HDTenEightyP/NetNews huggingface dataset:
From: jason@ab20.larc.nasa.gov (Jason Austin)
Subject: Re: parachute 101
Reply-To: Jason C. Austin <j.c.austin@larc.nasa.gov>
Organization: NASA Langley Research Center, Hampton, VA
	<6802@transfer.stratus.com> <1992Sep30.144200.1539@HQ.Ileaf.COM>
Date: Thu, 1 Oct 1992 16:28:16 GMT

In article <1992Sep30.144200.1539@HQ.Ileaf.COM> hal@HQ.Ileaf.COM (Hal Wadleigh) writes:
-> The "3-lobe" shroud line arrangement is, indeed, the best method for making
-> a minimum of differences in shroud line length in a hex parachute.  When you
-> attach the 'chute to the nose cone or swivel clip, put your finger into each
-> loop and tug the 'chute from the middle.  This evens out the differences in
-> shroud length so that your finger is now the middle of each loop.
-> 
-> Other hints:
-> 1. Use fisherman's snap swivels for your attachments.  It lets you store
->    'chutes separate from rockets and helps prevent fouling due to spin at
->    deployment.

	This works pretty good as long as you use pretty hefty ones
for large rockets.  The snap when the chute opens can break small
ones. 

-> 2. Use nylon coat thread for shroud lines on homemade 'chutes (and plastic
->    bread wrappers are the best cheap 'chute material).

	I like to use dacron kite string.  It's easy to tie and very
strong. 

-> 3. Pay special attention to the security of the attachment points.  Those
->    standard stickers often look secure, but are actually not attached.  A small
->    knot in the part of the shroud line under the sticker serves as a good
->    anchor point (with the rest of that part looped around the knot, as per
->    standard practice).

	I've given up on those little white circles that come in those
kits.  Take some UPS packing tape, stick the string down with a little
overhang, flip the overhange over the tape, and stick it down with
another piece.  I've never had a connection like this break.  

-> 4. Very small 'chutes should be crossform type.  Cut about a 5" square, then 
->    take out about 1.25" squares from each corner.  Attach 4 lobes of shroud
->    across the flat ends and secure as above.  Be careful to use small stickers
->    for the corner attachments.  These make good substitutes for streamers in
->    .5" body tubes and can also be used as drogues to help in the deployment of
->    large 'chutes.

	Also remember to coat the chute with plenty of talc powder
just before launch.
--
Jason C. Austin
j.c.austin@larc.nasa.gov
From: wcsbeau@alfred.carleton.ca (OPIRG)
Newsgroups: rec.models.rockets
Subject: Re: Guidance
Date: 26 Sep 92 02:20:58 GMT
Organization: Carleton University

In <1992Sep21.053509.27942@csi.uottawa.ca> cbbrowne@csi.uottawa.ca (Christopher Browne) writes:

>In article <wcsbeau.716950488@cunews> wcsbeau@alfred.carleton.ca (OPIRG) writes:
>>I have been thinking about guidance and model rockets for a little
>>while, and was wondering about the legalities involved (note that I
>>live in Canada, which may change the picture somewhat).

>Not much...  It mostly changes issues concerning which sorts of motors
>you can use, and who you contact concerning HPR stuff.  (HPR is
>typically defined as "anything bigger than an F", roughly speaking.  I
>gather that the NAR is seeking to change that "F" to a "G."  In
>Canada, it's still "F".)  For instance, Model Rocketry is regulated at
>the federal level, and NOT at the provincial level.  This is quite
>different from the state-by-state statutes that exist south of the
>49th...

I'm not too worried about motor size - the biggest bird I have at the
moment is a C to C two stager (Warp 2), and I'm designing everything
to fit into the nosecone.  The only serious weight I have at the
moment is the batteries and solenoids.  I'm probably going to take the
frames off the solenoids anyway (for space), so the batteries are the
only big problem in that respect.

