Complete failure. No clue what happened.

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Bat-mite

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Hello, all.

I launched two rockets on Saturday, both MAC Performance kits. One was my 3" Scorpion, and the other was my 4" Radial Flyer (which was my L3 cert bird).

The Scorpion had a single RRC2+ with one charge for each event. Because the maximum motor delay was too short for this flight, I emptied it, and had no motor back-up. Three potential points of failure: only one alt, e-match, no back-up.

My Radial Flyer has two alts: StratologgerCF for primary and RRC2+ for back-up. Primary and back-up charges at each end, with the back-ups having 33% more powder than the primary. Full motor back-up (and not a VMAX).

So which one failed to deploy at apogee? No-brainer, right! The Scorpion!

Only, it wasn't. Scorpion flight was perfect.

I am at a complete loss as to what happened with my Radial Flyer. I used the same set-up I always use. Same everything. Two alts, two charges, motor back-up. And I got no apogee separation.

The chute was not over-packed. In fact, the tiny 18" TFR inside a 4" tube is quite manageable. And no different from what I always do.

And yet, no separation. Rocket came in ballistic, main deployed at extremely high speed, main chute ripped off the shroud lines. Rocket core sampled. Both alts, batteries, charge wells, sled -- totally destroyed. So I have nothing to download; and because the AV bay was about a foot down in the ground and the charge wells sheared off, I couldn't see if the charges blew.

But even if both alts failed (and they didn't, because the main deployed), the motor back-up should have done the job.

Again, this is my "always" set-up, with ten flights under my belt on this bird. I know the charge amounts can separate the tubes and break the three #2-56 pins. Drogue was not tightly packed (no different from always).

What the heck happened?
 

Exactimator

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Gah. Sorry about your rocket. What e-matches were you using? A guy in our group ran the same setup (100% redundant DD) with the Firewire M-Tek (blue and white wire) ematches. Three out of four failed to light and his Darkstar came in under drogue. Slammed into the desert floor and broke every part of his rocket just enough to total it.
 

Nick@JET

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Wow John, very sorry to hear that, horrible end to a beautiful rocket.

Since this was your L3 bird, I remember your Alta were different power sources and different switches, and you had motor back up. This leads to a jam or stuck booster / AV bay connection Imho. 3 separation charges doubtfully failed - so they likely went off. Any burn marks on the drogue harness ? If 2 or 3 went off and didn't separate, I would think there would be sufficient burn marks to come to a conclusion.

I test a rocket several times - went up 15% and in cold weather would not separate (-4 deg), the booster would not separate with motor and one Alt, junking the rocket.
 

KenRico

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Gah. Sorry about your rocket. What e-matches were you using? A guy in our group ran the same setup (100% redundant DD) with the Firewire M-Tek (blue and white wire) ematches. Three out of four failed to light and his Darkstar came in under drogue. Slammed into the desert floor and broke every part of his rocket just enough to total it.
Those were the Firewire Initiators (blue and white), had a couple not light at Holtville Havoc with the AeroPack 'Blue By You' payload - think I had pulled them from my old ones by mistake .

Came down only on Motor Deployment drogue and both initiators were unburned and did not light when shorted to 9v directly either . Rocket only had payload tube shear in half so hokey repair under way .

Kenny
 

rstaff3

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Old/weak/dead/disconnected battery? Can't blame the motor eject on a battery, however.
 

Bat-mite

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I used some of Crazy Jim's e-matches.

I hadn't thought about the cold.... It was about 30* F, with winds somewhere in the 15 - 18 mph range. But still, it didn't affect the Scorpion.

As for burn marks, my harness and Nomex blanket have several flights on them, so they are plenty marked up. Also, part of the harness was buried and I had to pull it out of the dirt.
 

rharshberger

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Those were the Firewire Initiators (blue and white), had a couple not light at Holtville Havoc with the AeroPack 'Blue By You' payload - think I had pulled them from my old ones by mistake .

Came down only on Motor Deployment drogue and both initiators were unburned and did not light when shorted to 9v directly either . Rocket only had payload tube shear in half so hokey repair under way .

