SEN 690 - 7 Apr 2002

SCAT Electronic News 7 April 2002 issue 690

Table of Contest
Edge of yer seats - Edge [who else !]
F1C proposal - Boutillier
Inter City Meet - Shailor
Flyers aka Contest Notices
real world rubber in alaska - Rocket
DV propellers - Barker
Special Offer- Power Only - Roberts and McDurnett
Cyclon web page - The Alien
Need to reach - Roberts
D-box shells - Lipori and Speciale
Puppy Section much stuff and one has not even flown yet?
F1P - Kaynes
The new F1P Puppy Event - Mac the Bigot
F1P (P for phlop!) - Parker
F1P(uppie) - Coleman
More on (moron?) F1P - Ramrod250 [too small for a Puppy]
Know your Puppy - Jahnke

Edge of yer seats
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I've read the views in SEN on the new SuperMax and F1P
rules with interest. For me the thrill about free
flight is to watch your model thermalling against a
bright blue sky with its colours glowing (OK so it
doesn't happen much up in Scotland but I digress) so
I'll fly to whatever rules the powers decide.

I think there is a significant difference in the two
rule changes. For F1P and similar model SPECIFICATION
changes, it takes people a lot of time and effort to
make the kit. For a new class it is a challenge at the
end of which some flyers may think the class is not for
them and move elsewhere. I've seen two schools of
thought for F1P; one says they will go up like a
butcher's dog, the other more like a pregnant ewe. It
is therefore important that for F1P there is a REVIEW
stage by CIAM to see what kind of a job they've done
especially as it is regarded as being for the future of
free flight. Is this planned with the usual four year
period ?

The SuperMax rule change purely requires the flyer to
set a different D/T. If you look at the World Cup there
are hardly two events the same. At one extreme is the
14 round MaxMen (weather permitting) and at the other
we have had a Stonehenge Cup when three, 2:30 maxes
were flown. Isn't that part of the fun ? To be fair to
CIAM they published the rule change well in advance and
it got passed by a vote. I feel, however, that such
CONTEST rules should have the opportunity to be changed
on a shorter cycle than every four years to help hone
the required aim. After all such changes wont
significantly affect the model design will they ?

One final thought that came to me. If F1A had it's
towline length reduced by the same amount as F1C's
engine run, we would now be using a 50 foot line
length. Makes you think that engine run reductions
aren't the way to go.

Chris Edge

F1C proposal
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When I sent the proposal letter to Roger, there was as an
attached file the "official"proposal.
If anyone is interested in getting it, please feel free to drop
me a line at: This email address is being protected from spambots. You need JavaScript enabled to view it.
May I say that it was intended for both Juniors and Seniors.

Inter City Meet
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As reported, the Inter-City meet will be held June 22-23, 2002 in Muncie,
The day before, Friday the 21st, we will be holding an FAI qualifications to
accumulate time towards the Program. All events are combined, no rounds.
A seperate sanction has been pulled.
Although a flier will be posted, Email me if you would like one sent
directly to you. I am at This email address is being protected from spambots. You need JavaScript enabled to view it..

Flyers aka Contest Notices

We are pleased to publish Contest annoucments - but they should be
specially prepared for SEN. If you prepared them in a word processing
program - or want to adapt the pretty flyer you prepared to mail out.

Then set yoot font to Courier 12 point- prepare the document. Do not
put multiple columns on the page. Do not use fance fonts, bolding or

When finished save the file as ASCII Tect with line breaks. Then
import that to the text of your e-mail and send it to us.

real world rubber in alaska
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my two bits on rubber (tan II) performance in sub zero
5 deg F
3/16 inch tanII
16 strands
72 inches long(dont ask unless you really must
Armor-All type lube
motor breaks at 250-300 hand winds(test flight).

This was really interesting as moter was loaded
in house but after breaking moter and examining
it was like one thick wad of rubber with all the
strands sheared off with a clean cut across all.

It is much warmer now but no soft snow to fly
models that should not have bean built in the
first place. :)

Alaska USA

F1-A at The Nordic Cafe

[Rocket - its the lube. Try Al Brush's Gorrila Grease. It
is designed to lubricate rubber in freezing chambers, and probably
too many turns to put on without strteching the rubber.]

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Dear Roger,

What happened to Issues 687 and 688? I never received these! Can you re-trans


Graham Bryant.


from time to time the Internet e-mail does not get thru. It
could be your provider or mine or maybe Global Crossing !

I number the SEN so you know -

back numbers can be obtained from the web site

under the section that says Latest news and comentary.]

