[Trolls} Received the holy grail and are silent

Does it say "F39-9" anywhere on that package? Does AT advertise it as a

9 second delay? If so, then IMO it should have failed the cert since it didn't test out to within +-10% of the advertised delay.

That's something I'd like to see changed. If a motor doesn't test out to an H, it shouldn't be called an H.

IMO that's the root cause of all this squabbling over test data. Motor designations should fit the actual performance. It's one thing for a motor that tests as a G78 or something, to be sold as a G80. But when delay that tests out to 6 seconds is sold as a 9 second delay, that's just screwy. Publishing test data isn't going to correct this problem. If someone's buying a motor that they expect will have a 9 second delay, they shouldn't have to read the fine print to find out that it's really a 6 second delay.

Either the motor designation should be changed to fit the actual delay, or the motor should fail the cert. Same with an H that tests out to a G=2E


Reply to
raydunakin
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Not 100% of the people that were already there caused or were part of the problem. So even though about half the BOD members have changed in the last 3 years, that doesn't mean the BOD is half bad.

Reply to
Phil Stein

Do you read any of Bob's posts, or just mine? He confirmed it just a few posts back. Here are his exact words:

"The motor in this case is the AT F39-9 reload, which ON THE PACKAGE indicates that the certified delay value is a 6. It's a bit confusing, but it is clearly spelled out."

If that motor is supposed to have a 9 second delay, and it only has a 6 second delay, it should not have passed the cert.

Why even bother testing delays at all, if the manufacturer can call it whatever the hell they want?

Ok, so the 20% variability is from the tested value, not the advertised value? A motor that's supposed to have a 15 second delay could be certified even if it only tests to 1 second, as long as they stick "1 second delay" somewhere in the fine print? That doesn't make much sense to me.

I couldn't find it, all I found was an online order form.

Reply to
raydunakin

Yes, as a matter of fact, it says both, as in "F39-9T(6)*" where the footnote says "* = NAR Certified Delay times".

There are two things which need to be done here. One, proper testing requires the use of certified calibrated equipment. Every piece of test equipment in a test lab has a cal sticker on it saying when it was last calibrated. That's a must. Second, a manufacturer is behooved to not get too close to the line. Bad example: Building a full G that, with normal variability, could test to a baby H. (It's a bad example because a full G will be on the order of 80g of propellant, and hence a high power motor anyway.)

Given the hobby's inherent sensitivity to H, J and and M thresholds, manufacturers should be extra careful around those demarcations.

As for TMT, while I've ragged on them, and been frustrated by their website, I don't want to harp on them. Paul Holmes has replied to my inquiries, and is doing his best to make improvements. So let's give him some slack. FWIW.

Doug

Reply to
Doug Sams

Agreed. In fact, I think the rules are that as long as it's close, it's OK to label this way.

One thing to keep in mind here: The delay grain has a non-zero thrust component. While it's small, it's not 0. Determining when the motor has stopped producing useful thrust and has dropped to insignificant thrust is the key to making this measurement. IOW, I suspect the problem had more to do with when the timer started counting than how long the delays actually were. Basically, if the delay whoosh is close to the threshold (5% of peak? I can't remember.) then I can understand how this can happen.

Furthermore, it's common practice to re-label to the tested values. I find that entirely acceptable IF the tested values are all reasonably close to each other (ie, low std deviation). The motor testing bodies exist for the promotion of the hobby, and working with the manufacturers in this way to make the most of a situation...well, that's what they're supposed to do.

Still, having a dual labelled motor is at the very least confusing. I would think that the motor maker would want to go back and tweak his design to get it away from the problem - ie, make the thrust tail higher or lower, make the delay longer or shorter, or bump or decrease the impulse to get away from the threshold. That should be a win-win deal in terms of being good for the customers and being good for the makers.

My 2 cents.

Doug

Reply to
Doug Sams

I agree with you, except this isn't quite practical. Say KGB Aerospace decides to make a full H motor. We do a really good job, and they test out right at 319.97 NS, just a fraction under the limit. Then 3 years later the same motors test at 320.02 NS. Are they now I motors that you want to change the designation on? What happens next time when they test at 319.98?

