C6-0 make a C6-P

Hello, Can I (before I wreck my glider) make a C6-0 into a C6-P by adding Epoxy to the non-business end of the motor? Will this work to prevent burning of my
boost glider?
Thanks for your time Richard
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writes:

It *MAY* work. The burnout is pretty violent, and can rupture even epoxy plugs! As the Internats folks discovered when they tried this.
It definitely violates the NAR and TRA safety codes, and the laws of any NFPA 1122 state.
I've tried non permanent (i.e. legal) methods of converting booster motors to plugged motors. The results were unsuccessful unless your goal was to make the worlds most powerful cork Pop-gun!
Why does your boost glider need a plugged motor? Every BG and RG I can recall needs an ejection motor to do something to transition from boost to glide, with the exception of RC models.
--
Bob Kaplow NAR # 18L >>> To reply, there's no internet on Mars (yet)! <<<
Kaplow Klips & Baffle: http://nira-rocketry.org/Document/MayJun00.pdf
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Bob:
I think I'm going to have to disagree with you or at least take issue with the violation of NAR/TRA Safety Codes and /or NFPA 1122.
1st of all, a C6-x motor is a model rocket motor covered only by NFPA 1122 (and 1125 if you happen to be manufacturer) and since NFPA 1127 is the TRA Safety Code that ONLY applies to HPR NOT Model Rocket motors, the TRA Safety Code does not apply here.
The only NFPA 1122 code that may be applicable is:
4.19.2 No person shall dismantle, reload, or alter a single-use model rocket motor.
The "operative word here is "alter". Does adding a permannet modification to an motor with an epoxy plug constitute an alteration? Probbaly, but what if the person instead, uses a hardwood dowel type of plug?
Chapter 5 Prohibited Activities
5.1 Prohibited Activities. The following activities shall be prohibited by this code:
(4) Tampering with any model rocket motor or motor reloading kit or component in any manner or to any degree that is contrary to the purpose for which the model rocket motor, motor reloading kit, or component is designed and intended to be used
Does adding an epoxy plug to a C6-0 motor constitute "tampering" Is it contrary to the purpose that a C6-0 is designed and how it is inteneded to be used? Possibly. For an interpretation of "tampering" you would have to approach your local or state Fire Marshall and ask them. DO you really want to do this?
SO we are left with the NAR Safety Code. The NAR Safety Code ONLY applies to those individuals that happen to be 1. NAR members 2. Doing NAR model rocketry on NAR Model rocket time.
anyway the operative NARSC part is 2. Motors. I will use only certified, commercially-made model rocket motors, and will not tamper with these motors or use them for any purposes except those recommended by the manufacturer.
Again I guess it depends on what the word "tamper" means . Unfortunately NFPA 1122 does not define alter nor tamper. For enforcement of the NFPA 1122 code, is the responsibility of your local or state Fire Marshall authority. I suppose you could approach them and ask them if adding an epoxy plug is an alteration, or you could ask the NAR if adding an epoxy plug is tampering.
But this leads to my infamous question about whether or not there is any real "self-regualtion" (which implies self-policing or self-enforcement) in model rocktry .My question is this: if a tree falls in the forest and nobody is there to see or hear it fall, did it really fall? If you add an epoxy plug to a c6-0 motor on your own time , and tell no one, did it really happen?
My point being this: ONLY your local or state fire marshall person can interpret and enforce NFPA1122. Most Fire Marshall's don' even realize that NFPA 1122 exists in their states, much less, know what it says or have any idea on the interpretation of it. SO the interpretation is left to YOU, the individual. SO the regulation, policing and enforcement is left up to YOU, the individual, hence Self-regulation.. I mean think about it: lets say you mod a C6-0 by adding an epoxy plug. What is the maximum possible penalty for this violation? See, thats why NFPA codes as far as model and HPR are concerned are meaningless: There is no penalty , hence there is no enforcement.
shockie B)
shockie B)
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That was an awful lot of typing when you should simply contact the manufacturer to find out if what you intend to do is considered altering or a use that is not intended.
That is why "tandem" motors are not legal. They were asked and they said "NO". They had reasons which included the burnthrough of the casing wall. For modified boosters, they may be concerned with average Americans not being able to safely install a plug on their own.
You are not a lawyer and you are not a manufacturer. Please do not offer pseudo legal advice to others when you should simply advise them to contact the manufacturer. Or you can just ignore me.
--
-Fred Shecter
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fred;
Exactly my point: my psuedo-legal advise/interprtation is as valid or invalid as anybody elses psuedo-legal advice/interpretation on RMR.
And I disagree it as simply a matter of asking the manufacturer. The manufacturerers have no say so, its nfpa 1122 and the individual states fire marshalls that have the duty and responsibility for interpretation and enforcement for nfpa1122; the manufacturers have no such authority, just as the NAR has no such authority to interpret NFPA 11xx. As Mark Bundick told me , If I want an interpretation as to what a specific NFPA 11xx code segment means, hire an lawyer and find out for yourself. Its not the duty nor responsibility of the NAR to provide such. Which if you think about it is a suspect stance considering the fact that the NAR does sit on the NFPA PYRO-AAA committee that actuallyhelps to make the NFPA codes. You woudl think that since the NAR sits on that committee nd helsp to make the NFPA codes, they would be in the best position to interpret such, but they don't and won't. The NAR takes the psotion that its up to the individual state fire marshalls to interpret the NFPA codes: this of course leads to the posibility that the Kentucky state fire marshall may interpret a specific NFPA 1122 code segment one way, while the local Lexington,Ky fire marshall could interpret another way,while the CA state fire marshll may interpret it in a completely different way. I suppose we could end up with a minimum of 50 different interpretations, depending on where you live. I also suppose we could get hundred's of potential interpretations, as most cities have local fire marshalls.... Thats why I make the point that the NFPA codes are really irrelevant in todays world.
and why would I ignore you? when I value your input?
shockie B)
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I forgot the smilie after the optional "ignore me" comment.
;)
And if you *do* contact a state fire marshal, be sure to spell "marshal" correct. they hate it when you use two l's.
;)
--
-Fred Shecter
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What is a tandem motor? I've never heard of this term used in conjunction with rocket motors before. We aren't talking about CHAD staging are we? Or the process of inserting the end of a C type sustainer into the end of a D type booster for more positive ignition? What's up Fred, I'm all ears.
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Reece Talley wrote:

