SCAT Electronic News 21 March 2001 issue 559
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SCAT Electronic News 21 March 2001 issue 559
Table of Contents
=================
> F1A Self-Launcher - Linkosalo
Skykieng steps down as self-appointed gearing guru - Skykeing
F1c Timing - Morgan
SCAT Annual 2001 Results - Coussens & Coussens & Coussens
F1C Participation - Etherington
Rescinding 30 gram rule for F1B - Schroedter
Gears up or down - Blackam
> F1A Self-Launcher
===================
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> F1A Self-Launcher
> =================
>
> Is there a good method for launching a F1A while practicing by yourself?
Sure. Funny thing that no F1A flier has commented anything; I've used one
to launch my F1H's for years. The design is based on a one presented in
Aeromodeller in the 70's, and a launcher used by Matti Lihtamo.
The launcher is made with two wooden spars (approx. 10*30mm) across that
make a stand, with third spar hinged from one end to one end of the cross.
This spar is hinged so that it folds on top of the former, and opens flat
onto the ground the other way. Additional rest keeps the this spar
almost upright, maybe 20 degrees from vertical. To the top of this spar,
two parallel sheets of plywood are added, the model rest on it's wings on
these sheets, with the fuselage in between. The sheets have small tabs at
one end, the trailing edge of the wing resting against these tabs. Two
rubber bands run from these tabs over the wing and down the leading edge,
holding the model down. The rubber bands are attached to a pin running
through to eye bolts. The sheets are inclined so that when the spar is
upright the model faces some 20 degrees nose up, and when the spar
leans against the rest (20 degrees back) the model points 40 degrees up.
The pin is attached to a rope that pulls it out of the eyebolts, releasing
the rubber bands and the model. So you set up the model onto the launcher,
walk to the end of the towline, and start running. The vertical spar
swings forward, until the model is released.
Three points to pay attention to:
1) The release mechanism described above may have too much friction. In
this case the pin should release a lever (as in timers), to which the
rubber bands attach. This way the friction of the pin is minimal.
2) The swinging spar must be vertical when the model is released. If it
still leans back, it will stay in front of the tailplane smashing it.
When it is vertical at the point of the release, it will continue forward
to the ground, clearing the tail feathers.
3) It is useful that the model points nose up at the moment of release.
This way it will pull up even in calm weather. If the model is released
horizontal, you need to run VERY fast for a couple tens of meters to get
the model ascent. Just as if your helper released the model flat in calm.
The lancher needs to be attached to the ground with weights or pins. On
the other hand, built sufficiently stiff, it can handle rather high winds,
as the model leans back so much that the wind will not try to fly the
model away, only push it back.
-Tapio-
Skykieng steps down as self-appointed gearing guru
==================================================
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It is a humiliating consideration that if I had been
navigator on the Elona Gay America would have dropped its
first atomic bomb on some blissful whale floating a
thousand leagues off the japanese mainland.
In my previous "calculations" to disclose the advantage of
Verbitsky gearing I made a fundamental error. To the
mathematically challenged it seems apparent that the
difference between 60% and 80% is 20%. ( arbitrary prop
efficiencies ) But that is based on a scale of 100%. To
derive 80 from 60 the factor is 1.33 {%) So the difference
is actually 33% not 20%. If a normaly propped FAI ship
reaches 400 ft in the allotted time then the geared ship
with the 33% more efficient prop will get 1/3 of 33%, so 400
times 1.113 would be around 45 feet extra altitude for the
geared ship --- which seems to match up with some
estimates. That would mean the geared ship would have the
equivalent of around 4/10ths of a second longer engine run.
(If at a later date I discover additional errors you can
bet your bippy I will keep my mouth shut and concentrate
on more pressing matters.)
I want to acknowledge the fine work of Peter Computer King
whose sim on comparative F1C performance served as a
jarring wake up call to look into the mirror for errors.
To anyone lured into taking my previous efforts as gospel
please accept my humble apologies.
Skydunce
F1C timing
==========
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Looking through the new 2001 FAI rules for FF I see that the rule for F1C
motor run says
"Maximum duration of motor run.....5 seconds from release of model"
It does not say the run AS PERCEIVED BY THE TIMEKEEPER shall be 5 seconds
from release of model but of course this is what is actually recorded on the
watch by the timekeeper. We all know the timekeeper starts the watch when
he/she observes the launch and stops the watch for the motor run time when
they hear the motor stop (unless there are so many motors running that they
time the bunt). An astute timekeeper then, knowing that sound travels at a
mere 334 m per second would know that even if the model only got to a bit
over 100 m altitude (pretty low for a good F1C) the sound would take some
0.3 seconds to reach him and so he could quite reasonably deduct this time
from the run as recorded on the watch.
