HDTenEightyP/NetNews huggingface dataset:
From: soc1070
Newsgroups: rec.models.rockets
Subject: Re: Tracking
Date: 26 Jan 93 13:45:00 GMT
Organization: University of Minnesota CIS
News-Software: VAX/VMS VNEWS 1.41

In article <1993Jan26.011603.22455@hpcvaac.cv.hp.com>, billn@hpcvaac.cv.hp.com (bill nelson) writes...
>soc1070 writes:
>: 
>: As for decent rates, I think a basic problem would be that two
>: different rockets, each exactly the same weight and with the 
>: same size 'chutes, would fall at different rates, because the one
>: with the larger exposed area (i.e. fins, tube, etc) would be carried
>: further down wind. A one pound rocket and a one pound sphere with 
>: identical chutes will not likely fall in the same place, so its
>: difficult to say. In your case, what you computed was the *closest*
>: possible distance.
> 
>This is a little misleading. They will both fall at the same rate.
>They will not fall at the same descent angle - the one with the greater
>lateral area of resistance will drift further.
> 
>Bill

You are correct. When I first posted that, I started to type that the
decent rates would be the same, then I confused myself and thought the
rates would be different. Must be work-related stress :)

The decent rate is constant, the speed of the model relative to the
ground changes.

There are also other factors: thermals, sinks, gusts, wind direction
changes, etc. All will effect the landing point of a model. I once thought
of writing a computer program to figure the landing area of a model,
but there are just too many variables changing too fast (or unmeasurable).

------
Tim Harincar				A skunk is better company than
soc1070@vx.cis.umn.edu			someone who prides themselves on
 					being frank. -Lazerus Long
From: jack@rml.UUCP (jack hagerty)
Newsgroups: rec.models.rockets
Subject: Re: Igniters
Date: 25 Jan 93 21:01:53 GMT
Reply-To: jack@rml.UUCP (jack hagerty)
Organization: Robotic Midwives, Ltd.

In article <1993Jan22.171306.10814@hpcvaac.cv.hp.com> billn@hpcvaac.cv.hp.com (bill nelson) writes:
>jack@rml.UUCP (jack hagerty) writes:
>
>... delided ...

Well, I've been accused of being deluded, deranged and demented, but
this is the first time for delided :^)

>I missed your tirade, sorry about that.

You didn't miss much. Just my complaining that this ultra lightweight has 
been given enough ink to risk becoming a hazard.

>: Why did he vary the voltage and not the current? Because he could! 
>: Why didn't he vary the current? Because he couldn't! 

>Well, he did vary the current - he just didn't measure it. The current 
>changed every time the voltage was changed.

Since several people have pointed this out, let me change my complaint
to "Why didn't he *measure* the current" since this seems to be a more
significant factor in ignition system performance than voltage.
>
>: Does dipping an ignitor in plastic  and firing it under water determine 
>: how well it can ignite a rocket motor?

>I think he was talking about having to immerse an ignitor in water to determine
>the calorific output - that is obviously nonsense. I do not recall him ever
>stating that any such test was actually performed.

No, he actually performed the test, it's just that he buried the fact in
some world class hand waiving about the coating and the difficulties of
firing an ignitor underwater (the results are in the last row of his table). 
He seems to understand the concept of a calorimeter, but hasn't the faintest
idea how one works. All he had to do was come up with a thermally conductive
container (like a film can, back before before they were plastic), run 
some wires into it and immerse the *container* in the insulated cup.

>Hopefully, the NAR will not see fit to republish the thing anywhere.

Amen.

>Anything of any use in the articles, you could easily obtain by making a
>5 minute phone call to the manufacturer.

Ah, but how impartial would *they* be :^)

- Jack

=============================================================================
||Jack Hagerty, Robotic Midwives, Ltd.                 jack@rml.com        ||
||Livermore, CA		           NOTE! New, improved address! ^^^        ||
||(510) 455-1143	            (old ones will still work)             ||
||-------------------------------------------------------------------------||
||  "I'm sorry they're flying so low and jamming your radar, Dimitri, but  ||
||    they're trained to do that. It's called, you know, initiative"       ||
=============================================================================
Newsgroups: rec.models.rockets
From: hack@arabia.uucp (Edmund Hack)
Subject: Re: Igniters/Lack of Flames
Organization: Lockheed ESC, Houston
Distribution: usa
Date: Tue, 26 Jan 1993 15:20:45 GMT

Jack - what is the IP number for your site?  I have tried to send email
to you but our mailer and address resolver here can't figure out how to
deliver mail to you.