>>It's fairly obvious that building a rocket to track a specific target
>>would be against the law.  

>Not obvious - you're assuming too much about the law!

Yes, you're right.  I play a game called Nomic, where we *live* for
rules...

>>But what about building a rocket to track
>>the sun, or with some sort of (simple) INS to keep it flying upwards?

>Just to pick nits, the sun IS a specific "target."  People HAVE set up
>tracking systems that do the "sun-seeking" thing, with some success.

True.  I had meant 'traking to hit', as the saftey code indicates that
you may not launch rockets in a manner to carry against a target.


>>Would tracking the sun only be legal if the sun was within 30 degrees
>>of vertical?  Even if the rocket was launched straight up, and the
>>guidance didn't kick in for (say) 1s?

>The BIG issue is that you're not allowed under the CAR rules (CAR =
>Canadian Assocation of Rocketry.  I've got the address around
>somewhere...) to point the launcher more than 15 degrees from vertical
>(I THINK - it could be 30, but I seriously doubt it!).  If you don't
>break any of these and the other rules, then there's probably no legal
>problem.

I was planning to have the launcher point straight up - with active
guidance, I've got worse worries than the wind...

BTW: Does anyone know where I can get the articles about guidance
mentioned by a number of people (Please mail me your 'best bets')

Thanks again,

Christopher Allen
(wcsbeau@alfred.carleton.ca)
From: jack@rml.UUCP (jack hagerty)
Newsgroups: rec.models.rockets
Subject: Re: 1st Livermore Launch!
Date: 27 Sep 92 03:59:11 GMT
Reply-To: jack@rml.UUCP (jack hagerty)
Distribution: ca
Organization: Robotic Midwives, Ltd.

In article <1270@taniwha.UUCP> paul@taniwha.UUCP (Paul Campbell) writes:
>
>Well - there is one other club in the Bay Area - The "Waterfront Rocket
>Club" in Berkeley - we fly once a month on the 2nd Sat. of the month
>8:30-10:30am at the north side of the Berkeley Marina. 
>
>We're not a NAR club - the city requires we have site insurance and NAR wasn't
>offering this when we formed so we are an AMA chartered club. 

I did remember you when posting that launch summary, but the point (as you 
mention in the last sentence) was that the only other NAR sanctioned 
club around here is BAYNAR. I'm sure there are many other informal 
rocketry clubs or rocket groups within other organizations (e.g. scouting 
and Kiwanis) all over the Bay Area as well as, like yours, clubs with 
sanctions other than NAR.

Actually, even if you were an NAR sanctioned group, I don't think we
would step on each others' toes. Berkeley is about as far North of
here as Cupertino is south.

- Jack

=============================================================================
||Jack Hagerty, Robotic Midwives, Ltd.                 jack@rml.com        ||
||Livermore, CA		           NOTE! New, improved address! ^^^        ||
||(510) 455-1143	            (old ones will still work)             ||
||-------------------------------------------------------------------------||
||  "I, like all men, have never grown up. Other men lie and say they      ||
||    have. I refuse to lie. I try to be a creative child, using my        ||
||    immaturity in such ways as benefit my society rather than harm it."  ||
||                           - Ray Bradbury, _Yestermorrow_                ||
=============================================================================
Newsgroups: rec.models.rockets
From: hal@HQ.Ileaf.COM (Hal Wadleigh)
Subject: Re: Guidance - rc aircraft pains
Summary: no rocket shooting
Reply-To: hal@HQ.Ileaf.COM (Hal Wadleigh)
Organization: Interleaf, Inc.
Date: Mon, 5 Oct 92 13:59:18 GMT

What you really need is not a tracking rocket, but a good 12-guage skeet gun.`

Newsgroups: rec.models.rockets
From: smith@mrcnext.cso.uiuc.edu (Greg Smith)
Subject: Re: parachute 101
Organization: University of Illinois at Urbana
Date: Wed, 30 Sep 1992 21:14:02 GMT
Keywords: chute construction

> Other hints:
> 1. Use fisherman's snap swivels for your attachments.  It lets you store
>    'chutes separate from rockets and helps prevent fouling due to spin at
>    deployment.

