lakeroadster
When in doubt... build hell-for-stout!
I revised post #58 to include my query to NAR. And in regard to TRA, We already have @Steve Shannon's input in post #34
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Rocket motor delays explained?
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I revised post #58 to include my query to NAR. And in regard to TRA, We already have @Steve Shannon's input in post #34
Well intentioned attempts to “get clarity” are exactly the acts that sometimes result in undesired attention from regulators and officials within organizations. You’ve forced the NAR to issue an official opinion regarding something that was only being done by more experienced flyers, and which probably never affected you.
You made your point but by throwing others under the bus.
You made your point but by throwing others under the bus.
One of the reasons I’m a member of Tripoli is that I can make minor modifications to commercial motors and fly them under research rules. For example, on Saturday I put a Pyrodex pellet in the front end of an I300 motor to increase the likelihood that the sustainer in a two stage rocket would light. It did (thanks, CJ, for the advice). I don’t know whether my membership in NAR would allow me to do that, but I know my membership in Tripoli does. I’d feel the same about modifying a delay in an Aerotech motor. Although I used a reloadable for the booster, I reduced the delay from 14 seconds to 8, using Aerotech’s handy delay modifying tool. Perhaps I need to go back and re-read the thread, but I’m not seeing the problem, unless someone is trying to modify the delay in one of the smaller motors in a plastic case with a pre-loaded ejection charge. That wouldn’t be wise, in my opinion, even if the rules allowed it.
lakeroadster
When in doubt... build hell-for-stout!
You're a NAR member, as such you have committed to following their rules.
If you feel I'm "throwing you under the bus" by asking for clarity as to the scope of those rules and directing the NAR to this thread so they can undertand the topic, that's pretty telling, about you.
@Jmhepworth The topic at hand is modifying delays on single use composite motors.
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I have no problem following NAR rules at NAR launches and Tripoli rules at Tripoli launches. What I don’t do is force an interpretation when the manufacturer has already implicitly acknowledged the practice by experienced senior flyers.
lakeroadster
When in doubt... build hell-for-stout!
Maybe you're experience, and your position / title at Tripoli, makes this topic too close for you to see it clearly from the viewpoint of rocketeers that are inexperienced with single use LPR/MPR composite motors?
That's the topic. You understand that, right? Your posts about "experienced senior flyers" clouds the discussion.
The inexperienced folks have nothing to show that the manufacturer has acknowledged the practice, other than hearsay statements on a public forum where there is no accountability whatsoever for the validity of the statements.
I guess it's pretty clear why there is a NAR Safety Code, it's an attempt to take out the gray areas and dispose of the hearsay. Get things defined in Black and White.
So it's also clear why the NAR has an issue with adjusting delays on single use LPR / MPR composite motors. All that needs to be done is for the manufacturer(s) to take the written procedure they already have for their Disposable Motor System Adjustable Delay, tweak it for single use LPR/MPR composites, and include it with the single use motors.
I agree with most of this post. I absolutely agree that an inexperienced flyers should not adjust the delay on a single use motor. For that matter there are a lot of things that are covered by instructions that are frequently done incorrectly by inexperienced flyers.
I also agree that this should be covered by explicit instructions.
My issue is that forcing the NAR to issue an interpretation (for your own personal clarity) could have unintended consequences. You unnecessarily forced a spotlight on a practice that was not widespread and has never been reported as causing problems. Why?
This whole thread should have been in the research forum. Not because it's restricted information, but because the topic is intended for more experienced flyers and it filters out some of the problem folks. Oh, well. What's done is done. Good topic.
lakeroadster
When in doubt... build hell-for-stout!
This feels a bit like the inquisition.... but since you asked:
Why? For the same reason folks adjust the delay on Disposable Motor System motors.
I have a number of odd rocs that I designed that utilize 29mm single use composite motors. They are heavy rockets and thus would benefit from short delays, shorter than is available. I'd like to modify the delay charge.
When @jimzcatz said they could be modified on all composite motors I looked into this subject deeper as it might be something I could do to get the chute out quicker.