Kenny
Sounds like some of the old/first run MJG Firewires, they would fail to light even when direct power was applied.
 

Exactimator

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I used some of Crazy Jim's e-matches.
I've had 100% success with those. I'd be surprised if that was the issue.

Whelp, it was a worthy sacrifice to the rocket gods. I'll pour some BP out on the curb to honor it. But not too much, that stuff's getting hard to find.

ETA: My apologies, I missed that you had motor deploy backup too. That would make me think there was something up with your coupler fit. Is it possible moisture got in there and froze, holding the two sections together?
 

MikeyDSlagle

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Maybe something dealing with the motor or forward closure allowing everything to vent out the back of the rocket.
Or a really badly tangled harness held everything together.
Maybe you put steel screws in rather than nylon for your shear pins. Not insulting your intelligence or capabilities, but I supose it could happen could happen.

Sure is a bummer about your rocket, dang.
 

Crazyrocket

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Perhaps it was the cold. Given everything else appearing to work, kind of hard to believe that both the primary, backup, and motor eject not separating the rocket. Did you assembly the rocket at Higgs or did you have the rocket ready to go at the launch (i.e., assembled at home)? Maybe the temperature change was a problem. Sorry to hear about your rocket. It always sucks when it comes in ballistic!
 

timbucktoo

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What motor were you flying on? I saw a few CTI motors this weekend that failed to set off the BP charge & these came in hot (no electronics).
 

Bat-mite

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It was a CTI Pro54 5G K490.

I just can't get my head around two charges plus the motor failing all at the same time in the same rocket. And still getting the main out during the 500 mph ballistic descent.
 

timbucktoo

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Could you tell if the BP in the motor was ignited or is the paper cap still intact?
 

mpitfield

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Man that sucks. I also have had 100% success with the blue and white MJG firewire initiators, although I know that they did have a bad batch at one point, but it was identified and corrected.

Looks like you are going to have to make some assumptions based on the lack of data. I can potentially see an issue with the ambient temp and your batteries, assuming it was either a 9vot alkaline or 1/2S Li-Po. From what I have read both battery chemistries perform best at the higher temps like 80 and lose as much as 50% performance as they get down to the lower temps 30s. Of course this does not explain the motor ejection failure, but there could have been multiple failures.

I see that this rocket has had flights on it, however is the AV bay new or has it been modified since you first set it up?

I think you are going to need to take a harder look at the carnage and see if there are any more clues that will allow you to reduce the suspect list. Maybe take some high res pics and post them here for more eyes to go over, we may see something you miss.
 

Lowpuller

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Really nice rocket! Sweet paint job and decals!

Share any after the fact pics if you got em.
 

Bat-mite

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Sorry, guys. I did not take a camera with me, and I don't have a smart phone. So I got no pics. Much of it is still stuck in the ground. I recovered the nose cone (not usable due to shoulder tear), and the booster from the top of the MMT back. Good news is my BRB900 transmitter was unscathed, and I recovered the motor casing, closure and Aeropack adapter in perfect shape. I also grabbed the visible quicklinks and swivels. One piece of the harness is reusable; the other, no way.

There won't be a rebuild. I can't even salvage the fin can because the shredded booster part extends below the MMT.

If it was the cold affecting the batteries, then why did the Scorpion deploy successfully? I will check the top of the motor tonight, but otherwise this may go down as a great mystery.
 

rstaff3

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Sorry, guys. I did not take a camera with me, and I don't have a smart phone. So I got no pics. Much of it is still stuck in the ground. I recovered the nose cone (not usable due to shoulder tear), and the booster from the top of the MMT back. Good news is my BRB900 transmitter was unscathed, and I recovered the motor casing, closure and Aeropack adapter in perfect shape. I also grabbed the visible quicklinks and swivels. One piece of the harness is reusable; the other, no way.

There won't be a rebuild. I can't even salvage the fin can because the shredded booster part extends below the MMT.

If it was the cold affecting the batteries, then why did the Scorpion deploy successfully? I will check the top of the motor tonight, but otherwise this may go down as a great mystery.
Different batteries, different rockets? With redundant alts, it's unlikely both sets of batteries would have been underpowered in the one that died.
 

