over 2 miles AGL.
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My son AJ and I did a 2-stage about 16 years ago. The 54mm booster motor had a hiccup and the G-wiz took that as motor burn out and lit the sustainer. We have a ground photo of both parts under power. Your 2 photos made me think of our flight.
Tony
Tony
Okay I got this, booster burned out for awhile due to hiccup, then sustainer lit due to motor burn out detection, then booster re-burned and caught up with sustainer, which explains the awesome close up photo.
I am assuming the booster smacked into the sustainer?
Awesome flight. Sorry to hear it did not go as planned.
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I am assuming the booster smacked into the sustainer?
Awesome flight. Sorry to hear it did not go as planned
.Sent from my iPhone using Tapatalk
JimJarvis50
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OK, here's the flight report.
It's hard to find much good about this flight relative to our expectations. However, there were a few good things. We managed to get this project to Balls, which isn't all that easy, and to get it loaded safely on the pad. We got the rocket launched and also managed to distribute a valuable payload. Although the sustainer air frame was a total loss, the booster was recovered undamaged along with most of the on-board electronics, and the stabilization spool may be reusable. So what happened?
The first thing that happened is that the motor burn wasn't quite what we expected. You can see grain casings being spit in the ground video at around 5 seconds, and shortly after that, there was a drop in thrust that was interpreted as a burnout by all three of the flight computers (Raven, EasyMega and Kate). Unfortunately, about 15% of the motor energy was yet to be expended and the motor actually burned for a total of about 15 seconds. We're still looking at the motor data.
At about 7 seconds (2 seconds after "burnout"), the Raven fires the separation charge, which separates the sustainer and stabilization spool from the booster (Pic 1). You can see the canards from the stabilization spool. About a half second after that, the booster - still under power - crashes into the bottom of the stabilization spool. This causes the bulkhead on the bottom of the stabilization spool to come loose (Pic 2), which releases the stabilization spool chute. The chute shreds, but still pulls the stabilization spool away from the sustainer and the stabilization spool crashes. I believe the stabilization spool was providing reasonable roll control prior to being "dismissed", but it never got to the point in the flight where yaw/pitch control was active. The sustainer, meanwhile, is bumped ahead of the booster (Pic 3), and there are no longer any canards present.
With the booster still producing thrust, the booster tries to pass the sustainer again (Pic 4 and Pic 5), and the pieces collide for a second time. It is not possible to tell if this collision damaged the sustainer, but the roll rates and tilt angles of both pieces changed as a result of this collision. The view of the booster passing the sustainer from the sustainer vantage point is Pic 6).
Once the booster actually burns out, the sustainer passes by the booster (Pic 7) and eventually lights (Pic 8). However, due to a combination of factors, the sustainer was only at 17K when the motor lit versus the planned 27K. This would have increased the aerodynamic heating on the sustainer and could have contributed to the shred, which occurred at Mach 3.7 according to Kate.
Regarding the shred, I don't know exactly why that happened. The first indication of a problem was at time 27.5, right at motor burnout (Pic 9). This problem was very audible on the sustainer video, which means it was very loud. Maybe there was an air frame failure, although I suspect the most likely cause to be delamination of the fins due to elevated heating. Unfortunately, none of the fins were found. In any case, it took several additional seconds before the actual shred occurred. Perhaps someone can recognize the signature of the failure from the acceleration data.
Jim
It's hard to find much good about this flight relative to our expectations. However, there were a few good things. We managed to get this project to Balls, which isn't all that easy, and to get it loaded safely on the pad. We got the rocket launched and also managed to distribute a valuable payload. Although the sustainer air frame was a total loss, the booster was recovered undamaged along with most of the on-board electronics, and the stabilization spool may be reusable. So what happened?
The first thing that happened is that the motor burn wasn't quite what we expected. You can see grain casings being spit in the ground video at around 5 seconds, and shortly after that, there was a drop in thrust that was interpreted as a burnout by all three of the flight computers (Raven, EasyMega and Kate). Unfortunately, about 15% of the motor energy was yet to be expended and the motor actually burned for a total of about 15 seconds. We're still looking at the motor data.
