HDTenEightyP/NetNews huggingface dataset:
From: svoboda@rtsg.mot.com (David Svoboda)
Subject: Re: Radio dreams
Organization: Motorola Inc., Cellular Infrastructure Group
Date: Sat, 12 Sep 1992 04:11:37 GMT

In article <1992Sep9.190035.20060@usceast.cs.scarolina.edu> hutto@smtc.engr.scarolina.edu writes:
|
|    Actually, what you are asking for is best done using a set of techniques
|    collectively known as "spread spectrum".  Each transmitter/receiver pair
|    uses a unique pseudo-random sequence of numbers to "hop" frequency every,
|    let's say, 10ms.  As long as they stay in sync, the receiver "hears" the
|    transmitter pretty much continuously (except for a tiny interval where
|    the frequency is settling on its new value).  However, as long as all
|    transmitter/receiver pairs us sequences that are sufficiently random
|    (actual they just have to be sufficiently independant of each other),
|    the worst thing likely to happen is a very occasional missed 10ms frame
|    when two of the pseudo-random sequences "cross" on the same frequency
|    for one frame.

What you very nicely described is known as "frequency hopping" or "direct
sequence" spread spectrum.  That method is fairly old technology, having 
been used in some form or another since WWII.  (Quiz: who knows what famous 
movie actress has the basic patents on frequency hopping?)

A rather more elegant method of accomplishing spread spectrum is to take
your binary signal sequence and xor it with a long binary key which has a 
very high data rate compared with your signal.  The resultant signal is 
modulated, but the high data rate of the key causes the power to "splatter" 
about the spectrum.  Then, the receiver can cross correlate the key with
the incoming wideband signal, and when a high correlation is found, the 
signal can be recovered.  As long as the key of another "interfering"
transmission is orthogonal to that of your receiver (by design), it
will not correlate, and will simply look like low-power noise.  To a
narrow band receiver, the total power of the spread-spectrum transmitter
at a given frequency is down in the thermal noise.  And the spread
spectrum receiver doesn't see the narrowband transmissions because
their energy is concentrated in a narrow frequency region, and therefore
will not greatly affect the overall correlation.

If you make the key sufficiently long, say, 10e10 symbols, then repeat,
you can have a staggering number of mutually orthogonal codes, and
therefore non-interfering radios.  Synchronization between transmitter
and receiver is critical (the longer you have to make your search 
window for correlation, the more processing power it takes), but that
might be as simple as plugging your transmitter and receiver together
while charging.

This spread spectrum method is what is planned for cellular radio,
though rather more sophisticated in execution.

		Dave Svoboda, Palatine, IL
From: bloom@inland.com
Newsgroups: rec.models.rc
Subject: Re: Thermodynamic laws
Date: 9 Sep 92 09:07:43 CST
Organization: Inland Steel Company; East Chicago, IN

In article <1992Sep8.170741.8431@magnus.acs.ohio-state.edu>, mtissand@magnus.acs.ohio-state.edu (Michael D Tissandier) writes:
> PV=nRT is not a thermodynamic law, it is an equation of state.  In the
> absence of compression v. heat data for the additive combustion products,
> it is possible to increase pressure without increasing temperature.  In
> the equation, 'n' stands for moles of gas, if this were to increase due
> to an additive, the pressure could increase without adjusting the temperature
> of the reaction.  The question of running temperature effects due to
> additives is completely empirical in nature.
> 
>    --Mike

While it is true that 'n' can be adjusted upward to increase P without 
changing T, and if you balance the chemical reactions you will find that 
burning 100% nitro methane vs 100% methanol does produce more moles of 
combustion products, you will also find that the heat of reaction is 
greater for burning the nitro (if you use the same amount of oxygen from 
the air!).  Now since you are not going to significantly change the 
efficiency of your heat engine by substituting fuel, and your efficiency is 
in the neighborhood of 30-40% at best, then this extra energy is just 
going to increase the temperature of your engine.  For those who want to 
know how to increase the efficiency of their engine.....you just build 
it our of ceramic materials so less heat is lost to the air and your 
energy is more completely converted to driving the piston.
From: kasuga@sm.sony.co.jp (Tomoaki Kasuga)
Newsgroups: rec.models.rc
Subject: Heli-engines and Airplane-engines
Summary: Question about engines
Date: 11 Sep 92 09:04:14 GMT
Organization: Workstation Div., Supermicro Systems Group, Sony Corporation

I have been enjoying flying helis few years.
And recently started airplanes, too.

