SEN 683 - 12 Mar 2002
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SCAT Electronic News 12 March 2002 issue 683
Table of Contents
=================
SCAT ANNUAL 2002 REPORT - Coussens
Tan II contest, Tan Sport, Visa/Master card - Clapp
flaky airfoils - Skykeing
Sweeping instability - Blackam
Re: Vol Libre - Gregorie
Bob Lyons in Memorial... - Lorbiecki
Psychic problems - Woodhouse
The 5 minute Killer - Woodhouse
F1E and the issue of GPS guidance - Mac the Bigot
SCAT ANNUAL 2002 REPORT
=======================
Tom Coussens
The weather prognosis was all over the map the week prior to the
event, but hope springs eternal, and people still came to the SCAT
Annual to try their stuff. Nineteen Nordic fliers (plus one DNF),
a surprisingly few (9) Wakefield fliers and 7 Power fliers were
greeted by a chilly, but calm Saturday morning. The new FAI
scoring rules were put into effect for the first time on US soil,
with interesting results. The calm first round enabled the
planned full four minute max for glider and five minutes for Wake
& Power. One of the unique events of SCAT is Morning High Time,
an additional award for the highest time to the ground in addition
to the extended max. It’s for bragging rights, and a lesson
learned after the 11 minute F1A winner Ernesto Busnelli pulled his
feat late in the round is to limit the high time to the first
fifteen minutes of the round. Jerry Fitch and Gill Morris
delivered more down-to-earth times of 398 and 442 seconds
respectively.
The weather warmed up to shirt-sleeve conditions by early
afternoon, while the breezes varied from dead calm to maybe 5 mph,
mostly from the southwest. Conditions were deceptively tough, as
only two towline fliers stayed clean, three Wake and three in
Power.
The day was a CD's dream: perfect weather and the contest was
decided in the first fly-off round in each event! The fly-offs
proceeded normally, and the winners and placers were determined
without controversy. And then there was third place in
glider…Three fliers maxed the first round, but dropped 4, 5 and 9
seconds in one of the subsequent rounds, thus they believed that
they were 3rd, 4th and 5th. However, three other fliers posted
scores above three minutes but well under four minutes in the
first round, and maxed the remainder of the rounds. The new FAI
rules state that the time over three minutes does NOT contribute
to the overall score, as had been done prior to the rule change;
it was to be used only in the case of a tie-breaker. Thus, the
three that dropped and made over three minutes but not four in
the first round were actually maxed out, and their excess time
over three minutes was used to determine their placings. Thus,
the original fliers achieved not 4th, 5th and 6th, but rather 7th,
8th and 9th. The key point to understand is that the extended
times over three minutes are simply the bar to cross to get into
the flyoff, and are not added to the flyer's scores at all, except
to rank fliers who scored at least three minutes in Round 1 and
maxed the remainder of the day.
Sunday dawned very cold with a goodly breeze out of the west, and
overcast, but as the day progressed, the skies cleared and breeze
died down till the afternoon, and a great day was had by all.
Seven coupe fliers, 11 H'ers and 3 F1J guys lined up and shot.
The first two rounds saw only 4 drops among them all. In the
third round the air was significantly warmer and more turbulent,
and the wheels fell off. The final tally of max-outs was 3 in G,
3 in H and only one max-out Power, Tom Laird, who flew to victory
with his simple Astrostar, over the two other guys with high-zoot
screamers.
In the midst of this were two events, HLG and Cat Glider. As this
contest was not a National Cup (it will be next time), very few
fliers showed up. But at about 12:45 with 15 minutes to go, the
pen was abuzz with zooming mini-gliders. Tony Roberts shot up a
test flight that thermaled directly over the pen, with all five
competitors cocked and locked. Suddenly the sky above the pen was
full of thermaling gliders, a kaleidoscope of color and swirling
movement, just 30 to 40 feet above their heads. The rest of the
field stopped what they were doing and involuntarily whooped and
yelled at the spectacle. An then, in scant seconds, it was over
as the thermal broke away and took the little ships up and out.
Cat and HLG are here to stay at the SCAT Annual!
The mini-event fly-offs started at 1:30, just about the time a
stiff breeze picked up from the northeast. F1H concluded in the
five-minute round, with a happy Mike McKeever taking the trophy, a
sort of redemption after having dropped the last round the
previous day in F1A.
Coupe was another story. They started with 4-minute maxes, but
then it looked like the AMA record could be broken, so the third
round was upped to five minutes. Bob Critchlow dropped at that
point, so Jack Emery and John Sessums were left to battle it out.
