SCAT Electronic News 14 May 1998
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SCAT Electronic News 14 May 1998
Correspondence
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From : This email address is being protected from spambots. You need JavaScript enabled to view it.
Subject :Final F1A Results from Norcal Champs
Just to let you know the final correct placings in F1A at the NorCal for
the America's Cup Points. Bill Vanderbeek received confirmation from
both Risto Puhakka and Dimitru Kozlyuk (Risto's timer in the seventh
round) that he had recorded a 180. Therefore, the standings should be as
follows:
F1A
1 Brian Van Nest 1560
2 Hector Diez 1515
3 Martyn Cowley 1440
4 Tom Coussens 1424
5 Risto Puhakka 1250
6 Lee Hines 1246
7 Fred Terzian 1207
8 Pierre Brun 1192
9 Ernesto Busnelli 1154
10 Kate Joyce 953
11 Ken Kowal 872
12 Dimitru Kozlyuk 813
13 Norm Smith 766
14 Steven Coussens 626
Other News: Stop Watch Malfunctions.
Has anyone ever had problems with the Heuer digital stopwatches that
were sold over ten years ago (assembled in Hong Kong)? I don't know the
model number but many ff'ers have used them over the years. I have
experienced "mechanical" problems with the start/stop switch but nothing
with the digital aspects. It seems that you can audibly detect the
switch function, even feel it, but that doesn't guarantee that it has
begun to run the watch.
Normally when timing, I glance at it to make sure that it is running,
especially when timing engine runs. However there have been times when
I have noticed that it didn't begin immediately and then I have to press
the switch again to confirm that it is running. This is usually not a
major problem, as long as the individual flies well beyond his max.
Roger and Lindy can attest to a strange anomaly when she and I were
timing Roger's F1B flyoff round on Sunday morning of the NorCal. We
both started our watches at approx. the same time when he launched and I
even glanced down to make sure that it was running. At the end of his flight
(sub max) we stopped our watches and compared times. Mine was approx.
20 seconds shorter.
I have repeatedly tested it over and over with two other digital
stopwatches (different makes) and a digital countdown timer for five
minutes and have found no odd behavior (the batteries are new).
My only recourse is to use my other stopwatches for contests unless
someone out there has an explanation or a remedy to "fix" this unusual
behavior. Fred
[Possible Explanation]
Fred timed the event winner in the preceeding flyoff round where there
was also a similar problem with the time recorded. It is possible that
weather conditions, heavy rainsorm during the preeceeding round may
have caused problems. Or there may be an anomaly with the stopwatch
start button when it is let up, rather when it is depressed.
More On Electronic Timers
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Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Subject :Proposed: F/F S/C proposal to1999 CIAM Plenary Meeting
Add the following to the FAI CIAM Sporting Code:
1.3.1.1 No closed-loop flight path automation - No closed-loop control of
the model's flight path is allowed in any F1 model class, either with radio
control (where the control loop is closed by the flyer visually observing
and transmitting signals to control the model's flight path) or with on-board
sensors (e.g., rate gyros, accelerometers or attitude sensors)
computationally closing the control loop by electronically driving control
surface actuators to achieve a defined desireable flight path.
Time programmed open-loop control functions are allowable as are
control functions that combine sensing and actuation in the same device
with no electronic connection between sensing and actuation (e.g., torque
actuated propellers or control surfaces and magnet actuated rudders).
Reason - Free flight has always been defined as flying models with no real
time intelligence affecting the flight path once the model is released for
flight. In the beginning, free flight models were trimmed only prior to
flight. Subsequently, open loop (no feed-back) time programmed control
functions were added (e.g., dethermalizing and changing trim between
power and glide phases). Later, predefined torque controlled functions
were added in F1B. But, note that these were preprogammed torque to
control functions, not closed-loop flight path control functions. If
closed-loop sensing/flight path control is not prohibited, ultimately,
models will be developed that can fly optimum flight paths with no human
intervention other than to start and release the model. It is particularly
important to stop this progression of automation in free flight to the point
where purchased models don't have to be trimmed by the flyer but can just
be launched with on board intelligence taking them from an initial release
attitude to an optimum climb and glide path.
Note also that F3A in Sporting Code paragraph 5.1.2 prohibits feedback
closed loop control for flying radio control flight patterns because this
would violate the essence of the event.
Submitted by George Xenakis for F/F S/C consideration
A couple of quick Comments on George's Submission.
------------------------------------------------
I think what George has set out to do is a very challenging task. The FAI
Free Flight classes have always been the home of technical innovation, yet
on the other hand we have a certain spirit that we would like to maintain.
There are many hidden issues that we need to understand very clearly
before making a change to the rules. This area is new and we need get as
many comments as we can. All points of view need to be widely aired.
This will ensure that no points are left uncovered and the general feeling
of the active Free Flight sportsmen is known. My personal point of view is
different from George's or the CIAM F/F S/C. In writing the notes below I
have tried to be objective and constructive and if it does not come out that
way I applogise.
1. Definition of Free Flight
"Reason - Free flight has always been defined as flying models with no
real time intelligence affecting the flight path once the model is released
for flight. ... "
I thought it was "no direct connection between the model and flyer during
the flight".