-- 
Edmund Hack - Lockheed Engineering & Sciences Co. - Houston, TX
hack@aio.jsc.nasa.gov - I speak only for myself, unless blah, blah..
"I'm not an actor, but I play one on TV."
"Detail Dress Circuits" "Belt: Above A, Below B" "Close B ClothesMode"
From: jack@rml.UUCP (jack hagerty)
Newsgroups: rec.models.rockets
Subject: For Edmund's Eyes Only
Date: 27 Jan 93 18:01:37 GMT
Distribution: na
Organization: Robotic Midwives, Ltd., Livermore, CA


Sorry to bother the whole group with this, but apparently we have
a two way problem here. Please 'n' out now (except you, Edmund :-)

I tried sending the following twice by both straight return and direct
e-mail. Both bounced with "unknown host" errors:

In article <1993Jan26.152045.25542@aio.jsc.nasa.gov> you write:
>Jack - what is the IP number for your site?  I have tried to send email
>to you but our mailer and address resolver here can't figure out how to
>deliver mail to you.

None. My MX files are handled by my primary mail feed which is
lll-winken.llnl.gov at the Lawrence Livermore Lab. Most people 
have no trouble with jack@rml.com but you could always try 
jack%rml@lll-winken.llnl.gov or for an old style bang path: 
...uunet!lll-winken!rml!jack.

Part of the problem may be that my return path still shows my
machine as rml.UUCP, but the fix to that is in the works. I'm
currently bringing up a new system and when I recompile the news
software it should make things much easier.

- Jack

---
=============================================================================
||Jack Hagerty, Robotic Midwives, Ltd.                 jack@rml.com        ||
||Livermore, CA		           NOTE! New, improved address! ^^^        ||
||(510) 455-1143	            (old ones will still work)             ||
||-------------------------------------------------------------------------||
||  "I'm sorry they're flying so low and jamming your radar, Dimitri, but  ||
||    they're trained to do that. It's called, you know, initiative"       ||
=============================================================================
From: Roger.Wilfong@umich.edu (Roger Wilfong)
Newsgroups: rec.models.rockets
Subject: Re: Tracking
Date: 26 Jan 93 17:12:00 GMT
Article-I.D.: umich.19930126131220.Roger.Wilfong
Distribution: world
Organization: UofM Hospitals
NNTP-Posting-Host: robin.hosp.med.umich.edu
X-Newsreader: FTPNuz (DOS) v1.0

In Article <MAINE.93Jan26083030@altair.dfrf.nasa.gov> "maine@altair.dfrf.nasa.gov (Richard Maine)" says:
> Roger.Wilfong@umich.edu (Roger Wilfong) writes:
> > Kind of shoots hole in the 'X-form' parachutes don't drift as far a regular 
> > parachutes theory.  Doesn't it?
> 
> Yes.  I've long thought those claims "amusing."  Actually I'd expect an
> X-form probably wouldn't drift as far as other parachutes of the same area
> for the simple reason that the drag is probably lower and thus the descent
> rate higher; of cource you could achive the same effect by just using a
> smaller chute.
 
I agree.  My experiments with them show that they oscillate less - the air 
can easily spill out without tipping the canopy - but the 'bunk' about the 
lower cross section lettinf the air blow through is just that - bunk.
 
> David> Of course, a parachute design that tends to damp oscillation quickly can
> David> sometimes permit a higher vertical velocity without damage to the model,
> David> so you can have less drift by reducing the time in the air.  Just don't
> David> use it for parachute duration events.
> 
> Agree.  And if you have relatively high wind velocities (but still within
> flyable limits), a smaller chute can give you less damage to the model by
> minimizing the amount of dragging accross the lakebed (or whatever) after
> landing.  I have had flights where much more damage was done by such
> dragging than by anything during the flight.
> 
 
Saw a video of the last Danville.  The wind was high enough that it was 
blowing a guy holding what looked like a 10-12' parachute across the field.  
It was no act either - at one point he was down and being dragged across the 
ground.  I imagine that chute/wind combination could have dragged a rocket a 
long way.  (BTW - he finally got it under control by letting go, the chute 
collapsed to the ground.)
Newsgroups: rec.models.rockets
From: jws31@thor.albany.edu (John W Sicker)
Subject: Re: Fun (Really!) at NARFUN
Organization: State University of New York at Albany
Distribution: na
Date: Tue, 26 Jan 93 21:57:02 GMT


Well I be there. Looking forward to getting out of the cold and having
three days to fly. Internet group party sounds like fun. I am flying
in from Albany and staying at the Holiday Inn. Thinking of bringing my new
two stager but not sure if I can get a good motor combo that will not 
punch the wavier. Guess I have to send my rockets UPS to the hotel.  Looking
forward to meeting some of you folks from the net.

