SEN 768 - 26 Dec 2002

SCAT Electronic News 26 December 2002 issue 768

Table of Contents
Air Trails Magazines - Elliott
America's Cup Standings - Brocks
Re: icarex, how to apply? - Donde
Re Trimming - Segrave
Curvilinear Motion Problems - Morris
F1b rubber - Mik
National Cup - mattes
Salute ! - Brokenspar
Model Box - Ivers

Air Trails Magazines
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Do you have old Air Trails Magazines for sale.. if so, how do we make =
the deal? Thanks, Jim Claremore, Ok.

America's Cup Standings
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The latest America's Cup Standings (not including the King Orange) in Exc
el and PDF format can be found on the NFFS website
thanks to the new webmaster Alan Petersen.

Re: icarex, how to apply?
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Hi Roger,
Could someone write a primer on how to apply Icarex to a Free flight model.
Touch up on how to cut,
What bond to glue it with,
If dilute-what ratio?
What part of the wing to start with,
How to bond to open frame,
how to bond to sheeted surface,
How to bond to curved sheeted (D-box) undersurface.
Sources of tools and suppliers of adhesives and thinners,
Basically an A to Z manual.
Arik Donde

Re Trimming
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As a further note on adjusting, I remember watching Stamov's glider at the
1997 Poitou event. It passed by at a height lower than tow height, but was
obviously in good air. As it drifted to the left it began to climb and, as
the lift got stronger and stronger, the ship just put its nose up and began
climbing like a powered model. As the height increased, it passed another
A/2 which was in close proximity but was circling while doing a series of
small stalls. These were such that they preventd the ship climbing
further,(in the same air as Stamov's). The latter's model in the meantime
had reached great height against a huge cumulus cloud when it suddenly D/td.
The lift was so strong now, though, that the ship actually continued
climbing albeit at a slower rate. It got smaller and smaller in the
binoculars until all that could be seen was the flash from the mylar stab
covering as the model turned. Michel REVERAULT came to watch with me and we
continued straining our eyes watching the intermittent flashes for a further
20 minutes or so until the ship began to drop out of the lift while drifting
round to the right, and finally descending to the ground such that we could
get a very good line for retrieval.
Noteworthy with all this was the comparison between the Stamov ship and the
other A/2 which appeared not to have its trim optimised.

Another aspect of this subject is the stab. How many stabs does the regular
contest modeler make for one individual ship? One? or maybe two?I learned
long ago that the stab is the secret of performance such that I would make
the first stab to the chord and span as designed, then build a succsssion of
stabs to the same planform but varying the section. In one case I had to
make NINE different before reching what I thought was the optimum. But that
pales into insignificance with the redoubtable AA who has been seen with
FORTY different stabs in his box during one flying session. Yes, I said
FORTY. And the stab is only ONE of the parameters which can be varied for
optimisation purposes.

PS Stamov was able to find the ship quite easily with the on board beacon.
Besides it was in open country near Martaize about 10 kilometres away. Thats
another point. It seems that ships on long flights are dumped out every 7
miles or so. Elton Drew's glider at the 1980 UK Trials flew away but was
found and returned to him via the local police station. It had flown 7 miles
to touchdown. The NA rep of Vol Libre in an article in the mag had his A/1
fly 3-1/2 miles from a flight st Muncie at the Nats of that year. Need more?
Perhaps someone could start a record of distances flown so that we can have
an even more accurate rule of thumb!!!!!! if that's not a contradiction.

Regards Mike S..... and the best for the season to come both festively and

Curvilinear Motion Problems
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Regarding the F1C bunt problems, the "given" information is my judgment of
that of a typical modern F1C (not necessarily including canards :-) ). My
hope in posing the problem is to predetermine timer settings for maximum

There seems to be two schools of thought of what's best:
1. Coast as long as possible after engine cutoff maintaining the power
setting and then at the last possible moment make a sharp bunt for successful
transition to glide.
2. Bunt immediately or soon after engine cutoff with a gentle arcing
transition to glide.

Some educated assumptions will be necessary to solve. As an example, what to
use as a drag polar for a typical F1C airfoil inverted as the wing arcs in a
1/4 outside loop during bunt? For approximation, you might use that of a flat
plate or of a thin symmetrical airfoil. The "given" information may also be
altered to suit your belief of what is typical. Today's F1C's are very
similar and it is my belief that the same optimum bunt timing will apply to
nearly all of them. What is it?

