SCAT Electronic News 1 May 2001 issue 575 - May Day
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SCAT Electronic News 1 May 2001 issue 575 - May Day
Table of contents
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Flyoff visibility problems - what to do? - Blackam
9th Annual Spring Cup - Seguin - Parker
Flapping Folder !? - Bogie
Re: rolled tail boom - Wantzenriether
FootNote for SO mentors - Broken spar
More digital servo stuff - Van Wallene
wakefield history - Rushing
Flyoff visibility problems - what to do?
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Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Imagine the scenario:
The final of the 100 metre swimming event at the Olympic Games. The
starter fires the gun, the swimmers leave the blocks as the timekeepers
(one for each contestant) start their stopwatches.
One hundred metres later the swimmers each touch the wall and the various
timekeepers stop their watches. Unfortunately due to the splashing in the
pool, the reaction times of the timekeepers and the fact that the
timekeepers are situated in the stands to the side of the pool, there is
some uncertainty about the actual times recorded. Nevertheless placings
are awarded on the strength of the given result...
Of course, this situation would be ludicrous and would not be tolerated,
which is why such events use various electronic timing systems. Imagine
an athlete training for years for such a major event, only to have it
decided by luck, circumstance and the eyesight or reaction time of
someone else.
Yet it happens all the time in Free Flight. I have been in and witnessed
dozens of flyoffs where the result was decided entirely according to
which flyer had the timekeeper with the best eyes, the best binoculars, a
tripod or not, the best location and even the best imagination.
After weeks or years of preparation and training and a full day's hard
contest flying, where you keep your concentration together for several
hours in order to reach the final round, to have it all decided by luck
or circumstance is not just unfortunate, it is completely unjust and
unacceptable.
Before this all gets too muddy, I want to point out that I'm not
discussing the situation where one or two flyers in a round has such
problems; I mean to discuss only the situation where the local conditions
result in all or most competitors having an unclear result. For example,
in the result of the F1B flyoff at the Isaacson Winter Classic this year.
In that final round, the wind and low visibilty meant that virtually
everybody's flight was lost out of sight. The result could just as
accurately be decided by tossing a coin.
I think CIAM needs to consider this situation and look at implimenting
some rules which allow a way to resolve the situation in a more
satisfactory fashion.
My feeling on this is that there are three choices when such an
unsatisfactory result occurs:
1. Leave the (erroneous) results as they are (In my humble opinionr this
is completely unsatisfactory)
2. Scrap the result of that flight and re-fly the round at a better time,
visibility or weather-wise. This would be ideal but obviously requires an
additional time to be available.
3. Scrap the result of that flight and declare a draw for all
competitors. At least this reflects the last known accurate result.
And for those who say 'it's the nature of Free Flight' I can only reply,
'Is the nature of Free Flight competition to be unfair?'
Hopefully we can initiate some kind of discussion through SCATEN to look
towards creating better and fairer results.
9th Annual Spring Cup - Seguin
==============================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Results from 9th Annual Spring Cup - Seguin, Texas
Reported by Faust Parker (Contest Director)
F1A - (4 Flew)
1. Jon Schelp 1020 (Max Out) Steve's son!
2. Steve Spence 982 (Won Flyoff)
3. Mike Fedor 982
4. Jackie Sheffer 261
F1B (2 Flew)
1. Fred Pearce 1005
2. Richard Wood 999
F1C (3 Flew)
1. Henry Spence 989
2. Faust Parker 979
3. Don Chesson 545
Open Power (9 Flew)
1. Doug Jones 995
2. Russ Snyder 863
3. Marvin Mace 851
4. Bill Shaw 761
5. Mike Fedor 406
P30 (9 Flew)
1. Arthur Milam 336
2. Eddie Vanlandingham 330
3. John O'Dwyer 318
4. Allen Shields 317
5. George Patrick 303
F1G (6 Flew)
1. Eddie Vanlandingham 600 (Max Out)
2. Fred Pearce 568
3. Richard Wood 566
4. John O'Dwyer 554
5. Frank Parmenter 390
F1H (3 Flew)
1. Mike Fedor 538
2. Steve Spence 521
3. Jackie Sheffer 436
F1J (12 Flew)
1. Faust Parker 738 (Won Flyoff)
2. Fred Carstens 678
3. Jackie Sheffer 589
4. John Irwin 570
5. Russ Snyder 555
Flapping Folder !?
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Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Thanks Bill for bringing to the fore the elegant solution for the climb.
Symmetrical airfoil, indeed would eliminate the wing twist due to high speed.
I haven't used one since I found out that cambered airfoils work better.
What I think would better suit the situation is to have a symmetrical airfoil
during climb and a cambered section during the glide phase. Gil Morris is
well into that combo using, I might say, a Bo560-26 modified section.
Bill Bogart
[ I think that Skykeing gets his symmetrical airfoil by folding the wing
and putting two undercambered surfaces back to back ?]
Re: rolled tail boom
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Author : j.w.bourdonnay
For a Coupe boom, I have found the 1st part of R Blackham's method is
best_ Inside glass cloth 20 g/m2 or so, then balsa 1/32"_ The key
point in securing not-bending booms is the use of very soft balsa_ The
boom stiffness is obtained by the balsa pressing itself very hard to
the glass cloth core_ Tissue covering is not helpful, unless you want
very strong things, a coat of dope and spray color is enough_ Weight 5
grams for a 60 cm long boom, diameters 21 and 7 mm. - My favorite
release film is found by my flower seller : called cellophane and free
of charge.
--
Jean Wantzenriether, E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
FootNote for SO mentors
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Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Re SCAT 574encore ( what's that encore ? )
Where did Limberger come from, I wonder...
Brokenspar
Footnote to Science Olympiad mentors: Make sure your kid takes a leak
before going out on the flying compound.
And, make sure they put the same turns in the motor for the official,
as for the 4 minute test flights !! ( well, 2min, 24 seconds ).
These two points are related.
More digital servo stuff
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Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Hi,
About holding torque,
Well you're right when you say that holding torque is not very relevant if
the servo is switched off.
But this servo characteristic also directly relates to torque for small disc
movements. So if the holding torque is high, this means that the regulating
electronics apply relatively more power to the servo motor for small
movements.
Furthermore, if the servo is loaded (like under on line acceleration, cruise
and bunt) this is a good asset too. In particular ABAS type of steering,
where the servo has to move small bits at the time at full aerodynamic load.
Does it go faster on 6 Volts? Well, I didn't test this yet, but Graupner
advertises this digital servo suitable for a wide range of voltages. As the
battery is switched directly to the motor terminals through low impedance
FETS, one could safely assume the servo is faster and more powerfull at
higher voltage.
Some other things I noticed:
The servo has a built in fail-save mode. So if the incoming pulse is lost,
the servo actively holds its last position.
The gears allow a 190 degree disc throw, but this can not be used to the
full extent. In fact, only about 160 degrees can effectively be used. If the
incoming pulse is adjusted to go beyond this, the disc either doesn't move
at all (clockwise) or suddenly jumps to its end stop (counter clockwise).
I found an article about another digital servo from Graupner. It stated that
the microcontroller has a 13 bit resolution. This would translate into a
0.002 degree resolution!
Ciao, Allard
wakefield history
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Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Roger, My Book "The International Wakefield Cup A History 1911 to 1997" =
is no longer in print. Nor will I publish a revised edition. I am now =
recieving requests for my book which I am forced to return. Please =
notify others that my book is no longer availible. Charles Dennis =
Rushing; This email address is being protected from spambots. You need JavaScript enabled to view it.
....................................
Roger Morrell
