Hi Terry (and congratulations on your IGC role, and work winning Worlds
for Australia)
The handicap system was devised by Peter Rigby of the Wollongong Gliding
Club, and more recently maintained by a committee chaired by Graham
Brown of Bathurst SC. In essence, the committee agree on a polar for
each glider, then use it to predict theoretical cross-country speed on a
closed circuit task in nil wind, on a day when the thermals are all a
nominal "Standard Australian Thermal" of a given diameter and lift
cross-section. It is a similar system to the BGA one but our thermal is
bigger and stronger than theirs!! :-))
We now use two sets of handicaps, one for ballasted gliders and the
other without ballast (i.e. dry) for club and sports class comps. There
is a glider type (currently the LS4) that is assigned a handicap of
100.0% and other types are scaled relative to this one to produce the
final handicap figure.
The Murray Evans system did almost a reverse of this process - it worked
from the achieved speed to input to the polar curve and determine the
actual thermal strength used - scoring could then be done to award the
daily maximum points to the pilot who used the best thermals (or who
used streets to best advantage or cruised in rising air to the greatest
extent). This has the advantage of automatically adjusting for wind on
the day, the greatest failing of the standard handicap. In the UK
nowadays, or last time I looked, they actually change the handicaps on a
daily basis depending on the observed wind for the task, so higher
performance gliders do not get an inbuilt advantage on windy days and
lower performance gliders are not penalised by the wind. However, this
still does not overcome Peter R's problem that to complete a fixed task,
he has to fly for a longer time and thus risk having to use weaker lift
than his competitors who only use the stronger past of the day. Hence
the idea of the variable task which developed into our current form of AAT.
So some pilots spend a lot of time, effort and money working on their
glider to try and make it perform better than others of the same type,
and handicappers invent factors for winglets, turbulators and actual
wing loadings of lighter pilots flying unballasted - but nobody yet
regularly uses a reference thermal that reflects the actual conditions
on the day, or the fact that some sites experience consistently better
thermals than others.
Pilot-based handicaps sounds more like golf than flying!
Wombat
On 7/03/2013 11:06 PM, Terry wrote:
The ME formula was used for many years, but it was used to compare
results across classes for team selection, not handicaps. ME would
apply the formula to produce a team solution and then some "wise"
heads would critique and then ME would "adjust" the factors and
produce a new set of results. Eventually an answer was agreed. The
most subjective objective process.
Handicaps were formulated by another member (? Brown?) who spent a lot
of personal time reviewing polar curves and calculating thermal
characteristics to calculate the "right" handicap. The concept was
good but Unfortunately, the polar curve data was from many sources and
therefore no consistency. The first club class I went to the pilots
spent the whole two weeks arguing about handicaps.
We then invited another group of wise heads to use their experience
and invent some handicaps. Since that time, there have been very few
issues with handicaps. It is not an exact science.
At Gawler we now use Pilot handicaps also , which is even less
scientific, but good fun. A little retrospective adjustment resolves
any errors.
Terry
Sent from my iPhone
On 07/03/2013, at 8:10 PM, <gstev...@bigpond.com
<mailto:gstev...@bigpond.com>> wrote:
Peter,
That is an interesting suggestion! I wonder if it could be
practically (and fairly), done?
Re "poor" task setting, I tend to think that your objection 'having
to start early/finish late" is actually *as a general principle*,
just the opposite - at a National level and probably a State level
too, this is what good tasking should be all about! In general, the
task setting at most competitions, on most reasonably soarable days,
is far too conservative. {Everybody, please carefully note those two
provisos - "most" & "reasonably"!}
Having said that, I tend to agree with your last paragraph, which
then gets back to the question I raised in *my* first paragraph above.
The points noted by Matthew Scutter, in his email below, are all
reasonable too. Emilis Prelgauskas in a recent posting on this site,
talked (amongst other things), about some of the problems facing the
gliding movement in this country, including a gradual loss of
knowledge held collectively by the membership, and knowledge
(mostly), lost to the current Board and those administrating the GFA
system. Once upon a time - I think it was just around the time of the
introduction of computers into gliding scoring - a guy called Murray
Evans (Murray-Evans?), came up with a system that related everybody's
performance back to their glider polar, and the results for the day
were then "corrected". The system was tried once, and promptly
abandoned, as being unworkable - which was fair enough *_at the
time_*. The first and possibly major problem then, was obtaining
realistic polars, for the gliders competing. Number crunching
(laughable today), was also a problem, as I recall. In my view, it
might now prove profitable to revisit the *_principles_* of the ME
concept, and check their workability in the current hi-tek environment.
*Ann Woolf - given the tremendous (mind boggling?) - work that you
have done on compiling the electronic AG data base - could I
please call upon you to put the article(s?), that appeared in
/Australian Gliding/, on this web site, for the perusal and comment
of a latter generation of glider pilots?*
**
Gary
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