HDTenEightyP/NetNews huggingface dataset:
From: mlm@arreaux.East.Sun.COM (Mike McMullen-Sun Cary-NC SE)
Newsgroups: rec.models.rockets
Subject: Piston Ejection
Date: 15 Dec 1992 18:24:33 GMT
Organization: Sun Microsystems, Inc.
Distribution: world
Reply-To: mlm@arreaux.East.Sun.COM
NNTP-Posting-Host: arreaux.east.sun.com

Has anyone built and used rockets with piston ejection for parachutes? I'm building
a Public Missiles Phobos and have concerns about residue forming on the inside tube
from the ejection charge. It seems to me that residue buildup could cause too much
friction on the piston unless you clean well after each use. Has anyone run into
problems with this?

Thanks,
Mike

---

    /\        Mike McMullen
   \\ \       Systems Engineer
  \ \\ /      Sun Microsystems Computer Corporation
 / \/ / /     125 Edinburgh South, Suite 105
/ /   \//\    Cary, NC 27511
\//\   / /    
 / / /\ /     Phone:    (919) 460-2924 
  / \\ \      Email:    mike.mcmullen@East.Sun.Com
   \ \\       NAR#      56252
    \/        Tripoli#  1966


Organization: Doctoral student, Urban and Public Affairs, Carnegie Mellon, Pittsburgh, PA
Newsgroups: rec.models.rockets
Date: Wed, 16 Dec 1992 11:56:39 -0500 
From: Lawrence Curcio <lc2b+@andrew.cmu.edu>
Subject: Re: Exhaust Deflector Material Question

Aluminum reacts with acids, like HCl from composites, and with bases,
like K2S, K2O, K2CO3 etc from black powder. These agents aren't in
solution when they emerge from an engine, but they're hot. It's no
wonder people have observed pitting. 

Aside from using coffee can lids in my youth, I haven't experimented so
I guess I don't qualify to comment, but Hey! I got this dandy computer
network and all... Try stainless steel. 

There! I've said it and I'm glad. Yes GLAD! GLAD, do you hear me!

GLAD I TELL YOU!!!!!! 
Newsgroups: rec.models.rockets
From: sbbrown@magnus.acs.ohio-state.edu (Stephen B. Brown)
Subject: Re: Exhaust Deflector Material Question
Organization: The Ohio State University Radio Observatory
Date: Tue, 15 Dec 1992 17:01:08 GMT

In article <1992Dec14.081911.1@travis.llnl.gov> massey@travis.llnl.gov writes:
>	I'm looking for someone who has had first-hand experience, either good
>	or bad, with using 1/8-inch aluminum plate (6061) as a launch-stand 
>	exhaust deflector. For the launchers that I'm building, the planned 
>	deflectors are about 10 inches square and perpendicular to the launch
>	rod. Will there be a problem with burn-through or melting? At what 
>	engine size does this begin to be a problem?

Some time ago, I used some scrap aluminum to construct a blast shield.  I
don't know the alloy--it was reclaimed from a scrap of aluminum gutter.
It was about 3/32" thick.  I cut an 8" disc and brazed a 3/16" ID AL tube
into a hole in the center so that it would drop onto an 3/16" launch rod.
The blast plate was perpendicular to the rod.

We noticed fairly quickly that the D engines (black powder) were causing
pinholes in the aluminum, some as big as 1/16".  I suspect that the holes
were melted by the exhaust, rather than being punched, but I can't really
confirm this hunch.  It was very consistent--at least half of the launches
caused a new hole.  We fixed this by cutting a hole in the middle of a
large tin can lid, and dropping it over the rod, so that it was supported
by the aluminum plate.  This has worked very well.

