Failure Analysis of Hyperion

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noffie79 said:
I wouldn't either, but couldn't one wrap their main with the CR, and if the main is deployed at apogee for some reason, at least it won't drift so far? And if the main charge is set for 1000', the CR could be set for 800. If anything it could save the owner a really long walk or drive to recover and could keep a potentially lost rocket on the flying field.
Click to expand...

Sure, but I wouldn't trust the puny chute release with a very large parachute used for a large rocket. Would work with smaller rockets. Kurt
 
NateLowrie said:
I PM'd Mark with this. I will be happy to share the program but it needs some work to make the interface more accessible. Right now it's in 2 parts: a C command line app to generate the output and then rather hackish script to generate a graph using the google graphing package. In order for it to really be usable I need to tweak the interface so the average person doesn't have to compile it with make, run it, and feed the output into a python script. I'll see what I can do to get this done in the next week or 2.
Click to expand...
The other way to do this is with a spreadsheet where you just copy in the pressure output from openrocket. I whipped one up based on the phenomenal filter math that was linked to earlier in the thread. I'd be happy to share it with folks (though it's pretty raw) if people want. I can't take credit for any cleverness though, just implemented the math that others worked out.
 
Matt, this is just an opinion here, but at this point I think you have transitioned into far too much second and third guessing yourself. There have been many useful ideas, but really doing more hypothesizing on this will lead to more self doubt. More discussion really only useful if the rocket is found.

Keep your chin up.
 
markkoelsch said:
Matt, this is just an opinion here, but at this point I think you have transitioned into far too much second and third guessing yourself. There have been many useful ideas, but really doing more hypothesizing on this will lead to more self doubt. More discussion really only useful if the rocket is found.

Keep your chin up.
Click to expand...

The purpose of this thread was initially to get ideas, but now, I'm looking more for things to watch out on. I'm looking for things that people have had failures with.

It's also given me good resources, such as the winds at altitude app, and the SAR app. :)
 
ECayemberg said:
Valid point, Kurt. See, I knew I was posting grumpy this morning!:wink:

I am all for learning; that's what makes a place like TRF great! Learn from others' victories and losses. My main point is that we have 5 pages of replies of speculation without any concrete evidence of what actually went wrong (except for tracker related issue...good content there:)). Apologies as my opinion is driven by a career that is largely based on problem solving. IE: something *bad* happens, we reflect, determine root cause(s), assign corrective actions, and so on. It's really hard to generate meaningful corrective actions without understanding what actually went wrong. I parallel this thread to that concept.

Creating change without understanding the problem tends to make chaos. Not saying this is chaos, but there's a whole lot of armchair quarterbacking going on...and it frustrates me when people say you can or can't do x based upon computer stuff...some things you just gotta get out in the real world and live and learn through trial and error. Sims and formulas are great, but by actually doing is where true learning is derived.

Rant off. Don't let me be a downer; I'm looking forward to learning as well. Just don't go changing everything without understanding what needs changing!



Nate, not sure if I understand this statement exactly. If your design calls for dual deploy where the main is deployed at low altitude (1000' agl for example) and the main is dumped at apogee, *I believe* the cert is void. One doesn't need traditional dual deploy for an L3 attempt (or the other levels for that matter), but *I've always been taught* the flight events have to function as intended in order to be a "successful" attempt.
Click to expand...



Tripoli changed the rules. If you pop main at apogee, you get cert. No matter intended flight profile.
 
Sorry late and didn't read all the comments. But unless I am missing something there are multiple failures here.

1) Your stopped receiving a signal from your egg finder.
2) You had a deployment of the main at apogee.
3) You lost sight of the rocket on descent.

Now the question I didn't see in a couple pages is - did both main and rogue deploy at apogee? Or just one of them?

I am also left wracking my brain to recall if heart beats are sent while the egg finder doesn't have a lock. I missed if you had a heartbeat and no location or no heartbeat. Evidently you didn't have a second spotter with eyes on the rocket (or they lost it as well making another failure). I do recall from my L1 that my egg finder lost lock at launch and picket it up several seconds after deployment (single deployment).

I am assuming also that you took your receiver out while looking for the rocket on chance that it might pick up somewhere along the way.

One thing I will leave you with is don't give up hope on it. I lost a rocket on an L1 attempt. Three months later, I got a voicemail (on my birthday no less) from the club president's wife that it had been returned. (And my wife gave me an egg finder that day as well.)
 
jimzcatz said:
Tripoli changed the rules. If you pop main at apogee, you get cert. No matter intended flight profile.
Click to expand...