I did a search and found an Apogee video where Tim Van Milligan demonstrated how to modify a DMS motor delay charge. He specifically talked about how AeroTech was initially going to make the delays on all composite motors changeable... but they decided against that. go to 3:57 here. He said that may change.
Since this was a 2017 video I decided to find out if modifying the delay on SU LPR/MPR composite motors was now allowed.
I could find nothing in writing stating this was acceptable.
A few folks here were adamant that it was acceptable and you, @Steve Shannon, said Tripoli accepted. I spent 40 years as a QA Inspector as part of my paying day job and 2 rules we lived by were:
#1: Trust But Verify
#2: Always follow the rules of the applicable code.
Whenever we ran across an issue such as this where there was in-house disagreement as to the meaning of the code, we would submit a request for an interpretation to the board. They would review the request an issue their finding.
So that's what I did here. I went to the NAR site, and to the AeroTech site, and the Apogee site, and asked the question. I never heard back from AeroTech, Tim Van Milligan replied he didn't know and suggested I contact NAR, and NAR responded via email yesterday.That's the journey...
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I honestly don’t think it’ll end up being that much of a problem. Tripoli membership seems to be more permissive (with the notable exception of recertification requirements) and comes with many of the same benefits as NAR anyway.
For those who are members of both, the question of which rules to follow becomes a bit trickier. I’d guess that each organization would encourage members to follow the rules of the sanctioning organization of a given event. NAR goes hands-off for LDRS, Tripoli goes hands-off for NARAM (just as a speculative example).
Any issue is likely to be with regard to flying at a launch with the involvement of both (some clubs are both NAR Sections and Tripoli Prefectures, and some fliers who fly solo are members of both bodies) and having to look into an insurance claim (God forbid). If you’re the one making the claim, make it with the sanctioning body that allows you to do what you were doing and leave the other out of the equation. If a third party files a claim against the organization that doesn’t allow it, consider legal options to kill it and proceed with the claim with the more favorable body.
Was it entirely necessary to draw the attention of NAR to the discussion here? Probably not. It wouldn’t have been hard to go “well, those guys are playing by a different set of rules and they had the blessing of the manufacturer. Nobody got hurt in these instances and the accident rate overall appears to be pretty low. Let’s make sure the discussion has a don’t-try-this-at-home warning on it and be done with it.” Then everybody flies safely and we wouldn’t get interference from national.
Alas, that was not to be.
For those who are members of both, the question of which rules to follow becomes a bit trickier. I’d guess that each organization would encourage members to follow the rules of the sanctioning organization of a given event. NAR goes hands-off for LDRS, Tripoli goes hands-off for NARAM (just as a speculative example).
Any issue is likely to be with regard to flying at a launch with the involvement of both (some clubs are both NAR Sections and Tripoli Prefectures, and some fliers who fly solo are members of both bodies) and having to look into an insurance claim (God forbid). If you’re the one making the claim, make it with the sanctioning body that allows you to do what you were doing and leave the other out of the equation. If a third party files a claim against the organization that doesn’t allow it, consider legal options to kill it and proceed with the claim with the more favorable body.
Was it entirely necessary to draw the attention of NAR to the discussion here? Probably not. It wouldn’t have been hard to go “well, those guys are playing by a different set of rules and they had the blessing of the manufacturer. Nobody got hurt in these instances and the accident rate overall appears to be pretty low. Let’s make sure the discussion has a don’t-try-this-at-home warning on it and be done with it.” Then everybody flies safely and we wouldn’t get interference from national.
Alas, that was not to be.
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lakeroadster
When in doubt... build hell-for-stout!
"Interference from national".
I don't understand that mentality? But it seems other are in agreement with it.
It does explain the hostility directed toward me, for merely asking the known national authority for our sport to supply clarity on a topic.
jimzcatz
Boss, Carolina Rocket Mafia
ONE of the authorities, the one with more strict guidelines. There has to be room for interpretation. I mean heck, we have been trimming delays in single use composite motors long before reload able motors hit the scene. Never had the practice questioned, ever.