At about 7 seconds (2 seconds after "burnout"), the Raven fires the separation charge, which separates the sustainer and stabilization spool from the booster (Pic 1). You can see the canards from the stabilization spool. About a half second after that, the booster - still under power - crashes into the bottom of the stabilization spool. This causes the bulkhead on the bottom of the stabilization spool to come loose (Pic 2), which releases the stabilization spool chute. The chute shreds, but still pulls the stabilization spool away from the sustainer and the stabilization spool crashes. I believe the stabilization spool was providing reasonable roll control prior to being "dismissed", but it never got to the point in the flight where yaw/pitch control was active. The sustainer, meanwhile, is bumped ahead of the booster (Pic 3), and there are no longer any canards present.
With the booster still producing thrust, the booster tries to pass the sustainer again (Pic 4 and Pic 5), and the pieces collide for a second time. It is not possible to tell if this collision damaged the sustainer, but the roll rates and tilt angles of both pieces changed as a result of this collision. The view of the booster passing the sustainer from the sustainer vantage point is Pic 6).
Once the booster actually burns out, the sustainer passes by the booster (Pic 7) and eventually lights (Pic 8). However, due to a combination of factors, the sustainer was only at 17K when the motor lit versus the planned 27K. This would have increased the aerodynamic heating on the sustainer and could have contributed to the shred, which occurred at Mach 3.7 according to Kate.
Regarding the shred, I don't know exactly why that happened. The first indication of a problem was at time 27.5, right at motor burnout (Pic 9). This problem was very audible on the sustainer video, which means it was very loud. Maybe there was an air frame failure, although I suspect the most likely cause to be delamination of the fins due to elevated heating. Unfortunately, none of the fins were found. In any case, it took several additional seconds before the actual shred occurred. Perhaps someone can recognize the signature of the failure from the acceleration data.
Jim
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JimJarvis50
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And here is the video of the flight as described below.
https://youtu.be/87BVKLiDqXI
As always, a project like this gets nowhere without good pad slaves. This years' group included Dan DeHart, Chris Harris, Geoff Huber, Steve Heller, Peter and Alexis Thorny, and my wife Gloria. Oh, and Stu helped too, although I don't see him there holding the ladder??? Thanks to everyone that helped out. No way we would otherwise have gotten this launched.
Jim
https://youtu.be/87BVKLiDqXI
As always, a project like this gets nowhere without good pad slaves. This years' group included Dan DeHart, Chris Harris, Geoff Huber, Steve Heller, Peter and Alexis Thorny, and my wife Gloria. Oh, and Stu helped too, although I don't see him there holding the ladder??? Thanks to everyone that helped out. No way we would otherwise have gotten this launched.
Jim
Jim that is an amazing flight.
Were the canards located below the sustainer's fin can area? If so the most likely cause of the shred could of been due to rear shock waves from the mach speeds.
The canards probably had a hard time trying to stabilize before the shock waves laid waste to them.
Just a theory, but it could be something to consider.
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Were the canards located below the sustainer's fin can area? If so the most likely cause of the shred could of been due to rear shock waves from the mach speeds.
The canards probably had a hard time trying to stabilize before the shock waves laid waste to them.
Just a theory, but it could be something to consider.
Sent from my iPhone using Tapatalk
Perhaps a sustainer fin got damaged when the booster collided with the sustainer. The damaged fin may have then subsequently failed when the speed reached Mach 3.7.
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Kip_Daugirdas
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Damn Jim that's absolutely insane! Good job on the analysis and keeping the suspense high! Can't wait to see what's flying next year.
P.S. I guess you can blame this on Stu...😉
P.S. I guess you can blame this on Stu...😉
markkoelsch
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Jim, that is a rough one. I think you explanation of events seems reasonable. Very possible a fin or the airframe were damaged during the collision.
That had to be a pretty substantial chuff/unstart of the booster motor for all three avionics systems to measure it as a burnout.
That had to be a pretty substantial chuff/unstart of the booster motor for all three avionics systems to measure it as a burnout.
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