HDTenEightyP/NetNews huggingface dataset:
From: gpayne@gn.ecn.purdue.edu (Gregory A. Payne)
Newsgroups: rec.models.rc
Subject: Re: extensions from engine to propeller?
Summary: clarification about question
Date: 16 Dec 92 03:24:20 GMT
Organization: Purdue University Engineering Computer Network

In article <95021@rphroy.ph.gmr.com>, pfoss@cmsa.gmr.com (Pete Foss PO/46) writes:
> 
> In article 19647@gn.ecn.purdue.edu, gpayne@gn.ecn.purdue.edu (Gregory A. Payne) writes:
> >I would like peoples opinions and experiences on using a shaft
> >to move the propeller farther in front of the engine (instead of
> >'directly' in front of it).  I curious about problems this leads to
> >also.
> 
> How long an extension are you talking about, 1/2 inch or many inches.  I have
> seen 1/2 inch extensions advertised (I think).

Sorry, I should have specified this..I was mostly looking for extensions of
5 inches or greater. Thanks
Greg Payne
gpayne@gn.ecn.purdue.edu
Newsgroups: rec.models.rc
From: okof@jec322.its.rpi.edu (Frederick Joseph Oko Jr.)
Subject: RC AH-64 Apache?
Reply-To: okof@rpi.edu
Organization: Rensselaer Polytechnic Institute, Troy, NY.
Date: Sat, 12 Dec 1992 02:32:33 GMT

Keywords: 
       With all the advanced models on the market, I was wondering if any company makes an Apache or if anyone knows of plans for the model.
From: jrauser@staff.tc.umn.edu (Johnny R.)
Subject: Re: From the Aeronautics File
Organization: University of Minnesota
Distribution: usa
Date: Wed, 16 Dec 1992 18:10:37 GMT


Sorry for those of you who got this twice. It was first posted with a
local distribution.

In <6484.2b1f92b5@hayes.com> bcoleman@hayes.com (Bill Coleman) writes:

>In article <1992Dec02.170624.6435@bmerh85.bnr.ca>, mkfeil@bcrki9.bnr.ca (Max Feil) writes:

[much nonsense deleted]

>Action / Reaction and Bernoulli both account for the lift of a wing. Both.
>Indeed, in some ways they are manifestations of the same thing.

>In certain types of wing designs, Bernoulli plays less of a role. It is,
>nevertheless, always present.

What?!?  Listen to what you are saying.  How can I make a mathematical 
relationship somehow less effective by designing a wing in a
particular way?

You seem to be saying that somwhere in the world there is a big book
where I can look up the percentage contributions of Newtonian
mechanics, and the Bernoulli equation to the lift of a given airfoil
at a given angle of attack. 

In reality, if one wanted to calculate the lift and drag
characteristics of an airfoil analytically, one would use Newtonian
mechanics and the conservation laws, to develop the Navier-Stokes
equations, and Prandtl's boundary layer equations.  Solve them
(probably numerically) for the particular flow field of interest, and
arrive at a velocity distribution.  Then one would use the Bernoulli
equation (or some other method) to determine, from the velocity
distribution, what the pressure distribution over the airfoil looks
like.  One would then integrate this pressure distribution over the
airfoil, and reslove the lift and drag components of the total force.

Lift is _caused_ by the interaction of air molecules with their
neighbor molecules and a nearby airfoil.  Saying that lift is somehow
_caused_ through a combination of the Bernoulli effect and Newtonian
mechanics doesn't make any sense.  The Bernoulli equation can be
_used_ (in part) to _describe_ why lift happens, and how it works, but
to say that it _causes_ lift is meaningless.  If you don't buy this,
tell me how much of the lift of a given airfoil is attributable to the
Kutta-Joukowski lift theorem, or for that matter Prandtl's lifting line
theory. 

