4 second delays from 7 sec delays

4 second delays from 7 sec delays

Post by Keith Bara » Mon, 19 Mar 2001 16:58:16



I have a BUNCH of E motors with 7 sec delays. I need E motors with 4 sec
delays. At LDRS 19 someone told me it is possible to remove some areas of
the delay with a drill, thus creating a shorter delay time. Has anyone done
this , and how exactly is it done...

Thanx

Keith Baran

#77531

 
 
 

4 second delays from 7 sec delays

Post by Bob Kapl » Mon, 19 Mar 2001 23:11:41


Quote:

> I have a BUNCH of E motors with 7 sec delays. I need E motors with 4 sec
> delays. At LDRS 19 someone told me it is possible to remove some areas of
> the delay with a drill, thus creating a shorter delay time. Has anyone done
> this , and how exactly is it done...

What E motors do you have? While most delays are standard, some different
delay trains burn at different rates. And at least inthe case of the 24mm
RMS E reloads, many of the delays aren't what they claim to be. For example
the E28-7 tests as an E28-5 IIRC. You may be closer to a correct delay than
you think.

While it is possible to do this with some motors, it violates both the NAR
and TRA safety codes, and would be illegal to fly motors so modified in most
states. The best recommendation would be to buy some motors with the right
delay.

        Bob Kaplow      NAR # 18L       TRA # "Ctrl-Alt-Del"

Kaplow Klips & Baffle:      http://www.nira.chicago.il.us/Leading_Edge/MayJun00.pdf
NIRA:   http://www.nira.chicago.il.us  NAR:    http://www.nar.org

Quote:
>>> NOTE: My domain name has changed from decus.org to encompasserve.org! <<<


 
 
 

4 second delays from 7 sec delays

Post by The Silent Observe » Tue, 20 Mar 2001 07:38:04


 > I have a BUNCH of E motors with 7 sec delays. I need E motors with 4
  sec  delays. At LDRS 19 someone told me it is possible to remove
 > some areas of  the delay with a drill, thus creating a shorter
 > delay time. Has anyone done  this , and how exactly is it done...

First, you should be aware that modifying a delay is a violation of the
Safety Codes of both NAR and TRA.

That said, if you're going to do it, do it right -- either get a Peach
Pitter from Aerocon and use it, with its instructions, or make sure you
know how much to drill out.

The usual figure is 1/32" per second of delay reduction, with a rule not
to cut the delay shorter than three seconds total (can lead to a blow
through under thrust if the remaining delay web is too thin).  Thus, to
reduce a seven second delay to four seconds, you'd drill to a total
depth of 3/32" using a drill bit of 3/32" to 1/8" diameter.  Best to use
some kind of positive depth stop; at the very least, a tape wrap around
the drill, if not an R/C wheel collar locked on or a commercially made
depth stop of some sort.

--
It is well to approach all wonders and miracles by gradual stages or
degrees . . .
                                                            Fritz Leiber

Donald Qualls, aka The Silent Observer           NAR # 70141-SR Insured
Rocket Pages                http://silent1.home.netcom.com/launches.htm
Telescope Pages            http://silent1.home.netcom.com/astronomy.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

 >   sec  delays. At LDRS 19 someone told me it is possible to remove  some
 >  areas of  the delay with a drill, thus creating a shorter  delay
 > time. Has anyone done  this , and how exactly is it done...

First, you should be aware that modifying a delay is a violation of the
Safety Codes of both NAR and TRA.

That said, if you're going to do it, do it right -- either get a Peach
Pitter from Aerocon and use it, with its instructions, or make sure you
know how much to drill out.

The usual figure is 1/32" per second of delay reduction, with a rule not
to cut the delay shorter than three seconds total (can lead to a blow
through under thrust if the remaining delay web is too thin).  Thus, to
reduce a seven second delay to four seconds, you'd drill to a total
depth of 3/32" using a drill bit of 3/32" to 1/8" diameter.  Best to use
some kind of positive depth stop; at the very least, a tape wrap around
the drill, if not an R/C wheel collar locked on or a commercially made
depth stop of some sort.

