SEN 3290
- FAI Stuff from FFn
- Bureau meeting
- ABCQ Champs
- Re: SEN 3289 How great is your Gummi
- Credit to Clapp and Jones
FAI Stuff from FFn
From: Ian Kaynes
CIAM BUREAU MEETING
The CIAM Bureau meeting was held in Lausanne on December
6 and 7. The preparations for 2025 Championships were
reviewed, with particular reference to the draft bulletins. More
work is required on all of them and they should be issued later
this month, although possibly later for F1E which needs most
work.
Among other decisions, a Working Group is to be formed under
the Technical Secretary about automated timing in all CIAM
classes. I have nominated 3 people closely associated with the
F1 timing developments. The 2025 Plenary meeting will be held
In Lausanne like this year, with the Technical meetings held
remotely during March.
Championships News
F1ABCPQ
The F1ABCQ World Championships and the F1ABP Junior
Championships will be held together at Salonta, Romania.
Separate bulletins are being issued but since the schedules are
combined they will be describe together here.
A current issue is that the international contest before the start
of the championships has not got World Cup status. Romania
chose to give their 2 World Cup event allocations to other
F1ABCQ events in Romania at other times of the year. If that is
not changed then the event will be an Open International.
The preliminary schedule is:
July 18-19 International competition F1ABCQ
July 20 Model processing, practice day, opening ceremony
July 21 Junior Euro F1P contest
July 22 Senior World F1Q contest
July 23 Junior Euro F1B contest
July 24 Senior World F1B contest
July 25 Junior Euro F1A contest
July 26 Senior World F1A contest
July 27 Reserve day, prize giving, banquet, closing ceremony
July 28 Departure.
Entry fees will be
€310 per senior and junior competitors and team managers
€260 per assistant team manager
€60 per supporter and helper
Banquet will cost €50 per adult, €40 for juniors
F1E World Championships
The bulletin from the Czech Republic for the event at Rana is
some way from being acceptable, but the proposed schedule is:
August 11 Opening ceremony, registration, model processing
August 12 Junior Championship
August 13 Senior Championship
August 14 Reserve day
August 15 Award and closing ceremony, banquet
August 16 World Cup 1
August 17 World Cup 2
Re: SEN 3289 How great is your Gummi
From Peter Martin
Dear SEN,
In issue 3285, our esteemed friend Alex Andriukov stated “The energy of 40 grams of the best Pirelli is equal to 23 grams of the current rubber” and supported this in issue 3289 stating “Best Pirelli produced 1200 kg*m/kg and today rubber generates 2000”.
However, I have to question the figures for rubber energy density used in the discussion around possible reduction of F1B rubber weight to 25 grams. In old English units, the best rubber I’ve ever owned and tested was 4910 lb-ft/lb, which translates to 1496 kg-m/kg in Alex’s units. As far as the mythical 1999 Tan 2 is concerned, I have seen figures around 5500 lb-ft/lb published in NFFS Sympos (2003/2004) and Free Flight News, which is 1675 kg-m/kg. Clearly the “best rubber ever” is a long way short of 2000 kg-m/kg, or perhaps Alex is admitting to having another source of mega rubber, please let me know!
In terms of published comparisons for Pirelli and Tan rubber, Richard Blackam’s 2003 NFFS Sympo shows best Pirelli at 4554 lb-ft/lb and his best ever rubber test was 5558 lb-ft/lb for July 1999. Ron Pollard’s article in the 2004 NFFS Sympo shows best Pirelli at 4092 lb-ft/lb and best ever rubber test was 5341 lb-ft/lb for May 1999. This evidence suggests that we may have an improvement of up to 30% over Pirelli nowadays, as Super Sport is very good but not significantly better than 20 years ago. Having flown myself with Pirelli in the 1980s, this feels intuitively about right. Also, consider that if your rubber energy increased 30% per weight, then you could keep energy constant by reducing weight to 77% of previous – A quick calc shows that 40 grams x 77% = 30.8 grams. That can’t be all coincidence!
Alex’s energy figures of 2000 versus 1200 suggest an improvement of nearly 67% in energy density, which I cannot believe based on published figures and my own experience with rubber model performance. Of course, the modern carbon, high aspect ratio models are more aerodynamically efficient than balsa models of the early 80s, so that seems like the place to look – We don’t have more energy, we just use it more efficiently now! I think any reduction in rubber weight should be based on competition evidence – If we want to reduce weight by nearly 17% (5/30), are we consistently getting 20% more people into comparable flyoffs and seeing 20% higher flight times? I’m not sure that is the case.
All the best,
Peter Martin
Credit to Clapp and Jones
There has been some discussion in recent SENs about the Rubber and it’s energy.
I agree this is maybe important. One side issue , Pirelli was not put up as the best ever. We all know that some 97-99 was primo BUT it was an outlier and because of what went into it is unlikely to be repeated.
The Most important thing about the current rubber source is very consistent between batches and certainly not the great variances of the past. And as Alex A points out great stuff! Credit must go to John Clapp for working with the “Rubber Company” on that and to John for having no favorites and treating all customers the same. We are fortunate that current owners of FAI Model Supply, Charlie and Geralyn Jones have continued that tradition and continue to supply us with a consistent supply rubber. We would be in deep Dudu without them. .. or is it dodo
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