My question is about difference between Heli-engines and Airplane-engines.
I know usual Heli-engines have piston ring, and Airplane-engines have not.
Why?

I want to use my Heli-engines for my airplane.
Will it be any trouble?

Thanks in advance.

	------------------------------------------------------------
	Tomoaki Kasuga <kasuga@sm.sony.co.jp>    Workstation div. Sony Corp. 
-- 
	------------------------------------------------------------
	Tomoaki Kasuga <kasuga@sm.sony.co.jp>    Workstation div. Sony Corp.
From: umteghts@ccu.umanitoba.ca (david teghtsoonian)
Newsgroups: rec.models.rc
Subject: Re: AM vs FM AGAIN? - Have Mercy
Date: 7 Sep 92 23:56:38 GMT
Organization: University of Manitoba, Winnipeg, Canada

In <1992Sep5.042114.3993@nntpd.lkg.dec.com> fisher@kay.enet.dec.com (kay::fisher) writes:

>>   Dual conversion on an AM?   I thought that dual conversion was impossible/
>>   useless on an AM receiver because of the method of detecting an AM signal.
>>   Besides,   I've yet to see an AM receiver that had 'Dual Conversion' on it.
>>
>>-- 
>>          _____________________________________________________________
>>          -                *                      _______   _~;       -
>>          -            Paul Moreau               |       =_= /        -
>>          -    Sr. Diagnostics Software Eng.     \   USA    /         -
>>          -         Irvine, California      --->  *-_  ___ /          -
>>          -     UUCP: ..!uunet!storcon!paulm         \/   \\          -
>>          _____________________________________________________________

>Well - I didn't want to answer till I was sure.
>Check out Model Aviation October 1992 issue page 160.
>The add for Kraft Midwest Inc. shows a dual conversion AM receiver.

>Bye          --+--
>Kay R. Fisher  |
>---------------O---------------
>################################################################################


   Actually, dual or single conversion superheterodyne receivers work equally
well using AM, FM, PCM or just about any other modulation technique. Dual
conversion, without getting too technical, takes place BEFORE the demodulation
stage of the receiver, so the modulation scheme used is irrelevant. Dual
conversion makes the receiver less susceptable to interference from other
signals as well as reducing the spurious emissions (interference to other
people's receivers) produced by your receiver. The modulation scheme used
also has an impact on the receiver's susceptabilty to interference. AM is
naturally more susceptable to interference than FM or PCM and probabley
stands to gain the most from using a dual conversion receiver.

-Curt
Newsgroups: rec.models.rc
Subject: Re: What about Dynaflite ?
From: kaiser@elec.canterbury.ac.nz (Chris Kaiser)
Date: 11 Sep 92 12:38:23 +1200
Distribution: world
Organization: Electrical Engineering, University of Canterbury, New Zealand

In article <2373@rnivh.rni.sub.org>, torsten@rnivh.rni.sub.org (Torsten Leibold) writes:
> This company is quite famous for Fun Scale kits, at least here in
> Germany. BTW I'm just about finishing a .60 Mustang from them.
> Now, I've never seen more than about 2 or 3 articles in this group
> dealing with Dynaflite kits. Nor have I seen any ads or someone
> offering these kits in Model Airplane News. I wonder whether they have
> a bad reputation or what else is the problem with Dynaflite ?