--
It is well to approach all wonders and miracles by gradual stages or
degrees . . .
                                                            Fritz Leiber

Donald Qualls, aka The Silent Observer           NAR # 70141-SR Insured
Rocket Pages                http://silent1.home.netcom.com/launches.htm
Telescope Pages            http://silent1.home.netcom.com/astronomy.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

 
 
 

4 second delays from 7 sec delays

Post by Jim Yan » Wed, 21 Mar 2001 00:39:03




Quote:

> > I have a BUNCH of E motors with 7 sec delays. I need E motors with 4
>  sec  delays. At LDRS 19 someone told me it is possible to remove
> > some areas of  the delay with a drill, thus creating a shorter
> > delay time. Has anyone done  this , and how exactly is it done...

>First, you should be aware that modifying a delay is a violation of the
>Safety Codes of both NAR and TRA.

Except for the Aerotech RMS-plus system.Then it's standard operation.

Quote:
>That said, if you're going to do it, do it right -- either get a Peach
>Pitter from Aerocon and use it, with its instructions, or make sure you
>know how much to drill out.

>The usual figure is 1/32" per second of delay reduction, with a rule not
>to cut the delay shorter than three seconds total (can lead to a blow
>through under thrust if the remaining delay web is too thin).  Thus, to
>reduce a seven second delay to four seconds, you'd drill to a total
>depth of 3/32" using a drill bit of 3/32" to 1/8" diameter.  Best to use
>some kind of positive depth stop; at the very least, a tape wrap around
>the drill, if not an R/C wheel collar locked on or a commercially made
>depth stop of some sort.

--
Jim Yanik,NRA member
remove X to contact me

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4 second delays from 7 sec delays

Post by Darren J Longhor » Wed, 21 Mar 2001 01:02:03


Quote:

> >First, you should be aware that modifying a delay is a violation of the
> >Safety Codes of both NAR and TRA.

> Except for the Aerotech RMS-plus system.Then it's standard operation.

I think you're confusing the Aerotech RMS plus with the Cesaroni (sp?) ProXX
range?
I've never heard of modifying an RMS plus as a standard operation.
 
 
 

4 second delays from 7 sec delays

Post by David Weinshenke » Wed, 21 Mar 2001 06:04:05


Quote:

> I think you're confusing the Aerotech RMS plus with the Cesaroni (sp?) ProXX
> range? I've never heard of modifying an RMS plus as a standard operation.

It's not, although the delay can be changed (in either the "original"
or "plus" versions) by installing different length delay grains and
the corresponding spacers.

The Cesaroni motors are the ones that come with a single delay grain
length and an "adjusting tool" (which has a drill bit and an adjustable
depth stop) to get various delay times.

-dave w

 
 
 

4 second delays from 7 sec delays

Post by Jim Yan » Wed, 21 Mar 2001 09:25:46




Quote:

>> >First, you should be aware that modifying a delay is a violation of
>> >the Safety Codes of both NAR and TRA.

>> Except for the Aerotech RMS-plus system.Then it's standard operation.

>I think you're confusing the Aerotech RMS plus with the Cesaroni (sp?)
>ProXX range?
>I've never heard of modifying an RMS plus as a standard operation.

Sorry,you're correct,I'm not.Thanks!
--
Jim Yanik,NRA member
remove X to contact me

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4 second delays from 7 sec delays

Post by The Silent Observe » Wed, 21 Mar 2001 14:09:35


Quote:



> >First, you should be aware that modifying a delay is a violation of the
> >Safety Codes of both NAR and TRA.

> Except for the Aerotech RMS-plus system.Then it's standard operation.

