Do you want to launch with 100 metre lines?
This month’s biggest F3J question is when and if we are going to get
our launch lines shortened to 100 metres. That’s the explosive issue
that 2008 CIAM plenary meeting will decide on 29 March in Lausanne.
Another decision due that day is whether the first two metres of the
landing tape will be divided into 20 cm lengths so that the landing
score can be anything from 100, 99,98 etc. down to 91 before the old
tape scores of 5 points lost for every metre resumes. That proposal is
not likely to be controversial, and the first metre of it has been used
in Holland and Germany for a couple of years under local rules. The
object of the changes is that FAI wants to see are bigger differences
between top scores, particularly in the flyoffs.
The Belgians - and others - also want to see penalties for spear
landings, and their way is to give zero landing points if the tail of
the model is not touching the ground. While sympathetic to the aim, I
don’t see this solution getting a positive vote, simply because pilots
could lose their score even if they land gently and hit an odd lump of
mud or tuft of grass.
What lies behind shorter line thinking?
F3J models and pilots have become too good in recent years. Top pilots
reckon to score 9 minutes 54 seconds plus and hit the 100 spot in all
but horrible weather. Quite a number rarely fail to achieve 14 minutes
54 seconds plus in the flyoffs, although doing it four times running in
calm or tricky air is not so easy.
So the F3-RC soaring subcommittee has proposed an amendment to Rule
5.6.8.7 Towlines, where b) is set to read “The length of the towline
shall not exceed 100 metres when tested under a tension of 20 N.”
Chaired by Tomas Bartovsky, the committee reckons that flight times
will be become shorter and fewer pilots will fly out the working time.
That in turn will put greater emphasis on the skill of pilots finding
thermal lift. Instead of the all-too-common “launch and landing”
competition, the event will turn into more of a thermal hunting - or
“aerodynamic quality” - competition.
The likely result of shortening towlines for F3J is more complex than
that!
*
Tomas Bartovsky, chair of CIAM’s RC Soaring Committee, at Martin’s WC’s.
The committee also notes that shorter lines would allow a smaller field
to be used, and that cannot be disputed. But I am not sure that F3J
competitions are seriously restricted because the organisers cannot
find a big enough field to cope with 150 metre lines.
There is a problem. At the start of every FAI world or european
championship, the early discussion among pilots is how close the scores
will be. Top pilots do spend plenty of effort into deciding whether to
make a two or three second launch to gain an extra point or two. It is
not unusual for all the flyoff places to be within 20 points of the
maximum possible after ten rounds - allowing for one dropped round. But
in all fairness, that is the very nature of F3J.
F3J as a class started as the simplest way to run a thermal soaring
event. In F3B, still the most difficult and demanding contest for RC
sailplanes of this model size, more and more pilots became fed up with
the increasing physical and mental effort - and money - to compete at
top level. F3B still thrives in many countries, it remains the pinnacle
of our sport in my view, but the numbers of pilots enjoying the class
are diminishing even amongst the leading nations.
The answer was F3J, a derivative of the British Association of Radio
Control Soarers Open thermal contests, and official FAI championships
started in 1997. Keep it simple, try to fly out your slots and land
reasonably accurately to gain maximum points, flying “man-on-man” to
reduce the advantages gained between slots when thermal conditions
changed. Pilots often delayed their launches, waiting for someone else
to find a thermal. When does that happen today? In fact by the first
world championships at Upton in 1998, everyone launched on the buzzer,
or even before!
Inevitably when rivalry is involved, the sport moved on quickly. Pilots
wanted to launch quickly and as high as possible. Tow using two men,
speed up the line and zoom to gain extra height, new aerofoils to allow
pilots to cross the skies at speed with minimum height loss, greater
manoeuvrability for precision landings, more reliable towlines and
pulleys. Many of today’s pilots have seen the whole period of
development for it is less than 20 years in total.
Development still continues, albeit at a slower pace. Even five years
ago when the Sharon and Pike Plus and a few others reigned supreme, few
pilots guessed that another generation of aerofoils and better use of
high tech materials would be significantly better and more likely to
win.
What will shorter lines lead to?