DV propellers
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I have used the letters DV for diameter variable because, like Louis
Joyner, I feel it is wrong to use the poxy acronym VD for such a
beautiful thing as a propeller. I am not sure what is being looked for
when varying the propeller diameter so I won't try to go too far but I
hope the following brief notes may be of use.

A standard formula for the torque coefficient of a propeller shews that
Torque absorbtion increases as the fifth power of the propeller diameter
or conversely if the torque is increased and we want to maintain the
same rotational speed then the diameter must increase in proportion to
the fifth root of the torque. Putting this into an equation D23D D1 x =
the fifth root(Q2/Q1) where D1 and Q1 are the initial diameter and
initial torque and Q2 and D2 are a second torque and corresponding
diameter. I hope an example will make that a lot clearer. Assume an
aeroplane with a 20" diameter propeller (D1) which flies quite happily
on 40 inch ounces of torque(Q1). Now assume when fully wound the torque
increases to 120 inch ounces (Q2). What diameter (D2) is required to
keep the propeller rotating at the same speed? Now Q2/Q1 is 120/40 =
3. The fifth root is 1.246 so the required diameter is 20 x 1.246 =
24.9". Now this will not be precise for a DV propeller because the
formula assumes the propellers are geometrically similar, so the blade
width should also increase in the same proportion but I hope it gives an
indication of the sort of figures involved.

On the related matter of the pitch change as a blade is increased in
diameter. If the pitch is based on the blade angle at 0.75 radius then
a simple formula can be derived. Obviously the pitch distribution will
not be correct in the larger diameter case but I think that the formula
gives a useful practical indication. The formula is: (P/D)ext3D =
3(P/D)/(4-x) where (P/D)ext is the pitch/diameter ratio of the
propeller with the blades extended, (P/D) is with the blades normal and
x is the increase in diameter as a fraction. Usinig the above example
here again. The diameter has increased from 20 to 24.9 so x is 1.246.
If we assume the original P/D was 1.2 then the P/D of the extended
propeller is 1.307.

I have avoided derivations and detail here because email is not very
suitable for such work but if anyone would like any more detail I could
supply it by an attached 'Word' file.

John Barker - England

Special Offer- Power Only
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A special offer to FAI Power Flyers world wide. Should you come to the
Tangent Classic FAI meet the 16th and 17th of August in Tangent Oregon;
Ron McBurnett and I are offering to the first two power flyers the
1. Free Fuel
2. Free Entry
3. Free use of chase bikes that have real suspension.
4. Free use of starter and tach set-ups. Your choice of the Batuik box
type or the hand crafted Gil Morris design.
5. Free transportation to the field each day from beautiful downtown
Albany Oregon.
6. Free fine Oregon Pinots, Gris, Blanc or Noir or beer if that is your
choice, but Please
7. Free local knowledge.
And a "Free" good time.

First come, first served, so start lining up now to let us know.
Hope we see someone.

Mike & Ron

Cyclon web page
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Does anyone have the latest web page for Cyclon engines?

Need to reach
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I need to reach Thom Greenhalge and or Lee Campbell. Can anyone help?
Time is somewhat critical.

Thank you

Mike Roberts
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Ph 206-937-2740

D-box shells
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Received this note in the FreeFlight Message Center: If anyone can help, please respond in
the message center as I don't know if the writer is connected with SCAT.

Bob Lipori

I have been searching the web for instructions on how to fabricate D box
shells. I have my own vacuuming bagging equipment and would like to give
it a try with as few mistakes a possible.
Does anyone out there know where I can look ??
Thanks, T. Speciale
Sat, Apr 6, 2002 at 18:37:27 - -

Puppy Section

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Just a brief response to all the anti CIAM sentiment.

Yes, as you say there is no dispute that the low level of Junior
participation needs to be addressed. And yes it was almost nine months
since the last junior Championship.

While there is now this clamour for democratic consideration from people
who wanted to have made an input, they had it within their power to
INITIATE something during the time since the last junior champs. To start a
discussion and to make a national proposal for the CIAM agenda. But out of
the 30+ countries with FF interest how many used their democratic right to
make a proposal? Yes, you know the answer - NONE. Was this because these
countries are all content to have only 4 national teams in junior power? I
do not think so. Or because it is easier to criticise than to take the

It was in response to this lack of national proposals that the Bureau
identified the need to kickstart change....


Ian Kaynes

The new F1P Puppy Event
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Here is my two cents worth on the F1P Puppy event.