Gil Morris

Vol libre Xmas
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Merry christmas and a happy New year to all Vol Libre readers and subscrib-
ers ;_ Th new issue nr. 148 is available -
Thanks a lot to the committee of the hall of fame NFFS - for my admiting
in to the famous circle of the free flight world
personalitys .
Joyeux Noel , Bonne annee - yous les lecteurs et abonnes de
vol libre . Le nr. 148 vient de paraetre . Merci au comite du
Hall of Fame de la NFFS de m'avoir admis dans le fameux cercle du monde
du vol libre .
Frohliche Weihnachten und ein glocklishes Neues jahre an alle Les
er un Abonnenten von Vol Libre . V.L. nr 148 ist
erschienen . Dank auch an das Komite von dem Hall of fame der NFFS ,
das mich korzlich in den berohmeten Kreis der
Freiflieger aufgenommen hat .

F1b rubber
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Hello, Roger,

We hear so much about the loss of FAI rubber due to the lack, or =
unavailablity, of some ultra-secret exotic substance crucial to making =
rubber that provides superior energy return. Just why should this be? =
How can a chemical material be available last summer and suddenly, to =
all appearences, disappear completely off the face of the earth? Surely =
there is much more to this tale than is being revealed to John Q. Flier. =
We can't expect John Clapp to publish trade secrets, but perhaps someone =
could enlarge on this just a tad for the masses.

Mik Mikkelson


John has already explained it - but it goes something like this.

Tan 2 used a synthetic rubber in the mix. This is made by Goodyear.
Changing fashions in golf balls, partly influenced by what Tiger Woods buys,
has meant that this compound will no longer be produces for golf
ball manufacturers. This means it has to be made just for our rubber.

The cost is now too high - I think John told me that the minimum purchase
amount was 50,000 pounds.

This means they will now make the rubber with out it - hence Tan Sport.
the manufacturer has risen to the challenge and will try a a
different formula with this syntheic but doing something
else hence Tan Super Sport to be.

From flying with Tan Sport it appears that while the synthetic increased
energy return it make the rubber less durable.]

National Cup
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National Cup Stuff

Although this is not FAI stuff I was hoping you would include this in
your newsletter.

New forms and rules for the 2003 National Cup are on the NFFS web site.
Please make use of the forms to let me know about your 2003 plans.
Input for any contests planned during the first three months of 2003 is
requested. Probably the most significant rule change for 2003 is the
addition of one "Exempt" contest for each NFFS district with the NATS
already being exempt for the North East District. The change was made
to make the National Cup competition more equitable for those unable to
attend the NATS on a regular basis due to excessive driving distances.
It should also help boost participation at the larger contests while not
detracting from participation at smaller local contests since six
non-exempt scores are still allowed and for some cups required to be in
the running for the top places. The wording about exempt contests from
the rules is repeated below.
"The AMA / USOC Nationals is exempted from the restriction of the
2-Event scores per site and 6-highest Event scores per year rule, thus
allowing a 3rd score to be attained in NC Events by NATS winners of 1st
through 5th places and a maximum of 7 total scores in NC Events during
the year. In addition a contest from the other three NFFS Districts may
also be classified as an exempt contest allowing the use of scores from
any one of the exempt contests to be counted as a seventh score overall
or the third score from that particular site. If a National Cup
participant flies in more than one such exempt contest, the greater
score received at either exempt contest for an individual event shall
count as the seventh score. Scores for that same event received at other
exempt contests shall fall under the 6 score limit and the 2 per site
limit. A CD must request that their contest be exempt for their district
prior to 1 December of the preceding year. The Competitions Subcommittee
member for each area and the Administrator shall then coordinate
selection of the exempt contests."

Exempt Contests have been coordinated for 2003 and are:

N. East District - NATS at Muncie on 7/28 to 8/1
Central - Minneapolis MAC Fall Contest at N. Branch on 9/6 to 9/7
S. East - KOI at Palm Bay on 12/29 to 12/31
West - Northern Cal Free Flight Champs at Waegell on 5/3 to 5/4

Most if not all NC events will be offered at these contests.

A second change is replacement of 1/2 A NOS by 1/2A Classic for the
Junior Cup. This change was made due to the extremely limited Junior
participation in the NOS event.

If anyone wants to be put on a email listing for National Cup stuff
please send me a email request. I put out a newsletter, a contest
listing with events, and point standings about 9 times a year. The
latest of these items are always available on the NFFS web site. Some
of the Cups are very closely contended and will probably be decided at
the KOI. All other contests for 2002 have reported their results which
have been tabulated and are posted on the NFFS. Please check it out.
Also if you have a contest which is not have National Cup status please
consider adding it to the Cup listing. There is no cost to have your
contest be a National Cup contest except for possibly a few stamps and a
little time to request National Cup status and report results.

Thanks for all of you who have provided timely input during 2002 and
catch some big thermals in the new year.

Bob Mattes
National Cup Guy

Salute !
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I always liked Lorbiecki !


Model Box
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Does anyone have building plans for an air travel worthy model box large
enough for several FIA's. Inside length dimension to be 46" min.


Dick Ivers

Roger Morrell