>Bill Coleman, AA4LR                ! CIS: 76067,2327    AppleLink: D1958

-- 
John Rauser                      "All that we see or seem
jrauser@staff.tc.umn.edu          is but a dream within a dream"
jmr@ddt.biochem.umn.edu              -Edgar Allan Poe
mf12003@sc.msc.edu


-- 
John Rauser                      "All that we see or seem
jrauser@staff.tc.umn.edu          is but a dream within a dream"
jmr@ddt.biochem.umn.edu              -Edgar Allan Poe
mf12003@sc.msc.edu
Newsgroups: rec.models.rc
From: ntaib@silver.ucs.indiana.edu (Iskandar Taib)
Subject: Re: rumor: Lubbock may NOT be 93 Nats site..
Organization: Indiana University
Distribution: rec.models.rc
Date: Fri, 18 Dec 1992 23:19:48 GMT

In article <BzGHz7.ED5@acsu.buffalo.edu> trljim@ubvmsb.cc.buffalo.edu (JIM SONNENMEIER) writes:
>In article <1992Dec17.154349.19252@syscon.rn.com>, miked@syscon.rn.com (Mike DeMetz) writes...
>>I belive it said in the AMA mag that they still needed the FAA
>>permission and if they could not get it they would go back to
>>Lawernceville or Muncie.

>I have heard that in fact the nats will be at Lawenceville. Lubbock is out.
>This comes from people with AMA's ear. (its second hand, but its reliable)

Hmmmmm... this is good news and bad news I guess. Good news because its
90 miles from where I am but bad news because I was looking forward to 
the trip and meeting Larry and Lyman. Lets have a net.dinner or something 
wherever it is.




-- 
-------------------------------------------------------------------------------
Iskandar Taib                          | The only thing worse than Peach ala
Internet: NTAIB@SILVER.UCS.INDIANA.EDU |    Frog is Frog ala Peach
Bitnet:   NTAIB@IUBACS                 !
Organization: University of Maine System
Date: Tuesday, 15 Dec 1992 12:42:28 EST
From: <WOLPERT@MAINE.MAINE.EDU>
Newsgroups: rec.models.rc
Subject: Re: Super Decathalon 40
Distribution: usa
 <1gdltfINNa42@rave.larc.nasa.gov>

Well, chalk up another wrecked Decathlon.  A guy at our field did a
beautiful job building one.  On its second flight, it fell out of an
inside loop, went into a terrible spin and literally disintegrated
on contact.  The owner/pilot was an experienced,  although reckless
flyer who avowed not to rebuild it or any other Decathlon.

Seth Wolpert
Bangor R/C Gulls
Newsgroups: rec.models.rc
From: haley@ee.ualberta.ca (Richard Haley)
Subject: motor speed control error
Summary: error in schematic for speed control from R.Haley
Keywords: motor, control, throttle, speed
Organization: University Of Alberta, Edmonton Canada
Date: Fri, 11 Dec 1992 19:07:17 GMT

Sorry but the schematic that some of you got from
haley.ee.ualberta.ca has an error in it.
If you have a beautiful OrCad copy it was my first experience
using the auto opamp feature.
If you have the clunky hpgl version with text it is correct.
The opamp sections AB&C have the input terminals reversed.
Only the last section before the driver transistors is correct.
To be sure: if Vin enters through D1 first then R6 
your copy is correct.
-- 
Richard  Haley                          haley@ee.ualberta.ca
Electrical Engineering                  VE6AKF 
University of Alberta 238 Civil Elect   Voice (403)492-2954
Edmonton, Alberta, Canada               Fax   (403)492-1811
From: earl@trsvax.tandy.com
Date: 17 Dec 92 15:38 CST
Newsgroups: rec.models.rc
Subject: Re: The Dago Red Slope Glider
Message-ID: <1195667333@trsvax>
Nf-ID: #R:gn.ecn.purdue.edu:25345:trsvax:1195667333:000:2234
Nf-From: trsvax.tandy.com!earl    Dec 17 15:38:00 1992