I think the Puppy event is a step in the right direction for junior
participation. If they want to graduate to F1C later on they can but it
certainly keeps the entry point down to a level that is more realistic for a
junior. The one thing that did not seem to get considered in creating the
Puppy event is the use of electric power instead of gas for the motor. If we
can learn anything from the trends going on in the RC world it is that
electric is quickly surpassing gas as the power source of choice. I'm
currently working with my 11 year nephew on learning to build models, I
picked up an old Star Duster kit on E-bay because that is what I learned to
fly on and I so the nostalgic part of me wanted to do it again with him. The
first thing my nephew said was "can we put an electric motor on it instead
of the gas motor"? What could I say? The variety of electric systems are
growing and the gas motors are decreasing. If the Puppy event is aimed at
juniors then let's get with program and make the event enticing for them and
not let our old fart mentalities get in the way.

Mac the Bigot

F1P (P for phlop!)
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> Where do the CAIM people come up with this stuff. F1J is NOT as technical
> as the F1A and F1B ships the Juniors are flying today. They are much
> easier to deal with than the larger and more powerful F1C's, but DO
> provide a good base for a kid who will hopefully transits into the larger
> class at some point. Participation and interest in F1J are starting to
> peak around the world and as this is happening a certain number of Juniors
> will be attracted. There were 20 F1J fliers at the MaxMen this year,
> compared to 25 in F1C. The young people that are participating in power
> should be allowed to compete with the "experienced" fliers for that all
> important "on the job training".
> But make no mistake, the root problem (lack of Juniors) has nothing to do
> with the events. Today's youth do not have the love of "flight" that most
> of us grew up with. I can remember running out side every time I heard the
> rumble of a radial engine and scanning the skies to make an I.D.( I still
> do that when one of the oldies flies over the house). That interest became
> even more intense as jets came on the scene. Today "flight" is routine.
> How many kids do you think are aware that someone actually flew around the
> would non-stop without refueling or have a clue about the next space
> shuttle launch? The ominous silence in the skies of the U.S. on 9/12 got
> people's attention - they suddenly realized that they had grown so
> accustom to the constant din of aircraft overhead - that now something was
> missing. Aircraft in general and model aircraft in particular are just
> plain not very exciting to the new generations.
> Don't get me wrong, there are juniors out there who love free flight and
> will become long time modelers, but the majority of those have parents who
> have been modelers and have taken extreme measures to foster a special
> relationship with these kids. These parents understand the value of our
> magnificent hobby in helping to mold a strong personal ethic. We are all
> responsible for nurturing these special few. A real disadvantage for the
> "power" events is that the younger kids tend to be a little standoffish
> when it comes to engines. It may well be that an age group modification
> (start the power guys a little later and let them fly a little long, say
> 20 yrs old) might be a better solution.
> F1P will not promote anything and if it happens to be around for a couple
> of years it will become just as "high tech" as all of the other events.
> These things are not going to be slow or subdued performers - they will be
> out of sight in ten seconds. There will be little acceptance of the event
> in this country and my suspicion is that the juniors that really want to
> make the team will be forced to fly with the F1J guys, with a reduced
> engine run (7 sec) and max (2 min) to qualify for the Junior World
> Championship Team while being marginally competitive in the event. Does
> the CAIM expect these F1P juniors to make the transition to F1C after
> their junior years are over? What will they have learned? Will the low
> tech event drive them away in short order? Worse case, could F1P result in
> the death of "Power" for the Junior World Championship Program?
> We cannot live in the past - we can only learn from those experiences.
> The evolution of technology is relentless.


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I agree with the folks that say, "We should have solicited more opinions
on the lack of youngsters flying power". Did you ever try and compete
with the young at the latest computer games? Embarrassing isn't it. They
beat the heck out of you. What we need is to find out what they would be
interested in, then do a good job of promotion on some form of power
that they might be willing to try.

When I was young, long ago, I was drawn to power models because they
were fast and sleek. Here in the USA, young folks have turned *Drag
Racing" into a big time sport, and those cars are fast, loud and sleek.
At these events, the under 25 year age group outnumber the rest of us

I find it a real lack of judgment when a bunch of old folks, especially
a group that doesn't fly power feel they have the answer. I also agree
that the proposed F1P class can be made to be competitive as proposed,
but I ain't the one you need to impress. I love the power events but at
65 years of age , will readily admit I have but one clue about how to
get the young involved. It's simple, "Ask Them". The assumption that the
kids of today can't handle power shows a lack of vision on our part.
Propose and promote an event that they might like and don't be surprised
if they want it more technical than you've got it at this time.
Roger C.

More on (moron?) F1P
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Overall I am glad to see the up-in-arms reaction of most folks to the new
class foisted on aeromodelers in another ill-advised attempt to induce youth
participation. During my time at AMA I saw a number of attempts by various
groups to stuff rule changes through the system without proper discussion
among fliers--this by declaring the need for an "Emergency" rules change,
similar to the suddenly Urgent status granted F1P.