It's sort of the latter. But instead of just inserting the 18mm sustainer into forward end of the 24mm booster, you GLUE it in. When the 18mm sustainer lights the 24mm combustion chamber continues to be used. This is not what the manufacturer intended, and possibly not within the design limits. So you'll probably get a much higher rate of burnthrough, nozzle loss or other CATOs.
... at least in theory. The known fact here is the manufacturer was asked and said "NO", thus tandem motor means unsupported motor modification. QED
(What you described, Reece, is legitimate use of the motors.)
--
Steve Humphrey
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Thanks for the info. Been in rocketry since the very late 60s and never even thought of gluing the motors together. As to using epoxy in the C6-0...I've done it many times in the A10-0. It was the only way I could get motors to fly my Lil Wild Thing on for a long time. Legal...no. Does it work? So far. Do I recommend it? Hmmm, tricky question. Since I never recommend illegal activities I guess for consistency sake I won't recommend this either...wink, nod, wink, wink, nod, nudge.
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But now you can get A10-P motors that are already plugged. MANY years ago, Estes made a plugged B motor, for "static test" demos.
--
Bob Kaplow NAR # 18L >>> To reply, there's no internet on Mars (yet)! <<<
Kaplow Klips & Baffle: http://nira-rocketry.org/Document/MayJun00.pdf
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You are so right Bob. Wally Mart has them for just a few drachma per 4 pack so why bother to use anything else. I'm with you on this one. Didn't know about the static motors.
--
R. J. Talley
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NO.
Inserting a smaller motor into the top of a larger motor would not be good. Reason: Nozzle on smaller motor is smaller than the nozzle on the larger motor, so you would not get a properly choked nozzle and you would get less thrust and less total impulse.
The point of tandem motors was to take two identically nozzled motors and epoxy them end to end with a reinforcement sleeve epoxied over the outside (like a C6-0 with a C6-7 on top). The sleeve was typically a CMR RB74 and the airframe then had to be RB77.
The firing of the booster motor produced normal results but when the upper stage ignited the thrust curve was 10% higher. Why (when the nozzles are identical)? Because the firing of the upper motor into the lower casing would scour away the inside of the lower casing nozzle. This additional mass being accelerated out the lower nozzle produced more thrust. F=m*a
Of course, it also resulted in lots of motor failures (remember Challenger?) where the lower casing burned through the sidewall.
-Fred Shecter NAR 20117
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reece:
back in the mid-70's and even prior to that, people would take 13mm motors and glue them into the tops of 18mm or take 18mm and glue them into the top of 24mm motors or even just glue (2) 13 or (2) 18 or (2) 24mm motors together with an outer body tube sleeve: hence "tandem" motors. In some combinations you would actually get more nt-sec in total impulse then if you used them as typical staged motors. hence they were popular for maybe 2 years for competition. In mid to late 1978, I guess Estes determined that this was NOT a manufacturers suggested or recommended use and the practice was ended..
shockie B)

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Tandem motors worked great. Many used them in competition even, that is of course what drove their design.
Some didn't like them. Once in a while, they might have gotten a burn thru, but for the most part worked great.
The NAR Model Racketeer published a nice report on their use and benefits in 1974. I'll post this article scanned sometime in the next 7 days for those who are interested, as I still have it.
The manufacture knew and looked the other way, it didn't bother them.
Someone(s) around 1977(?) who didn't like tandems finally asked estes if they had Estes' permission to make tadem motors. Estes of course has to say no for liability reasons, and hence they got banned from competition, which was what a few had wanted.
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I would be very interested in that article. I'll be looking for it.
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R. J. Talley
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the engine in question is a C6-0 Moron.....
shockie B)
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You guys takl about the "code" too much. Heres what you do. I have a rocket that clusters 3 D12-3's and I remove the charge for every flight. Take an exacto knife, scratch off all the gray stuff on top of the motor, under the gray stuff, you will find black stuff, this is the election charge. Get rid of the black stuff until you see more gray stuff, you now have a "code violating" plugged motor that wont CATO, I gaurantee that if you do this right, it will work.
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why don't you use D11-Ps instead of D12s?
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What's your point? That a C6-0 does not have an ejection charge? Now that you think about it, don't you feel foolish?
-- David
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I suppose an argument could be made that you are just "gluing" a glue plug to the casing:
http://nar.org/SandT/releases/r63.html
And NO a -0 motor does not have an integral ejection charge: it does have a little more pressed BP in the motor so it will have the same total impulse characteristics as a C6- with delay and ejection charge. The additional BP in the motor is of course to prevent premature blowthru..... I don't consider that and nor do the manufacturers "ejection charge".... SO whats your point?
shockie B)
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