(Edit: SORRY FOR THE LONG POST.)
NATIONAL / INTERNATIONAL Organizations and Regulatory Body's need to review and move on very quickly. Many times the "knee jurk reaction" to a question like this is to do whatever limits exposure to lawsuits, rather than spend time, and money, to review and understand Past, Current, and Future implications of a question / decision.
Many times leaving something that only 1 in 1000+ would consider doing in a "grey area" is best. I don't think more than "a couple" of people on this fourm (or anywhere else) have modified delays, and only a few more have changed black powder charge volumes on SU motors where it is not expressly allowed. (ie 18mm, 24mm, 29mm Q-jets, Econojet, EconoMax, etc) It can't be done on Black Powder motors, and is explicitlly allready allowed for all "kit" motors, and some dispisable composite motors. This whole issue only effects a few motors, and a very few number of people. Most of whom have been in the hobby for MANY years, and do this with a lot of experience and understanding of implications of what is done. (Also with RSO knowledge and approval bacause of that experience.) You could have seeked out someone experienced and talked to your RSO. If the RSO wanted a opinion from the club BoD, or the National organizations, let them run it up the chain.
On a side note this same process of "JUMP TO THE TOP" with questions, happens other places too...
I used to deal with international safety regulations for industrial equipment. (Still do for a different company.) We sold stuff to one country for many years with no issues.
One "well meaning" distributor went to the national government organization, with a question about a standard, and our product, instead of asking us as the OEM, and/or his local AHJ ( Authority Having Jurisdiction). Because of the way he posed the question, and the generic data sheet, and information he provided... our product got banned across the country.
It took us 5 years, and a LOT of dollars to get the ban removed. Lost sales is on going... because the competition and potential customers STILL point to that ruling 20+ years later; EVEN THOUGH it was overturned and no longer applicable.
NATIONAL / INTERNATIONAL Organizations and Regulatory Body's need to review and move on very quickly. Many times the "knee jurk reaction" to a question like this is to do whatever limits exposure to lawsuits, rather than spend time, and money, to review and understand Past, Current, and Future implications of a question / decision.
Many times leaving something that only 1 in 1000+ would consider doing in a "grey area" is best. I don't think more than "a couple" of people on this fourm (or anywhere else) have modified delays, and only a few more have changed black powder charge volumes on SU motors where it is not expressly allowed. (ie 18mm, 24mm, 29mm Q-jets, Econojet, EconoMax, etc) It can't be done on Black Powder motors, and is explicitlly allready allowed for all "kit" motors, and some dispisable composite motors. This whole issue only effects a few motors, and a very few number of people. Most of whom have been in the hobby for MANY years, and do this with a lot of experience and understanding of implications of what is done. (Also with RSO knowledge and approval bacause of that experience.) You could have seeked out someone experienced and talked to your RSO. If the RSO wanted a opinion from the club BoD, or the National organizations, let them run it up the chain.
On a side note this same process of "JUMP TO THE TOP" with questions, happens other places too...
I used to deal with international safety regulations for industrial equipment. (Still do for a different company.) We sold stuff to one country for many years with no issues.
One "well meaning" distributor went to the national government organization, with a question about a standard, and our product, instead of asking us as the OEM, and/or his local AHJ ( Authority Having Jurisdiction). Because of the way he posed the question, and the generic data sheet, and information he provided... our product got banned across the country.
It took us 5 years, and a LOT of dollars to get the ban removed. Lost sales is on going... because the competition and potential customers STILL point to that ruling 20+ years later; EVEN THOUGH it was overturned and no longer applicable.
I apologize for my reaction yesterday, but I’d like to take the time to explain it.
I used to work at a job that was subject to a lot of regulations. We almost never asked for an interpretation for one simple reason; once you ask you’re obligated to adhere to the interpretation. You never get a chance to argue the other side when asking for an interpretation and indeed, Steve Lubliner never got to hear anything from anyone else that might have altered his opinion. A better path would have been to write to customer service at Aerotech.
