[F-FT] Comments on motor decertification requested

decertified,

expiration

I disagree. First off, even if previously manufactured and certified motors were allowed to be used indefinitely, the manufacturers would still be required to submit new motors of that same type periodically for testing to assure that safety and performance hadn't changed. If the manufacturer stops submitting motors, the new motors would be uncertified. A dishonest manufacturer could continue making new motors, never get them tested, and just slap on an old date to pass them off as previously-certified motors.

Bingo!

Great. May I submit "renewal samples" to TRA from each of three subcontractors and see if they can tell any difference at all?

Jerry

The playing field is level now. You just insist on playing a different game.

Submit motors and complete paperwork EXACTLY in accordance with the regs, and your motors WILL be certified.

whats needed is some kind of temperature sensitive strip embedded in the paper casing that would turn colors if its been temperature cycled....

shockie B)

So let's be clear. You are suggesting I submit ATF LEMP paperwork (the only discrepency at issue) that the "manufacturer" (a subcontractor from my perspective) does not legally need (according to the ATF) and refuses to get, unnecessarily?

And how does that jive with YOUR position on ATF and the lawsuit?

Jerry

What "three subcontractors" would those be?

And..., if you have "subcontractors" that would make you the "contractor", or in other words, "the manufacturer".

Do these "subcontractors" each have their own EX numbers? If not, who's EX numbers are they using?

from NFPA 1125:

This is ALL that is said about decertification in any of the NFPA codes...

If you take this "literally" , for a motor to be decerted, the certfiying entity, in this case, the NAR/TRA, has to make a determination (by restesting?) that the motor or motor reloading kit no longer complies with the original certifctaion criteria or current certifcation with respect to safety.

Now heres the NAR decertification criteria:

Removal of Certification

---------------------- The process of decertification of a motor is based on the date of a significant event. Significant events include (but are not limited to):

• The day the manufacturer ceases operations.
• The day the manufacturer informs S&T (or it becomes generally known) the manufacture of a motor has ceased.
• The day the manufacturer fails to submit the motor when requested for triennial recertification.

Once the significant event has occurred, decertification begins. During the decertification period, motors manufactured after the date of the significant event are not certified. Motors manufactured before the date of the significant event remain certified according to the following timetable:

• Contest certification for that motor is dropped at the end of that contest year. A contest year runs from July 1 through June 30 and includes the NARAM at the end of that contest year, which may be after June 30.

• General certification as a model or high power rocket motor is dropped three years from the date of the significant event.

The only exceptions to the above decertification schedule is as follows:

• In the case of government regulatory action, decertification may be immediate.

• In the case of consumer complaints, safety problems, blind testing failures, or triennial testing failures, NAR certification may be suspended or withdrawn if the manufacturer fails to solve the problem within six months from the date of notification.

NFPA 1125 and NAR S&T don't seem to exactly mesh with one another.

Doe anybody know what the TRA criteria are for motor decertifcation? Is it the same as the nar DECERT POLICY?

shockie B)

No jerry, you also need valid DOT papers with valid EX numbers in the same name as the LEMP, the name of the manufacturer.

Hence why I regularly BEG to simply submit recert samples.

"complies with the original certification criteria"

were so lax when they were certified, essentially no paperwork at all was required.

Even I can comply with that and this language is the LAW (and formal TRA rules).

I am proveably being unreasonably withheld from the market.

Even if you believe the rmr claims (which TRA never made) that relabeling happened and it was intentional and malicious, that is not a decert criteria. ONLY safety is.

Nobody has EVER made such a claim re any USR product.

In fact it is often stated the motors are more reliable than others.

I for one have not had NAR motors decertified. On one case, my subcontractor, Aerotech by GCR, simply refused to submit recert samples and I failed to retain sufficient quantities from prior orders to resubmit myself. AT has always been supply constrained since 1982.

Jerry

From NFPA 1125:

7.9.1 When the performance of a solid propellant rocket motor or motor-reloading kit deviates from the sample test criteria

and limits detailed in 7.8.6 within 5 years from the date of manufacture, it shall be withdrawn from commercial sale and

redesigned to provide reliable operation when ignited within 5 years from the date of manufacture.

a "use before" date on the package or motor casing.

Since I have never seen a motor or reload kit with a Use before date, motor and reloads kits sem to have a shelf life > 10 years....

of its manufacture, then its cert can be withdrawm, ie, it becomes decertified....

