SEN 680 - 2 Mar 2002
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SCAT Electronic News 2 March 2002 issue 680
Table of Contents
CIAM Meeting Stuff
Open letter to Bill Bogart - Morris
Another [In] famous SEN pre-CIAM Meeting Survey
F1 proposals - Achterberg
Re: Norway Contest attendees - Ioeger
Choice of binoculars.
Wright Pat Info - Poti
Long runs - Segrave
Re: why do indoor duration models turn left? - Magill
Why left-hand circles? - Markos
Recent email - Segrave
Konfusion in Kansas and the P-38 - Toto in Kansas
March 9 SCAT Annual
B-6456f and twin props - Segrave
B-6456-f and contra-rotating props plus long runs - segrave
Left vs Right. - O'Connor et al
Turning and rotating - O'Dwyer
Nor Cal 2002 3rd Draft-Feb. '02 - Terzian
Applogy to Dan Tracy who sent the questionaire to me sometime
back but I did not get to it becase opf pressure of work, flying, e-timers
and other trivual distractions.
CIAM Meeting Stuff
Open letter to Bill Bogart
1. Are you the FF representative to AMA for the upcoming CIAM meeting?
2. If so, how will you vote or advise regarding banning the geared
I would appreciate your comments.
Another [In] famous SEN pre-CIAM Meeting Survey
The FAI CIAM will meet in Lausanne, Switzerland 21-22 March. The FF
Subcommittee will vote on a few items that address changes to F1
administration and a very few rule change requests. Because of the
policy to attenuate the timing of model specifications and rules
adjustments, significant changes to the spoting code will not be
actually voted on in the Plenary session until the 2005 CIAM. Those
changes would take effect in 2006. The meetings until that time will act
as a discussion series and a platform that will consider accruing rules
and spec change recommendations as well as handle necessary
The only technical regulation that might be worthy of note to the US
flyers is offered by France for F1A and has to do with the size of the
towline drag pennat.
rule 3.1.11. Launching Devices - chance paragraph c) as follows:
" To facilitate observation and timing, the cable must be equipped with
a pennant. having a rectangular area of 2,5 dm sq. and the smallest side
of 5 cm, attached directly to the cable."
Reason: At the last World Championship, it has been noted that some
pennants were so long and narrow that they could be difficult to be seen
at a distance. With the current rule as it is, a competitor could fly
with a 50m cable that has a min dia. of 0.6mm and claim that to be the
Also on the official Plenary Agenda there are 4 rule administrative
changes also offered by France that ask to include Juniors in the World
Cup venue considerartions. These are for the events of F1A and F1E
The Agenda includes deliberations on Class F1K ( CO2 ).
- Change Tank size from 3 cc to 2 cc
- Refine definition of an attempt to include adjustments made after the
"waiting" period has commenced.
- Institute a graduated 60 or 120 second static motor run (decided by
the contest director -a priori) for flyoff decision facilitation.
There are two F1 rules change proposals that will be discussed by the FF
Technical Subcommittee at the 2002 CIAM but not be voted on by the
Plenary this year.
1) Allow the F1B Flyers involved with a flyoff situation to wind their
motors before the round starts - outside of the normal 10 minute flyoff
round window.This is a rule adjustment offered by the USA and is aimed
at providing the full 10 min for launch decisions.
2) Ban gear reduction machinery on F1C models - offered by France to
preclude the excess preformance believed to be provided by these
devices. The reductors are preceived to be attandant to the loss of
event participation because of cost and availability.
I shall accompany Bill Bogart as part of the US delegation at the CIAM
this year. Bill is the replacement for George Xenakis and is the AMA's
delegate to the FF Technical Subcommittee. I am an "observer" at the
CIAM and as a member of the US FF Team Selection Committee (Dist XI)
represent the current FAI Free Flight Flyers and participants in the
USA. However, I am not allowed to vote on anything.
I would appreciate putting an edited form of this letter on the SEN in
the form of a survey. Even though some of these rule adjustments are
innocuous and some have been recently debated to a fair-thee-well, the
flyers ought to know what is going on and who is involved.
