[F-FT] RMS delay question/comment

Actually John Kane of NAR S&T was involved in the infinite adjustment data review and methodology with CAR as well. Mike Dennett knows all the history.
Anthony J. Cesaroni President/CEO Cesaroni Technology/Cesaroni Aerospace http://www.cesaronitech.com / (905) 887-2370 x222 Toronto (410) 571-8292 Annapolis
writes:

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On Sat, 9 Apr 2005 13:44:20 -0400, "Anthony Cesaroni"

I think John has been waiting for Jerry to send him some certification motors ... or was that one of his kids
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writes: -----snip-----

certified
approached
a
-----snip-----
The motor testing protocols now in place were developed when we were entirely dependent on the accuracy of the manufacturer's delay to safely recover our rockets. Thusly, it was entirely correct to test and verify that a 3 second delay is in fact 3 seconds. Longer than expected delays are bad, and shorter than nominal can be much worse. Testing and certification provided an independent check on delay accuracy. For motors where the delay composition is inaccessable, like an Estes BP the independent testion should continue.
However, there is a whole new class of motors available to us today. Reloadable designs *do* allow access to the delay element and can easily be modified with a simple twist drill. More high-tech approaches use an adjustable jig to repeatably drill the delay to the same depth.
But, we place an artificial (and unnecessary) restriction on ourself if we limit our ability to shorten delay times to only a few discrete quanta that mimic the delay steps which have historically been avaliable from the manufactures.
Specific example: the 5.5x Streak I am currently building for my Level-1 certification sims consistently with an apogee at eleven seconds. Without any modification the stock 13 second delay from the Pro38 I will be using is much too long, and the rocket is subjected to needless stress when ejection comes that long after apogee. Likewise, the next step on the DAT is 10 seconds, and the ejection charge goes off while the rocket is still going up, and I'd just be asking for a zipper. Nope, I need a delay of 11 seconds (trusting RockSim here pending flight tests).
Let's loop on this for a few iterations. An analgous situation exists in the FF airplane community regarding DT time. It is purely up to the discretion of the flyer what fuse length or timer setting to use to maximize the chance of maxing out, and still recover the model.
Shouldn't the HPR community have the same discretion ? We're not talking about somebody just starting out following an impulsive purchase at Wally-World. Someone going for HPR certification should know, and be able to hold a technical discussion about, the factors involved in making an informed delay time selection.
Relative to the testing and certification process, I would recommend the following change to the extant methodology; test the manufacturer's delay adjustment method (whether through the use of a jig or a simple depth to drill) to see if that process does produce accurate, repeatable variable time delays. The testing would thusly certify that the manufacturer's procedure consistently produces reliable delay times. Exactly what time delay to select should be up to the discretion of the flyer based on factors like specific rocket design considerations and flight weather conditions.
John<==what a marvelous scientific age we live in
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writes:

It's very simple. Get the manufacturer to document the procedure in a manner that can be done safely and accurately by the consumer, and submit the motors and the process for testing. CTI did so. AT or any one else could do so if they choose to. But as long as AT says NO, then to modify the delay is to use it in a manner not recommended by the manufacturer, and a violation of the safety code.
The ball is in the manufacturers court.
    Bob Kaplow    NAR # 18L    TRA # "Impeach the TRA BoD"         >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle:    http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org
You need only reflect that one of the best ways to get yourself a reputation as a dangerous citizen these days is to go about repeating the very phrases which our founding fathers used in the struggle for independence. -- Charles A. Beard
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I'm gonna try to reformat this thread. Hope I don't trash it...
writes:

be modified

jig to

we
that mimic the

manufactures.
manner
do
is
-----snip-----
I know that Anthony Cesaroni and Gary Rosenfield are following this thread. Perhaps they'd like to comment ? Pesonally I think we need to approach the concept of adjustable delay time from the other end.
First re-write the test parameters published by NAR and TRA to include verbiage outlining a test procedure to certify a manufacturer's process for adjusting delay times without requiring set, specific delay times.
Secondly, test the motors using 2-3 delay times adjusted per the manufacturer's procedure to certify accurate, repeatable results.
That way, the choice is left up to the manufacturer. If they feel that we shouldn't mess with their available reload times, then they don't have to submit anything for testing and certification. If they do believe we can modify the delay element in a safe manner to produce the custom delay needed for a particular flight then they can submit that process for certification.
And, we flyers can vote with our wallets for the manufacturer who best meets our needs in matching motor delay time to our rockets.
Alternatively, we could revise the sections of the code about motors to specifically exclude any reference to delay time. That way we could drill as necessary (just like we choose the proper amount of BP for an ejection charge) without violating any of the Safety Code provisions and the manufacturer's don't have to bear the cost of providing testing samples.
Or, I have to add additional deadweight to my rocket to match the flight profile to the handful of available delay times :-(
Times and technology change. When I started flying back in the Sixties having a Safety Code which prohibited any modifications to the motor was just plain good sense. We shouldn't have been messing around with the available BP motors. But we're not in Kansas anymore, Toto. Right now the *only* flight event which is beyond my control (because both AT and CTI provide instructions in adjusting the size of the BP ejection charge) is the exact (not quantized) ejection delay time. We need to modify our Code and certification process to acknowledge that fact.
Personally, unless the rules can be revised my solution to provide the exact 11 second delay my Streak needs is to utilize the apogee detect capability of my RRC2 altimeter to get the streamer out at the right time and not use the motor's ejection charge at all. Well, that's not entirely accurate, I will recycle the BP from the reload kit into a canister fired by the altimeter :-).
John<==thinks we are being overly restrictive in the rules here...
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John Bonnett wrote:

include
process
times.
that
believe
best
could
an
testing
flight
Sixties
We
Well said, John! It seems to me that trying to get adjustable delays certified under rules created for non-adjustable delays is like trying to put a square peg into a round hole.
t
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Which I guess would be interpreted by the existing lovers of bad rules as a motor modification in violation of the safety code :)
--
Jerry Irvine, Box 1242, Claremont, California 91711 USA
Opinion, the whole thing. <mail to: snipped-for-privacy@gte.net>
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For the Pro series of motors that incorporate an ejection charge, that modification is outlined in the reload instructions and is approved by the sanctioning organizations.
Anthony J. Cesaroni President/CEO Cesaroni Technology/Cesaroni Aerospace http://www.cesaronitech.com / (905) 887-2370 x222 Toronto (410) 571-8292 Annapolis

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God bless.
See,everyone IS watching todays threads.

--
Jerry Irvine, Box 1242, Claremont, California 91711 USA
Opinion, the whole thing. <mail to: snipped-for-privacy@gte.net>
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Jerry,
The instructions are non denominational and respect the separation of church and state. :-)
Anthony J. Cesaroni President/CEO Cesaroni Technology/Cesaroni Aerospace http://www.cesaronitech.com / (905) 887-2370 x222 Toronto (410) 571-8292 Annapolis
wrote:

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God bless the queen!
Or is that Queen.
--
Jerry Irvine, Box 1242, Claremont, California 91711 USA
Opinion, the whole thing. <mail to: snipped-for-privacy@gte.net>
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wrote:

We'll call you which ever one you prefer.
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As it suddenly downs on me why your instructions have you drill the propellant end instead of the ejection end: that's what's exposed before motor assembly, so that's the side you have access to. The other side has the pre-installed ejection charge already in place.
And since I'm suddenly curious, I keep seeing 1/32" per second quoted, but that only applies to AT delays, or at least some/most AT delays. Are the CTI delays also 1/32" per second, or is there some other burn rate.
It's been a LONG time, but IIRC the Rocketflite BP motors had delays that were either 1/8" or 1/16" per second, but it was definitely a faster burning delay than the typical AT composite.
    Bob Kaplow    NAR # 18L    TRA # "Impeach the TRA BoD"         >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle:    http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org
"I tell you, freedom and human rights in America are doomed. The U.S. government will lead the American people in and the West in general into an unbearable hell and a choking life."
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writes:
-----snip-----

Which in turn causes me to wonder, if you drill a deep hole to shorten the delay to, say, 6 seconds, is there any danger the electric match will be inserted past the igniter pellet and fail to light the propellent ?
Pardon the dumb question, but it will be another two months before I actually touch an H143SS reload kit. Love the case, though :-)
John<==still need an 11 second delay
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Unlikely. The very few ignition failures we've had reported generally are due to the match getting folded over or caught between grains - they won't light the propellant directly. With the H143 just straighten out the leads, and when the match touches the pellet you can generally hear a little clicking sound. You can also feel it contact the hard surface of the pellet once you get a feel for it, assuming it's not mid-winter and your fingers are frozen..
Mike D.
writes:

has
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In which case if you get it right the motor will STILL work like a charm!!
--
Jerry Irvine, Box 1242, Claremont, California 91711 USA
Opinion, the whole thing. <mail to: snipped-for-privacy@gte.net>
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wrote:

are
won't
leads,
pellet
fingers
Righteous ! Mid-winter here at 30.2 N means you have to wear a sweater over your Tee shirt !
John<==don't get me started about August, though :-(
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Not on your reload.

--
Jerry Irvine, Box 1242, Claremont, California 91711 USA
Opinion, the whole thing. <mail to: snipped-for-privacy@gte.net>
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Isn't that the case for you folks from mid-fall through mid-spring :-)
    Bob Kaplow    NAR # 18L    TRA # "Impeach the TRA BoD"         >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle:    http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org
    Homeland Security Administration: The Gestapo of the 21st Century
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kaplow snipped-for-privacy@encompasserve.org.TRABoD (Bob Kaplow) wrote:

Unless you are banned.

--
Jerry Irvine, Box 1242, Claremont, California 91711 USA
Opinion, the whole thing. <mail to: snipped-for-privacy@gte.net>
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