John Sicker


Newsgroups: rec.models.rockets,rec.models.rc
From: mckiou@cbnewse.cb.att.com (kevin.w.mckiou)
Subject: Journal of the International Spacemodeling Society
Organization: AT&T
Date: Mon, 25 Jan 1993 20:26:25 GMT

Since the AMA will be doing the US Spacemodeling team selection this
year, I thought there might be some (new) interest in technical info.
I just received the first issue of the Journal of the International
Spacemodleing Society, Tim Van Milligan - ed.  It is a technical
(mostly) journal about "Spacemodeling".  What is "Spacemodeling"
you ask. Well, there is an area of international (FAI) model rocketry
competition called Spacemodeling.  

The events include Radio Controlled Rocket Glide (my favorite), 
free-flight Boost Gliders, Scale, Scale-Altitude, Altitude, 
Streamer Duration and Parachute Duration.

If you are interested, the journal is available either of two ways.  
You can send $10 (for 5 issues) to 

Tim Van Milligan
727 Floral Ave.
Canon City, CO  81212

or by Joining the International Spacemodeling Society.  To join,
contact 

Charles Weiss
49 North St.
Broadalbin, NY

Sorry, I don't have more info on cost of membership.

If you want to contact Tim for more info, he can be reached at

76300.1211@CompuServe.com

Kevin 
Newsgroups: rec.models.rockets
From: maine@altair.dfrf.nasa.gov (Richard Maine)
Subject: Re: Tracking
Organization: NASA Dryden, Edwards, Cal.
	<1993Jan26.011603.22455@hpcvaac.cv.hp.com>
	<19930126100940.Roger.Wilfong@umich.edu>
	<1k3lm0INN93@transfer.stratus.com>
Date: Tue, 26 Jan 1993 16:30:36 GMT

Roger.Wilfong@umich.edu (Roger Wilfong) writes:
> Kind of shoots hole in the 'X-form' parachutes don't drift as far a regular 
> parachutes theory.  Doesn't it?

Yes.  I've long thought those claims "amusing."  Actually I'd expect an
X-form probably wouldn't drift as far as other parachutes of the same area
for the simple reason that the drag is probably lower and thus the descent
rate higher; of cource you could achive the same effect by just using a
smaller chute.

On 26 Jan 93 15:34:24 GMT, det@sw.stratus.com (David Toland) said:
David> The assumption I don't exactly swallow is that a parachute will
David> have a zero horizontal airspeed.  This is not necessarily true,
David> and could depend on the parachute geometry.  If the parachute
David> deforms in such a way as to maintain a particular airspeed,
David> then you can have a ground speed that differs from the wind
David> velocity.

Yes, I was simplifying.  That's what my qualification about "non-gliding"
was intended to refer to.  I was trying to avoid side issues.  Even
if the airspeed is non-zero, the important point is that it is that a
given configuration will maintain a given airspeed, which is essentially
independent of the wind velocity.  For non-gliding chutes that airspeed
happens to be 0, which simplifies the explanation, but doesn't really
change the principle.

David> Parachute oscillation and other factors can also delay reaching a
David> steady state.

True enough.  Another simplification on my part.  But I can't imagine
any such delay being significant in terms of the total amount of drift.

David> Of course, a parachute design that tends to damp oscillation quickly can
David> sometimes permit a higher vertical velocity without damage to the model,
David> so you can have less drift by reducing the time in the air.  Just don't
David> use it for parachute duration events.

Agree.  And if you have relatively high wind velocities (but still within
flyable limits), a smaller chute can give you less damage to the model by
minimizing the amount of dragging accross the lakebed (or whatever) after
landing.  I have had flights where much more damage was done by such
dragging than by anything during the flight.