2. Un-necessary explict penalization of electronic devices in
" .... as are control functions that combine sensing and actuation in the
same device with no electronic connection between sensing and actuation
(e.g., torque actuated propellers or control surfaces and magnet actuated
rudders)."
Why should an electronic device be explicity excluded when a non
electronic device [mechanical, pneumatic , hydraulic or even electrical ?]
is permitted ?
I assume that 'mechanical' closed loop devices cannot be banned because
in the limiting case that's what a well trimmed Free Flight airplane is . I'm
not an aerodynamacist but if a airplane is stable, do not the aerodynamic
forces tend to right the plane when it gets into a 'bad' position i.e. a closed
loop control system.
3. Question on the use of F1A tow hook sensors and electronic tow hooks
It appears that this proposal could ban the use of sensors, in this case
switches on tow hooks. It could be argued that the switch is the start
device but it is actually much more than that. Typically most electronic
systems have two switches on the tow hook, one to sense hook forward
and one to sense unlatch.
During the towing phase the hook forward sensor can be used to change
the position of the wing wiggler and rudder, in addition it is used to detect
a fly-away condition if the towline breaks or is dropped.
The second, unlatch sensor in used in the conjunction with the first to
determine the start of the flight. They are also used to determine if the bunt
sequence should be started or the model 'floated off the line'.
In the final case these are replaced by a tow hook that has no moving parts
but includes a strain gage. The hook is unlatched by a timer controlled
solenoid at a predetermined tension. Note that this is a closed loop device
because under some conditions the the hook can be made to relatch.
It could also be argued that fly away abort and bunt abort functions are
'safety' related but seems somwhat of a marginal argument.
The functions mentioned operate mainly prior to the moment of launch but
actually can carry over to the first few seconds of timed flight. For this
reason the permitting of certain functions during the tow phase of F1A is
also questionable.
All of these uses of sensors seem to be clearly within the spirit of Free
Flight, even taking it to almost the most conservative point. [I assume the
most conservative would ban the user of circle tow and zoom or bunt
launches] But they would be prohibited by the above rules change
proposal.
4. Apples and Oranges comparison with F3A
"Note also that F3A in Sporting Code paragraph 5.1.2 prohibits feedback
closed loop control for flying radio control flight patterns because this
would violate the essence of the event."
In F3A, the object is to pilot the airplane and smoothness of flight and
shape of the manoevers are what the event is judged on. Such closed loop
device would be directly assisting with this task. In Free Flight events the
airplane is set up before take off and the pilot does not touch it during
flight. Those who support no restrictions on on-board devices, electronic
or otherwise maintain that the setup of a closed loop device is just part of
the setup [i.e. trimming] of the airplane so is part of the event.
For example, how to set up the use of electro-static sensors on the airplane
as suggested by Bill Bogart below is by no means apparant. These can
sense the attitude of the wings for example and make the plane fly level,
but what is to say that flying level will produce the optimum trim ? maybe
it should be banked 1/2 degree into the turn , or something different. The
determination of the optimum adjustment with an electronic device is just
as important as it is now and will still play an key role in airplane
performance.
A real example of this, is the use, now discontinued, by Matt Gewain of a
mercury switch to determine the best moment to pitch over into the bunt on
the launch of an F1A model. Matt found that the adjustment of this sensor
to be to critical/unreliable for practical use.
Seen on the Internet
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Subject :Auction Site
The site http://www.ebay.com has a lot of stuff
available for bid. Cox engines, antique spark ignition engines, out of
production kits (Comet, Cleveland, Guillow, etc.) magazines and other
stuff FF'ers love. Type "model" or "airplane" or "engine" in the search
utility to see what is available.
Static Charge Sensors
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Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Subject : Static Charge
Here is a piece that may cause us to put night lights on our ships.
Bill Bogart
What Static Charge and Electronics can do for Flight Time
Upwards of thirty years ago, I new a fine F1A flyer whose name was
Dennis Mihora. We both were in the employ of Lockheed California
Company in Burbank. He is the one I timed out of sight before he released
the model. He towed east from Taft (straight tow was the only way then)
and when he approached the canal, the terrain dropped. That was just to
set the story.
Another time, in the 1950s, Maynard Hill from Maryland, made an FAI
altitude record with an RC model of 16000 feet. A Navy shipboard range
finder followed the model to determine the height. Maynard perceived
that at great height he could not determine the bank angle of his model. To
handle that situation, he used static charge sensors in each wingtip and
measured the difference in reading of the two as the ship banked. The
difference was sent to an aileron to bring the ship within level attitude,
roll-wise.
Dennis looked into static charge as possibly a means for determining
thermals at ground height. He correlated the charge readings with
suspected thermals wafting by and found that the system was not reliable at
ground height. However, he did find in his research that the charge
decreases with altitude and is more easily detectable to thermal activity.
Putting all this together with today's onboard electronics would allow the
ship to glean better flying conditions while in the gliding phase. I can
imagine a ship with perhaps a 90 second glide circle in steady air sniffing
a thermal and tightening the circle by sending the signal to the rudder.
I can honestly say I do not know how to measure static charge or if Dennis
was blowing smoke, but it might be another avenue to persue by those who
deal in tiny wires and stuff.
......................................................
Roger Morrell
