L1 Motor Must be Unopened?

+1 on not assembling then disassembling and reassembling. Just saying that sounds crazy.

samb said:

Ok, relax. Cesaroni reloads require zero practice IMO.

Watch the video: [video=youtube;2EFChga49VQ]https://www.youtube.com/watch?v=2EFChga49VQ[/video]

Bring the motor on launch day and assemble it in the presence of your cert team. Light the candle and celebrate your success.

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And yet people screw them up. I didn't see it personally, but a buddy of mine who often flies Cessaroni told me someone screwed up a Cessaroni motor at one of our launches. Its been a while, so I don't remember what they did, but I'm thinking they took something out that should have stayed in. Maybe the outer sleeve? Made a mess of the case as I recall.

mccordmw said:

All I need to do is take the paper off the top to remove the black powder since I'm doing electronically controlled dual deploy.

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On my DD flights, I always leave the motor ejection in as an emergency backup in case there's a complete electronic failure. Usually I leave the delay "long" so it doesn't go off at the same time as the electronics. The only time I take the powder out is if the delay on the motor isn't long enough for the rocket to reach full apogee.

djs said:

On my DD flights, I always leave the motor ejection in as an emergency backup in case there's a complete electronic failure. Usually I leave the delay "long" so it doesn't go off at the same time as the electronics. The only time I take the powder out is if the delay on the motor isn't long enough for the rocket to reach full apogee.

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My rocket sims to apogee at 11 seconds. The default time on the I242 is 13 seconds. That's not a bad idea. I have 2 x Eggtimer Quantums set to deploy the drogue at apogee and apogee +1 second. Main is at 800 ft and backup at 600 ft. Somethings​ going to pop with all that. :-D

Funny, I don't recall having to show anybody how I assembled the CTI motors I used for either L1 or L2. Maybe once you tell them you're using CTI they figure you can't screw it up... although you CAN cross-thread the 38mm plastic screw-in nozzle closures.

cerving said:

Funny, I don't recall having to show anybody how I assembled the CTI motors I used for either L1 or L2. Maybe once you tell them you're using CTI they figure you can't screw it up... although you CAN cross-thread the 38mm plastic screw-in nozzle closures.

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It is definitely in the requirements, but yeah, ultimately if the person signing your paperwork doesn't care, then, well....

Zeus-cat said:

And yet people screw them up. I didn't see it personally, but a buddy of mine who often flies Cessaroni told me someone screwed up a Cessaroni motor at one of our launches. Its been a while, so I don't remember what they did, but I'm thinking they took something out that should have stayed in. Maybe the outer sleeve? Made a mess of the case as I recall.

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The CTI 38mm seems especially susceptible to failures, even with the well intentioned. I believe both failure modes are due to the thrust ring being on the reload instead of a metal case component. Over-torqueing the load into the case strips threads which leads to all sorts of strange things, and then there are numerous stories (and a few videos) where people have put the reload sans METAL CASE into their rocket and pushed the launch button! RSO fail?

mccordmw said:

My rocket sims to apogee at 11 seconds. The default time on the I242 is 13 seconds. That's not a bad idea. I have 2 x Eggtimer Quantums set to deploy the drogue at apogee and apogee +1 second. Main is at 800 ft and backup at 600 ft. Somethings​ going to pop with all that. :-D

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You would be surprised. I've seen about a half dozen dual redundant systems fail so far this summer, either apogee charges (drogue) or main charges, and twice I've seen a dual redundant system fail both charges. Motor deploy as a tertiary back up would have saved a bad day.

If available, and the delay is long enough, I try to size the delay to expected apogee +2 seconds. That way if my primary doesn't go at apogee, my secondary will go at apogee +1. If that fails, the motor should go at apogee +2ish. Not ideal, but way better than ballistic to the main altitude and a shredded main.....or worse.

Banzai88 said:

You would be surprised. I've seen about a half dozen dual redundant systems fail so far this summer, either apogee charges (drogue) or main charges, and twice I've seen a dual redundant system fail both charges. Motor deploy as a tertiary back up would have saved a bad day.

If available, and the delay is long enough, I try to size the delay to expected apogee +2 seconds. That way if my primary doesn't go at apogee, my secondary will go at apogee +1. If that fails, the motor should go at apogee +2ish. Not ideal, but way better than ballistic to the main altitude and a shredded main.....or worse.

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Ditto. And use two e-matches in series for each charge.

Zeus-cat said:

And yet people screw them up. I didn't see it personally, but a buddy of mine who often flies Cessaroni told me someone screwed up a Cessaroni motor at one of our launches. Its been a while, so I don't remember what they did, but I'm thinking they took something out that should have stayed in. Maybe the outer sleeve? Made a mess of the case as I recall.

