Re: [Aus-soaring] Murray Evans formula

[Mike Borgelt]

The acronym for the Murray Evans Scoring System  is MESS which more 
than adequately describes it.
The problem was that at the time there were 3 classes, Standard, 15M 
and Open and only 4 slots per country at a World contest despite the 
IGC or its predecessor having created a 3rd Class some years before. 
Yes the IGC is run by fairly stupid people and they are still 
promoting them into these positions. It seems to be a requirement.


So a method of comparing results across Classes was required. There 
was considerable pressure from the pilots to have some objective 
system and Murray came up with this system.
The real aim was to pretend to have an objective system but retain 
the ability of the senior silly old farts in the GFA to select who 
they wanted to send as with their superior wisdom and knowledge  they 
could send people more likely to do well OS than those who had merely 
won contests. (*/sarc off) So the MESS had a number of coefficients 
that could be adjusted post facto to obtain the desired results.


The whole issue of team selection became very contentious before the 
1974 World Contest at Waikerie when at the previous Nationals at 
Waikerie the favourite for selection who had won many Nationals 
before and was a Waikerie local "only" came second in the vastly 
numerically superior Standard Class and the powers that be 
decided  this just wasn't good enough and they dropped him and 
selected an new young promising candidate  - who had come third in 
Open class and who wasn't a local from the area the World contest 
would be flown in.


Didn't work out so well but failure never stopped TPTB in the GFA 
from forging ahead with fatally flawed policies or procedures and 
even the objective outcomes of such always failed to convince TPTB 
that they had ever been wrong.


So we have the state of gliding today and you folk who are trying to 
sell expensive sailplanes into the used market will know all is not 
rosy in the garden.


Mike





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Re: [Aus-soaring] Murray Evans formula

[Matthew Gage]

It's worth looking at how sailing tried handicapping 20 years ago, as they went 
through a similar process. I was heavily involved both as a competitor and as 
someone trying to make the system work.

Some bright individuals came up with the idea of handicapping based on a polar 
so that the wind conditions were taken out of the results - heavy boats do 
better in strong winds, light boats do better in light winds on a fixed 
handicap (in general).

There were 2 ways of working this. The way commonly used was similar to the ME 
system, in that the polar was used to generate an apparent wind and the highest 
wind won. This was almost universally hated by the sailers, but loved by the 
organisers, so it prevailed - until the sailers moved to other classes. The 
biggest problem is that as there was no actual handicap in use, it was 
impossible to work out how you were doing during the race.

The alternative was to calculate the handicap (in seconds from a scratch boat) 
based on the exact course and the actual (and forecast) wind conditions. This 
was also able to factor in the tide, which could have a huge impact. Given 15 
boats, we could get the handicaps calculated and broadcast to the boats in 
about 5 minutes. This was loved by the sailers who used it, but panned by the 
main race organiser, mostly because they had invested so heavily in the first 
option.

Right now, sailing has moved completely back to a fixed number handicap the 
same as we use - it's not the theoretical optimum solution, but in practice, it 
works better than anything else ! Easy to use, easy to understand and very few 
complaints.

When you look in detail at comp results, there is very little difference 
between strong days and weak days in terms of the types that win. Actually, you 
could score most recent standard and 15m nationals with no handicap and get the 
same results, even though in 15m the winners are flying older or un-flapped 
gliders. In other words, it's obvious that differences in pilot ability is far 
greater than any inaccuracy in the handicaps we are using !




On 07/03/2013, at 23:56 , Mike Cleaver  wrote:

> 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 s

Re: [Aus-soaring] Murray Evans formula

[emilis prelgauskas]

On 07/03/2013, at 11:26 PM, Mike Cleaver wrote:
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.


In gross terms, the US the CH factors differ between west and east 
sides of the continent trying to reflect the presumed difference in 
strength in soaring weather.
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Re: [Aus-soaring] Murray Evans formula

[emilis prelgauskas]

And if you want hard copy sets of AG (sorry not complete back to the 
1950s because we have run out of the early small print runs) email 
Keith Willis


(there are some mighty people like Ann and keith doing work of value in 
the sport unheralded)


On 07/03/2013, at 9:49 PM, Ann Woolf wrote:


I have sent the relevant pages to Gary.

If anyone has their own AGs, there are Excel files which contain the 
index of everything in these AGs, on the Waikerie Gliding club website 
that you may download and search for anything in the AGs from 1951 to 
1997 when they went to A4 size.


Ann


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Re: [Aus-soaring] Murray Evans formula

[Mike Cleaver]

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, > 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 M

Re: [Aus-soaring] Murray Evans formula

[Michael Scutter]

The scorer also won the regatta too! I'm not suggesting any inappropriate 
behaviour but that was good fun too

Michael

On 07/03/2013, at 10:36 PM, Terry Home  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,  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
>>  
>> - Original Message -
>> From: nimb...@internode.on.net
>> To: aus-soaring
>> Sent: Thursday, March 07, 2013 6:00 PM
>> Subject: Re: [Aus-soaring] Boring
>> 
>> How about letting the previous generation 20m gliders fly in 15m class where 
>> the handicaps are much closer as compared to current generation open class.
>> 
>> The other factor that gives the higher performance gliders an advantage over 
>> the previous generation gliders when there is a large handicap spread is 
>> poor task setting. 
>> This occurs when racing tasks are set that force the lower performance 
>> gliders to fly in weaker conditions by having to start early or finish 
>> later. Where there is a significant spread in handicaps then racing tasks 
>> should not be set.
>> 
>> Regards
>> Peter
>> 
>> Sent from my HTC smartphone
>> 
>> - Reply message -
>> From: "Matthew Scutter" 
>> To: "Discussion of issues relating to Soaring in Australia." 
>> 
>> Subject: [Aus-soaring] Boring
>> Date: Thu, Mar 7, 2013 12:29
>> 
>> 
>> Ron,
>> Because the handicaps have practical limitations as gliders have
>> different performance characteristics in different weather, which
>> handicaps can't take into account.
>> The handicaps are probably fair for a Cirrus and an ASG29 on a 3kt
>> day, but they certainly aren't on a 12kt day.
>> This seems to be th