[F-FT] Regarding Aerotech RMS motor delays

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Ooohh! Ooohh! Ooohh! Mr. Kotter, Mr. Kotter, I know!!!
This is/was precisely one of my arguments, that having only 3 delay times across several classes of power does not provide enough range for 'optimal' safety.
For example, let's take a rocket that on a 'medium' delay is still heading up, and on an 'long' delay is heading down ballistic. In either case, there is a real danger of damage to the recovery system -- either through zippering, shock cord failure, etc. Trimming a 'long' delay down to be between the 'medium' and 'long' times will allow for a more optimal deployment, lessening the possibilities of failure.
Granted, the improvements made may well be incremental, but it DOES add an additional 'element' of safety to the equation. More importantly (for some, including myself), it's one more way one can use to 'optimize' a flight.
Or, perhaps your question meant that when there is added safety, people don't enjoy it? (I know that's the case with the 'helmet laws', for example)
Bear in mind that the whole point of ALLOWING delay modification is that for those who have the additional want/need to improve their flights, they now have the option to do so. Nothing REQUIRES users to modify their delays -- for example, Aerotech didn't suddenly remove their 'short' and 'medium' delays and state that henceforth all delays MUST be modified by the end user.
David Erbas-White
Reply to
David Erbas-White
Very good, I absolutely agree 100% with both examples, but I sincerely doubt that's where jerry was going with his statement. If you know what I mean. :)
Anyway, now that You answered the question before jerry did/didn't, he'll claim that You stole his answer.
Reply to
Dave Grayvis
I will let others answer so you cannot use "attack the messenger" as a reply.
But your post indicates your knowledge and experience in rocketry. Thank you.
Jerry
Reply to
Jerry Irvine
Must remove drink spray from computer keyboard . . .
Jerry
"I have purchased a couple of rocket kits from Jerry over the past several months. I have to admit to being reticent because of the many comments.
I was overall fairly pleased with the kits. The first kit that I bought had some 'improvements' that I suggested to Jerry, mostly from a matter of clarifying the instructions for 'newbies' (there was no problem for those with any experience building kits). I was actually pretty impressed with the quality of his fins. I also appreciated the 'design' of the rockets I purchased, but I can't quite explain why .
I haven't built the second kit yet (just got it and been busy), but each time I ordered, the kits were shipped that day, well packaged, and whenever I had a question or comment on the kits I received a well-thought out response (for example, some of my comments about the first kit were based on incorrect assumptions on my part -- but he felt that certain other comments were valid -- and that's what communication is all about).
I won't hesitate to buy more kits from in the future.
-David Erbas-White
Reply to
Jerry Irvine
I see it didn't stop you anyway!!
You live for this shit Brian.
This is your only full time job!!
You do not even have offsettiong benefits you yourself cited re me:
Ever married Ever have kids Have a living brother Have a living father etc, etc, etc.
CLEARLY a jealousy thing.
Sad motive.
Jerry
Reply to
Jerry Irvine
No it doesn't. Yes, the delay burns faster under pressure (at least on a cored composite motor). That is accounted for in the original delay. What determines the delay is the TOTAL THICKNESS from one side to the other. THus it doesn't matter which side you drill, the thickness will be the same.
Easilly done on motors with paper caps, like the old ROcketflite or FSI or even AT, as opposed to the clay cap used by Estes.
Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!
Reply to
Bob Kaplow
The park is probably not a good place to do so in an NFPA state. Our (NIRA) launch sites over the years all required NAR insurance. If yuou've got yuour own "back 40", you can probably get away with flying them there.
Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!
Reply to
Bob Kaplow
No. I don't consider it illegal because I suspect that the process came from the manufacturers to begin with. What's the difference is it's verbal or written?
Reply to
Phil Stein
Someone seems to feel that they can modify the delay grain to nail ejection delay to within a half a second. You're lucky if an unmodified delay grain is accurate to within half a second. Am I right Gary?
Reply to
Phil Stein
In article snipped-for-privacy@4ax.com, Phil Stein at snipped-for-privacy@ArielSystems.spamsks.net wrote on 4/13/05 4:17 PM:
It's often tough to stay within the 20%, let alone 1/2 second. There are so many variables involved, as someone else mentioned. Sub-1 second adjustments are in the noise level.
Gary/RCS
Reply to
Gary C. Rosenfield
Agreed with, all of the comments, but I'd much rather have trimmed a delay to 8 +/- 2 seconds when I know that 8 seconds is optimal, then using a 10 +/- 2 second delay.
The goal is to simply get all of the variables 'centered' as much as possible, with the understanding that there is some variability. I don't understand why some folks are having a difficult time understanding this.
David Erbas-White
Reply to
David Erbas-White
"Bob Kaplow" wrote in message
(NIRA)
The park is fine here bob ;-)
they don't even require people to have insurance in the suburban parks.
you just go to the park and park. you could even setup an ez-up. you fly, eat lunch , fly , and when done go home.
and yes, the local park & fire department has been asked many times that it's ok to fly rockets their, and kites, and model cars, and electric planes. just about anything but Nitro R/C planes due to the noise.
and no, it's not even an NFPA suburb so we don't have to worry about that silly stuff either.
Reply to
AlMax
-----snip-----
Concur. In my particular case the available delay times are way too long, or just a little bit short. Hopefully CTI will follow suit and issue instructions on how to safely modify the delay grain to values which are not currently available using the DAT.
John
Reply to
John Bonnett
Even the variables are less variable for a particular user at a particular site on a particular day.
The temperature and pressure and humidity is near constant.
Jerry
Reply to
Jerry Irvine
Well, if you really think about it, they are already telling you to drill the delay.
they also sell a tool seperatly that does easy drilling for you.
if you have your own drill just do it. they are already telling you to drill.
Reply to
AlMax
TRA unilaterally decided to FORCE them to be incremental.
If CTI were to issue a memo like Aerotech by RCS did, then they too would be compliant with consumer mod. But the certified motors as "sold" would still be in increments.
There are no motors certified as intended for infinitely variable delays at this time by TRA and NAR due to narrow thinking by TRA and NAR.
CAR has been setting well needed trends. It is ONLY because CTI received CAR certs for variable delays that AT was motivated to offer the memo requested for a decade or more. It was competitive pressure that encouraged Gary to do the right thing in the final analysis.
His own memo says so.
Jerry
Reply to
Jerry Irvine

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