The record, held by Peter Brocks, was 27:43, or 5:43 into the 6
minute round, and John and Jack went for it. As a testament to
both of them and their air-picking, by this time the breeze was
basically steady and cold, yet they both managed to pick separate
thermals and max, both in record territory. But Jack’s ship
actually specked out, and he stayed out looking for it.
Meanwhile, John was hot on the trail for the record. At that
point, it was decided to settle the contest at a later date,
rather than call a round and win by default. Now it was just for
the record. John wound his model and threw in a tiny bubble that
gave hime the 7-minute max! Then, with moments to go before
sunset, he threw for the 8-minute flight, and achieved a still-
repectable 3:24. Thus, another record was added to the history
of the SCAT Annual. Four current records stand at this contest.
And so concluded the SCAT Annual, in fine style. We hope a few
more modelers will come out of the woodwork for the next one, as
we will have National Cup status next year.
2002 SCAT ANNUAL SCORES
F1A
Contestant R1 R2 R3 R4 R5 R6 R7 FO1 FO2 TOTALTie-Breaker
1 TERZIAN 180 180 180 180 180 180 180 300 1560M
2 ZINK 180 180 180 180 180 180 180 286 1546M
3 BRUN 180 180 180 180 180 180 180 1260 33
4 KOZYLUK 180 180 180 180 180 180 180 1260 21
5 COUSSENS B (JR) 180 180 180 180 180 180 180 1260 20
6 PARKER J 180 180 180 176 180 180 180 1256M
7 BUSNELLI 180 180 180 180 180 180 175 1255M
8 DIEZ 180 180 180 180 180 171 180 1251 48
9 LIMBERGER 180 180 156 180 180 180 180 1236M
10 MC KEEVER 180 180 180 180 180 180 134 1214M
11 VAN NEST 180 171 134 180 180 180 180 1205M
12 COUSSENS T 180 180 180 180 150 180 145 1195M
13 HINES 180 111 180 180 180 180 180 1191M
14 ALLNUTT 180 180 140 88 180 180 180 1128M
15 BROCKS 77 156 180 152 180 180 180 1105-
16 BARRON 180 180 148 134 99 180 180 1101M
17 PARKER D (JR) 180 180 88 180 72 180 180 1060M
18 SMITH 60 180 120 180 180DNF DNF 720-
19 LEATH 43 143DNF DNF DNF DNF DNF 186-
F1B
Contestant R1 R2 R3 R4 R5 R6 R7 FO1 TOTALTie-Break
1 FITCH 180 180 180 180 180 180 180 287 1547M
2 MORRELL 180 180 180 180 180 180 180 252 1512M
3 SESSUMS 180 180 180 180 180 180 180 165 1425M
4 WOOD 180 180 180 175 180 164 180 1239 42
5 PISERCHIO 180 180 180 153 180 150 180 1203M
6 NORVALL 180 180 180 180 180 161 128 1189 94
7 PECK 166 124 124 168 180 180 180 1122-
8 TYMCHEK 180 180 130 176 180 123DNF 969 92
9 LUEKEN 180 180DNF DNF DNF DNF DNF 360M
F1C
Contestant R1 R2 R3 R4 R5 R6 R7 FO1 FO2 TOTALTie-Breaker
1 HAPPERSETT 180 180 180 180 180 180 180 300 1560M
2 JOYCE 180 180 180 180 180 180 180 264 1524M
3 CARROLL 180 180 180 180 180 180 180 217 1477M
4 MORRIS 180 180 180 180 180 126 180 1206M
5 GEWAIN 180 180 180 23 180 136 180 1059 77
6 MC BURNETT 4 180 180 152 180 180 180 1056
7 KERGER 180 180 180 151DNF DNF DNF 691M
F1G
Contestant R1 R2 R3 R4 R5 FO1 FO2 FO3 FO4 TOTAL
1 EMERY 120 120 120 120 120 240 240 300 360 1740
2 SESSUMS 120 120 120 120 120 240 240 300 360 1740 420 204New Record!
3 CRITCHLOW 120 120 120 120 120 240 240 198 1278
4 BROCKS 120 120 114 120 120 594
5 WOOD 120 120 120 92 120 572
6 NORVALL 120 120 120 69DNF 429
7 TYMCHEK 120 107DNF DNF DNF 227
F1H
Contestant R1 R2 R3 R4 R5 FO1 FO2 FO3 TOTAL
1 MC KEEVER 120 120 120 120 120 180 240 240 1260
2 BUSNELLI 120 120 120 120 120 180 240 208 1228
3 VAN NEST 120 120 120 120 120 180 240 125 1145
4 BRUN 120 120 120 120 120 600
5 SMITH, N 120 120 120 92 120 572
6 TERZIAN 120 120 78 120 120 558
7 HINES 120 120 120 62 120 542
8 COUSSENS, B (JR 120 35 120 120 120 515
9 PARKER, D (JR) 120 120 120 31 120 511
10 ZINK 120 120 120 0DNF 360
11 NORTON 57 120 0 41DNF 218
F1J
Contestant R1 R2 R3 R4 R5 TOTAL
1 LAIRD 120 120 120 120 120 600
2 ROBERTSON 120 120 117 120 120 597
3 CARROLL 120 120 74DNF DNF 314
Catapult Glider
Contestant Att 1Att 2Att 3Att 4Att 5Att 6 TOTAL
1 HINES 35 20 120 38 120 112 352
2 COUSSENS B 34 5 69 120 223
3 PARKER D 12 10 119 35 166
Hand-Launch Glider
Contestant Att 1Att 2Att 3Att 4Att 5Att 6 TOTAL
1 PARKER D 80 77 31 120 119 120 359
2 TERZIAN 74 52 120 26 120 51 314
Junior Combined High Time
