Gordon Rigg <<gordon.rigg245km>>
writes:

My concern about penalties for sprog angles is not about wanting
to set sprogs lower without penalty.

My concerns are two fold:

1 - Lack of repeatability of sprog measurements leading to penalising the
innocent.

2 - Lack of absolute clarity as to what measurements are applied to what glider.

Regarding point 1

Temperature variations affect the sprog angle directly. Differential expansion
between aluminium and stainless steel is enough to make a glider that feels
perfect in over 30 degrees in NSW, into one that feels like a death trap in the
winter in UK. Where carbon is used I'm not sure if it is worse or better. But
the difference between a very hot and a cool day could be well over 0.5 degrees
in sprog settings.

Humidity variation affects the dimensions of the sail, and the dimensions of
composite materials - dryness makes the sail tighter, hot and dry stretches the
sail more on the frame too - this pushes the sprogs down more when it is rigged
for measuring, but doesn't necessarily affect its aerodynamic stability. The
difference between a hot and dry glider and a cool and wet glider will be quite
large. These variations could easily occur over a period of days during the
competition. Plastics lose moisture fairly quickly (over hours) but absorb
moisture slowly (over days).

Claims for accuracy of measurement of 0.1 degree, or 0.2 degree are unrealistic
and not borne out by my experience during measurement at cat1 comps, or my own
measurements on my glider that I repeat regularly - the same glider has been
failed and then passed by officials simply being represented an hour later
without adjustment!

Where a glider is measured and passed, there must be a failure margin applied to
allow for variation of measurement conditions and accuracy of measure (there is
a good understanding of such error and measurement margin applied for airspace
infringement and turnpoint checking, but somehow, so far, the point is not taken
on board for sprog measuring!). This margin in my opinion needs to be of the
order of 0.5 degrees (Possibly more if the affects of heavy landing are to be
included) or innocent pilots might be penalised.

Expecting the pilots to adjust above the allowed limit, to allow for variation
themselves, is not fair on the pilots. If a glider is passed, and the pilot
makes no adjustments to it - the pilot should not be penalised. It is not for
the pilot to somehow asses the accuracy of measure, the affects of weather on
the glider etc with no help from the officials. This is the question that is
always asked at every competition, and there is never an answer - the officials
don't seem to understand the concept.

What I mean is if a glider passes on 4.5 and 6.5 degrees minimum angle, then
when it is checked it must measure 0.5 degrees (or whatever margin that is
decided and published in section 7) below that minimum before the pilot is
penalised. To maintain safety the pilot can be compelled to adjust back up to
the minimum angle before they are allowed to fly the next task, and officials
may choose to measure him again, but unless that error margin is exceeded it is
not fair to accuse the pilot of cheating or to penalise him. There has always
been a worry that after passing the official measures, and making no
adjustments, the glider could still fail with a hefty penalty, and accusations
of cheating, when the pilot has done nothing wrong at all.

There is very little data on repeated measuring of gliders over a period of
changing weather and temperature, and nothing published. So perhaps more data
must be acquired before the necessary error margin is established so that
penalties can be safely applied, but to start the error margin must be quite
generous to avoid any possibility of penalising innocent pilots. The worry of
unfair penalties being applied is what causes a lot of ill feeling among pilots
during the measuring of the gliders.

Regarding point 2 - what the measurements are to be applied to the gliders

It needs to be stated clearly how the glider needs to be presented for measure.
In Laragne in 09, not all pilots presented their gliders with the VG pulled to
the fullest extent, and the officials enforced that for some people but not all.

In Monte Cucco my team mate was forced to change his nose wires as it was said
he had too much keel bend, I had two gliders with the same frame as him, all of
us had the same keel bend with the with std wires supplied by the manufacturer.
I was not forced to make any change to either my comp glider or my identical
spare. There is no clarity as to what can be measured on gliders other than the
sprog angles and not all pilots have been treated the same.

In Turkey I am reliably informed different measures were applied for different
pilots with the same glider size and model (probably not by intent, but it
happened).

The first step must be to publish the required sprog angles well in advance of
the competition. If they are not available for all glider models then list that
glider as awaiting information from the manufacturer - the pilots might then
apply pressure to the manufacturer to provide the info if there is a risk they
might not be allowed to fly. Commonly pilots spend many test flights tuning
their glider and that is all pointless if the sprog angles have to be changed
just before the competition. The information should be always available on the
CIVL website and kept up to date.

So far the sprog angle info has been provided just in time (or even a bit late),
and kept on the official's computer, not made generally available. There has
been no published list so the pilots cannot be certain they are all being
treated the same. There is mistrust. The pilots cannot prepare their gliders in
advance. The pilots obviously don't like making late adjustments to their
gliders - there is a safety issue if the glider is adjusted and not test flown
before the competition. The possibility of the glider not flying straight, or
being trimmed incorrectly due to "official" enforced late adjustments, is just
as much of a safety issue as the pitch stability! Please consider that more
pilots have landed badly and hurt themselves, or flown into obstructions, than
have ever tumbled! Forcing adjustments onto peoples gliders should not be taken
lightly!

If checking of the gliders is to continue a serious effort must be made to gain
the confidence of the pilots, so they start to believe that the exercise is both
fair and worthwhile. So far the pilots have low confidence in the officials,
they have a poor attitude, turn up late and have minimum cooperation. So far the
aim of measuring every glider before the first scheduled task has never been
achieved. The whole exercise is an unpleasant experience for the pilots and
especially unpleasant for the officials and it takes an inordinate amount of
time. If checking of the gliders is to continue somehow the system has to gain
the support and confidence of the pilots and also support from the manufacturers
so that they provide the measurements. Somehow the way sprog measuring has been
introduced makes the pilots feel the officials believe they want to cheat,
somehow we are all assumed guilty and have to prove our innocence - overall its
effect has been entirely negative in terms of fostering good sporting relations
between the pilots of different nations, which is after all the primary aim of
the cat1 meetings.

Once again we approach a world championships and what will happen with glider
measuring is a total mystery. This is simply not good enough. I'm not at all
surprised nobody wants to bid to hold a championship - the bad feeling sprog
measuring has created together with all the extra cost and wasted time has made
me seriously consider giving up cat1 competition, and I am sure I am not the
only one who thinks that way.