/* ---------- "The Dago Red Slope Glider" ---------- */
	As the Christmas building season approaches (and I can justify 
spending more money on models), I am considering building an intermediate/
advanced slope glider.  I am looking for something to build around two 
S-133 servos, a FP-R114H 4 channel receiver, and the NR-4G 250mAh battery
pack.  
	This past summer I saw a couple guys flying these small, scale P-51
slopers out on the Palos Verdes Peninsula just south of LA.  They were 
very fast, and seemed to be quite maneuverable...not to mention that 
they were guided by excellent pilots.  From a limited look around at the
kits available, the only scale P-51 I found was the Dago Red glider.  
	Has anyone had any experience with this model?  Are there any
other models of this type around, either in a kit or in plans?  Also, 
what are some good sources for slope gliders in general?  
Joel Grasmeyer 
grasmeye@gn.ecn.purdue.edu
*********************************************

    I remember a while back, that the House of Balsa P51 was popular as a
slope plane. Great Plane's P51 would work OK too. The new 1/12 scale P51's
and et cetera in 1/12th scale would all work OK for slope models too.
    Actually just about any regular gas powered RC model would work as a
slope glider. As to how good it would be depends on the wind and the
model itself. A long time ago, we used to take profile control-line models
for 20-40 size engines and use them for slope gliders, it was a lot of
fun way back then. All you needed was two channels and you were in business.
    A few months ago, someone flew a giant Bud Nosen P51 as a slope glider
over in Hawaii. If it works then anything would work. It's up to you.


***********************************************************************


<This information is provided by an individual and is not nor should be
 construed  as  being  provided  by  Radio  Shack or Tandy Corp.  Radio
 Shack/Tandy Corp has no obligation to support the information provided
 in  any way. > 
						
						Earl W. Bollinger
						@ <earl@trsvax>


"You were in the Clone Wars!", said Luke excitedly.
"Yes", replied Obi Wan, "I was a DOS programmer. But that was before the dark
 times, before OS2."


Newsgroups: rec.models.rc
From: mmcevill@mitre.org (Michael A. McEvilley)
Subject: Re: YS61 LS and the Robart ultra fueler..
Organization: The MITRE Corporation
Date: Thu, 17 Dec 1992 20:40:12 GMT

In article <1992Dec17.155129.11804@sol.ctr.columbia.edu> 
douglas@apache.ctr.columbia.edu (Paul Douglas) writes:
> Also, what type of refueler do YS 2 stroke users generally employ?

The setup that I am using on a YS120 is two Dubro Kwik-Fill valves, one in 
the fuel feed line and one in the return pressure line.  To refuel, I have 
to release the pressure via the return line valve (if you release pressure 
on the feed line you will get a nice stream of fuel flowing out of the 
valve under pressure!) and while that valve remains open (to vent the tank 
as it fills) I fill the tank via the feed line valve.  Its a simple and 
clean configuration.

 

Michael
From: wwebster@bnr.ca (Bill Webster)
Subject: Re: Q: Speed Controls (again!)  attn: Jeroen, Chris, Paul, et al.
Followup-To: rec.models.rc
Organization: Bell Northern Research
Date: Tue, 15 Dec 1992 14:07:56 GMT

In article <1992Dec10.095043.23488@dxcern.cern.ch>, jeroen@dxcern.cern.ch
(Jeroen Belleman) wrote:
> 
> Braving the risk of becoming a bit dogmatic about this,
> I'll have a go at wiping out a few mis-understandings.

(stuff deleted)
 
> That leads me to a remark made by Bill Webster: The ON-resistance of
> some power MOSFETs is in the region of 10 milli-Ohms. That's about
> the resistance of a metre of 2.5mm-sqr copper wire. No lies. I
> measured it and found it true.

That may be true for a solid piece of wire.  You should 
get the new data books from Harris, International Rectifier and
Siliconix.  They do manufacture FETs with ON-resistance down to
7 milli-Ohms and they have thick leads.  These results are only
found under certain test conditions which the ESC manufacturers
take full advantage of in their bogus advertising.
  