--
--
Richard Maine
maine@altair.dfrf.nasa.gov

Newsgroups: rec.models.rockets
From: rbs@cyclops.micr.Virginia.EDU (Robert B. Sisk)
Subject: Re: JULBPP.ZIP still bad on archive site
Organization: University of Virginia
Date: Mon, 25 Jan 1993 13:31:34 GMT

In article <22JAN199308272846@vx.cis.umn.edu> soc1070                          writes:
>In article <1993Jan21.172905.6280@ennews.eas.asu.edu>, elder@enuxhb.eas.asu.edu (Greg Elder) writes...
>>Some months back, I had posted that the file julbpp.zip on the r.m.r
>>archive site (sunsite.unc.edu) appeared to be bad (it won't
>>unzip).  Someone, I don't remember who, was going to upload a
>>good version.  I looked today and it seems that the old file is still
>>there.  Does anyone know where, or if, a good copy is available?
>>Thanks.
>> 
>>--
>>Greg Elder                                        elder@enuxhb.eas.asu.edu
>>Department of Computer Science            or      elder@seine.eas.asu.edu
>>Arizona State University
>> 
>
>Hmmmmmm....
>
>I downloaded that once (after your first post) to check it, and it was in
>fact somehow corrupted. So, I uploaded another copy. Once I got it on
>this here vax that I use, I redownloaded it to make sure my modem was
>uploading it ok. It was fine then, so maybe there is something that screws
>up a .zip file between my vax and sunsite. This is probably where the 
>problem comes from: The text was mac, copied to a PC, zipped, xfered
>it back to the mac, uploaded it to a vax, and ftp'd it to a sun. Any
>questions? :)
>
>I'll see if I still have the files and send them to you directly, maybe
>that'll help.
>
>------
>Tim Harincar				A skunk is better company than
>soc1070@vx.cis.umn.edu			someone who prides themselves on
> 					being frank. -Lazerus Long	


Tim,

I think that the archive is fixed.  The problem was that the file was
being corrupted when it was on the archive.  If you have the file handy
please try to upload it to the uploads/rockets directory on SunSite.unc.edu.
Sorry for all of the problems.  

Thanks

Bob

-- 
---------------------------------------------------------------------------
Robert B. Sisk  PhD			Internet: rbs@virginia.edu
NAR #53448				UUCP:     uunet!virginia!rbs
TRIPOLI #1583                           CIS:      71501.1651@CompuServe.COM
Newsgroups: rec.models.rockets
From: tes@motif.uucp (Thomas E. Smith)
Subject: Re: Tracking
Organization: Software Technology Branch, NASA/Johnson Space Center
Date: Wed, 27 Jan 1993 01:36:51 GMT

 
>Of course, what were really interested in is how far down range the rocket 
>lands.  That 'B' egglofter I chased for 1.5 hours was only moving at 4 or 5 
>miles ground speed (same as the 1/2A streamer I'd chased earlier) but I have 
>no idea how far away it landed - I gave up when it disappeared as a tiny dot 
>over head - I don't think an X-form would have made any difference in that 
>thermal :-)
> 
>-Roger

Try chasing a rocket with a G motor :) . I lost sight of it after it went
behind the clouds. I was wondering if there were any smoke devices you could
put in your rocket to track it. One that wouldn't have any danger of starting
a grass fire when it landed?

-- 
____________________________________________________________________________
| It's not my damn planet, understand  | Tom E. Smith                      |
| Monkey Boy?!!       John Bigbootey   | tes@gothamcity.jsc.nasa.gov       |
----------------------------------------------------------------------------
From: 161685732@vill.edu (JOE PRYSZLAK)
Newsgroups: rec.models.rockets
Subject: Re: JULBPP.ZIP still bad on archive site
Date: 24 Jan 93 17:52:00 GMT
Organization: Villanova University
News-Software: VAX/VMS VNEWS 1.4-b1

In article <1993Jan21.172905.6280@ennews.eas.asu.edu>, elder@enuxhb.eas.asu.edu (Greg Elder) writes...
>Some months back, I had posted that the file julbpp.zip on the r.m.r
>archive site (sunsite.unc.edu) appeared to be bad (it won't
>unzip).  Someone, I don't remember who, was going to upload a
>good version.  I looked today and it seems that the old file is still
>there.  Does anyone know where, or if, a good copy is available?
>Thanks.
> 
>--
>Greg Elder                                        elder@enuxhb.eas.asu.edu
>Department of Computer Science            or      elder@seine.eas.asu.edu
>Arizona State University
> 


I noticed the same thing.  I also noticed that the FAQs don't find their way
to the FTP archive anymore.  Any objections to me uploading the newest one
there?