F1A F1H CAT HLG
1 PARKER 1060 511 166 359 2096
COUSSENS 1260 515 223 1998
Tan II contest, Tan Sport, Visa/Master card
===========================================`
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
New Tan II Contest rubber ( 1/8") went well at the factory this week
and a new small shipment
(already oversold ) will be in this coming week. It will take one more
week to obtain test reports.
We hope to have a much larger order of all sizes in approximately 45
days.
We also expect to be introducing Tan Sport rubber. First will be
1/8", and then later next month 3/16". This will be followed by 1/4" at
a later date. Tan Sport will be much lower in cost for those modelers
who do not need World Class Tan II rubber.
Later this week we will be able to accept Visa and Master Card orders
(world-wide) by e-mail or fax. We plan not to accept phone orders using
charge cards as time and accuracy is adversely affected. We will post
instructions in approximately 10 days. We are doing this primarily to
lower the transactional cost for our over-seas customers.
Thank you, John Clapp
flaky airfoils
==============
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
After my computer died thus keeping isolated and out of the loop for a
couple of months I have been burning midnight oil doing catch-up on the SEN
Archives. (incidentally, those interested in such please note my new email:
This email address is being protected from spambots. You need JavaScript enabled to view it.)
I was particularly taken by the comments regarding airfoil stability. Some
of the comments and counter arguments left me more confused than when I
started. From what I understand thin, narrow-nosed airfoils are very tricky
in that they generally create large bubbles over the top surface. These
tricky bubbles can change shape and length and, of course, burst. All of
which can see an immediate and sometimes dramatic change in lift and drag
values accompanied by changes in cp. Getting the bubbles properly back in
place and flow attached is not always an easy accomplishment ... as made
evident by the so-called hysteresis phenomena seen on airfoil performance
read-outs. And of course the higher the aspect ratio the trickier the whole
affair becomes and the more dependent top glide performance is dependent on
maintaining a very critical and narrow range of angle of attack.
I don't know how much the "look" of an airfoil has to do with determining
how the flow will go. I have used many knife sharp sections without any
so-called Phillips Entry. They seemed to do fine; but perhaps my c.g. was
overly safe and I was not operating the section at its optimum angle of
attack. In a related manner the characteristics of the stab airfoil my be
even more critical in assuring a powerful recovery from the dive. The
Woebeking section, or a symmetrical section such as the HS3 would be
assurance in this aspect.
To keep things in perspective it must be kept in mind that stalling down to
the ground does not seem to be limited to radical looking sections. I've
seen this happen on modified Clark Y's as once seen ubiquitously on FAI
Power ships in years past. For example It happened to Bissonet on his first
flight at the W.C. in Denmark (when was that? 79?) What a bummer that was!
The memory comes to me that the late Mike DesJardines tried an Eppler E-58
on a Nordic. This section has a very moderate, shallow look in the front
but accompanied by sizable cusp on the trailing edge. He said it drove him
nuts, couldn't get it to behave. I believe he ended up turbulating the
thing ...which of course circumvented its original design target. I was a
bit concerned in my case since some of my "Flapper"sections looked somewhat
similar.
All of this has led me to be convinced of the possible value of using a
rectangular wing to avoid major changes in the r.n. along the span, AND to
rely on trimming techniques that are helpful in getting a ship out of an
apparently locked-in stalling cycle....but I may be simply kidding myself in
order to justify my use of less elegant but simpler to construct wings.