Except I think if any rocket drifts out of the waiver zone it's "supposed" to be a do not finish. In reality, I'd suspect a little bit over the line and an expedient recovery and presentation would get the gold as long
as nobody tells. Kurt
 
1tree said:
Sorry late and didn't read all the comments. But unless I am missing something there are multiple failures here.

1) Your stopped receiving a signal from your egg finder.
2) You had a deployment of the main at apogee.
3) You lost sight of the rocket on descent.

Now the question I didn't see in a couple pages is - did both main and rogue deploy at apogee? Or just one of them?

I am also left wracking my brain to recall if heart beats are sent while the egg finder doesn't have a lock. I missed if you had a heartbeat and no location or no heartbeat. Evidently you didn't have a second spotter with eyes on the rocket (or they lost it as well making another failure). I do recall from my L1 that my egg finder lost lock at launch and picket it up several seconds after deployment (single deployment).

I am assuming also that you took your receiver out while looking for the rocket on chance that it might pick up somewhere along the way.

One thing I will leave you with is don't give up hope on it. I lost a rocket on an L1 attempt. Three months later, I got a voicemail (on my birthday no less) from the club president's wife that it had been returned. (And my wife gave me an egg finder that day as well.)
Click to expand...

Sure,
Go read message #132: https://www.rocketryforum.com/showt...re-Analysis-of-Hyperion&p=1686707#post1686707 and some of the posts thereafter. Basically wrong battery for the EggFinder and a few failure modes/reasons
were narrowed down for the apogee appearance of the main chute.
I can appreciate your questions as sometimes it's hard to make the connections with long threads unless one followed it from the beginning. The bottom line is there are several things that can be done to minimize the risk of some of the
postulated failure modes although it's not totally certain which one (or if all) were involved. The 1S battery issue with the EggFinder is certain and should have been a 2S battery. Kurt
 
jimzcatz said:
Tripoli changed the rules. If you pop main at apogee, you get cert. No matter intended flight profile.
Click to expand...

I see this change bemoaned, and I don't know enough to have an opinion, but I do have a question- if a main charge were to fail, and the secondary fired and deployed, would the flight pass? I guess the question is, should it be a perfect flight, or should it be successful and safe to pass? Not being a wiseass, honest.
 
jimzcatz said:
Tripoli changed the rules. If you pop main at apogee, you get cert. No matter intended flight profile.
Click to expand...

Your intended profile should be to open the main anytime before the rocket hits the ground and recover safely.
 
DavidMcCann said:
I see this change bemoaned, and I don't know enough to have an opinion, but I do have a question- if a main charge were to fail, and the secondary fired and deployed, would the flight pass? I guess the question is, should it be a perfect flight, or should it be successful and safe to pass? Not being a wiseass, honest.
Click to expand...

I have always believed that at the L3 level, anything less that intended should be a fail. But obviously it is not based on this discussion.

I think the certification process is too easy and should be more of a challenge. L1 and L2 there is no difference just a bigger engine and that does not make any sense to me. I am likely a minority on this discussion, but I would love to see the challenge raised, at least on the L2 with there being electronic deployment requirement. On the L3 technically it is fine but as I said the standards should be at the highest level.

For my L1 I used an altimeter with a LiPo, a magnetic switch, full dual deploy with a piston cable cutter and a Com-Spec AT-2B tracker. My electronics failed on my first attempt but my engine back-up, kicked a large 18" drogue out, and my rocket safely came down somewhere around 25'/s from 4K and landed without any issue 100' from the pad...zero damage. But my observer would not sign off as he said it failed because it did not recover as intended. I was just as happy to run a failure analysis and try again. Personally I get way more out of the failures than the successes and I would probably not even be into the hobby as much if I just succeeded.

Look how much Matt is learning from this experience, it is absolutely invaluable, especially at such a young age.
 
mpitfield said:
I have always believed that at the L3 level, anything less that intended should be a fail. But obviously it is not based on this discussion.

I think the certification process is too easy and should be more of a challenge. L1 and L2 there is no difference just a bigger engine and that does not make any sense to me. I am likely a minority on this discussion, but I would love to see the challenge raised, at least on the L2 with there being electronic deployment requirement. On the L3 technically it is fine but as I said the standards should be at the highest level.
Click to expand...

the trouble I see with that is, these are compententcy tests, not awards. I'd like to see testing done on flight style not simply motor size, but that's not how it is.

The test is send it up, bring it back safe. If your flight is designed in a manner that it is able to fly safely without perfection, why require perfection?
 
mpitfield said:
I have always believed that at the L3 level, anything less that intended should be a fail. But obviously it is not based on this discussion.