I fly their 40 sized Spitfire and it goes great with an OS 46 SF-ABC. I modified the
kit by mounting the engine inverted, which makes a much cleaner nose, changing the balsa
wing spars to hardwood and adding retracts (Goldberg mechanical). The plane looks very
good in the air with the wheels up - much more scale like than some of their other kits.
It also flies very nicely, slowing down for three point landings without danger of
tip-stalling.

As far as the kit goes, I wasn't that impressed (although they are cheap). Much of the
wood is unsuited for where it's supposed to be used (especially the curved fuselage parts),
and the die-cutting ranges from average to poor and inaccurate (especially the ply
fuselage formers). However having said that, if you don't mind a bit of fiddling and
trimming to get parts to fit, the kit is resonably cheap and builds into a great flying,
great looking model - a leap up from the hordes of P-51's :-)

Chris Kaiser

Postgrad, Elec. Eng. Dept.
University of Canterbury
Christchurch, NEW ZEALAND
From: kinstrey@crd.ge.com (M. A. Kinstrey)
Newsgroups: rec.models.rc
Subject: Update to: RC Competition in Rhinebeck, NY
Date: 10 Sep 92 20:01:59 GMT
Reply-To: kinstrey@crd.ge.com
Followup-To: rec.models.rc
Organization: GE CRD

--------
I spoke to my dad last night, who I had tasked
with getting more info on the Rhinebeck Aerodrome
RC show. Dad talked to one of the flyers going to
the meet, so this should be fairly accurate:

   The meet at the Aerodrome is a competition,
starting Saturday, and completing on Sunday.
I don't know the exact start times, but the
guy figured that it would start fairly early in
the morning on Saturday (~9:00am), and going on
up until 2:00-2:30pm, when the Aerodrome's
real plane show begins. The "real" show is usually
~2 hours. The RC competition may continue afterwards.
The rest of the competition will be held on Sunday,
same times, same format and schedule as Saturday.

Hope this helps.
				Mike Kinstrey
				kinstrey@crd.ge.com


-----------------------------------------------------------------------------
kinstrey@wsqtba.crd.ge.com  | Sattinger's Law:
uunet!crdgw1!wsqtba!kinstrey|      It works better if you plug it in.
____________________________|________________________________________________
Newsgroups: rec.models.rc
From: gregt@col.hp.com (Greg Tarcza)
Subject: Re: Talon - suggestions from builders?
Date: Wed, 9 Sep 1992 14:20:28 GMT
Organization: HP Colorado Springs Division

robertw@informix.com (Robert Weinberg) writes:
> I plan to use transparent yellow monocote as the wing covering for high 
> visibility on low-ceiling foggy days, which we get a lot of in Pacifica.

     Don't use transparent yellow on the whole wing.  One fellow in our
local club has done that one three planes now and it causes really severe
orientation problems.  His smallest plane is a 2 meter ship and confusion
sets in when the plane is only 200 feet away!  The problem is that you 
can't tell if you are looking at the top or the bottom of the wing.
     If you want to use the yellow, I would suggest maybe using it on 
only the inboard half or outboard half of the wing.

                                                           Greg

===============================================================================
Greg Tarcza      WA2OOD                                               /
Hewlett-Packard Company                                              /
P.O. Box 2197                                                       /-,  /-,
Colorado Springs, CO  80901                                        /  / /  /
719-590-2471                                                      /  / /--/
                                                                      /
gregt@col.hp.com                                                     /
===============================================================================

Newsgroups: rec.models.rc
From: pturner@sedona.intel.Com (Pete Turner)
Subject: FOR SALE: Futaba FP-T7FG/K 7 Ch. Radio
Followup-To: pturner@sedona.intel.com
Originator: pturner@turner
Keywords: Futaba, sale
Organization: Intel Corp.
Date: Tue, 15 Sep 1992 15:48:23 GMT


FOR SALE:	Futaba FP-T7FG/K 7 Ch. AM Digital Proportional R/C
		system. FP-R117H receiver, 4 servos (FP-S28's), and
		all original materials (batt. packs, charger, etc.).
		72.630 MHz; RF Checked and modified at the factory
		a year ago. This unit has never been used in any model.
		$200.00

		I've had this radio for a while, and it's a shame I
		haven't found a use for it. If you have a use for it,
		it's yours!