I *strongly* discourage the use of snap swivels.  I have seen far too 
many of them break, even sometimes during perfectly gentle looking 
deployments.  (Typically, the wire hook breaks right at the tightest 
bend.)  I just split the shroud lines in two bundles and pull the 
parachute through between them; it's a LITTLE harder to take off this 
way, but not too inconvenient, and saves both the weight and 
unreliability of the snap swivel.  I've never once seen a swivel that 
turned easily enough to actually prevent twisting or tangling of the 
shroud lines anyway.

Bob Kaplow showed me some huge swivels made by a high-end kite supply 
company that looked like they'd be beefy enough for even high powered 
models, but one of these things probably weighs more than many of the 
whole competition models I've built, and probably wouldn't fit in any 
tube under BT-55 size or so.

> 2. Use nylon coat thread for shroud lines on homemade 'chutes

The nylon thread is very good for small, lightweight competition 
parachutes, but it's not real strong and does have a tendency to melt if 
it encounters a bit too much ejection charge heat.  For sport and 
payload models with 12" - 24" plastic 'chutes, I use 15 lb. *braided* 
nylon fishing line.  It's thicker than the coat thread, similar in 
diameter to the Estes cotton stuff, but tremendously stronger.  In the 
last fifteen years, of the plastic parachutes I have built using this 
line (and always crossed over the top of the 'chute for reinforcement), 
I have had *zero* shroud line or attachment failures.  The braided line 
has a hard, smooth surface that doesn't encourage tangling, and it 
doesn't unravel where cut.

Greg Smith N9LHI
NAR 15881 * TRA 1974
smith@mrcnext.cso.uiuc.edu

Newsgroups: rec.models.rockets
From: <Roger.Wilfong@umich.edu>  (Roger Wilfong)
Subject: Re: Cost of Competition (was NARAM SUMMARY????)
Organization: UofM Hospitals
Date: Mon, 5 Oct 1992 11:30:00 GMT

In Article <3OCT199209303474@vx.cis.umn.edu> "soc1070                         " says:
> In article <580@rml.UUCP>, jack@rml.UUCP (jack hagerty) writes...
> >In article <1992Sep28.225911.20271@rsd0.rsd.dl.nec.com> buzz@rsd.dl.nec.com (Buzz McDermott) writes:
> >>|> <comments about choice of events potentially being based on cost
> >>|>  considerations deleted>
> >>It was good thinking on the part of the CD and contest committee
> >>for the next NARAM to try to ensure inexpensive events were available.  That
> >>wasn't my opinion at first, but it is now, and I think it is the right way
> >>to approach an event like a NARAM.
> > 
> >Maybe I'm missing something here, but compared to the cost of flying/driving
> >across country, staying in a big hotel for a week (even at group rates),
> >eating resturaunt food and other miscelaneous travel expenses, worrying
> >about the difference in the cost of motors seems trivial.
> > 
> >The point is, that to anyone who can afford dropping $2-3K on a week of
> >rocket flying, the difference between a $1 motor and a $4 motor is
> >lost in the noise. Unless you're going to be making *hundreds* of BP
> >flights or *dozens* of HP flights, the difference just won't be significant.
> > 
> >- Jack
> 
> This was the same point that I was trying to point out when I first opened
> this can of worms. When you look at the TOTAL cost of attending a NARAM
> (or any other national meet), the rocket flying becomes the cheap part of the
> trip. Therefore, basing to events on the cost of flying to the
> participant is moot. (unless you're local and have no travel expenses).
> 
While I generally agree with you, you are over looking one problem that this
causes.  People show up to NARAM and fly for the first time.  By that I mean
that they are flying untried designs/motors.  Examples:
NARAM-30 - D-ELA, numerous would be flyers purchased their first D8's from
  Aerotech the day before the event.  The result was numerous catos as a 
  result of improperly installed ignitors (to the point that the RSO made an
  announcement on the PA explaining how to install the ignitor).
NARAM-33 - B-ELA, ditto except change the vendor to Apogee and the failure
  mode to broken eggs from the energetic ejection charge.
 