I don't beleive any of this testing is currently being done by NAR S&T... but as I pointed out in a nother post to this thread, NAR S&T and NFPA 1125 seems to contridict one another as to how decerts are supposed to take place, ie testing must be done to show that the old motor(s) are no longer safe for use...

shockie B)

Yes. I hope you have that 'little misunderstanding' cleared up with DOT.

The ATF lawsuit was never mentioned.

Don't confuse what TMT requires with anything else.

Who cares - let Big Fine prove his stupidity again if he wants to. Come on Jerry - live the life.

Send them to NAR. Maybe you comply with S&T requirements. You know you don't comply with TMT's. They are posted on the web site and according to you, you don't comply.

The problem is, the temperature-cycling cracking of a rammed BP motor can be caused through temperature excursions in either direction. I have motors purchased ten years ago which have never left the hobby den and are kept between 65 degrees (SWMBO starts to shiver) and 80 degrees (I start to sweat). More problematic is what temperatures they might have been exposed to during the truck ride from the distributor to the store. I tend to make motor purchases in the spring and autumn, but you never really know.

However, if I put them in my range box and took them out to the field on an nice sweltering South Georgia summer day they might heat up to over 120 degrees. Conversely, there were at least two days this winter when they would have gone down to below freezing.

So, you'd need TWO different strips. Or some kind of really inexpensive min-max recording thermometer :-) At the really, really large rocket factory I work at our motors are kept under controlled temperatures which are monitored and recorded from the moment they are cast until they are either launched or destroyed.

Personally I deal with the problem by careful storage, and always try to expend all the motors I take out on each trip to the range.

John

He doesn't.....

Maybe we can help him. ;-)

No.

Here is my standard BP motor failure explanation document cut & pasted here.

Here is why temperature cycling can cause Catastrophic failures (CATOs). The nozzle, propellant and the casing all expand and contract at different rates. Since the motors are so small, this is only a problem if the temperature that the motor "sees" swings between wide extremes. When this happens, we see several effects:

2) The casing and the propellant can de-bond. They aren't really bonded in a "glue" sense, but the mechanical bond is weakened from the stretching and contraction. (For wet rammed motors, there may be a tiny glue-like "bonding", but the cycling will break that bond). The flame can propagate along the entire inside of the casing and propellant interface and result in a huge overpressure. This leads to a casing split (if the delay is still "grabbing" the casing tightly) or a "blow through" which is like a Roman Candle.

The two of these can combine to form different CATO scenarios:

a) Blow through at ignition or just after ignition (on the pad/rod). Clearly a sign of a nozzle/propellant interface crack allowing the flame front to reach the debonded casing to propellant interface at or just after ignition.

b) CATO above the pad (like 50 feet up). Clearly there was no crack along the propellant/nozzle interface and the flame front had to wait until it naturally reached the casing wall and then propagate up the de-bonded propellant/casing interface.

A final scenario is the cracked propellant grain. These can go BLAM (or KA-PLOW) quite spectacularly since they really overpressurize the casing big-time and can happen with a perfect casing to propellant bond. A defective tool used to form the centerbore of the propellant can cause these. The C5-3 had such a problem when a tool was mis-manufactured. I believe the root cause was a lack of radius on the tip, which formed a sharp edge, which led to cracking. Motors also could be cracked if any contaminant got on the tool or in the propellant during ramming, but dropping or rattling will not cause a crack!

As for the temperature cycling - avoid firing a motor at a temperature

Why would a normally stable rocket fly unstable when using a motor that it flew stable with before? Did you look at the nozzle? We have had several VERY scary "flights" where the rocket had little thrust and/or veered into cruise missile mode. After crashing and putting out the brush fire, we examine the nozzle and find that it is either too wide (wider than normal at the throat) or it is eroded asymmetrically. The asymmetric erosion is bad and you can clearly see the exhaust residue all over the missing area of the nozzle indicating that it disappeared at ignition or shortly thereafter.

All unstable flights with Estes motors from years "A" and "B" and maybe "C" need to be inspected and if the motor/nozzle is the cause, a M.E.S.S. form filled out and the manufacturer notified. The least that will happen is a package of replacement motors and a kit. The most that will happen is an improvement in materials used in manufacturing and a product that performs like we remember for decades and decades.

I hope this info helps folks.

-Fred Shecter NAR 20117