The only other lesson I've learned from this is that the tolerance on the
tube which slides over the rod was too tight.  It worked beautifully at
first--didn't wobble at all (still doesn't)--but after a season's corrosion
they could no longer be seperated, so it doesn't break down as compactly
as I'd intended.  However, it usually stays at someone else's basement,
where it doesn't inconvenience me.
-- 
Steve Brown, N8HFI              sbbrown@magnus.acs.ohio-state.edu
Chief Engineer, The Ohio State University Radio Observatory ("Big Ear")
From: cdt@sw.stratus.com (C. D. Tavares)
Newsgroups: rec.models.rockets
Subject: Re: Hello and finless tec
Date: 15 Dec 1992 19:36:39 GMT
Organization: Stratus Computer, Inc.
Distribution: world
NNTP-Posting-Host: rocket.sw.stratus.com

In article <1992Dec15.093645.14393@aio.jsc.nasa.gov>, jackson@sn.jsc.nasa.gov writes:

> >Rule 5.5 - Momentum
> >
> >A launcher must not impart to the model any velocity or change of momemtum
> >except that caused by the model rocket motor(s) contained in the model.

> Then, .... that makes it sound like 'linear' momentum and not
> angular momentum.

Sounds like wishful thinking to me...

> Anyway one could not gain any advantage by
> imparting angular momentum about the roll axis, except stability.
> Would there be less drag on a spinning finless rocket?

Much less.
-- 

cdt@rocket.sw.stratus.com   --If you believe that I speak for my company,
OR cdt@vos.stratus.com        write today for my special Investors' Packet...

Newsgroups: rec.models.rockets
From: hrbob@ixstar.ih.att.com (R.E. Wiersbe)
Subject: Re: FAA response update
Originator: news@cbnewsb.cb.att.com
Organization: AT&T Bell Laboratories
Distribution: usa
Date: Wed, 16 Dec 1992 17:01:31 GMT

In article <1gldgkINN90v@transfer.stratus.com> cdt@sw.stratus.com (C. D. Tavares) writes:
>The response file at FAA as of the December 9 deadline contains 83 items.
>One is the NAR response, and 78 of these are from modelers (we assume),
>in support of the NAR's response.
>
>Three negative responses were received.  Two of them were from the Air
>Line Pilots' Association and the Air Transport Association -- not a great
>sign.  Aside from the Arizona Pilots' Association, who wrote in support,
>they were the only responses received from the aviation industry -- in
>fact, from anywhere outside the hobby.
>
Hmm....78 from modelers (assumed) in support, and 1 in support from the 
avaiation industry (I'm assuming a small part - only the State of Arizona).
2 against from major league associations, and 1 from someone who appears to
be misinformed/paranoid/downright ornery. I hope the FAA has sense enough
to realize this person is grinding an axe, and it doesn't have much to do with
the issue at hand. I wouldn't lend much credibility to someone who doesn't
sign their name either.

I'm just afraid that the FAA will listen to the 2 negatives, and basically 
ignore the rest of us (my usual pessimistic thinking). I hope I'm wrong.

>When I get a chance to OCR all the negative comments in, I will post
>them here.
>-- 
Thanks, I'll be looking forward to reading them. So what happens next? Do we
live or die by what they decide, or are there alternatives if they don't
decide the way we'd like them to? Any idea just when they will come out with
a decision?

Bob Wiersbe	NAR# 44588SR	hrbob@ihlpb.att.com

Newsgroups: rec.models.rockets
From: Roger.Wilfong@umich.edu  (Roger Wilfong)
Subject: Re: Club Projects
Organization: UofM Hospitals
X-Newsreader: FTPNuz (DOS) v1.0
Date: Fri, 11 Dec 1992 21:48:00 GMT

In Article <1992Dec11.190041.15979@hpcvaac.cv.hp.com> "billn@hpcvaac.cv.hp.com (bill nelson)" says:
> Roger.Wilfong@umich.edu (Roger Wilfong) writes:
> :  
> : I also don't know how they do it, but altimiters have worked on barometric 
> : pressure in moving airplanes for decades.  I suspect that (as with wings) 
> : Bernoulli effect is greatly over rated - that is while there is an 
> : atmospheric vent(s), it is not sufficiently aerodynamic to produce a 
> : significant vacuum.
> 
> The altimeter in an airplane is not really subject to the Bernoulli effect.
> The static port is open to the cabin of the craft - except for high altitude
> craft, which use some sort of static chamber. The unpressurized cabin or
> unpressurized chamber is at ambient atmospheric pressure. This might not be
> the case if the aircraft were making 30,000 ft/minute altitude changes.
> 
 
While airplanes do not typically perform 30,000 ft/minute altitude changes 
(at least usually not +30,000 f/m), this speed (340 mph) is well with in the 
range of many unpressurized aircraft.  While in thoery, I am familiar with 
flying an airplane; in practice, I am ignorant of how many of the details 
are implimemnted.
 