What's in this JULBPP.ZIP file anyway?
Newsgroups: rec.models.rockets
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Igniters
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
Date: Thu, 28 Jan 1993 00:23:29 GMT

ntaib@silver.ucs.indiana.edu (Iskandar Taib) writes:
: In article <1993Jan26.145748.3731@hpcvaac.cv.hp.com> billn@hpcvaac.cv.hp.com (bill nelson) writes:
: 
: >Note that the voltage applied tells us very little. We don't even know if
: >that is sufficient voltage drop, across the ignitor, to cause it to ignite.
: >All we know is that this is a minimum value - practical values are likely
: >to be higher. How much, we cannot determine, because he did not tell us about
: >his test setup.
: 
: >Now, this problem could have been eliminated very simply. All he would have
: >had to do was measure the circuit current. Then, it does not matter how the 
: >resistances of the circuit may be distributed. You know that, if a certain
: >current flows, then the ignitor will function.
: 
: Well, actually, I think its a good idea, *provided* he measures
: the actual voltage drop across the ignitor, or uses a current source
: with very little internal resistance. Current is dependent only on 
: the voltage drop and the resistance of the ignitor, and the latter
: value can easily be determined and shouldn't vary from sample to 
: sample.

That was my point - we have no way of knowing how the voltage was
obtained. Voltage is fine, for a short run using a large wire size.
It is not good when running 500 feet of twinlead 22 gauge wire. There
is quite a bit if voltage drop in the wiring alone.

: Measuring either the current or voltage drop is difficult, since the 
: reading is instantaneous (one the thing goes off your circuit is bro-
: ken) so perhaps measuring cell voltage and using thick, short wires
: might be a good compromise, especially if he uses nicads (very low 
: internal resistance). Actually, this should be useful info, since (es-
: peacially with smaller setups) one simply uses a given number of cells
: to fire off the ignitor - one doesn't worry about building a current-
: regulated circuit.

To make it even more difficult, the current drops - as the ignitor heats
up. 

The article added nothing to our empirical knowledge - that a well charged
12 volt battery is sufficient for rapid ignition of all currently supplied
ignitors - even with fairly long runs of small (20 or 22) gauge wire.

Bill
Newsgroups: rec.models.rockets
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Tracking
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
Date: Tue, 26 Jan 1993 08:20:16 GMT

maine@altair.dfrf.nasa.gov (Richard Maine) writes:

: That's still misleading.  I've seen several people in the past make
: the same mistake.  Presumably none of them are pilots (which I am) nor
: parachutists (which I'm not, but I presume they must have the right
: intuition even more strongly).  The lateral area has essentially
: nothing to do with either descent rate or descent angle.  Anything
: falling on a non-gliding parachute will move laterally with "exactly"
: (to as close as matters, excepting mainly transient gusts) the
: wind velocity, making lateral area irrelevant.

You are right. I noticed the error, after I had made the posting.
If they descend at the same rate - they will drift the same distance,
no matter what their shape or size may be.

: The pilot in me notes that flight dynamics are always relative to the
: wind, not the ground.  This is *VERY* apparent in light aircraft;
: if you have a pilot friend that doesn't appreciate this, I'd advise you
: not to go flying with him/her.  The misunderstanding is a common cause
: of stall/spin accidents.

Yeah - wind shear on takeoff or final approach does do in a number of
people every year.

As a pilot myself, and ex-parachutist, I should not have forgotten.
Thanks for the riminder.

: I'd estimate that it probably takes on the order of one second after
: chute opening to reach the steady state condition.  That one second
: or so is the only time that there is significant lateral velocity
: relative to the wind.

Agreed - thanks again for the clarification.

Bill
From: mckiou@cbnewse.cb.att.com (kevin.w.mckiou)
Newsgroups: rec.models.rockets
Subject: Journal of the International Spacemodeling Society
Date: 26 Jan 93 17:43:55 GMT
Organization: AT&T

Since the AMA will be doing the US Spacemodeling team selection this
year, I thought there might be some (new) interest in technical info.
I just received the first issue of the Journal of the International
Spacemodleing Society, Tim Van Milligan - ed.  It is a technical
(mostly) journal about "Spacemodeling".  What is "Spacemodeling"
you ask. Well, there is an area of international (FAI) model rocketry
competition called Spacemodeling.  

The events include Radio Controlled Rocket Glide (my favorite), 
free-flight Boost Gliders, Scale, Scale-Altitude, Altitude, 
Streamer Duration and Parachute Duration.

If you are interested, the journal is available either of two ways.  
You can send $10 (for 5 issues) to 

Tim Van Milligan
727 Floral Ave.
Canon City, CO  81212

or by Joining the International Spacemodeling Society.  To join,
contact 

Charles Weiss
49 North St.
Broadalbin, NY

Sorry, I don't have more info on cost of membership.

If you want to contact Tim for more info, he can be reached at

76300.1211@CompuServe.com

Kevin