Daniel J. Tracy
1. The country that I would represent in a World Champiomship ....
2. I am current particpant in that country'e team selection program yes/no
3. the FAI Freeflight Event[s]I fly e.g. F1B , F1E
4. I support the French clarification on F1A flag dimensions. Yes/no
5. I support the change in F1K rules
6. I support the propsal to permit F1B sportsmen to wind before the
start of the flyoff round Yes/No
7. I am against the banning of gears on F1C - no matter what reason / pretext.
againt ban/for ban
Note that this question is phrased slightly differently that the others.
the reason for this is that given the rules cycle it should not be possible
to change this rule - unless on safety grounds. There has been some
dicussion in SEN on this and there is some historical evidence to
indicate that safety has been used a pretext to get a rule changed, when
it was probably not the real reason.
Mr. Ackerly, I do not know what is on the Ciam agenda. The information I
was going on was from the SCAT page dated Feb. 12, 2002 issue # 675.
Item "F1 rules proposals- Bogie.
E-mailed Mr. Bogart and asked for clarification and he responded by
informing me that the only way it could be address at the meeting was on a
safety issue. We have been down this road before!!
Just a few years ago Mr. Koster got the engine run reduced in F1C from 7
seconds to 5 seconds on a safety issue, which we all know was really bunch
of BS.,not the reason, but it got backdoored before we new what hit us!
At the WC in Hungary we had a number of meeting about excessive
performance and what to do about it. What I told Ian Kaines was that if we
went to 5 seconds we would just start over an get the performance back! If
we went to 6 seconds and let "sleeping dogs" lie, we would probably just
keep flying our old toys and go our merry way. I mailed out letters to
everyone I knew and collected their responses. It was overwhelmingly for 6
seconds if a change had to be made!
But then Mr. Koster went to the meeting and we got 5 seconds! Enter the
gear!!! And here we are!!!
My point to all this is that it happened once before and it was not on the
CIAM agenda then either!!
So what you may see on the posted agenda may or may not get undated till you
here about it after the fact!
Hopefully, we have learned to be safe( gears) and not sorry( backdoor rule
I have not flown in 4 years, but plan to this cycle and will probably fly
direct drive and not gears, but do not want to have something banned that
really has not proven to be an overwhelming advantage.
Might like to try one myself someday. Most of the worlds F1C flyers, have
one or are planning on getting one or do not care one way or the other. Then
there are those who want to ban it; why I am not sure? Gear models are 0 for
3 in contests this year. Certainly leaves room to think you can win with
regular models!! I am sure there time will come, but still a lot of R&D to
Thankfully Evgueny Verbitsky fixed the vibration problem and eliminated
the safety issue, not that there ever was really one!!
Now, in closing let the boys play with there toys!!
Have fun, fly and stop whining about change!! Life is nothing but change and
the evolution of modeling is all the better for it!!
Thermals" ~~~ Michael Achterberg
Re: Norway Contest attendees
Do you know anyone going to the contest in Norway who would be willing
to bring back two sets of prop blades for me?
Stepan Stephanchuk will be bringing them with him to Norway.
The Max Men was a real Hummer this year wasn't it?
Choice of binoculars.
I'm F1B flyer from Israel.
Please, suggest me a binoculars the best one for this kind of models (for FF
class). Believe that it will help in competitions- at least I hope so, much
better that without.
What's your experience, what the most people using?
Thanks in advance,
I have a pair of Steiner 7X50 that are Israeli Army Surplus !. They
have compass and work very well]
Wright Pat Info
Homeland Security Closes WPAFB to Visitors!
The recent attacks on American have brought about as increased awareness and
emphasis on security worldwide. Nowhere is this more apparent than on
military installations. Since the attacks, WPAFB has implemented new strict
security procedures including 100% government identification and vehicle
checks. This unfortunately has also stopped the casual use of WPAFB
facilities to visitors for activities such as soccer tournaments, baseball
leagues, and of course Free-Flight modeling. Additionally construction has
commenced on the third Air Force Museum building, impacting the remaining
flying area. In the past the Free Flight Aeromodelers Society has hosted
contests as well as test flying sessions at the base. This year there will
be no modeling activity at WPAFB. See you at Muncie.
Norman D. Poti
Try this for size. Take a motor of usual size, say 28 strands of 3 x 1, and
wind it to half turns. Now let it run off completely and not the run time.
Now do it again. Same again,n'est-ce pas? Oui,monsieur! Continue doing this
and you see that the time remains the same. I forgot, you should have flown
the model with this motor. As stated, the rtun will remain essentially the
same. BUT, you will note that as you progress through the number of times
you wind the motor to half turns, that the height achieved wiil gradually
decline after say the 5th or 6th wind up.,until much later the ship will
hardly be climbing at all. Now substitute a new motor of the same dimensions
and you will see that the height achieved will return to that of the first
motor. The reason? the POWER of the motor to carve through the air and
counter the drag.It's as simple as that.