That's swapping a delay for another approved by the manufacturer and
certified by NAR/TRA for that motor.  The only motor in current
certification that uses a user-trimmed delay is the Cesaroni Pro-38
system, which includes a tool for cutting delays to preset lengths.

--
It is well to approach all wonders and miracles by gradual stages or
degrees . . .
                                                           Fritz Leiber

Donald Qualls, aka The Silent Observer           NAR # 70141-SR Insured
Rocket Pages                http://silent1.home.netcom.com/launches.htm
Telescope Pages            http://silent1.home.netcom.com/astronomy.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

 
 
 

4 second delays from 7 sec delays

Post by Darren J Longhor » Wed, 21 Mar 2001 20:26:36


Quote:
> > I think you're confusing the Aerotech RMS plus with the Cesaroni (sp?)
ProXX
> > range? I've never heard of modifying an RMS plus as a standard
operation.

> It's not, although the delay can be changed (in either the "original"
> or "plus" versions) by installing different length delay grains and
> the corresponding spacers.

Yeah, but I don't think he's talking about modifying, not swapping.
 
 
 

4 second delays from 7 sec delays

Post by Jim Yan » Wed, 21 Mar 2001 22:21:47




Quote:



>> >First, you should be aware that modifying a delay is a violation of the
>> >Safety Codes of both NAR and TRA.

>> Except for the Aerotech RMS-plus system.Then it's standard operation.

>That's swapping a delay for another approved by the manufacturer and
>certified by NAR/TRA for that motor.  The only motor in current
>certification that uses a user-trimmed delay is the Cesaroni Pro-38
>system, which includes a tool for cutting delays to preset lengths.

Sorry,I had the wrong system,but the fact remains that modifying a delay
grain IS acceptable and standard practice.Otherwise Cesaroni could not have
gotten their motors approved.They take a delay charge and trim it,thus
-modifying- it.Now,Aerotech -could- bring out a delay trimmer/adjuster,and
perhaps save on making and stocking different delays for each motor.It
would allow for greater flexibility WRT delay times,you could trim to what
RocSim calculates is optimum.
--
Jim Yanik,NRA member
remove X to contact me

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4 second delays from 7 sec delays

Post by David Walli » Thu, 22 Mar 2001 02:45:24


Quote:

> Sorry,I had the wrong system,but the fact remains that modifying a delay
> grain IS acceptable and standard practice.Otherwise Cesaroni could not have
> gotten their motors approved.They take a delay charge and trim it,thus
> -modifying- it.Now,Aerotech -could- bring out a delay trimmer/adjuster,and
> perhaps save on making and stocking different delays for each motor.It
> would allow for greater flexibility WRT delay times,you could trim to what
> RocSim calculates is optimum.
> --
> Jim Yanik,NRA member
> remove X to contact me

Modifying a delay grain is only acceptable *if* the manufacturer
states that it is ok. It may be common, but it violates NAR and
Tripoli safety codes, plus NFPA codes if your location is governed by
them.

Cesaroni got their system approved because TMT could test each
manufacturer approved delay setting. Even with the Pro-38 motors, it's
only acceptable to trim the delays to the Cesaroni (and TMT) approved
settings. Trim a delay halfway between 2 settings, and your're in
violation of the codes again.

The rules that TMT and NAR motor certification work under require them
to verify that published delay times are withing +/- 10% of the
published value. Unless that requirement is changed, I don't think
you'll see any infinately variable delay systems.

I agree that delay timing on larger rockets is a pain. That's why I'm
going to move to electronic deployment.