First I heard of shortening competition lines was in 2002, the world
championships in Lappeenranta, Finland. The problem of tight scoring
was already apparent, but also a few pilots saw shorter lines as a way
to launch more quickly. Jo Grini was the pioneer promoter, and used 75
metre lines in one or more rounds. He persuaded CIAM to agree to
examine the merits of shorter lines, but they slept on it and nothing
happened at Red Deer in Canada, nor at Martin in 2006 except that the
matter as briefly talked over at the managers’ meeting.
Then out of the blue in June last year, CIAM’s F3-RC Soaring committee
was circulated on the line change now up for decision. Nobody I know is
sure whether the committee really wants to see the change or whether
they are offering the proposal to get Jojo off their backs.
If they pass the proposal next month, will the shorter lines be used in
Turkey this coming July? Unlikely according to Tomas; if the proposal
passes, then normally it would be published in the Sporting Code next
January and then apply. Since it is not an urgent change, likely start
is 2009. But there’s nothing to prevent the jury and the Turkish
organisers choosing the shorter line as a local rule earlier.
UK’s tentative reaction is not to support the change at this stage.
They would like to see “extensive trials”, they warn of dangerously
increased pre-launch line tensions and greater chances of models
veering off course on launch. They note that some UK flyers would
support the move but a majority would not, and suggest a more modest
reduction to say 135 metre lines.
There have been trials.
In Norway they have flown several F3J cup events last year with 100
metres to the stake, and according to Jo Grini 19 of the 20 pilots
loved it. Those flying F3B models managed to launch slightly higher
than the F3J models, but the differences between launch heights were
smaller overall, which might be seen as fairer for all.
One serious snag with lower launch heights, and this was also noted in
the Martin discussion, is that a long safety corridor with 15 or more
pilots can put some pilots at a disadvantage when the air is kinder on
one side of the field, and that happens more often than not.
The Dutch have gained valuable experience with shorter lines, and I
respect the lessons they drew as one of Europe’s leading F3J countries.
In 2006 they held a contest with 75 metre lines, not so much as a trial
of possible CIAM changes, but the club organising it was having its
75th birthday!
There was a mix of models, and some of the pilots felt they could not
apply full tension without risking the model breaking. Because it was a
fun event, many were using old lines and suffered line breaks. Line
breaks happened with new lines too. The starts were explosive in all
senses, the zoom after launch was very high, a feature which might have
been exaggerated with the model is much closer to the pilot. Pilots
typically reckoned that launches were 40-50 metres lower than normal,
and the apt description was “catapult start.”
In 2007, the Dutch had a contest using F3B winches with the return
pulley set at 150 metres. The day happened to be pretty calm and most
pilots gained slightly higher launch heights. That trial is irrelevant
I think to the current proposal.
(The Brits have allowed winch launching for three years now, and I
suspect that many if not most countries apart from Germany and Czechia
do the same for national events. In varied conditions, UK experience
found little difference in height between winch and towmen, but after
one season everyone was winch launching because at the end of the day,
we were less knackered! It also showed that some winches were much
better than others.)
Back to Holland: in 2004 several F3J enthusiasts tried putting the
turnaround stake 50 metres from the launch corridor, still using the
150 metre line. So the towmen start running 100 metres from the
corridor. The shorter towline was balanced against very high speeds on
the line and the elasticity of the full 150 metre line. Launch height
was judged to be almost the same as usual, perhaps 10 metres lower.
Launch times were at least one second faster. (Grateful thanks to Rob
Sanders, Frank van Melick, Peter Zweers and Cor de Jong for their
memories!)
Could be that many other teams have tried shorter lines. We all use
short bungies for trimming out new models, and there’s nothing more
satisfying than catching a low level thermal from a hand or short
bungee launch.
If you have views or experience of 100 metre lines or shorter, then
send your information and opinion to Tomas Bartovsky
(tomas.bartovsky[at]vscht.cz), your national committee or FAI
(ciam-rcsoaring[at]fai.org) I’d like a copy too.
My reservation about shorter lines? They will encourage further
sophistication in model design and materials, they will not hinder many
pilots for long in flying out the working time, and they will
discourage newcomers to the sport from even trying to fly with the
experts. KISS - Keep It Simple S-----!
Sydney Lenssen (sydney.lenssen[at]ntlworld.com)
February 2008
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