If you are going to compete competitively, you have to be familiar with what
you are flying.  That involves test flying and additional expense.  While 
most people can afford $8 a flight for 1 or 2 contest flights, they are 
unwilling to invest $50 in a half dozen test flights.
From: hrbob@ixstar.ih.att.com (R.E. Wiersbe)
Newsgroups: rec.models.rockets
Subject: Re: 'cheap' Aerotech motors
Date: 6 Oct 92 16:24:46 GMT
Article-I.D.: cbfsb.1992Oct6.162446.1313
Distribution: na
Organization: AT&T Bell Laboratories
Originator: news@cbnewsb.cb.att.com

In article <1992Oct6.145057.1682@rsd0.rsd.dl.nec.com> buzz@rsd.dl.nec.com (Buzz McDermott) writes:
>I just received my September/October AmSpam.  I don't know if I'm one of the
>first or one of the last to get this issue.  There is an ad for RocketMan
>Hobbies on page 15.  The 'No "G" Sale'.
>
>  All single use D's:  2.70
>  All single use E's:  3.70
>  All single use F's:  5.70
>
>The prices look pretty good.  Anyone ever do business with this outfit before?
>
>(I am not affiliated with and have never done business with RocketMan Hobbies.
>I just saw the ad).
>
>============================================================================
>Buzz McDermott                   Internet: buzz@rsd.dl.nec.com
>NAR     13559
>TRA      1785
>============================================================================

I've visited and mail ordered a bunch of stuff from RocketMan. In fact, it was
when I tried to get some 29mm casings and H reloads from them that I found out
the DOT wouldn't let them ship it. Walt Meeks is the owner, and a real nice
guy. They also have this awesome corn field to fly out of (when there's no
corn). And you can't beat free shipping! (See if they still give an extra 10%
off for NAR and Tripoli members)

By the way, I haven't seen the new AmSpam yet so I hope this is RocketMan
Hobbies in Peoria, Illinois. If not, ignore this message! :)

I'm not affilliated with Rocketman, just a satisfied customer.

Bob Wiersbe	NAR# 44588	hrbob@ihlpb.att.com
Newsgroups: rec.models.rockets
From: <Roger.Wilfong@umich.edu>  (Roger Wilfong)
Subject: Re: parachute 101
Organization: UofM Hospitals
Date: Thu, 1 Oct 1992 19:37:00 GMT

In Article <JASON.92Oct1112816@ab20.larc.nasa.gov> "jason@ab20.larc.nasa.gov (Jason Austin)" says:
> 
> -> 2. Use nylon coat thread for shroud lines on homemade 'chutes (and plastic
> ->    bread wrappers are the best cheap 'chute material).
> 
> 	I like to use dacron kite string.  It's easy to tie and very
> strong. 
> 
My theory is to use weak lines, but lots of them.  This way the load on
any single line is low and the failure of a single line does not drastically
affect the performance of the chute.  Unless you're running the lines over
the top or using a light-weight snap swivel, the weak point in the entire 
parachute system is the attachment of the lines to the canopy.  Using lines 
that are stronger than the attachment is a waste of weight, bulk and/or 
money.  Weak lines also have the advantage that when your rocket lands in a 
tree, it is easy to break them one at a time to get it down (on more than one
occasion that has allowed the return of a winning ELD flight from the top of
a 40-50 foot tree).
One comment on snaps.  The C/L folks have bee using snaps to attach control
lines for years.  They do not use the standard, brass, fishing snap swivels 
you find at most sporting goods stores.  Instead, they use a much heavier 
snap (sans swivel).  Speed and some other events require pull tests of 
several hundred pounds to ensure that the planes, lines and attachments are
strong enough.  If you insist on using snaps for parachute attachment, you 
might look into these snaps - I think Sig sells some and I know that fishing 
speciality shops carry them.
From: cdt@sw.stratus.com (C. D. Tavares)
Newsgroups: rec.models.rockets
Subject: Re: NARAM SUMMARY????
Date: 28 Sep 92 17:40:47 GMT
Organization: Stratus Computer, Inc.