Good to be back! Bill G.
Sweeping instability
====================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Mike Segrave wrote:
>Note also should be of the Goettingen 495 which although of
>much less camber, exhibits similar unstable characteristics and it has a
>shallow top curve with max position well back AND a good Phillips entry,
>too!!! Looks like we don't know very much about airfoils, n'est-ce pas?
I would like to make this point:
Calling a wing section (in some air conditions) unstable is a most
sweeping comment. All wing sections will be unstable under some
conditions. Much more depends upon the design, configuration and trimming
of the model upon which the wing section is used.
After one or two bad experiences with a section it is quite within the
rights of the modeller to depart from the use of that section forever.
Perhaps, however, others don't feel the same way?
I remember clearly the W/C flyoffs in Hungary when Alex stalled to the
ground after a period of apparently gliding perfectly, I believe someone
writing on this subject recently commented how stable his section was
compared to the b6456f. In fact, using his section I experienced the same
problem myself.
Can I recommend referring to the writings of M. Wantzenreither for a
clearer understanding of some of the issues surrounding these problems.
More of his writings will appear in forthcoming FFQ issues as well as
other results of theoretical and practical tests related to stability in
particular.
Richard Blackam
Re: Vol Libre
=============
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Mike S asks:
>
Has anyone received a Vol Libre later than #l45?
You're lucky, mate! The latest copy I have is 142.
Martin Gregorie
Bob Lyons in Memorial...
=========================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
I am truly sorry to hear of the passing of Dick Lyons. Dick and I flew against
each other at Bong in the 60's and 70's (possibly 80's?). Dick was one of those
individuals that didn't let others dictate what he would fly. His towline glider
(with the Snoopy nose) was one that commonly scored high amongst the other look
alike gliders. His power model though was unique. Flat sided fuselage with beam
mounted sideways engine as well as flat center sections. His ultimate achieveme nt
was placing on the USA WC team. The best part was that he used an engine that I
reworked for him. Bob was a gentleman, with always a smile and willingness to
help. I truly enjoyed my times with him and know that he is now running 5 secon d
engine runs and maxing in heaven!
John Lorbiecki
Psychic problems
=================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
How did you know about my problems with this section!? You are corrrect it
does exactly the same tricks. It was "cured" with an undercambered tail.
After my diversion into the 7406 and the 495 I went back to the 6356
derivatives and I reckon that's where I'll stay!
Michael J Woodhouse, Norwich, UK
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on 8/3/02 3:00 pm, SCAT user at This email address is being protected from spambots. You need JavaScript enabled to view it. wrote:
> Note also should be of the Goettingen 495 which although of
> much less camber, exhibits similar unstable characteristics and it has a
> shallow top curve with max position well back AND a good Phillips entry,
> too!!! Looks like we don't know very much about airfoils, n'est-ce pas?
The 5 minute Killer
===================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Agree!! Agree!! I think the 5 minute first round is a comp killer!
Michael J Woodhouse, Norwich, UK
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on 8/3/02 3:00 pm, SCAT user at This email address is being protected from spambots. You need JavaScript enabled to view it. wrote:
> In the northern contests on ice 5 minutes first round looks too bad.
> Most people in Pori thought it is too difficult especially for a
> wakefield with an ice cold 30 g motor, and the feeling of the contest
> falls when the first flight is decisive.
F1E and the issue of GPS guidance
==================================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
F1E and the issue of GPS guidance
Steve Philpott did a nice job raising the question as to whether GPS is
really appropriate for F1E and in spite of my love of gadgets I think Steve
may right in saying that GPS might not be the best thing for the event. One
thing that seems certain to me is that the rules are not clear about it and
what follows below is some recent e-mails discussing the current rules and
different opinions about how they are interpreted. The fact seems clear to
me that at the CIAM level there will need to be some clarification. At the
moment I would be in favor or not allowing GPS in the event as I feel the
arguments that Steve and Klaus (the one who tried GPS) are both persuasive
about keeping GPS out of the event. As always, anyone with an opinion
should chime in. I have have also included Bill Bogart in the loop and I
look forward to his interpretation of the current rules and the opinions of
a wise sage.
Jon
Hello Pierre, (Chaussebourg- Jury member at 2001 F1E World Champs)
I want to see if you can help with some F1E questions and clarifications.