I think the certification process is too easy and should be more of a challenge. L1 and L2 there is no difference just a bigger engine and that does not make any sense to me. I am likely a minority on this discussion, but I would love to see the challenge raised, at least on the L2 with there being electronic deployment requirement. On the L3 technically it is fine but as I said the standards should be at the highest level.
Click to expand...

I agree completely.

L2 adds a written exam, but it is treated as a minor memorization task. Just look at all the forum members who proudly put their L2 credentials in their signature but don't really understand CP, CG, nor how to perform stability tests/simulations. How did they pass the exam? I'd like to see more test emphasis on knowledge of rocket flight and less emphasis on memorizing how many N-s are in an I motor, J motor, and a K motor. (The latter of which are easily found in the first hit of a Google search).

Certification should be like TARC. Define a flight plan/profile that fits within the launch day parameters, and then successfully demonstrate it. Doesn't matter how many altimeters are used ....
 
In my opinion the L3 certification flight proves nothing. Especially with the level of the fiberglass kits and electronics available today. Anyone who has zero knowledge and best practices could build and fly an L3 rocket and still have a decent probability of a single successful flight.

However the certification process does have value. Requiring the flyer to do a progression of flights under the guidance of a mentor culminating with a detailed build and flight plan with documentation and close supervision with the TAP or L3CC is where the value is. This is the part of the process that should be scrutinized and adhered to. The actual flight is just noise.
 
jderimig said:
In my opinion the L3 certification flight proves nothing. Especially with the level of the fiberglass kits and electronics available today. Anyone who has zero knowledge and best practices could build and fly an L3 rocket and still have a decent probability of a single successful flight.

However the certification process does have value. Requiring the flyer to do a progression of flights under the guidance of a mentor culminating with a detailed build and flight plan with documentation and close supervision with the TAP or L3CC is where the value is. This is the part of the process that should be scrutinized and adhered to. The actual flight is just noise.
Click to expand...

At some point the rubber has to meet the road and all the great theories, processes, mentorship, and documentation need to be confirmed with an actual flight. The L3 preparation process was probably great in this case. The actual flight was not.
 
I think that any flight that is successfully recovered within the waiver area that can fly again is a success, even if anything went amiss. I'm going back to Dave's post about the back-up charge deploying the chute. Not perfect, but it proves you were smart enough to have sufficient back-up.

Take a baseball game. A perfect game is when a single pitcher faces 27 batters and gets them all out. These are extremely rare. If your starting pitcher can only go six innings, but your relievers come in and win the game, then you still won the game. You proved that you don't need a perfect game from your starter in order to get a win.

I can see both sides, but in the end what seems to matter most is that you safely and legally launched and recovered your rocket.
 
DavidMcCann said:
I see this change bemoaned, and I don't know enough to have an opinion, but I do have a question- if a main charge were to fail, and the secondary fired and deployed, would the flight pass? I guess the question is, should it be a perfect flight, or should it be successful and safe to pass? Not being a wiseass, honest.
Click to expand...

It passes because that's the reason to have a second deployment device. Both NAR and TRA want one to have success on an L3 attempt. If the secondary
device does the work on an otherwise nominal flight, it passes. There are a few pimp-a***s who even bemoan this.

My view on the main at apogee issue is I agree with the TRA BOD mainly because it still has to land within the radius limits of the waiver. If not, it doesn't conform to the flight environment. If a DD rocket performs but drifts outside of the radius, it too is considered an unsuccessful attempt. Although I can see
the local certifying people might turn a blind eye if the infraction wasn't "that much", the off site landing place was safe and the rocket was returned quickly for
inspection. It behooves one to know an off site landing is a "did not finish" certification attempt and don't have a leg to stand on to protest if ruled that
way locally. Matt's flight I believe landed too far but I'm not aware of the radius in place at LDRS. Kurt
 
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Bat-mite said:
I think that any flight that is successfully recovered within the waiver area that can fly again is a success, even if anything went amiss.
Click to expand...

I guess I don't agree. In robust optimization, there is noise and there are control factors. Flight noise happens due to real world environmental conditions, and you try to design against that and reduce variation around the mean. Major control factors (things you can control, like parachute deployment sequence) should not go amiss for a certification. If the control factors are not dialed in to a good mean value, then next time that rocket may land with a thud next to your car on the flight line. Not cool when that happens.
 
ksaves2 said:
It passes because that's the reason to have a second deployment device. Both NAR and TRA want one to have success on an L3 attempt. If the secondary
device does the work on an otherwise nominal flight, it passes. There are a few pimp-a***s who even bemoan this.