If Bernoulli is going to have an effect on lowering the pressure as a result 
of velocity, the cabin pressure of an airplane traveling 340 mph in any 
direction should be lowered by the same amount.  A rocket traveling at the 
same speed, should be subjected to the same change in pressure due to its 
motion as the plane.  As long as there is a sufficiently large vent in the 
payload chamber (and that vent isn't attached to a venturi), the internal 
pressure should be able to track the atmospheric pressure at least as well 
as the cabin pressure in an airplane can.  
 
If this is the case, as long as Tim takes into account the pressure drop due 
to Bernoulli effect, he should be able to correct for it.  Actually, I would 
think that the investigation of Bernoulli effect on the altimeter would make 
a good R&D topic.
  
--
 
BTW - I'm suprised no one jumped on my discounting Bernoulli effect on wings.
Newsgroups: rec.models.rockets
From: jackson@sn.jsc.nasa.gov
Subject: RE: Piston Ejection
Reply-To: jackson@sn.jsc.nasa.gov
Organization: Organization, City, State, etc.
Date: Wed, 16 Dec 1992 01:31:10 GMT


>>>  Has anyone built and used rockets with piston ejection for parachutes?
>>>I'm building a Public Missiles Phobos and have concerns about residue
>>>forming on the inside tube from the ejection charge.  It seems to me
>>>that residue buildup could cause too much friction on the piston unless
>>>you clean well after each use.  Has anyone run into problems with this?
>
>  Yeah Mike, I built a PMI model once.  I think the piston mechanism is
>a poor design.  Not only is there a cleaning problem, but there is also
>a construction problem because it is VERY difficult not to get epoxy on
>the piston mechanism when you slide the motor mount in the rocket.
>
>  Ejection sounded like a LARGE firecracker due to the sudden realse of
>pressure when the piston leaves the body tube.  I suspect that there is
>a large over pressure condition that would tend to spit out the engine
>until the piston clears the body tube.
>
>  I would suggest that you do not use the piston.
.....
Gee, Stu , I have had success with Public Missiles models, 
I never had much fouling of the piston that a little sanding
would not fix. I like that I have never burned any chutes with
the piston system. 
Only problem I have had is with phenolic, they just dont take      
stress normal to the airfraOnly air frame IDynacom fibreglass
Blackwidow, but its a heavy dude. Will be trying the carbon
fibre composites soon.

Al Jackson
Tripoli 1625
NAR 55412

Newsgroups: rec.models.rockets
From: soc1070                         
Subject: Re: Other reloadables besides Aerotech? (Re: Info. about solid rocket-
News-Software: VAX/VMS VNEWS 1.41    
Organization: University of Minnesota CIS
Date: Tue, 15 Dec 1992 13:17:00 GMT

In article <1gj5tpINN8q3@transfer.stratus.com>, cdt@sw.stratus.com (C. D. Tavares) writes...
>In article <1992Dec14.214737.3742@rsd0.rsd.dl.nec.com>, buzz@rsd.dl.nec.com (Buzz McDermott) writes:
> 
>> I took the announcement to mean that Aerotech was simply going to re-label
>> what currently says 'ISP' to say 'Aerotech'. 
> 
>Right, that's how I understand it.