In article <1992Sep25.210357.18991@rsd0.rsd.dl.nec.com>, buzz@rsd.dl.nec.com (Buzz McDermott) writes:
> 
> My hope is that the price of the Apogee engines will come down over the course
> of the next year.  Perhaps some other manufacturer might come out with 
> small composites in the B-D range to provide a little competition?

I doubt it.  Apogee engines are made by AeroTech.  Who is left?  Vulcan?
(Snicker.)  No one else has ever sent their existing engines in to S&T to
be tested.  I can't imagine they're going to get enthusiastic about the
NAR competition community all of a sudden.

> I don't know the reasons why next year's CD (who IS next year's CD, anyway?)
> picked the events chosen, but I suspect that the expense and low participation
> in G R/C R/G this year might have had an impact.

It's Tom Lyons (or Lyon, whichever).  I doubt the participation in G R/G
this year had anything to do with it, since the events were chosen well in
advance of NARAM week.

I know Roger asked what the other events are, but I don't have the list at
work.  I'll try to remember to bring it in.
-- 

cdt@pdp.sw.stratus.com      --If you believe that I speak for my company,
OR cdt@vos.stratus.com        write today for my special Investors' Packet...
Organization: Doctoral student, Urban and Public Affairs, Carnegie Mellon, Pittsburgh, PA
Newsgroups: rec.models.rockets
Date: Wed, 30 Sep 1992 11:52:48 -0400 
From: Lawrence Curcio <lc2b+@andrew.cmu.edu>
Subject: Re: Drag coefficients for Estes rockets

I've been fooling around in this area for some months now, at least part
time. According to garden-variety RASP programs, a given rocket
configuration (thrust curve, diameter, and mass) gives possible
combinations of Altitude, Drag Coefficient, and Ascent Time that fall on
a curve (i.e., not a suface) in three dimensions. The shape of that
curve is such that, if you know one of these, you can get the other two.
I tried testing the validity of RASP programs (that is, the validity of
a single drag coefficient for the whole flight) by measuring altitude
and ascent time, then plotting the data on the theoretical graph.

My pilot experiment, in which I used a one-observer optical altitude
procedure, looked promising (after I re-weighed the rockets weeks later,
though). I tried a three-observer altitude determination procedure on a
windy day, and I got no correspondence of theory and data. The actual
ascent times were markedly short.

This week, I reviewed Gregorek's data in ESTES technical Report, TR11.
Dr. G. gives average velocities and peak altitudes for several rockets.
Ascent time should be altitude/velocity (Dr. G. did the reverse to get
average velocity). His measured ascent times were also markedly short;
however they were not monotonically decreasing with drag coefficient, a
fact that makes me wonder about them.

I tried using a Runge-Kutte RASP program to see if that gave better
correspondence. (I used the one in ESTES AEROTREK.) Improvement was very
slight. Either RASP programs don't work at all, or we are measuring the
wrong point in time for apogee. I'm going to video tape some flights,
perhaps this weekend. I have a feeling that apogee, even in a
near-vertical flight, should be measured as the point when the rocket is
horizontal. In the last, say, second, the rocket travels only about 17
feet, and without visual cues, this shouldn't be noticeable. In the last
second, since it is traveling slowly, gravity roll will be considerable.
It should veer visibly from the vertical, even if the launch angle were
only a fraction of a degree off. This veering might look like the
beginning of a descent. 