My view on the main at apogee issue is I agree with the TRA BOD mainly because it still has to land within the radius limits of the waiver. If not, it doesn't conform to the flight environment. If a DD rocket performs but drifts outside of the radius, it too is considered an unsuccessful attempt. Although I can see
the local certifying people might turn a blind eye if the infraction wasn't "that much", the off site landing place was safe and the rocket was returned quickly for
inspection. It behooves one to know an off site landing is a "did not finish" certification attempt and don't have a leg to stand on to protest if ruled that
way locally. Matt's flight I believe landed too far but I'm not aware of the radius in place at LDRS. Kurt
Click to expand...

I create a flight packet for all my HPR flights. The key points for a successful flight for me are that the milestones are passed:


  • goes up in a controlled fashion
  • at apogee, the drogue (or drogueless cord) comes out
  • at a set altitude, the main comes out
  • it lands slow enough to not be damaged
  • it lands in the boundaries

I have a primary, a backup, and sometimes a 3rd backup motor eject. I don't care which one fires. They're all in my plan. If those milestones pass, I'm happy.
 
Buckeye said:
I guess I don't agree. In robust optimization, there is noise and there are control factors. Flight noise happens due to real world environmental conditions, and you try to design against that and reduce variation around the mean. Major control factors (things you can control, like parachute deployment sequence) should not go amiss for a certification. If the control factors are not dialed in to a good mean value, then next time that rocket may land with a thud next to your car on the flight line. Not cool when that happens.
Click to expand...

That seems fair and reasonable.
 
ECayemberg said:
Two 7.5" rockets at ldrs count? Biggest we tried yet...windy as heck but worked as intended with 70 and 78" chutes. Ymmv.

Eric
Click to expand...

Adding to this, the U of Illinois NASA Student Launch team that I mentor just had a very successful flight in Huntsville using two JL Chute Releases in series around a 96" Iris Ultra parachute in a 6" rocket. Did it work perfectly the first time? No, the chute worked its way out a bit early, but with more attention and practice to the packing, it went well in competition. That said, this adds additional points of failure, too, so it's not necessarily the right solution.

As for the "intended" vs "successful" cert flights as it relates to early main deployment, I think this goes beyond rules, and into the spirit of the certification. Flame suit on, but don't you want to "get it right?" I'm with "intended." Plan your flight, fly your plan. My opinion, only, of course.

Mark
 
mccordmw said:
I create a flight packet for all my HPR flights. The key points for a successful flight for me are that the milestones are passed:


  • goes up in a controlled fashion
  • at apogee, the drogue (or drogueless cord) comes out
  • at a set altitude, the main comes out
  • it lands slow enough to not be damaged
  • it lands in the boundaries

I have a primary, a backup, and sometimes a 3rd backup motor eject. I don't care which one fires. They're all in my plan. If those milestones pass, I'm happy.
Click to expand...

Yep, this makes perfect sense. Number of batteries and shunts are not milestones. I add a couple more criteria to my successful HPR flights:

  • Altitude achieved is within 20% of what I expected.
  • First deployment occurs within ~2 sec of apogee. Not too early and not too late because of bad altimeter programming or poor motor backup delay.
 
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I think if you punish people (with a failed cert) for having success based on redundancy, you eliminate some of the incentive to add complexity to a cert flight. Why do dual-deploy at all, if that's just one more thing that can go wrong and fail my cert? But I think that's a bad thing, because you kind of want people to demonstrate as many of the skills the certification will allow them to use with less supervision in the future.

I think "outside the waiver = fail" is a good standard. But "main at apogee = fail" isn't, because I think it's a relatively common failure even for well-seasoned fliers (sometimes, poop happens). Leaving the field is dangerous. An early main that otherwise lands safely and in-bounds is an inconvenience. Part of designing for failure tolerance is trying to fail safe - a flight plan that puts you outside the waiver with a main at apogee is a bad flight plan.

Either way, I'd think the penalty for a safe-but-off-nominal flight shouldn't be "start over from scratch". E.g. for level 3, if the rocket is still flyable, they shouldn't have to build a new bird from scratch, they've already demonstrated competence in the build part. They should be able to just submit the same rocket (with TAP approved repairs/updates as needed) for a reflight.
 
Oberon said:
... if you punish people (with a failed cert) for having success based on redundancy...
Click to expand...

Wait, what? Does this really happen? The L3 requires "redundancy", yet you can be penalized for using it?

Hmm, I guess I won't be attempting an L3 anytime soon. There are too many process rules for my liking. I am perfectly happy with L2, as I have barely scratched K motors and haven't even whiffed L motors.

Anyway, good luck finding your rig, Matt. This has been an interesting thread all the way around.
 

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