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almost all the CTI 38mm failures I've seen were due to the rear closure being plastic. Either the liner jammed and they don't seat it, or they strip the threads. Both lead to boom, or a torch.

Best thing to do is take it off, seat the load, then carefully thread it in.

Hmmmm, I'm glad about the olden days. Assembled the motor at home to keep from getting my fingers greasy with no means to clean up on site. Presented the empty package to the certifier and it was obvious the motor from the package was used
in the rocket flight. Oh, it's nice to be trusted and amongst friends.
The key here was I had to use a head magnifier to read the teeny-tiny type in the AT instructions and took a caliper to the O rings that looked very close to being the same. Simply not practical out in the field. I pre-load as I want to fly on a launchsite
not dink around loading cases. Kurt

Oops. Got home and checked my motor. CTI I242 has a 15 second delay. I'll leave it as-is. Don't want to drill that out. So...

Primary drogue: Apogee (~11s)
Secondary drogue: Apogee + 1s (12s)
Motor charge: Apogee +4s (15s)

Looks good to me.

mccordmw said:

Oops. Got home and checked my motor. CTI I242 has a 15 second delay. I'll leave it as-is.

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I would agree with your logic here. Do you have a chance to test the electronic setup before putting it up on the L1 motor?

djs said:

I would agree with your logic here. Do you have a chance to test the electronic setup before putting it up on the L1 motor?

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Yes.

[video=youtube;eB8vqssPK-w]https://www.youtube.com/watch?v=eB8vqssPK-w[/video]

I love the concept of wirelessly arming.

I would be hesitant just for the risk of losing components....

Zeus-cat said:

And yet people screw them up. I didn't see it personally, but a buddy of mine who often flies Cessaroni told me someone screwed up a Cessaroni motor at one of our launches. Its been a while, so I don't remember what they did, but I'm thinking they took something out that should have stayed in. Maybe the outer sleeve? Made a mess of the case as I recall.

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I have heard of folks NOT putting the reload in the case. This goes back to when the Pro 38s first came on the market too. Sigh.....

pondman said:

I have heard of folks NOT putting the reload in the case. This goes back to when the Pro 38s first came on the market too. Sigh.....

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Saw that at a launch. "5 ... 4 ... 3 ... 2 ... 1 ... launch!" Rocket bursts into flames and melts onto the 1010 rail. Guy later admits he forgot to put the load in the case. Live and learn!

Bat-mite said:

Saw that at a launch. "5 ... 4 ... 3 ... 2 ... 1 ... launch!" Rocket bursts into flames and melts onto the 1010 rail. Guy later admits he forgot to put the load in the case. Live and learn!

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What kind of igniter was used in that situation? I'd think the delay would burn and then pop the chute, not necessarily burn up the rocket? Kurt

I assume the standard CTI e-match, but I don't know. But with no casing to retain the heat, the liner immediately melted. I don't know enough about motor physics to explain it, but that is what happened.

I would assume that the pressure of the motor lighting would push the delay section out, and cause all sorts of burning in all sorts of places. Probably similar to grains burning out in the open, but contained in the rocket. No surprise it melted the rocket down.

They don't say it on the NAR website, but you must also do this.

[video=youtube;y4cafPOBubc]https://www.youtube.com/watch?v=y4cafPOBubc&feature=youtu.be[/video]

yes it does say it, (see post #2) just after it says that the package should be unopened. this for l1 and l2 certs. I didn't look up the requirements for l3.
Rex

rstaff3 said:

I didn't look at the new instructions, when I used them you had to glue them. So, maybe I AM wrong.

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Don't think so. I have flown 4 of the I59's this year from two different distributors and all had the new instructions and all had to be glued. Maybe this is something they are planning on doing in the future.

[video=youtube;JYYYqeniVwE]https://www.youtube.com/watch?v=JYYYqeniVwE[/video]
I did not understand well, grains glued to the tube or not? Good motor , I like it

Banzai88 said:

The CTI 38mm seems especially susceptible to failures, even with the well intentioned. I believe both failure modes are due to the thrust ring being on the reload instead of a metal case component. Over-torqueing the load into the case strips threads which leads to all sorts of strange things, and then there are numerous stories (and a few videos) where people have put the reload sans METAL CASE into their rocket and pushed the launch button! RSO fail?



You would be surprised. I've seen about a half dozen dual redundant systems fail so far this summer, either apogee charges (drogue) or main charges, and twice I've seen a dual redundant system fail both charges. Motor deploy as a tertiary back up would have saved a bad day.

