SCAT Electronic News July 21, 1998
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- Category: Archive 1998
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SCAT Electronic News July 21, 1998
Table of Contents
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Reminder - SCAT Composite School
Time Keeping Issues - Richard Blackam
Portugal Power - Martin Gregorie
Reminder SCAT Composite School
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This Saturday at Leuzinger High School [in the band room]
in Lawndale. 8am til 2 pm.
Speakers include Matt Gewain, Alexander Andruikov, Dimitri Kozyluk,
Doug Joyce, Allen Ulm and Bob Piserchio.
CST will have composite products for sale and Sal Fruciano
will have some of his wares as well.
Timekeeping issues
==================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Roger,
It was interesting to read Mike Fantham's recent 'opus' on electronic
assistance in FF, however his comment regarding timekeeping as being a
much more pressing issue is right on the money. I hope this followup
'opus' of my own is not too much for the Scat readers!!
I believe the problems of timekeeping can be broken into a number of
sub-areas for clarity:
Type 1. Errors of timekeeping due to visibility. These errors result from
distance flown, atmospheric conditions during the flight, quality of
binoculars used etc.
Type 2. Errors of timekeeping due to variations in timekeepers' reaction
times. This primarily affects the timing of engine runs in F1C although a
second here and there in total flight time recorded has been known to
have a significant effect on the results of some contests.
Type 3. Errors of timekeeping due to timekeepers' experience. This of
course affects the problems of type 1,2 & 4 errors as well.
Type 4. Errors of timekeeping due to timekeeper bias. This may open a few
cans of worms! These errors result from the subconscious or deliberate
altering of the score achieved by a timekeeper having a strong bias for
or against some particular competitor.
In more detail...
Type 1.
>From looking at the results of World Champs over the past 20 years it is
clear to me that there are two major factors which have caused the
significant rise in this type of timekeeping error.
The first MAJOR FACTOR is the technology transfer that started in the
late 80's from the ex-Soviet bloc to the West. This resulted in a rapid
rise in performance standard of many Western fliers which in turn
dramatically increased the likelihood that each would reach a flyoff.
Added to this was the increase in competing nations from thos ex-Soviet
States which began to be autonomously affiliated to the FAI and competing
at major events.
So we have many more high performance competitors...
The reaction by CIAM to the increasing numbers of competitors in flyoffs
was to introduce the two minute flyoff time increment in a bid to sort
out the contest faster. This however is the 2nd MAJOR FACTOR which has
caused timekeeping problems. This is because a contest progresses from 3
minute flights to 5, then 7, then 9 in the space of a short time. If
there is any moderate wind speed then that 9 minute flight is a long way
away. Compare this with the previous situation where a contest (over the
same time period) progressed from 3 minutes to 4, then 5, then 6.
There is a big difference between timing 6 minutes and 9 minutes. In a 5
m/s wind the 6 minute flight is 1.8 km away, but the 9 minute flight is
at 2.7 km and this neglects the likelihood that the wind speed is much
higher at altitude... Add to this the effect of timekeeper fatigue...
Possible solutions?
Change the flyoff increments back to one minute but start at 5 (instead
of 4)...
Increase the first round max to 5 minutes (this WILL dramatically reduce
the numbers in the flyoffs)... maybe the second round as well... but the
contest MUST start at dawn for this to be worthwhile.
Reduce performance of the models further (but this is not a popular road
to follow)...
Maybe a dramatic change to the format of a World Champs. Perhaps there
should be two elimination rounds where the large field is split in half
(table A and table B) and each half competes for a berth in the finals.
Perhaps the top half of each tables' results then progresses to the
finals. Then instead of 100 competitors in F1B we have 50. Less
timekeepers needed (better quality, easier to find and less expense to
the organisers). The other advantage of this approach is that the person
who gets 'lucky' in one contest will probably not in the second, so it
means the winner overall is probably more deserving.
Type 2.
This causes much aggravation and confusion. The rules already have a
built-in allowance for reaction times (round the time recorded down to
the nearest 0.1 seconds, so 5.09 seconds becomes 5.0) and if a competitor
takes a risk and gets 5.09 sec for the price of 5.0 then he has worked
the system to his advantage AND been lucky in his timekeepers.
There are two major causes of these errors:
The first big cause of these problems is when a competitor has launched
and another motor/s is running on the ground next to the timekeepers.
There is no way a timekeeper can hear a motor at 200m altitude shut down
under these circumstances.
The 2nd major cause is the dramatic variation in timekeepers' reaction
times.
One other problem I see is the timing of burble at the end of the run.
This does not add to the model's altitude and should be discounted but
how do you do this?
Possible solutions?
An organiser-supplied (or standard design) onboard audio sensor which
notes when the engine stops and telemeters the info to a timing device on
the ground... This would not be difficult or expensive nowadays.