By your persistence you forced the NAR to adopt an official position that solves no problem and results in prohibiting a practice that folks have safely performed for years. Although Steve’s interpretation only affects NAR directly, it could also be used against other organizations by an insurance company seeking to avoid paying a claim.
It’s like the people who wrote letters to ATF and asked, “I’ve seen my friend shoulder his pistol brace; is that legal?”
There’s never an upside and often a significant downside to asking the regulators for an interpretation. They will always adopt the most stringent interpretation because that empowers them the most. Until forced to do something, regulatory agencies are often perfectly content ignoring harmless practices which can be interpreted multiple ways.
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Well, it's certainly now black and white for any flight covered by NAR insurance.
Many flights that were potentially available for interpretation and latitude are now explicitly Thou Shalt Not.
@lakeroadster I don't think anyone faults you for wanting to know.
Please understand it's probably forcing both boards and all manufacturers quickly to make a Hard Ruling that rubs people the wrong way.
Note that going below about 4s is pretty unlikely to work regardless. There's not enough delay grain web thickness to contain the pressure of an operational motor.
Many flights that were potentially available for interpretation and latitude are now explicitly Thou Shalt Not.
@lakeroadster I don't think anyone faults you for wanting to know.
Please understand it's probably forcing both boards and all manufacturers quickly to make a Hard Ruling that rubs people the wrong way.
Note that going below about 4s is pretty unlikely to work regardless. There's not enough delay grain web thickness to contain the pressure of an operational motor.
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lakeroadster
When in doubt... build hell-for-stout!
I linked this thread in my query to Steve Lubliner. His response indicates he read the thread. Therefore he read your take, and he has your name. Be proactive if you're concerned, drop him an email.
I did write to Aerotek on March 13th, both here and on their website. @AeroTech responded yesterday, stating "We’ll review and discuss."
"Never an upside"?
Sure there's an upside, and you just defined it. If there's an accident, and you're modifying SU composite delays, your NAR insurance coverage wouldn't cover you. We all know that now. That's a good thing.
There's a quick and easy solution..
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Drilling a delay for all CTI motors and AT DMS and RMS motors is not a motor modification, that process is approved by the motor vendors and in fact they sell tools for that purpose and tell you how much to drill out if you do not happen to have the tool. They also sanction removing the BP charge if you're using electronic deployment.
Single-use LPR motors come with varying delays because they are integrated at the factory and the delays cannot be removed for drilling (which needs to be done at the end that faces the propellant grains). There's no way to drill the delay, so getting some kind of clarification on drilling them is a moot point.
Single-use LPR motors come with varying delays because they are integrated at the factory and the delays cannot be removed for drilling (which needs to be done at the end that faces the propellant grains). There's no way to drill the delay, so getting some kind of clarification on drilling them is a moot point.
My understanding is that this is exactly what is sometimes done, maybe by drilling from the other side, I don't know as I've never tried it (although it is mighty tempting... I very often need something between -4 and -7).
It is possible my understanding is wrong.
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If the motor vendor says it's OK to drill out the delay from the forward closure, then it would be an approved modification and would not be verboten. I wouldn't expect it to work as well as a delay that's drilled from the grain end, though. Personally, I'd just dump the powder and use electronic deployment, there are very inexpensive deployment controllers available that basically guarantee that you'll get the laundry out at apogee regardless of the size of the rocket/motor.
lakeroadster
When in doubt... build hell-for-stout!
Tim Van Milligan's "Disposable Motor System" video explains the DMS motor construction, how the delay works and how to modify it on a DMS motor.
The entire video is interesting, but he starts talking about the adjustable delay at 2:50.