And no, I don't beleive
the spec's any of the ESC manufacturers claim.  They look at the
FET manufacturer spec's and extrapolate.  Then they take the 
extrapolated resistance and divide it by the number of throttle FETs
used in the ESC.

> 
> Also, you should not confuse motor EMF with the voltage across a
> sense resistor which some manufacturers put in series with it in
> order to measure the motor current. In the case you described, the
> sense resistor was merely a (largish) PC board trace. Once again,
> the motor EMF is proportional to its speed. Since motor current is
> proportional to torque, current limiting is equivalent to torque
> limiting. This is done most efficiently by having a feedback loop
> fiddle with the duty-cycle of the speed controller so as to keep the
> current within bounds. This explains the need for the sense resistor.
> 

Sorry if I wasn't clear about how the voltage was sensed, but I
can't think of another way to say "a parallel trace".  I'm not
implying there is any sense resistor.  The parallel trace is acting
as an inductive pick-up.  Think of the thick source trace as the
primary side of a transformer and the thin trace as the secondary.
Once the secondary voltage is sensed by the op-amp it's feeding,
the PWM is modified by the PWM coming out of the op-amp.  Or at
least that is what has been observed on the Tekin, Novak and Corally
ESCs.

So there is no sense resistor in the circuit I described. 



Bill Webster (WWEBSTER@BNR.CA)
Organization: University of Maine System
Date: Thursday, 17 Dec 1992 13:59:00 EST
From: <WOLPERT@MAINE.MAINE.EDU>
Newsgroups: rec.models.rc
Subject: Re: Super Decathlon crash



Bloom wrote that the guy who wrecked the Super Decathlon was a reckless
builder, as well.  In this case, it was the reckless flying that did him
in.  The pilot (Let's call him Frank) is a cantankerous and strongly
opinionated retired gentleman whose many brushes with the pits have been
a source of suspense and entertainment for anyone in the area.

Frank brought out the plane one breezy Saturday morning.  I looked it
over, and it appeared to be very nicely built.  One of the clubs best
flyers checked out the plane and took it up for a first flight.  He
then landed the plane and told Frank that it was underpowered, and the
CG was a bit off, and that he should bring it back on a calmer day.
Frank, whose own opinions and denial mechanisms are a bit unreasonable
saw that the instructor flew his plane quite nicely, and so could he.
He gassed up and took it off.  Takeoff and climbout were a bit shaky,
but he got it up to altitude, and managed to keep it under control.
He then decided to have a little fun with it, with some tight turns
and loops.  His last, and most spectacular stunt was an inside loop
from what looked to be insufficient altitude, with insufficient air-
-speed, and perpendicular to the wind.  The plane stalled at the top
of the loop, and fell into a textbook spiralling spin.  Frank could
not recover and within three seconds, it was all over.

I would like to reiterate that this crash was not the fault of the
airplane.  It was total pilot error (i.e. stupidity).  What really
scares me now is that Frank has expressed an interest in becoming an
instructor.  It'll be a hot day in December.....

Seth Wolpert
Bangor R/C Gulls


Newsgroups: rec.models.rockets
From: jsivier@ux1.cso.uiuc.edu (Jonathon Sivier )
Subject: Re: Other reloadables besides Aerotech? (Re: Info. about solid rocket-
Organization: University of Illinois at Urbana
Date: Mon, 14 Dec 1992 21:52:33 GMT

billn@hpcvaac.cv.hp.com (bill nelson) writes:

>: billn@hpcvaac.cv.hp.com (bill nelson) writes:
>: > 
>: > I hope they use the ISP version of the reloadable, and not the Aerotech
>: > version used in their model rocket reloadables.

>Anyone else out there who has used both? Any comments?