LONGER motor runs to reduce the effect of reaction time, allied with
reduced power motors. Venturi restrictors as used in CL Combat seem the
best way to achieve this.
Flight launch windows to minimise the problems of a loud engine running
on the ground next to timekeepers...
Allow tuned pipes plus a noise restriction. This will reduce the problem
of noise on adjacent poles because the timekeepers' ears will not be
overloaded...Of course some way of reducing power MAY also be necessary...
Type 3.
The issues are aggravated by the larger numbers of people in the flyoffs
at big contests. The requirement for the organisers to find a large
number of timekeepers inevitably results in the use of MANY inexperienced
timekeepers.
Possible solutions?
Some form of FAI Standard accreditation for timekeepers should definitely
be developed.
Reducing numbers in World Champs as mentioned above (elimination
heats...)...
Type 4.
This is a serious problem. I have seen this at so many contests. Mostly
it takes the form of a timekeeper favouring a competitor and giving a max
when it was not achieved and this is usually deliberate.
A rule which is often flouted in these situations is that when the model
is lost from view and timekeeping continues for some significant time
before a count is begun. Then, even when the count is deducted from the
flight time the competitor has much more time on the clock than they
should.
Sometimes of course a flight is lost sub-max when the model is very high
and clearly going to max. In these situations perhaps a CD or Jury should
be able to either give the flier a second chance or award a max, but
there must be NO DOUBT.
Possible solutions?
Training of timekeepers, as mentioned above...
regards
Richard
Portugal Power
==============
Martin Gregorie via This email address is being protected from spambots. You need JavaScript enabled to view it.
Subject : Portugal Power
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Hi, Roger. I asked Martin Gregorie about Leonid's folder and he sent the
following observations. I trust he won't mind my volunteering his contribution
to "The Nexus of International Free Flight."
Martin Gregorie wrote:
High, Bill
(concerning Leonid's Folder, the Blazing Pelican) What a name!
I was there & saw it. Actually, the glide trim had been odd all day - it was
almost mushing round in very tight circles. If it was an A/2 you'd
automatically open the turn a lot and down trim it. Instead Leonid wound it
up a bit for the flyoff and got the stalls. To run down the rest of that
flyoff:
- it was the only evening of all 5 flying days calm enough for a flyoff
- Eugene did an excellent no -lift flight with a standard 6 panel model to
make the 5
- Ken figured it would be thermally and played cautious with 4.5 secs. He
was 12 secs short. A good flight using the same Kevlar covered model he flew
all day. Its not very big but has an excellent glide.
- Leonid had a good climb & excellent transition but stalled. This model is
2600, 6 panels with a carbon wing using the Makarov section. The two inner
panels are constant chord, 500mm span. The 300mm tip is essentially unsprung
and comes out quite slowly. The TE is continuous at a glance but, as we
thought, the tip root chord is about 40mm less than the inner chord so it
can easily fold in between the inner panels. Leonid now has a latex membrane
that seals the end of the wings when under power.
- Phil Ball was the 4th and last flyoff contender. He had a twisted bladder
which prevented his No 1 model from starting and hadn't assembled a 2nd
model, so got a zero. Still, that was good enough for a UK team gold.
Beja was generally windy, hot, dry and dusty. Temps were 35C at the start
and 41C by the end of the von Hafe. It got calmer too - all days were flat
at dawn. We flew from 0730 to 1400 apart from when the previous day's
flyoffs delayed the start to 0800. The wind got up , initially around 0900
though the last day it was calm to 1600 and by nominal flyoff time it was
strong enough to rip the canvas on the beer tent. It stayed windy till after
midnight - NO drop at dusk.
The field is covered by short dry grass and amazingly spiky castor plants -
to sit down, find a flat rock! It gets soft in winter and they run cattle
there. Then in spring it bakes solid and the grass grows to hide the holes.
Still, its huge - at least 5Km on every direction - and fairly flat - gentle
rolling mounds and valleys.
Everywhere you looked there were thermalling Montague's Harriers and storks.
Wonderful.
Oh,yes. Eugene had the geared ship there but didn't fly it. The workmanship
is wonderful. He ran it but I was downwind, so didn't get to hear it.
Did you hear that Rocca won the von Hafe. Only man to max in F1C. Virtually
no carbon, built-up eggbox wing. He's switched to Verbitsky engines from the
ADs he used for years.
PS: Verbitski and Stamov are planning to attend the Sierra Cup this year and
intend to come to the Stonehenge event on the way. Great!
Martin Gregorie
[Comment]
To put it in perspective for the US flyer - Other attendees have rated
the 'cow holes' in Portugal much worse than those at Waegell
Field in Scaramento.
........................
Roger Morrell