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Cerving pretty much nailed it. DMS™ motors were designed from the beginning to be adjustable from the bulkhead end with a special tool. Also, the DMS delay setup is completely different than the delays used in the MPR single use motors. The MPR SU motors cannot be reliably and accurately modified from the bulkhead end. For that reason we do not endorse the drilling of MPR SU motor delays and such modification will void the motor warranty.
jimzcatz
Boss, Carolina Rocket Mafia
NAR is fine with that, what you did was make a home made ignitor. Totally allowed. Just like when I pour BP in the noozle of my Este's motors and Tape a flashbulb on it. I only use this method for Clustering Estes motors, which works wonderfully.. Home made igniters, Nuff said. Boy did this thread get off Topic!!!
jimzcatz
Boss, Carolina Rocket Mafia
DMS motors ARE single use composite motors. Your reference is moot.
jimzcatz
Boss, Carolina Rocket Mafia
Sure there is. You drill from the end away from the propellant, thru the blow hole. It works the same way.
EDIT: I posted this before I saw Gary's post disallowing it. I'm going to leave this here, I can live with no warranty. Thanks Gary for getting involved in this roller coaster. Its much appreciated.
lakeroadster
When in doubt... build hell-for-stout!
The DMS motors come with delay adjustment instructions, the single use LPR / MPR composite motors don't. That was the point, and was clearly stated as such.
But it's all been clearly defined at this point. If you continue modifying single use LPR / MPR composite motors, you're violating NAR rules and the manufacturers recommendations.
Not necessarily. All you managed to accomplish was create a hard-and-fast non-negotiable rule against a specific, uncommon, and expert-exclusive practice that had never been the root cause of a proven range hazard. Prior to this, there would have been some room to argue in favor of the practice, and some method of recourse for an insurance claimant to argue against a denied claim. No longer.
Obviously practices that are proven to undermine range safety should be discouraged or prohibited, but it was clear that expert supervision over this activity was universal thus far, and the folks involved worked really hard to keep it that way.
Not to mention entirely derailing what could have been, should have been an extremely simple thread about how delay times work and which ones to use. Essentially you’ve taken a “Rocketry 101” type of question and needlessly brought NAR and AeroTech in to bring the hammer down on something that was already being done with a perfect safety record.
Apparently, you didn't "get the memo" . . .
https://www.apogeerockets.com/Rocket_Motors/AeroTech_Accessories/Universal_Delay_Drilling_Tool
https://aerotech-rocketry.com/products/product_d208be9f-32da-778d-77e9-093c84bb0508
https://www.apogeerockets.com/Rocket_Motors/Cesaroni_Accessories/Pro-38_Delay_Adjustment_Tool
http://www.pro38.com/pdfs/Pro29_instructions.pdf
https://www.freelists.org/post/ncrockets/CTI-delay-grain-drilling-tool,2
BTW - "Gary" is Gary Rosenfield . . . A "Pioneer / Outlaw", before HPR was "legal" . . . Do some research !
Enough with the dogpiling on @lakeroadster. There was no ill intent, and I too would have thought it to be appropriate to try to get an official answer to a question that I have been wondering about. If it turns out that was maybe not the wisest course of action in this instance, well then lesson learned (I have certainly learned it).
There's a bit of a schizophrenic nature to this board regarding safety issues. On the one hand, many are hyper-protective of the hobby and quick to jump on any suggestion of activity that might jeopardize it. On the other hand, those who are happy to engage in and/or talk about activities that, shall we say, explore the limits of the safety code. Both have their place.... although maybe not so great when they collide in the same thread.
There's a bit of a schizophrenic nature to this board regarding safety issues. On the one hand, many are hyper-protective of the hobby and quick to jump on any suggestion of activity that might jeopardize it. On the other hand, those who are happy to engage in and/or talk about activities that, shall we say, explore the limits of the safety code. Both have their place.... although maybe not so great when they collide in the same thread.
lakeroadster
When in doubt... build hell-for-stout!
Deja Vu all over again. The issue isn't the experienced fliers. Same correspondence I had with @Steve Shannon in Post #66.
lakeroadster
When in doubt... build hell-for-stout!
The links you provided is the same data discussed in this thread, Dave. Perhaps take a few minutes and read the rest of the thread before issuing a tongue lashing?
The point is... the data you linked to is not applicable to SU LPR / MPR composites, as we learned from the NAR who stated modifying these delays is a violation of the NAR Safety Code and as we learned from Aerotech who stated on this thread that the drilling is not endorsed by AeroTech.