If I were timing an F1C (that did in fact climb) and the watch read 5.2
seconds I could easily be persuaded that the time was a legal 5 second motor
run.
Vin Morgan
SCAT Annual 2001 Results
========================
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Hi Roger-
Attached is the scoresheet for the SCAT Annual 2001.
It was a CD's dream: Light and variable winds, warm, sunny and a changing sky w
ith each round that kept the spirits high and the thermals tricky.
All fly-offs were completed on the designated days, and some cagey flying and
tactics were employed to get the wins.
A great way to enjoy the warm sun after such a long winter.
2001 SCAT ANNUAL SCORES
F1A
Contestant R1 R2 R3 R4 R5 R6 R7 FO1 FO2 TOTAL
1 Zink 210 180 180 180 180 180 180 300 420 2010
2 Allnutt 210 180 180 180 180 180 180 300 201 1791
3 Parker, J. 210 180 180 180 180 180 180 300 197 1787
4 Kozyluk 210 180 180 180 180 180 180 300 182 1772
5 McKeever 210 180 180 180 180 180 180 143 1433
6 Cowley 210 180 175 180 180 180 180 1285
7 Puhakka 210 180 174 180 180 180 180 1284
8 Davis 210 171 180 180 156 180 180 1257
9 Brocks 210 180 180 180 103 180 180 1213
10 Busnelli 121 180 180 180 180 180 180 1201
11 Coussens, B. ( 208 180 180 180 180 81 180 1189
12 Brun 192 180 180 180 180 131 126 1169
13 Joyce, K. 192 153 180 180 180 180 99 1164
14 Smith, N. 204 180 104 180 180 99 180 1127
15 Parker, D. (Jr 210 180 0 180 180 180 180 1110
16 Cusick 139 180 180 85 180 180 150 1094
17 Barron 210 180 30 180 180 82 180 1042
18 Livotto 188 91 125 404
MAX 210 180 180 180 180 180 180 300 420
F1A Morning High Time: D. Parker 448 sec.
F1B
Contestant R1 R2 R3 R4 R5 R6 R7 FO1 FO2 FO3 TOTAL
1 Booth 210 180 180 180 180 180 180 300 420 339 2349
2 Norvall 210 180 180 180 180 180 180 300 420 319 2329
3 Tymchek 210 180 180 180 180 180 180 300 420 310 2320
4 Wood 210 180 180 180 180 180 180 296 1586
5 Piserchio 210 180 180 144 180 180 180 1254
6 Schroeder 210 133 180 180 180 180 180 1243
7 Brush 210 180 180 180 180 131 180 1241
8 Critchlow 210 180 180 180 180 180 113 1223
9 Ulm 192 93 180 180 180 180 165 1170
10 Batiuk 210 55 180 180 180 180 180 1165
11 Morrell 210 180 180 180 180 35 180 1145
12 Lueken 210 180 180 180 180 137 1067
13 Dorsett 210 180 180 180 180 97 1027
14 Mulligan 56 180 180 69 180 180 180 1025
15 Cole 193 180 180 175 180 45 953
16 Kendy 210 180 180 180 175 925
17 Fitch 162 162
18 Cooney 0
MAX 210 180 180 180 180 180 180 300 420 540
F1B Morning High Time: R. Piserchio 491 sec.
F1C
Contestant R1 R2 R3 R4 R5 R6 R7 FO1 FO2 TOTAL
1 Archer 240 180 180 180 180 180 180 300 420 2040
2 Kerger 240 180 180 180 180 180 180 300 403 2023
3 Mennano 240 180 180 180 180 180 180 300 381 2001
4 Oliver 240 180 180 180 180 180 180 300 363 1983
5 Joyce, D. 240 180 180 180 180 180 180 255 1575
6 Gewain 240 180 180 180 49 180 107 1116
7 Simpson, Roger 240 180 180 180 180 960
8 Happersett 240 180 180 160 760
MAX 240 180 180 180 180 180 180 300 420
F1C Morning High Time: R. Simpson 427 sec.