I hope they do some sort of additional labeling instead of just slapping
an aerotech logo on the old ISP casings. I think doing this will create
a lot of confusion over which reloads will fit in which case. I know that
when I was buying my first reloadable (RMS 3-in-1), I was confused at the
fact that ISP reloads wouldn't fit in the Aerotech casing. I figured all
the casings would be the same, just marketed different (we do the same with
our products all the time - different brand loyality and recognition)

I think it will create tons of confusion over reloads if there are two
compleatly different systems both with the Aerotech brand on them - I
would drop the ISP cases (labeled aerotech) under H or drop the RMS 40/240
(not likely) so there isn't any crossover. 
------
Tim Harincar				Millions long for immortality			
Central Minnesota 			who don't know what to do with
Association of Rocketry			themselves on a rainy Sunday 
soc1070@vx.cis.umn.edu			afternoon. -Susan Ertz
Newsgroups: rec.models.rockets,rec.models.scale,rec.models.railroad,rec.models.rc
From: berger@atropa (Mike Berger)
Subject: Re: Decals via Laser Printer
Organization: University of Illinois at Urbana
Date: Thu, 17 Dec 1992 16:40:29 GMT

cdt@sw.stratus.com (C. D. Tavares) writes:
>In article <Bz9GuK.EwF@usenet.ucs.indiana.edu>, ntaib@silver.ucs.indiana.edu (Iskandar Taib) writes:

>> The big problem is getting the knife to rotate. This is how the 
>> plotter knife thing works.

>But you can buy such knives at any graphic arts shop.
>-- 
The plotter has to have special hardware to rotate the knife or it
won't work.  Gerber and Roland both supply cutting plotters.
--
	Mike Berger
	Internet    berger@atropa.stat.uiuc.edu
Newsgroups: rec.models.rockets
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Other reloadables besides Aerotech? (Re: Info. about solid rocket-
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
Date: Tue, 15 Dec 1992 01:12:50 GMT

buzz@rsd.dl.nec.com (Buzz McDermott) writes:

... delided ...

: the old black and silver ISP design.  It's much sturdier, heavier, and more
: forgiving.  Some people like to buy and use the ISP 29/60 and 29/100 hardware
: sets rather than the Aerotech 29/40-120 for just this reason.  The 29/60
: gets you a 'light' F, the 29/100 gets you a 'light' G, and the 29/180
: Blackjack reload gets you a full, 160NS G.

Thanks for the confirmation Buzz - that was my impression, also.

: I took the announcement to mean that Aerotech was simply going to re-label
: what currently says 'ISP' to say 'Aerotech'.  This would be consistent with
: their recent announcement that Aerotech had completely separated from ISP.
: Their current reloads would not fit if they changed the design of the current 
: ISP hardware.

I hope that is what they mean, and not that (in the interest of economy), they
would be dropping the ISP design in favor of the cheaper Aerotech reloadable.

Bill
Newsgroups: rec.models.rockets
From: jackson@sn.jsc.nasa.gov
Subject: Re: Exhaust Deflector Material Question
Reply-To: jackson@sn.jsc.nasa.gov
Organization: Organization, City, State, etc.
Date: Mon, 14 Dec 1992 20:44:06 GMT

Xref: sparky rec.models.rockets:3282 rec.models.scale:674 rec.models.railroad:2679 rec.models.rc:5044
From: ntaib@silver.ucs.indiana.edu (Iskandar Taib)
Newsgroups: rec.models.rockets,rec.models.scale,rec.models.railroad,rec.models.rc
Subject: Re: Decals via Laser Printer
Date: 14 Dec 92 18:03:56 GMT
Article-I.D.: usenet.Bz9GuK.EwF
Organization: Indiana University

In article <1992Dec8.181914.895@tellab5.tellabs.com> fayne@tellabs.com (Jeffrey Fayne) writes:

> Speaking of plotter knives, is it possible to convert a standard plotter to use the knives?
>
>Roland makes a 'personal' cutting plotter, but I don't know about it's capability or price, so I
>was thinking the next cheapest thing to do was to use a standard plotter with a cutting knife.

The big problem is getting the knife to rotate. This is how the 
plotter knife thing works.





-- 
-------------------------------------------------------------------------------
Iskandar Taib                          | The only thing worse than Peach ala
Internet: NTAIB@SILVER.UCS.INDIANA.EDU |    Frog is Frog ala Peach
Bitnet:   NTAIB@IUBACS                 !
From: ntaib@silver.ucs.indiana.edu (Iskandar Taib)
Subject: Re: Piston Ejection
Organization: Indiana University
Date: Thu, 17 Dec 1992 16:54:20 GMT

In article <15DEC199216364920@vx.cis.umn.edu> soc1070                          writes:

>You might try Ed LaCroix at Apogee Components (71441.1111@compuserve.com).
>I know he has done quite a bit of work with piston ejection. He researched
>it mostly as a method of avoiding the dreaded "zipper effect" or other
>tube damage as a result of ejection. I wish I would have used this method
>on my scale Iris, which i destroyed by over coasting it and zippering
>the whole tube.