Below are a series of recent e-mails between myself, Klaus Salzer and Martyn
Cowley about F1E. Any comments you have would be appreciated but my primary
question has to do the clarification if GPS would be allowed in F1E. Klaus
thinks it is ok by the rules, Martyn thinks it is not legal. I do not have
an opinion on way or the other and I'm not advocating GPS either way. Since
it is being tried I think it should be clarified as soon as possible. I am
leaning towards an electronic timer for F1E and it seems like that would be
ok by rules. The other question I have concerns the possibility of having
an F1E world cup contest in the USA next year, somewhere close to Lost Hills
and just prior to the Max Men contest in February. I am assuming that an F1E
world cup contest is separate from the other events and would not cause a
conflict as to the number of world cup contests allowed each country? An
help, suggestions or advice you might have about it as well as your general
opinion would be great to hear. Thanks for your help!
Jon Davis
Hi Martyn,
You bring up some interesting points. I don't want F1E to become something
it was not intended to be so perhaps the GPS issue is one can of worms and
the electronic timer is another issue. I don't know enough about the rules
to know how to clearly interpret them and I'm not sure Klaus went to the
places you did in thinking through what could be done and what would violate
the spirit of the rules. I definitely like the idea of an electronic timer
vs. a mechanical timer which is commonly used now so I don't see a conflict
with that. Here is the definition of F1E from the Sporting Code (1993) I
need to check the newest addition, maybe there is an update I am not aware
of?
F1E- Aeromodels not provided with a propulsion device and in which lift is
generated by aerodynamic forces acting on surfaces that remain fixed except
for changes of camber or incidence during flight. The glider can be equipped
with a steering device, which cannot be controlled by the competitor during
flight.
Characteristics of gliders with Automatic Steering.
It then goes on to list areas, wing loading, and other detail things about
the model. It seems to me that this definition is too loose and that perhaps
the rules will need to be updated unless I am missing something in my
interpretation. The term "Gliders with Automatic Steering" leaves all kinds
of issues open and it is not my intent to exploit them but rather to
understand them right now. I don't want F1E to become what you described and
Klaus may be correct in that the steering technology should not get any more
complicated than it already is? My Romanian mentor has a bunt F1E model so
the gadgets are making themselves felt in the event. All the issues you
have raised are great so keep at it. I'm learning about it just like you
are, the only real difference being that I have flown the event a few times,
other than that I'm an F1E neophyte too.
Jon
Klaus,
o Hello - if the "closed loop" rule does apply to F1E, then surely GPS
steering is closed loop ? The system operates essentially by comparing the
GPS position of where the model is now, against the GPS position of where
the next waypoint has been programmed (by the competitor before launch) and
then continuously calculates and implements the course (and possibly other
trim settings) necessary to get there - closed loop ? This is really no
different than setting an altitude or airspeed (also possible with GPS)
which the competitor wishes his model to attain during the flight, or
multiple steps of altitude, speed and direction which the model would make
sequentially ? This would certainly be radically different from the
"classical" magnet event, although would no doubt also be fun from a
software programmers point of view although not necessarily from a
traditional mechanical engineers viewpoint ?
Martyn
From: Klaus W. Salzer on Tue, Feb 26, 2002 8:10 AM
The matter of legality of a GPS control system is - in my opinion - not in
doubt for F1E, as the difference to a "magnet" steering is just the
orientation from artificial means (satellites) instead of natural (earth
magnet field). But we will leave that to the bedroll lawyers?! Actually, a
swiss reader of my article in Thermiksense was quite upset about the GPS
idea, and had to convince himself from the English text that it was legal
(it seems, that the swiss translated "automatic steering" to
"Magnetsteuerung" in their rulebook?!)!
Adding altitude measuring etc. will cross the border towards "closed loop
control" - I am not sure whether this rule does apply to F1E, however.
Varying incidence is an "old hat", I used it very often to get free of the
slope turbulence rapidly, and then slow down for a stationary (hopefully)
flight. Intended to use it for circling as well, but hardly ever did. One
reason: with interval circling you release the magnet block (which is
responsible for the circle) as soon as the model has completed a minimum of
2/3 of the circle - coupling the incidence just might still make it spin in
in the last 1/3! I prefer a model setup which allows straight and circle
from the same trim (enough incidence, large circle). This is not valid for
continuous circling, of course, but I used interval circles much more often
Finally: It does seem strange, that as a PC teacher I favour non electronic
systems. The theoretical advantages are great, but you do introduce lots and
lots of new fault areas. The engineer in me prefers the most simple solution
fitting the problem, and that still is the mechanical solution, where you
can see wheels turning, hear a timer running and see a magnet freely turning
(as of now)!
Contests will be won by reliability. But still I like to test new ideas -
after enough playing around they too may get to be reliable
Sorry for all the philosophy
..................................
roger Morrell