Re: why do indoor duration models turn left?
Just some thoughts on Mike Segrave's good question on why indoor models turn
left. Before I started flying outdoor classes, I used to fly alot of
indoor, E.Z.B, H.L.G, and Peanut, and all were trimmed to fly left. My only
reason for trimming them to the left, was coz erveryone else did, but i
could never quite figure out why for myself!
With the E.Z.B's, they flew straighter at the beginning of the flight, and
the usual causes for this was the fact that with a fully wound motor, the
twist in the motor stick would cause reverse tail tilt(right hand side high,
looking from back)and also lots of washin on the left hand wing. Both of
these conditions combined to make the model fly right wing down, and
straighter than normal(side slipping). Obviously there are ways around
this, such as the tricks used in Jerry Nolin's Serandipidy design. Peanuts
seemed a bit different in that the ones i had(trimmed left) all turned
tightly at the start, then as the power ran down, they straightened out
gradually. Bearing in mind that in New Zealand, we fly in halls with not
much floor area, I have seen peanuts trimmed to the right, but i figured
left was better, as if it was to hit a wall, the left trimmed one would hit
a wall somewhere near the end of the flight, whereas one trimmed to fly
right might hit the wall not long into the flight!
"To fly left, or not to fly left, that is the question"
Why left-hand circles?
The intuitive answer to Mike Segrave's question about Indoor models going
left is that it's probably more energy conserservative that way. The model
is not fighting the propeller torque, but going along with it. Maybe that's
why Jim Brooks' F1Bs go left (I don't think he uses left-handed props).
Another factor is that Indoor sites have walls. It's easier to trim for a
constant diameter circle to the left than to the right to keep the model from
hitting the wall. A third factor is that everyone else goes left. If a model
went right, think of all the increased possibilities for collisions as a
flock of models are cirlcling at approximately the same altitude for several
My apologies to Jim O'Reilly in a recent email, where I named him Andresen.
This was in reference to his email concerning the P-38 and direction of
rotation of the props.
Konfusion in Kansas and the P-38
If I am going to be confused with someone else I could do worse than Herman.
Re the P-38 buffeting, see Warren Bodie's book on the P-38. I don't actually
know the answers but my speculation is as follows: The center nacelle was
too blunt in its aft contours and separation occurred. With the prop
rotation direction they had, the slipstream was dumping the burble right on
to the stab. When they reversed the direction of the rotation of the props
the new direction evidently caused the burble to come off above the stab.
One fact that reinforces this theory is the extended center nacelle aircraft
that Lockheed built. The aft contours were much extended and finer. That
aircraft had no buffet probl;em. It was a "one-off" varient of the P-38.
March 9 SCAT Annual
Where can I find information (time of day and location) of March 9 SCAT
[The SCAT Annual is at Lost Hills
Full details are in the 23 Feb SEN
F1A,B and C are on Saturday
F1G,H and J are on Sunday
the first round is at 8 am
F1A Nordic - 4 min. 1st Rd. Only
F1B Wakefield - 5 min. 1st Rd. Only
F1C Power - 5 min. 1st Rd. Only
New FAI Scoring Rules apply. Extended
Round times used for tie-breakers.
AMA Events: 8:00 AM to 1:00 PM
Round 1 Open FAI: Time to the ground for "Morning High Time"
B-6456f and twin props
When the B-6456f came out, we were cautioned that it was slightly unstable,
unquote. John GARD took this to heart, modified the section to produce his
own version (9510 or 910?). The lower surface he left alone but modified the
top to eliminate the "kink" AND the flattened section, as you will see if
you refer to this section. He used it on his Monarch Wake. But he also added
turbulators on the front at 7 and 23%, if my memory serves me well. It was
then used by Frank PARMENTER of his CHARISMA which he flew in the '73 W/C in
Wiener Neustadt, noting that" you should not push it too far" i.e., not too
close to the stall or it would become VERY unstable, which could read as
stalling down?Perhaps the trickiness of the section is due to using high
camber AS WELL As a rearwards point of maximum mean camber. Something that
the F1A boys shy away from like the plague. If you want to flap the
section(which gives a marked increase in performance) then you must reduce
the mean camber. The loss of lifting powere is more thhat compensated by the
extra lift of the flap. HIgh camber AND flap do not go well together asa is
shown in the B-6456f,hence the stallimg down. On another subject,the Grumman
Tigercat resorted to props UP in the centre after problems too.but they are
not clearly defined.Sergio MOntes showed us some of the fighters the last
war, but what of all the others, and the bombers,too@ From what I can
gather, many of the manufacturers used the same direction rotation for ease
of construction(orlaziness?)and seemed to have little concern with torque or
performance in extremis, juust get the most powerful engine possible or
available, then hang on more armaments, like the did with the Martin
Marauder which was called the "widow mmaker". They had a problem with the
high landing speed, so the wing was extended. That improved matters
somewhat, but then more bombs and weapons were added and the ship was still
difficult to handle. All this does not illuminate as to WHY the rotation UP
in the centre is better that the reverse. Does anyone know a full-size
designer who can shed light on this interesting problem? Mike S.