Please contact me via e-mail (address below), or call (602) 963-2329
after 5pm Mountain Time. Please save calling me at work as a last option.
-- 
-- 
 ______________________________________________________________________________

 Pete Turner              | "I'm not looking back -- but I want to look
 Intel Corporation        |  around me now"
 5000 W. Chandler Blvd.   |
 M/S CH3-36               |  -- Geddy Lee/Neil Peart
 Chandler, AZ 85226       | ---------------------------------------------------
 pturner@sedona.intel.com | "...yeah, I've been to Phoenix...they call that
 ATT: (602) 554-8906      |  place 'The Valley of the Sun'...they should call
 FAX: (602) 554-7281      |  it 'The Surface of the Sun'!..."
                          |
                          |  -- Some unknown late-night comic
 ______________________________________________________________________________
Newsgroups: rec.models.rc
From: ntaib@silver.ucs.indiana.edu (Iskandar Taib)
Subject: Re: FAQ? (questions about engines)
Organization: Indiana University
Date: Sat, 5 Sep 1992 03:10:51 GMT

In article <1992Sep2.215912.4276@rtsg.mot.com> svoboda@rtsg.mot.com (David Svoboda) writes:

>Look at it this way: if nitro cooled the engine down, then 50% nitro would be
>the answer for tightly cowled engines.  It's not.

Actually it would work, if you raised the head. The problem is 
that it would be bloody expensive, besides while the engine runs 
cooler its not _that_ much cooler.

-- 
-------------------------------------------------------------------------------
Iskandar Taib                          | The only thing worse than Peach ala
Internet: NTAIB@SILVER.UCS.INDIANA.EDU |    Frog is Frog ala Peach
Bitnet:   NTAIB@IUBACS                 !
From: pasmith@inland.com
Newsgroups: rec.models.rc
Subject: YS .61 Longstroke Eats Bearings
Date: 8 Sep 92 16:46:03 CST
Organization: Inland Steel Company; East Chicago, IN

I'm seeking information from flyers using YS .61 longstroke engines. Two of the
pattern flyers in my club have YS .61 longstrokes in their Summit III pattern
planes. They have gone through 5 sets of bearings between them this season 
alone. 

Lean runs aren't a problem. We fly together all the time and are careful in
avoiding overly lean settings. All of us use fuel with castor/synthetic mix,
10% or 15% nitro. We have tried Powermaster, Byron, Omega. I don't think fuel
is the problem. I haven't had any problem with my O.S. .61 nor has one of the
other guys who's second pattern plane has an O.S. .61 longstroke pumper. We
both went 3 seasons before needing to change bearings on the O.S.'s. 

Note that both of the YS engines are the early models with the smaller rear 
bearing.

My questions to other netters: 
- Are any others having problems with YS .61 long
  strokes eating bearings? 
- Has anybody solved this problem? 
- Is this a problem with the later models which have a larger bearing?

Thanks for any info.
-- 
Todd A. Smith            | Internet:   pasmith@inland.com
Inland Steel Co.         | 
Operating Technology Dept| CompuServe: 72557,3713
East Chicago, IN 46312   | America On Line: ToddS4
Newsgroups: rec.models.rc
From: Matthew D Marks <mmarks@magnus.acs.ohio-state.edu>
Subject: Airtronics / Futaba
Organization: The Ohio State University
Date: Tue, 8 Sep 1992 15:51:47 GMT
X-Mailer: ELM [version 2.3 PL11]

Hello Net...

Problem:
My mother-in-law hates me.  I got my father-in-law interested in RC.  He now 
has a PT-40, Sturdy Birdie, and a Super Box Fly 40.