Please describe this "zipper effect". Use colorful terms 9-)






-- 
-------------------------------------------------------------------------------
Iskandar Taib                          | The only thing worse than Peach ala
Internet: NTAIB@SILVER.UCS.INDIANA.EDU |    Frog is Frog ala Peach
Bitnet:   NTAIB@IUBACS                 !
Newsgroups: rec.models.rockets
From: hrbob@ixstar.ih.att.com (R.E. Wiersbe)
Subject: Re: Exhaust Deflector Material Question
Originator: news@cbnewsb.cb.att.com
Organization: AT&T Bell Laboratories
Distribution: usa
Date: Wed, 16 Dec 1992 21:14:13 GMT

In article <19921215131018.Roger.Wilfong@umich.edu> Roger.Wilfong@umich.edu  (Roger Wilfong) writes:
>In Article <Af=pz7S00WB2I7jGRe@andrew.cmu.edu> "Lawrence Curcio <lc2b+@andrew.cmu.edu>" says:
>> 
> 
>> Try stainless steel. 
> 
>I think that will work alot better than a computer network.
> 
>On the serious side, I've seen aluminum burn through on a D-12 that was 1/2"
>above it at ignition.  I have both stainless steel launch rods and aluminum.
>The aluminum need to be cleaned all the time because of corrosion buildup.  
>The stainless steel need cleaning too, but the buildup is not as fast.
> 
I've seen a D12 burn through a stainless steel deflector when the rocket hung
on the rod. I don't remember how thick it was, but we were launching E, F, and
G motors too, and none of them even pitted the plate. Left a real neat pattern
of gunk too, kind of like a star.

Bob Wiersbe	NAR# 44588	hrbob@ihlpb.att.com
From: cdt@sw.stratus.com (C. D. Tavares)
Newsgroups: rec.models.rockets
Subject: Re: Piston Ejection
Date: 17 Dec 92 18:05:03 GMT
Organization: Stratus Computer, Inc.
NNTP-Posting-Host: rocket.sw.stratus.com

In article <BzExMK.ELG@usenet.ucs.indiana.edu>, ntaib@silver.ucs.indiana.edu (Iskandar Taib) writes:

> Please describe this "zipper effect". Use colorful terms 9-)

You've seen Jiffy padded mailing bags, where you pull the string on one 
end and it rips across the entire bag, opening it up for you?  Imagine
a noce, strong Kevlar shock cord doing the same to your rocket body tube.
-- 

cdt@rocket.sw.stratus.com   --If you believe that I speak for my company,
OR cdt@vos.stratus.com        write today for my special Investors' Packet...
Newsgroups: rec.models.rockets
From: jackson@sn.jsc.nasa.gov
Subject: Re: Exhaust Deflector Material Question
Reply-To: jackson@sn.jsc.nasa.gov
Organization: Organization, City, State, etc.
Date: Mon, 14 Dec 1992 17:43:55 GMT

Anybody know a manfacturer of high power rocketry 
adjustable launch towers? Would like a metal one
ajustable 1 to 4 inchs in diameter.
...
From: barrett@add.itg.ti.com
Newsgroups: rec.models.rockets
Subject: Tripoli Legal fund
Date: 18 Dec 1992 14:34:37 GMT
Organization: Texas Instruments Incorporated, Austin
NNTP-Posting-Host: powder.add.itg.ti.com

  Most Tripoli members have received a mailing that updates them on the
status of the legal fight with the various government agencies that are
restricting our hobby.  The main theme is that we have retained some
very competent legal counsel that is representing us very well.

  However, this being America, we need to spend money in order for our
Government to listen to us.  We are in desperate need of contibutions to
our legal fund.  Please send any amount that you can afford to our legal
fund.  I have made a contribution of $100 which I think is easily
rationalized by amortizing it over a couple of years of enjoying my
model rocket hobby.