B-6456-f and contra-rotating props plus long runs
Long runs work only when the wing loading is low as can be seen with indoor
duration types(F1D etc). Climb is a combination of THRUST available together
with the lift of the wing which is made up of the area and the profile, the
area being combined with the weight of the ship in this case. If the thrust
is less thhan a certain value for a particular wing loading then the ship
will not climb. That's in simple terms. It's as simple as that. So if the
long run model at ,say 50% of the run drops below this value, the climb
stops. The wing loading does not change to help as this is a pphysical
impossibility. So it can be seen that it is the POWER that is the most
important factor. There seems to be an ongoing feeling that long runs are
advantageous, because it is said that you get something for nothing i.e., an
extra so many seconds of motor run over a ship with a more powerful motor
and thus a shorter run. But as we all know(don't we?) you don't get ANYTHING
for nothing in this life. You need the POWER of the thicker motor to produce
the thrust necessary to combat drag and provide part of the lift required to
combat gravityt as shown the the classic diagrams in the flight reference
Left vs Right.
Mike Segrave is curious about turn conventions for indoor and
Last year Jean Wantzenriether asked much the same question on
FFML. Here is part of a recent note I sent JW on the issue.
some more on the indoor turn subject.
I made a new F1D to fly at the National Champs in January.
In the scientific spirit I decided to turn right.
I soon (re)discovered some basic facts.
Even with a modest prop (39 cm diam.), the torque is so large
relative to the weight and span, that the wing must be offset about
1 cm to the left in spite of the right turn.
[Without the offset the model banks to the left because side slip is
loading the left wing tip very heavily to compensate for the torque.
It looks very odd when the model is turning right.]
However the drag of the wing (10 % or more of the weight)
is also offset to the left so it took quite a lot of rudder offset
and tail tilt to get a reasonable size right turn.
With the usual setup the prop axis has a +ve angle to the air stream.
Consequently the decending blade provides more thrust than the rising one.
This results in a left turning moment.
Because of the large prop diam. and highish thrust the effect is quite
Thus there are two effects which stongly favour a left turn when
the prop is large and the drag is high.
Of course one could eliminate the cross flow effect by giving
the wing more incidence relative to the stick. I plan to try this.
Sean O'C in Melb.Au
Turning and rotating
As I understand it, indoor models turn left to lessen the destabilizing
result of the top of the prop striking the ceiling. In a right turn, the
prop contact kicks the model to the left usually causing the nose to
drop before it can regain stable flight. There are other reasons I'm
sure but I have heard this one many times.
Outdoor models turn right to counteract the stong left roll/turn torque
of a motor wound to the maximum for competition.
The propeller rotation on a twin is important to the overall effeciency
of the aircraft. In early wind tunnel tests of the XV-3 tilt rotor at
NASA Langely, Confiurations with both center up and center down were
tested. The center up, or rotating opposite to tip votice, showed a 10%
decrease in induced drag or an apparent increase in effective span or
AR. But on a tilt rotor we have an extreme case as the "prop" diameter
was 80% of the wing span. The improvement would be worth while on other,
Nor Cal 2002 3rd Draft-Feb. '02
This is probably the final draft for the Oakland Cloud Dusters 13th Annual
Northern California Free Flight Champs. Put it on your calendar as a "must
attend" contest. It gets better and better every year. Plans for a cook out
on the field for Saturday evening should be well attended.