The problem is that he now has more planes than me.  :-(
--------------------------------------------------------

Question:
So, when my father-in-law made his order at Tower, they were out of Futaba 
Conquests.  He bought an Airtronics 4ch w/ trainer switch.  Does anyone know if
I can attach my Futaba training cable to my Futaba Conquest and his Airtronics 
radio???  I doubt it, but I though I'd ask...

Quesion #2:
He also has a spare Futaba s148 servo that he would like to use with his 
Airtronics radio.  All he needs to do is solder on a servo connector, but the 
Airtronics servo connector has the following scheme:

Airtronics:                                         Futaba:
             ---------black              black-------------
to connector ---------black              red--------------- to servo
             ---------black w/ red       white-------------

How do these connect?

Thanks
Matt
--
======================================================================
Matthew D. Marks                   ||   " In the race for quality,
Mechanical Engineering Department  ||     there is no finish line. "
The Ohio State University          ||
e-mail: marks.23@osu.edu           ||              - David T. Kearns
======================================================================
From: bloom@inland.com
Newsgroups: rec.models.rc
Subject: Re: FAQ? (questions about engines)
Date: 11 Sep 92 08:35:11 CST
Organization: Inland Steel Company; East Chicago, IN

In article <1992Sep10.025001.18866@c3177208.ssr.hp.com>, bill@c3177208.ssr.hp.com (Bill Chidester) writes:
> 
>  Cold plugs still use fat wires!                     
> 

OK, if you don't believe me, how about Mike Billington?  He holds 
FAI records for control line speed and writes a column on engine 
reviews including dyno tests every month.  I'll provide the reference 
if you wish.


> : 
> : 
>    At any rate, when I put FAI fuel in my cowled Cherokee and run an O/S
>    .45 up at 14,000 RPM, it runs too hot.  When I put in 10% nitro and
>    run at 14,000 RPM, it runs cooler -- no popping, no burnt oil odor, no 
>    skin sizzling head temperature.  Same RPM, same prop = same horsepower. 
>    It may well be that I'm running richer (not sure, may have to pay more
>    attention next time), but the nitro definitely gives me a cooler running
>    engine.  Now, we can extend this to leaning the mixture to the point that
>    we're now running the same temperature as the FAI, but we will then be
>    running more RPM.  The addition of the nitro is yielding more power at 
>    the same temperature.  Same power, lower temperature:  Same temperature,
>    more power.  In neither case did the addition of the nitro cause the
>    engine to run hotter!  

Running any engine too lean will cause the temperature to increase.  Your 
experiment is flawed.  The point is to run an engine on the two fuels 
in the proper mixture range and then measure the results.  You will find 
that higher nitro produces both higher rpm and higher engine 
temperatures.  As an example of nitro creating more heat in an engine, as 
engine displacement is decreased the glow engines require more nitro 
to maintain operating temperature to keep the plug lit.  This is the 
reason that the .049 engines need 25% nitro to run and your .40 inch 
engine will do fine on 5-10% nitro.  As displacement decreases, engines 
run cooler because the surface to volume ratio of the engine increases. 
The engine loses heat proportional to the surface area and generates heat 
proportional to the volume (displacement) of the engine.  
Little engines run too cool without the added nitro for heat.  
Any questions?  I'll use Clarence Lee and Mike Billington as references.
From: v064myby@ubvmsd.cc.buffalo.edu (Christophe J Quaranta)
Newsgroups: rec.models.rc
Subject: Wing failure
Date: 14 Sep 92 16:42:00 GMT
Organization: University at Buffalo
News-Software: VAX/VMS VNEWS 1.41