Please send your contibutions to:

  Tripoli Legal Fund
  Tripoli Rocketry Assoc. Inc
  PO Box 339
  Kenner, LA. 70063-0339

Make sure that your checks are made out to: Tripoli Legal Fund


We need to make a contribution to our counsel THIS MONTH, so try and get
your check in the mail ASAP.

Sorry if I offended anybody with this solicitation.

Stu Barrett  barrett@add.itg.ti.com
TRA#1277  NAR#4341
From: cdt@sw.stratus.com (C. D. Tavares)
Newsgroups: rec.models.rockets
Subject: Re: Other reloadables besides Aerotech? (Re: Info. about solid rocket-
Date: 14 Dec 1992 23:38:33 GMT
Organization: Stratus Computer, Inc.
Distribution: world
NNTP-Posting-Host: rocket.sw.stratus.com

In article <1992Dec14.214737.3742@rsd0.rsd.dl.nec.com>, buzz@rsd.dl.nec.com (Buzz McDermott) writes:

> I took the announcement to mean that Aerotech was simply going to re-label
> what currently says 'ISP' to say 'Aerotech'. 

Right, that's how I understand it.
-- 

cdt@rocket.sw.stratus.com   --If you believe that I speak for my company,
OR cdt@vos.stratus.com        write today for my special Investors' Packet...

Newsgroups: rec.models.rockets
From: buzz@rsd.dl.nec.com (Buzz McDermott)
Subject: Kit Review, NCR Phantom 4000
Organization: NEC America, Radio Software Dept
Date: Mon, 14 Dec 1992 17:40:45 GMT

I recall North Coast Rocketry getting a little 'bad press' in this newsgroup,
recently, so I thought I'd give my impressions of a kit I just received.

Recently, I purchased an NCR Phantom 4000.  This was bought to be a gift, so
I didn't build it.  I did have to open the box to pull out the receipt (I 
got the kit mail order from High Sierra) and I used the opportunity to 
check out the contents.

Model summary:     NCR Phantom 4000    single motor F/G sport rocket
Length:            50"
Diameter:          ~4in (standard 3.90 ID tubing)
Weight:            ~25oz. (from the NCR catalog)
Rec. motors:       F25, F50, G40, G80
List price:        $39.95

The kit comes with a full-length of 3.90ID tubing (34"), pre-cut plywood fins,
a 36" nylon chute, and the NCR style 'Gorrilla' shock mount.  For those 
familiar with LOC offerings this kit is similar in size, weight, and price
to the LOC/Precision LOC IV.  The Phantom comes with very good instructions,
compared to the LOC, AAA, and Microbrick kits that I've seen.  One really nice
touch is the inclusion of the estimated CP and notes on where the CG needs to
be.  The nose cone is an Ace PNC-3.90, 4:0 ogive, plastic.  The 29mm motor 
tube had a thrust ring for those who want to use it, but the instructions
mention why you might want to leave it out.  The motor tube is over 12" long, 
plenty long for those who might want to stick in an H70 or 29/180 or 29/240
reload of some type.

The one minor disapointment I have with the kit is that is does NOT
use through-the-wall fins.  The fins are attached via the outside of the body
tube, although the NCR instructions do go into some detail on how to
strengthen the joint.  One other note.  The motor mount adapter rings are
not plywood.  They are some other type of material, but they appear to
be very strong.

It appears to me to be equal in quality to the Loc/Precision kits.  If the 
other NCR kits are this good, then they've solved any quality problems they 
may have had in the past and are producing a product as good as any other 
manufacturer.  NCR kits took a big jump in price this year, but they are still 
competitive with LOC and others,

This ought to be a good kit to get NAR H or I certification, or to use for 
Tripoli confirmation.

================================================================================
= Buzz McDermott                Disclaimer: I speak for no one but myself, and =
= buzz@rsd.dl.nec.com                       anyone who listens to anything I   =
= NAR   13559                               have to say deserves whatever they =
= TRA    1785                               get!!                              =
================================================================================
Newsgroups: rec.models.rockets