Note that we also cover ALL of the current National Cup events as well as
Fred Terzian-FAI event director
Oakland Cloud Dusters
13th Annual Northern California Free Flight Championships
Waegell Field, Sacramento California
April 27th and 28th, 2002
AAA Category II or III AMA Sanctioned Contest
An America's Cup, National Cup, and CUFFMAC Points Contest
AMA, NFFS Nostalgia, Classic & Special Events, + SAM Rules Apply
Entry Fee: One Event $15.00 Two or more Events $30.00 Jrs $2 per event
$5.00 discount with proof of NFFS membership for two or more events
Waegell Field Rental: $5.00 per contestant '02 Waegell Card Holders: Free
Contest Directors: Bill Vanderbeek, Fred Terzian, Dick Douglas
Join us for dinner on the field Saturday evening! Last year was the first
Cash Awards will be drawn on Sunday. Contestants will receive one ticket with
entry fee. Contestants must be present to win.
One Design Events: Russ Hansen's 1/2A T-Bird—Nostalgia Rules T-D .049 or .051
acceptable. "'Lil Dip", "Jetstream", and "Ghost" Straight Tow A-1s
Saturday Events Sunday Events
8 a.m. to 5 p.m. 8 a.m. to 3 p.m.
Dawn Unlimited 15 min. after sunrise
F1A Glider (seven rounds) F1G Coupe (five rounds)
F1B Wakefield (seven rounds) F1H Towline (five rounds)
F1C Power (seven rounds) F1J Power (five rounds)
Both Days***All Events must be completed on the same day
Junior P-30 Rubber Junior 1/2A Nostalgia
Junior Hand Launch Glider Junior 1/2A Gas
Junior Hand Held Catapult Glider 1/2A "T-Bird" One Design Event
Junior A-1 Nordic Towline Straight Tow A-1 Glider
Old Time Small Rubber Cabin Old Time Small Rubber Stick
Old Time Large Rubber Cabin Old Time Large Rubber Stick
1/4A Gas Mulvihill Rubber R.O.W.
1/2A Gas Mulvihill Rubber
A Gas Moffett Rubber
B Gas .020 Replica
C Gas P-30 Rubber
D Gas Old Time Hand Launch Glider
Hand Held Catapult Glider O.C.D. Catapult Glider
Slow Open Power Hand Launch Glider
Nostalgia Rubber Classic 1/2A Gas
Nostalgia Wakefield Classic A-B-C-D Gas
1/4A Gas Nostalgia Early 1/2A Gas Nostalgia
1/2A Gas Nostalgia A-B-C Ignition Old Timer
A Gas Nostalgia A-B-C-D Gas R.O.W. Combined
B Gas Nostalgia 4 Ounce Wakefield
C Gas Nostalgia 8 Ounce Wakefield
1/2A Gas Rise Off Water Old Time Rubber Scale
A-1 Straight Tow Event Gollywock
FAI Events: One hour rounds beginning at 8:00 a.m. Flyoff flights will
increase in two minute increments
Slow Open Power Rules: Engine displacement up to .21 cu. in. No ball
bearings, no tuned pipe, no prop brake no auto surfaces (except DT). Any
tank/fuel system. Engine run: 8 seconds glow, 9 seconds diesel. Three flights
with a two minute max. Single fly-off flight at end of day
Bill Vanderbeek Fred Terzian Dick Douglas
13300 Simon Lane 4858 Moorpark Ave. 5303 Calderwood Lane
LosAltos Hills,CA 94022 San Jose, CA 95129 San Jose, CA 95104
1-650-949-3366 1-408-725-1390 1-408-266-3598
Days Inn Marriott Courtyard Fairfield Inn
10800 Olson Drive 10683 Whiterock Road 10713 Whiterock Road
Rancho Cordova 95670 Rancho Cordova 95670 Rancho Cordova 95670
1-916-638-2500 1-800-321-2211 1-800-228-2800
Directions to Waegell Field
Waegell Field is located southeast of Mather AFB near the corner of Sunrise
Blvd. and Jackson Highway. From the Stockton area, it is best to take Highway
99 north past Lodi and go northeast on Grant Line Road just below the town of
Elk Grove. Continue on Grant Line Road until you cross an aqueduct then bear
left onto Sunrise Blvd which heads due north. Cross Jackson Highway at the
four-way signal lights and count approx. 14 telephone poles from the corner
on the right hand side. After that you will see a gate leading towards a
sheep shed and pen. This is Waegell Field.