	After 1 year of tinkering and 2 planes, I finally got to solo
RC.  
	I had a strange problem on my last flight.  After taking my PT40
off and getting up to about 150-200 feet, I noticed that the wind "up
there" was significantly higher than on the surface, everytime I turned
into the wind, the plane would slow to a crawl and buffet.
	Since I was uncomfortable flying in those conditions, especially
w/ a trainer,  I decided to land after about 3 mins. flight.
The plane seemed much less controllable with the throttle cut down, so 
I flew the airplane down to about 50 feet ful throttle, into the wind.
I cut the engine down to idle and tried to bleed off excess airspeed before I
landed.
	All seemed well until I got within 3 feet of the ground. I heard
a loud "pop" and the plane mushed down, and did a big bounce.
I broke the prop, and bent up the nose gear a little.  However the wing
split at the center joint, and the left leading edge cracked also,
which wasn't apparent until I walked up to the plane. 
	Has this ever happened to anyone before - I think it's odd because
the wing didn't hit the ground, and it sure seemed like the wing cracked
while it was still in the air. 
	Please note that this plane did not have a glassed wing center
section.
					
					 Later - Chris Q.
Newsgroups: rec.models.rc
From: elec140@csc.canterbury.ac.nz (Chris Kaiser)
Newsgroups: rec.models.rc
Subject: Re: 6 volt reciever battery packs
Date: 5 Sep 92 03:49:37 GMT
Organization: University of Canterbury, Christchurch, New Zealand

In article <8255@boink.UUCP>, harald@boink.UUCP (Harald Milne) writes:
> In article <1992Aug25.095210.486@csc.canterbury.ac.nz>, kaiser@elec.canterbury.ac.nz (Chris Kaiser) writes:
>
>    It is interesting that your Futuba NZ rep says that 5 cell packs are
> "bad news". Futuba Corporation of America sells a 5 cell J-connector pack.
> The part number is NR-5PB and is 6 volts at 450 milliamps. You might want
> to ask him about that. Maybe Futuba should talk to itself 8^).

From the responses I've received over the net, and also from the particular
Futaba NZ rep's demonstrated lack of technical knowledge, I don't think he
really knew what he was talking about. 5 cell Futaba Rx packs are available
from at least one distributor here in NZ, so I'll invest in one soon and give
it a try.

*********************************************************
Chris Kaiser
Postgrad - Elec Eng Dept
Canterbury University
Christchurch, NEW ZEALAND

E.MAIL: kaiser@elec.canterbury.ac.nz
*********************************************************
	"When you're fresh out of lawyers
 	 You don't know how good it's gonna feel"
		- Al Stewart, 1988
*********************************************************
From: torsten@rnivh.rni.sub.org (Torsten Leibold)
Newsgroups: rec.models.rc
Subject: What about Dynaflite ?
Date: 10 Sep 92 07:27:30 GMT
Organization: Rhein-Neckar-Informationsdienst Viernheim

This company is quite famous for Fun Scale kits, at least here in
Germany. BTW I'm just about finishing a .60 Mustang from them.
Now, I've never seen more than about 2 or 3 articles in this group
dealing with Dynaflite kits. Nor have I seen any ads or someone
offering these kits in Model Airplane News. I wonder whether they have
a bad reputation or what else is the problem with Dynaflite ?

Bye,
  Torsten.

-- 
+-----------------------------------------------------------------------------+
|       Torsten Leibold, Hard- und Software, Viernheim, West Germany.         |
|   UUCP: torsten@rnivh.rni.sub.org  ..!unido!cat!orfeo!rnihd!rnivh!torsten   |
+-----------------------------------------------------------------------------+
From: db2i+@andrew.cmu.edu (David Vincent Bongiovanni)
Newsgroups: rec.models.rc
Subject: Re: Gas cars.,1/8 scale gas Vanning/testing/new user
Date: 6 Sep 92 18:26:12 GMT
	<1992Aug28.191145.1@acad2.alaska.edu>
Organization: Senior, Materials Science and Engineering, Carnegie Mellon, Pittsburgh, PA

I've got a 1/8 scale Kyosho Mint gas car that wasted its spur gear and
main gear.  They still make the spur gear, but the main gear is out of
production.  If anyone has any info, please help me out.