    I have used both and I think the ISP models are a bit sturdier built, but
the reloading process is little less complex with the AeroTech models.  The
greatest advantage of the ISP reloadables over the AeroTech, IMHO, is that the
end pieces are knurled instead of smooth.  Tightening the ends and later
removing them on the AeroTech reloadables, especially when they're covered with
grease, can be very difficult.

Jonathan

---------------------------------------------------------------------------
|  Jonathan Sivier               |  Secretary, Central Illinois Aerospace |
|  jsivier@ux1.cso.uiuc.edu      |  NAR #56437                            |
|  Flight Simulation Lab         |  Tripoli #1906                         |
|  Beckman Institute             |  Home Address:                         |
|  405 N. Mathews                |    5 The Summit                        |
|  Urbana, IL  61801             |    Champaign, IL 61820                 |
|  217/244-1923                  |    217/359-8225                        |
---------------------------------------------------------------------------
From: cdt@sw.stratus.com (C. D. Tavares)
Newsgroups: rec.models.rockets
Subject: Re: Exhaust Deflector Material Question
Date: 16 Dec 1992 18:26:19 GMT
Organization: Stratus Computer, Inc.
Distribution: world
NNTP-Posting-Host: rocket.sw.stratus.com

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?

> 	Remember, I'm looking for first-hand experiences, not opinions.

I've had first hand experiences with several types of metals.  I've never
found a piece of aluminum that was worth dog-doo as a deflector.  In the
higher engine ranges, even steel will give you problems, especially with
maintenance.  Stainless isn't much help, since it still cruds up.

What we use are discarded grinding wheels.  Fireproof, non-conductive,
free, plentiful, large, and pre-drilled.  The only negative on these is
that when an engine catoes they tend to lose large chunks or crack in half.
This happens to us maybe three times per year, but as I say, they're free
and they're plentiful.
-- 

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: mckiou@cbnewse.cb.att.com (kevin.w.mckiou)
Subject: Re: Exhaust Deflector Material Question
Organization: AT&T
Date: Thu, 17 Dec 1992 19:01:03 GMT

In article <1992Dec16.130245@primerd.Prime.COM> j.cook@primerd.prime.com (C. James Cook) writes:
>
>For a long lasting deflector look for something ceramic.

I agree.  I went to he local tile dealer and bought a piece of 
terra-cotta (~1 sq foot).  Cheap.  Won't burn through.

If you want to be fancy, get glazed floor tile.  Heck, make a mosaic <G>.

Kevin
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Club Projects
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
Date: Fri, 11 Dec 1992 18:52:33 GMT

hage@netcom.com (Carl Hage) writes:
: billn@hpcvaac.cv.hp.com (bill nelson) writes:
: : 
: : I would have to see the altitude/time chart. Unless you have a well
: : shielded chamber that is open to ambient pressure, you are going to
: : get quite incorrect readings - until the rocket gets close to peak
: : altitude (low velocity).
: 
: I can't see how the altimeter would be accurate except at peak altitude.
: How can you get a shielded chamber that is open to ambient pressure?

That is a problem, isn't it? I don't even know if a rocket with a payload
section that consisted of screening would work.

: It seems to me that if there was an air passage to the inside of the
: rocket, the Bernoulli effect would lower the measured air pressure while
: the rocket was ascending. If the air passage was constricted, there would
: be a time lag, raising the measured air pressure. After ejection, the
: altimeter should be accurate, but ejection altitude might not be the minimum
: pressure recorded.

That is wy I stated that the reading is not likely to be very accurate, except
at peak altitude. 

Bill
Newsgroups: rec.models.rockets
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: Barometric Altimeters
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
Date: Fri, 11 Dec 1992 22:16:20 GMT

barrett@add.itg.ti.com writes:
: 
:   He said that it is not a problem until the speed gets well above Mach
: 1. He said that the only thing you need to do is make sure the chamber
: is not effected by the vacuum created by the rear of the rocket and the
: chamber is vented with a ~1/4" hole.