--
David Wallis

 
 
 

4 second delays from 7 sec delays

Post by Jim Yan » Thu, 22 Mar 2001 06:53:13



Quote:

>> Sorry,I had the wrong system,but the fact remains that modifying a
>> delay grain IS acceptable and standard practice.Otherwise Cesaroni
>> could not have gotten their motors approved.They take a delay charge
>> and trim it,thus -modifying- it.Now,Aerotech -could- bring out a delay
>> trimmer/adjuster,and perhaps save on making and stocking different
>> delays for each motor.It would allow for greater flexibility WRT delay
>> times,you could trim to what RocSim calculates is optimum.
>> --
>> Jim Yanik,NRA member
>> remove X to contact me

>Modifying a delay grain is only acceptable *if* the manufacturer
>states that it is ok. It may be common, but it violates NAR and
>Tripoli safety codes, plus NFPA codes if your location is governed by
>them.

>Cesaroni got their system approved because TMT could test each
>manufacturer approved delay setting. Even with the Pro-38 motors, it's
>only acceptable to trim the delays to the Cesaroni (and TMT) approved
>settings. Trim a delay halfway between 2 settings, and your're in
>violation of the codes again.

>The rules that TMT and NAR motor certification work under require them
>to verify that published delay times are withing +/- 10% of the
>published value. Unless that requirement is changed, I don't think
>you'll see any infinately variable delay systems.

>I agree that delay timing on larger rockets is a pain. That's why I'm
>going to move to electronic deployment.

From what I've read on that,ED is even more of a pain.And not really
useable on small rockets.That magnetic apogee system is attractive,though.
--
Jim Yanik,NRA member
remove X to contact me

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4 second delays from 7 sec delays

Post by M Dennet » Fri, 23 Mar 2001 08:06:13


Gentlemen,

FYI, the reason it is allowed with the Pro38 motors is:

- it is the configuration that TMT tested and certified
- we supply a tool with preset stops
- the instructions explain how to do it
- the instructions offer a method of "safely disposing" of the remnants,
which our own feds insisted be included, and which we were happy to include.
- it works

Just so you know.

Cheers,

Mike D
Cesaroni Technology Incorporated


Quote:





> >> >First, you should be aware that modifying a delay is a violation of
the
> >> >Safety Codes of both NAR and TRA.

> >> Except for the Aerotech RMS-plus system.Then it's standard operation.

> >That's swapping a delay for another approved by the manufacturer and
> >certified by NAR/TRA for that motor.  The only motor in current
> >certification that uses a user-trimmed delay is the Cesaroni Pro-38
> >system, which includes a tool for cutting delays to preset lengths.

> Sorry,I had the wrong system,but the fact remains that modifying a delay
> grain IS acceptable and standard practice.Otherwise Cesaroni could not
have
> gotten their motors approved.They take a delay charge and trim it,thus
> -modifying- it.Now,Aerotech -could- bring out a delay trimmer/adjuster,and
> perhaps save on making and stocking different delays for each motor.It
> would allow for greater flexibility WRT delay times,you could trim to what
> RocSim calculates is optimum.
> --
> Jim Yanik,NRA member
> remove X to contact me

> -----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
> http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
> -----==  Over 80,000 Newsgroups - 16 Different Servers! =-----

 
 
 

4 second delays from 7 sec delays

Post by Rick Dickinso » Sat, 24 Mar 2001 13:28:32




[re: delay t***]

Quote:
>FYI, the reason it is allowed with the Pro38 motors is:

>- it is the configuration that TMT tested and certified
>- we supply a tool with preset stops
>- the instructions explain how to do it
>- the instructions offer a method of "safely disposing" of the remnants,
>which our own feds insisted be included, and which we were happy to include.
>- it works

Just out of curiosity, what is the Fed-approved safe disposal method
for delay remnants?

 - Rick "Inquiring mind"***inson

--
"I have no idea what's going on here, but it's quite entertaining."
                  -- Jason Willoughby, in rec.humor.oracle.d

 
 
 

4 second delays from 7 sec delays

Post by RayDunak » Sun, 25 Mar 2001 05:47:14


Quote:
>>the instructions offer a method of "safely
>>disposing" of the remnants,
>>which our own feds insisted be included

Typical government idiocy.