No matter where you draw the line between motor types, there is always going to be that motor that tests right at the edge. Given very minor testing irrigularites, one day it will test on one side of the line, and the next day on the other side.

I'd still like to know what happened years ago, when the AT H128 tested as a G and the G75 tested as an H. Knowing the differences between the same size chunks of WL and BJ propellant, we know that just couldn't happen. But for 3 years, that was TRA policy: you could HPR cert on a G75 but not an H128.

Bob Kaplow NAR # 18L >>> To reply, there's no internet on Mars (yet)!

Reply to
Bob Kaplow

It's no different than the M1939-XL that TMT certified as an -XXXL. Back when TRA actually admitted that delays weren't what the manufacturers claimed.

Bob Kaplow NAR # 18L >>> To reply, there's no internet on Mars (yet)!

Reply to
Bob Kaplow

He said "NO" to Bruce. I can't say more than that without giving up the confidentiality I promised the person. Kevin knows the details. And now, so does the TRA BOD I guess.

Bob Kaplow NAR # 18L >>> To reply, there's no internet on Mars (yet)!

Reply to
Bob Kaplow

My personal opinion? Partnering with another magazine is in the best interest of neither party. I'd like to see Tripoli Report as the only official publication of Tripoli, and the organization SUPPORT any magazines that are out there, with all of the magazines being treated equally.

"Support" in that context meaning encourage members to subscribe to the magazine(s) that interest them, and contribute to them, as well.

-Kevin

Reply to
Kevin Trojanowski

Is this the same individual we have discussed, or is this another individual? If it's a second individual, I would like further information if s/he doesn't mind my receiving it.

-Kevin

Reply to
Kevin Trojanowski

As Bob indicated, he truly cannot provide further information without betraying a trust.

Bob's not making anything up, or exaggerating anything -- he is relaying what this person said to him. Yes, I know the details -- I've spoken with the same person and he told me what the deal is. I cannot provide any further information without violating an agreement with the individual, as well as with Bob Kaplow.

-Kevin

Reply to
Kevin Trojanowski

Yeah, I see your point.

Reply to
raydunakin

Ok, thanks. I don't want either of you to betray a trust. And for the record I'd like to make it clear that if indeed Kelly is making BOD-level decisions without authority from the BOD, I think that's something that should be presented to the BOD and should be corrected.

Reply to
raydunakin

Actually, I don't have time to read every post in RMR. Kaplow is a key word that I look for and usually read. I skip many of the dunakin posts.

To be clear, The certification test data is definitive. In the case above the motor is supposed to have a 6 second delay (+/- 20% of 6). If your batch of those motors actually deliver 9 seconds of delay they are WAY out of spec at +50% and should be returned to the manufacturer. If that problem persists, the cert should be pulled. The fact that the error is in the direction of the manufacturers improper label is not a factor. Two wrongs do not make a right.

That sounds closer to the TMT philosophy. In any case, what ever manufacturers call their motor products is something that you need to take up with the manufacturer.

Right!

No.

There were freely available the last time I checked.

Alan

Reply to
Alan Jones

Do you have a complete list of motors that you want decertified and pulled from the market? Do you expect other consumers to join your holy war to decertify motors?

I do agree that manufacturers should use NFPA code compliant product designations, but S&T does not control the manufacturers, or their product designations.

Alan

Reply to
Alan Jones

So the members are free to "tolerate" fraud and deceit by "ignoring the problem" through raffles at the annual meeting?

Cool! Where can I donate!

Reply to
Jerry Irvine

Huh?

Note:

Note:

Anybody see an inconsistency here?

No wonder Brucie gets away with murder year after year. Folks like Phil Stein are doing oversight!!

Laughable to the extreme.

Reply to
Jerry Irvine

At least he had a "reason"!

:)

Reply to
Jerry Irvine

That certainly didn't seem to bother Brian Teeling, Chuck Rogers, Bruce Kelly or Fred Wallace one bit.

Jerry

Reply to
Jerry Irvine

Reply to
AZ Woody

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