Bat-mite

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Different batteries, different rockets? With redundant alts, it's unlikely both sets of batteries would have been underpowered in the one that died.
Yeah, and the fact that I got main ejection from at least one of them kind of shoots that down, too.
 

djs

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I would agree with the "stuck coupler" type theory. I've had a few rockets that will go from "fit together easily" at home to "#$#&*-ing thing- why won't you come apart?!" on the field. Certain rockets seem to behave this way for me, for reasons that I'm too lazy to do any further analysis on.

Presuming you've flown this altimeter combo before, it's the likely solution. Either that or you just somehow angered the rocket gods, and they demanded a sacrifice.
 

kcobbva

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Aw man John. I'm really sorry to hear this!! Really sorry!!! Only sounds like a stuck coupler, as it sounds like you had everything else dialed in. No issues during ground tests? Again really sorry to hear about this!
 

Steve Shannon

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Wow, John, that really stinks. I hope you can recover some of the still buried parts and see if they reveal something. It's much less depressing if you can determine what happened.



Steve Shannon
 

Oberon

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Core samples suck - especially a beautiful cert rocket :(

From the previous discussion it sounds like some sort of coupler hang-up (fouling, temperature, tougher than expected or hung-up shear pins) is most likely, certainly more likely than both altimeters and ematches failing (but working fine for the main) AND the motor eject failing.

One other thought though - is there any chance something blew out, opening an alternate depressurization path? How does the motor casing look? Maybe a crack through the airframe or centering ring? Maybe the coupler was too loose and a more-than-usual amount of gas escaped at ejection?
 

Bat-mite

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Wow, John, that really stinks. I hope you can recover some of the still buried parts and see if they reveal something. It's much less depressing if you can determine what happened.



Steve Shannon
I won't be back to the field prior to LDRS. The area where it came down is not accessible by car, and a half-mile from the driveway. i doubt I'll be walking back out there; or maybe it will already have been plowed over by the time I do.

The pieces that were on the ground were literally shards. When I tried to pull out the coupler/payload assembly, it just broke off. Canvas phenolic, while it has a lot of great features, is not as tough as FG.

If I see tonight that the motor charge didn't fire, I'll go with two bad e-matches and delay grain snuffout prior to BP ignition. That's a crazy amount of failures! If the motor charge did blow, then I have to go with stuck coupler.

The
 

Bat-mite

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Core samples suck - especially a beautiful cert rocket :(

From the previous discussion it sounds like some sort of coupler hang-up (fouling, temperature, tougher than expected or hung-up shear pins) is most likely, certainly more likely than both altimeters and ematches failing (but working fine for the main) AND the motor eject failing.

One other thought though - is there any chance something blew out, opening an alternate depressurization path? How does the motor casing look? Maybe a crack through the airframe or centering ring? Maybe the coupler was too loose and a more-than-usual amount of gas escaped at ejection?
All good guesses. I'll be looking at the motor tonight.
 

Bat-mite

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Aw man John. I'm really sorry to hear this!! Really sorry!!! Only sounds like a stuck coupler, as it sounds like you had everything else dialed in. No issues during ground tests? Again really sorry to hear about this!
how about air tests? This was the tenth successive flight with this configuration.
 

ksaves2

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Aw man John. I'm really sorry to hear this!! Really sorry!!! Only sounds like a stuck coupler, as it sounds like you had everything else dialed in. No issues during ground tests? Again really sorry to hear about this!
That's plausible in the cold but nonetheless please accept my sympathies. Really frustrating when one takes all the precautions and left with an unfortunate result.

Kurt Savegnago
 

NateLowrie

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Sorry I am late to the mourning and analysis. I liked that radial flyer too. I have another theory. Did you use shear pins on the drogue bay? If so, were the holes loose or tight when you inserted the shear pin? If the holes got bigger over time, I would bet that what happened was the pin(s) deformed instead of shearing clean off. That can happen when the holes are not tight and the deformation ends up taking a lot more total energy to break. I would bet at least one of the 3 charges fired and it wasn't enough to break the pins.
 
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