Right now, the data don't make much sense. If RASP programs can be made
to work, then one could measure altitude and Cd by timing an ascent. The
altitude measurements should be at least as good as single-observer
altitudes, but the drag coefficients should be as good as the best
optical statistics. (In fact, they certainly are, but it is possible
that neither is any good at all right now.)

I emphasize that lack of correspondence would demonstrate that RASP
programs don't work, and hence that drag coefficients are useless in the
hobby.

Regards,
-Larry C.
From: jack@rml.UUCP (jack hagerty)
Newsgroups: rec.models.rockets
Subject: Re: NARAM SUMMARY????
Date: 26 Sep 92 17:33:27 GMT
Reply-To: jack@rml.UUCP (jack hagerty)
Organization: Robotic Midwives, Ltd.

In article <6774@transfer.stratus.com> cdt@sw.stratus.com (C. D. Tavares) writes:
>> Have an F payload altitude - if no one flys, drop
>> it. If people want to fly, they'll invest $4 in a motor.
>
>I don't understand how this argument applies to a NARAM.  It's a little
>late to "drop it" on the day no one showed up to fly it.

You mean like the Super Scale event at the last NARAM. There were only
*two* entrants from the whole country! Well, there were 3, but one of
us (ahem) was DQ'd for not having a launcher :-)

- Jack


=============================================================================
||Jack Hagerty, Robotic Midwives, Ltd.                 jack@rml.com        ||
||Livermore, CA		           NOTE! New, improved address! ^^^        ||
||(510) 455-1143	            (old ones will still work)             ||
||-------------------------------------------------------------------------||
||  "I, like all men, have never grown up. Other men lie and say they      ||
||    have. I refuse to lie. I try to be a creative child, using my        ||
||    immaturity in such ways as benefit my society rather than harm it."  ||
||                           - Ray Bradbury, _Yestermorrow_                ||
=============================================================================
Newsgroups: rec.models.rockets
From: soc1070                         
Subject: Re: Cost of Competition (was NARAM SUMMARY????)
News-Software: VAX/VMS VNEWS 1.41    
Organization: University of Minnesota CIS
Date: Sat, 3 Oct 1992 14:30:00 GMT

In article <580@rml.UUCP>, jack@rml.UUCP (jack hagerty) writes...
>In article <1992Sep28.225911.20271@rsd0.rsd.dl.nec.com> buzz@rsd.dl.nec.com (Buzz McDermott) writes:
>>|> <comments about choice of events potentially being based on cost
>>|>  considerations deleted>
>>It was good thinking on the part of the CD and contest committee
>>for the next NARAM to try to ensure inexpensive events were available.  That
>>wasn't my opinion at first, but it is now, and I think it is the right way
>>to approach an event like a NARAM.
> 
>Maybe I'm missing something here, but compared to the cost of flying/driving
>across country, staying in a big hotel for a week (even at group rates),
>eating resturaunt food and other miscelaneous travel expenses, worrying
>about the difference in the cost of motors seems trivial.
> 
>The point is, that to anyone who can afford dropping $2-3K on a week of
>rocket flying, the difference between a $1 motor and a $4 motor is
>lost in the noise. Unless you're going to be making *hundreds* of BP
>flights or *dozens* of HP flights, the difference just won't be significant.
> 
>- Jack

This was the same point that I was trying to point out when I first opened
this can of worms. When you look at the TOTAL cost of attending a NARAM
(or any other national meet), the rocket flying becomes the cheap part of the
trip. Therefore, basing to events on the cost of flying to the
participant is moot. (unless you're local and have no travel expenses).

When I mentioned reloads for competition (and started THAT can of worms
:) ), I was simply trying to illustrate that there are ways that
participants can keep flying costs down (reloads not being one, since
they are not contest certified, I now know.:) ).

----------
Tim Harincar				Kill Your Television.			
Central Minnesota 		
Association of Rocketry		
soc1070@vx.acs.umn.edu