If available, and the delay is long enough, I try to size the delay to expected apogee +2 seconds. That way if my primary doesn't go at apogee, my secondary will go at apogee +1. If that fails, the motor should go at apogee +2ish. Not ideal, but way better than ballistic to the main altitude and a shredded main.....or worse.

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Not to mention one flight at NSL 2016. Single altimeter system with no deployment. Maiden flight and the rocket came in ballistic. The entire front 3/4 were lost. Including the nose cone and full a/v bay. Brand new Stratologger destroyed. Motor backup with max delay would most likely have save enough of the rocket to salvage it.

Of course, had the idiot ever remembered to arm his altimeter to begin with, the flight might have gone better to begin with.

Bat-mite said:

I assume the standard CTI e-match, but I don't know. But with no casing to retain the heat, the liner immediately melted. I don't know enough about motor physics to explain it, but that is what happened.

Click to expand...

djs said:

I would assume that the pressure of the motor lighting would push the delay section out, and cause all sorts of burning in all sorts of places. Probably similar to grains burning out in the open, but contained in the rocket. No surprise it melted the rocket down.

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I imagine this inside a rocket would suck......

Banzai88 said:

If available, and the delay is long enough, I try to size the delay to expected apogee +2 seconds. That way if my primary doesn't go at apogee, my secondary will go at apogee +1. If that fails, the motor should go at apogee +2ish. Not ideal, but way better than ballistic to the main altitude and a shredded main.....or worse.

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Something for me to remember. Thanks

Bat-mite said:

Saw that at a launch. "5 ... 4 ... 3 ... 2 ... 1 ... launch!" Rocket bursts into flames and melts onto the 1010 rail. Guy later admits he forgot to put the load in the case. Live and learn!

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Are you sure the guy forgot to put the grains in the case or was it he forgot the nozzle? A puny delay grain burning in the case I'd expect perhaps some case damage if anything but not a burn through.
Now if the grains were in place with no nozzle, then there would be a high temperature road flare that might burn for over a minute and really cook the aft end of the rocket. Kurt

ksaves2 said:

Are you sure the guy forgot to put the grains in the case or was it he forgot the nozzle? A puny delay grain burning in the case I'd expect perhaps some case damage if anything but not a burn through.
Now if the grains were in place with no nozzle, then there would be a high temperature road flare that might burn for over a minute and really cook the aft end of the rocket. Kurt

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I've heard several stories that went like this "take reload out of package, insert directly into rocket *roadflare* "

DavidMcCann said:

I've heard several stories that went like this "take reload out of package, insert directly into rocket *roadflare* "

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With 38mm CTI reloads, in the last year+ish since becoming a BAR, I've seen 2 of those. Both ended poorly (total loss on the pad).

ksaves2 said:

Are you sure the guy forgot to put the grains in the case or was it he forgot the nozzle? A puny delay grain burning in the case I'd expect perhaps some case damage if anything but not a burn through.
Now if the grains were in place with no nozzle, then there would be a high temperature road flare that might burn for over a minute and really cook the aft end of the rocket. Kurt

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No, you've got the wrong picture. With a CTI load (38mm specifically, maybe smaller sizes also?) you have a liner with the grains already in it, a complete forward closure and a complete aft closure/nozzle that even serves as the thrust ring. But you have to slide this into the case, which is really just a tube with one end curved so the opening is a bit smaller, and screw it on with the threads on the aft closure, or else there's nothing to hold the 3 parts together. So the reload looks ready to fly if you're unaware of the fact that there are pressures involved and something needs to keep it all together (and that the threaded end is actually supposed to screw on to something). I've never made that mistake, but I can see how someone might, while there's no pretending that an Aerotech reload is anywhere near ready-to-fly.

I guess what I don't quite get maybe depends on the propellant or just luck. I witnessed a J250W DMS CATO where the top of the casing blew off while the motor was coming up to pressure, and in that case the motor blew itself out, so no fire, just the top of the motor casing blowing through the top of the rocket (even the delay grain seemed to blow out, it didn't pop though maybe the jolt blew the BP cap off and the BP left the well), and the rest of the motor shooting out the bottom after it broke the Aero Pack retainer off the end of the cardboard MMT (the JB Weld took a layer or two of the cardboard with it). And I'd have hoped this casing held at least some more pressure before it blew than a case-less CTI load would (where there's really nothing but the friction of the O-rings holding the top & bottom closures onto the liner/grains). I guess maybe some propellants will burn even without the pressure, or we just got lucky that our J250W wasn't so interested in making a candle out of our rocket?