As a longtime flier of small Power models, and the father of two potential
Junior fliers, let me tell you that Mike Achterberg is right-on when he
suggests that what kids want is "high-tech, speed and racy looks." We're
talking video games, instant gratification, and extreme sports--and their
equivalent in aeromodeling.

My eight-year-old, for instance, wants nothing to do with my F1Js or other
Power models: "Boring!" he says. However, catapult gliders are cool to him,
and his real favorite is my flying saucer. A little disheartening, maybe, but
it shows how interests have shifted, even during the past few years: he likes
supercross, skateboarding, and snowboarding much more than "traditional"
sports, which our 16-year-old prefers (and both prefer gliders to Power

If an event is going to be developed for Juniors, it had better show some
thought toward the X-Games generation, or things will surely die off sooner
than later. It might take an entirely different format--qualifying, with
single-elimination brackets, perhaps--to generate interest in enough kids to
make 'em pursue competitive Free Flight.

Of course, F1P was not really "developed"--it was stuffed down our throats.
And with all due respect to Martin Dilly (and plenty is due him), this is
exactly the sort of action that alienates people from CIAM, AMA, and modeling
rulesmakers in general: "We make the rules, and we can do with 'em what we
want, when we want." Any wonder why sport flying is so popular?

Perhaps the most amazing part of the whole F1P thing is the unanimous vote.
Was there no one present who could think through the proposed rules and see
the problems, as Mike Achterberg did?

Perhaps another Urgent/Emergency action could be taken to at least table this
event until a better solution can be worked out, to save us from ourselves.
And rather than just complain about it, I will volunteer to be part of a
group or committee to work on a long-term solution.

Jim Haught

Know your Puppy
Ross Jahnke

Could someone "in the know" please give a more comprehensive outline of the
rationale for F1P? It seems like a sure way to isolate juniors ( I marveled
at the number of juniors competing successfully agains open fliers at the
last US Nats in F1B and F1J). I understand that the situation is often
different in the rest of the world than in the US. I would like to hear
(read) at length from the originators of this concept, not on the design of
the model, but on thier view of how competition at regional, national, and
"Cup" competitions will be structured and how junior modelers will be
"mentored" into the program. Should we open this event to all ages to make
it viable at smaller contests? What are the factors that make F1J
inappropriate? Why didn't they just change the F1J rules? My concern is
that this remedy, if it does not work, will leave a gaping hole in the
junior program for several cycles - proponents clearly see a gap already I

I'm just a rubber flier butting in.

Ross Jahnke

F1P and SCS
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There is another issue about the way F1P has been defined - namely
the requirement that the incidence or camber change only ONCE in
flight, except DTing. The intent, evidently, was to have a simple
climb/glide trim setting. Hopefully the model will wobble/tumble/
\flopover from climb to glide.

A mechanical timer irreversibly switches the stab from a climb to a
glide position. The same applies to the line-releasing old style
electronic timers.

But the new generation electronic timers use a servo to control the
stab, or SCS - servo controlled surfaces. SCS comes in two flavors:
one uses a rod/tube to control the stab e.g.Gwain/Stoyev while the
other has a pair of wires and a pulley under the stab, e.g Stamov.
The stab can be programmed for multiple states as well as the rate
of change between states.

Suppose the stab's climb position is 0 and glide is -3 degrees. A
mechanical timer would switch the stab from 0 to -3 by releasing a line.
In contrast, a SCS can be programmed for the sequence {0, +2, -3},
were the middle state lasts for .5 seconds, effectively creating a
shallow bunt. If the stab movements are restricted to be in one direction,
then the sequence {0, -2, -3} with the middle state lasting 4 seconds,
effectively creates a fast glide transition. Even without a middle stage,

if the transition {0,-3} takes 3 seconds, one gets a fast glide transition.
In practice, fliers using SCS could be asked to demonstrate that their
stab movements only have two positions with an instantaneous
transition before each flight. (As electronic timers can easily by re-
programmed.) But this would impose an unbearable administrative
burden on the organizers, particularly in light of the view in a certain
circle about the hardship in giving a two-minute warning before a
flyoff round.

The issue of transition depend on how high the model climbs. If these
models reach a 1000 feet, as some have claimed, then who cares.
But if these model get to a mundane 200-250 feet, the transition may
become an important factor, particularly in flyoff rounds. It is certain
that more competitive/affluent fliers would opt for SCS.

In other words, if the intent was to create a simple power class, then
the usage of SCS should be debated.

Aram Schlosberg

Roger Morrell