That is nice to know. Apparently, he feels that any venturi effect from
the flow of air over the vent holes in the chamber is negligible. 

:   Bill, I don't see how, if the venturi effect was a factor, that an
: altimiter would accurately record apogee.  The venturi effect might
: cause the lowest pressure to occur at max velocity rather than max
: altitude.

I was not really concerned with the venturi effect. I was concerned
with the pressure inside the chamber being higher than the outside
air. At apogee, there would be time for the pressures to equalize.

That was actually my primary concern.  You may have noticed, at the
HP launches you attended, that occasionally a rocket loses its nose
cone during assent - usually during the coast phase.  This can be due
to increased pressure inside the body tube - when the aerodynamic load
is reduced, the nose cone pops out.

Bill
From: cdt@sw.stratus.com (C. D. Tavares)
Newsgroups: rec.models.rockets
Subject: Re: CPRESS Vocabulary
Date: 11 Dec 92 22:17:02 GMT
Organization: Stratus Computer, Inc.
NNTP-Posting-Host: rocket.sw.stratus.com

In article <1gare0INNgsg@cuda.add.itg.ti.com>, barrett@add.itg.ti.com writes:
> 
>   I just FTP'd the CPRESS program off of the sunsite.unc.edu machine.
> 
>   I have a few questions wrt vocabulary.  Can anyone define these terms
> that the program needs values for:
> 
> 
>         "FIN ROOT CHORD"

The length of the "glued edge" of the fin (including any unglued extension).

>         "FIN TIP CHORD"

Same for the opposite edge, assuming it's vertical (don't remember what
you do if it's raked).

>         "SPAN RIGHT ANGLE"

Distance between body wall and fin tip, measured at a right angle to the
body.

>         "FIN SWEEPBACK"

Don't remember without my notes.

>         "LENGTH, NOSE TIP TO ROOT TIP"

Distance between nose cone tip and foremost part of root edge of fin,
measured parallel to the 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: johnu@scic.intel.com (John Urbanski)
Subject: Re: Other reloadables besides Aerotech? (Re: Info. about solid rocket-
Organization: Intel Corporation
Date: Wed, 16 Dec 1992 19:40:37 GMT

Could someone post the information that was in the latest 'mini Am Spm' issue
about reloads and DOT.

thanks - john

Newsgroups: rec.models.rockets
From: j.cook@primerd.prime.com (C. James Cook)
Subject: Re: Other reloadables besides Aerotech? (Re: Info. about solid rocket-
Organization: Prime Computer R&D
Date: Mon, 14 Dec 1992 18:35:07 GMT

billn@hpcvaac.cv.hp.com (bill nelson) writes:
> msjohnso@donald.WichitaKS.NCR.COM (Mark Johnson) writes:
> : 
> : Aerotech/ISP has announced that all their 'consumer' motors will henceforth
> : be sold under the Aerotech nameplate. Those above 160 nt-sec, including
> : H-M reloadables now sold as ISP, will carry the 'Aerotech High Power'
> : trademark. [I'm not sure it's been 'officially announced' yet, but they
> : were talking about this at NARAM last summer.]
> 
> I hope they use the ISP version of the reloadable, and not the Aerotech
> version used in their model rocket reloadables.
> 
> Bill

I would be very interested to hear why you say this.

Jim
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: Mon, 14 Dec 1992 05:33:57 GMT

msjohnso@donald.WichitaKS.NCR.COM (Mark Johnson) writes:
: 
: Aerotech/ISP has announced that all their 'consumer' motors will henceforth
: be sold under the Aerotech nameplate. Those above 160 nt-sec, including
: H-M reloadables now sold as ISP, will carry the 'Aerotech High Power'
: trademark. [I'm not sure it's been 'officially announced' yet, but they
: were talking about this at NARAM last summer.]

I hope they use the ISP version of the reloadable, and not the Aerotech
version used in their model rocket reloadables.

Bill