F1G
Contestant R1 R2 R3 R4 R5 FO1 FO2 TOTAL
1 White 120 120 120 120 120 240 216 1056
2 Tymchek 120 120 120 120 120 240 176 1016
3 Cole 120 120 120 120 120 240 168 1008
4 Wood 120 120 120 120 120 189 789
5 Brocks 120 120 120 120 120 126 726
6 Critchlow 120 120 120 116 120 596
7 Cooney 120 120 104 120 114 578
8 Schroeder 102 120 120 120 112 574
9 Keppler 120 94 120 120 120 574
10 Burt 120 120 120 92 110 562
11 Batiuk 120 115 114 120 90 559
12 Dorsett 120 90 107 120 120 557
13 Morrell 120 94 120 73 120 527
14 Norvall 120 120 120 111 471
MAX 120 120 120 120 120 240 360
F1H
Contestant R1 R2 R3 R4 R5 FO1 FO2 FO3 FO4 TOTAL
1 Busnelli 120 120 120 120 120 180 240 360 420 1800
2 Cowley 120 120 120 120 120 180 240 360 206 1586
3 Brun 120 120 120 120 111 591
4 McKeever 120 120 120 109 120 589
5 Davis 93 120 120 120 120 573
6 Smith, N. 120 120 68 120 120 548
7 Zink 120 120 120 120 31 511
8 Coussens, B. ( 120 120 0 120 80 440
MAX 120 120 120 120 120
F1J
Contestant R1 R2 R3 R4 R5 FO1 FO2 FO3 TOTAL
1 Augustus 120 120 120 120 120 240 360 480 1680
2 Robertson 120 120 120 120 120 240 360 423 1623
3 Mennano 180 80 120 120 120 620
4 Laird 120 120 120 360
MAX 120 120 120 120 120 240 360 480
F1C Participation
=================
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Jimmy B (easyrider) suggests, "Lets all get real, if you really want to see so
called "wonderful growth" in FIC, then eliminate the high-tech spiral that we
have been on." How do you do that Jimmy? The "high-tech spiral"
you refer to is
driven by high level competition. The effect of making F1C more restrictive
(adding more rules/banning more devices) requires more creative high-tech
(expensive) solutions to remain competitive. Compare F1C with AMA Gas. Being
less restrictive, AMA Gas models should out perform F1C's but they
don't because
the F1C's are driven by a more competitive environment. Look at Formula 1
(Grand Prix) auto racing. The more rules and restrictions that are imposed, the
more expensive the cars get. To back F1C down to a lower-tech, less expensive
event, by definition, would mean the level of competition would
have to decrease
and the ultimate brass ring, being named World Champion, would somehow have to
be diluted. I don't see that happening any time soon.
Chuck Etherington
Rescinding 30 gram rule for F1B
==============================
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Roger:
I want to whole heartily endorse Paul
Crowley's thoughts on rescinding the 30 gram rule, which will go into effect
next January 1. As I have written here before,
I am worried that due to the very
small annual quantity of free flight rubber purchased by John Clapp, combined
with the extreme difficulty in consistently producing good contest rubber, the
present factory may decide it is not worth all the trouble. There is another
worry: In my experience trying to find a factory that could produce better
Champion Rubber (that I sold for a few years), no major producer of rubber
strip would even talk to me if I wasn't going to buy at least 50,000 pounds
annually. Some even wanted twice that amount. So it is only the small companies
who will even consider making rubber strip for us. Often they are producers of
golf ball rubber strip. But small companies are quite often bought out by big
corporations. So our present source is definitely at some degree of
risk.
The argument for going to 30 grams was that there
are now too many maxing out in F1B and making the fly-offs difficult to
manage. Good grief! There are all sorts of ways of making the fly-offs more
manageable rather than reducing the weight of motors. Pierre Brun has come up
with an innovation for his contest in 2 weeks at Lost Hills. I think his format
could be a very good one. Those with 5 maxes after Saturday's A,B and C events
will be timed to the ground at 7:30 Sunday morning. Those times will be used to
determine the winners among those with all maxes at the end of 10 rounds. So
when the 10th round is over at 12:30 Sunday, the contest will also be over. We
can then pack up and head home much earlier than usual. No late Sunday
fly-offs!
This is just one approach to the fly-off problems.
I'm sure other CDs can come up with other good innovative formats. But
let's get the ball rolling to return to 35 grams a.s.a.p. Over the years, there
have been several F.A.I. rule changes rescinded.
George Schroedter
Gears up or down
================
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>Re: JATO like effects of gearing?
>Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
>
>... but it seems that the projected altitude
>gain from gearing doesn't match up with subjective
>observations. Roughly, IF propellor efficiency of gearing is
>80% and a fixed propellors say, 60% then there is a 20%
>advantage going to the gears.
Even worse, there must be at least 10% losses through friction in the
gears...
Nothing is for free!
Rich Blackam
...................
Roger Morrell
