SEN Feb. 15 2000
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News and Reports 2000 - First half
SCAT Electronic News 15 Feb 2000
Table of Contents
Stamp F1A Program for SCAT - Bauer
Class differences - Gregorie
FFN CIAM Proposal Issue? - Hines
Rubber for the Champions - Schroedter
Appolgy to Reid Simpson - Editor
Micafilm - Schroedter
Answer to Peter Kings Boeing 777 water over wings! - Davis
2001 World Champs - Greenwood
Electronic Timer - Kowal
Stamp F1A Program for SCAT
In response to the inquiry about the software I wrote that Jim Parker has been
using, I've decided to distribute it to the world as
shareware. Attached is a text file for a Basic Stamp 1 program for a simple si
ngle servo F1A glider. Jim & I both have modified
versions for our own models that drive a second wing wiggler servo, along with
other small changes, but they were all derived from
this first program. I'm happy to share my other programs as well I lend help,
time permitting. I also have a much more complicated
Basic Stamp 2 program for 4 servos, but I don't recommend it to anyone. If the
program is put to good use and is valuable to you,
then a $10 donation would be appreciated to help offset my costs of
sharing free flight technology. Right now I'm trying to put RDT
systems in the hands of several friends who eagerly want it.
I've found that it is one thing to build devices for my own models,
but it takes much more time to make something that will work for
others - generally it is a net loss of time and money.
A few notes on the program as I never wrote a manuel for it-
1. The basic stamp costs only $34 and the program that runs on the PC is free
on the web at www.parallaxinc.com. You can also make
the programming cable. For a schematic of the wire hook ups, contact me, or if
there is interest I'll let Roger distibute it with SCAT.
2. The text program is setup with all the settings at the top - dt times, bunt
times, etc... In this way, when the program comes
up, everything you need while flying is on the PC screen - you don't need
to scroll down and mess with anything else. There is also
space here for notes on the model history - what settings worked
best on what days, etc. This is one advantage of the PC.
3. Most will want to modify the program for your own use. The F1A version is
the most complicated because of the circle towing and
towhook functions. Versions for other models would be simple subsets of this.
Everything is done in 20 mS timing loops, as the
servo likes to see a pulse every 20 mS for control.
4. There are 2 DT settings - test and max. If you want the shorter test
setting, then hold the hook forward when turning on the
timer. Otherwise you get the max setting.
5. There is an audio beeper with 2 functions:
a) it confirms the DT setting when you turn on the model - 3 beeps = 3 min
utes, 7 beeps = 7 minutes, etc..
b) it makes noise when the towhook is unlatched as a warning.
6. A very significant feature of this program is that it applies battery power
to the servo only for 1 second at a time when the
servo actually moves. Otherwise at all times during the flight the
servo is not draining the battery - the only battery load is 1mA
from the basic stamp which helps greatly to make the batteries last longer and
allows for smaller batteries. The only exception to
this is during the glider launch when the servo power is kept on because of the
high loads. Neither Jim nor I has ever had any
problem with a servo moving when it is not supposed to under glide conditions.
That's it for now, here I am spending too much time again.
Hopefully this program will inspire others to come up with custom things
for their models. The main reason to use a basic stamp timer is that it gives
you total power and flexibility to do whatever you
want with a servo. It doesn't take very long to figure out how to modify a pro
gram like this, and once you do you can let your
imagination run wild.
2306 Turquoise Circle
Chino Hills, CA 91709
'Ken Bauer F1A Standard Program Model: "#??"
'1 Second Power When Hook Forward and Back
symbol dtTEST=60 'seconds
symbol towpos=152 'postion range is 100 to 200
let b6= 25 /2 'pitch time seconds/100
let b1= 50 /2 'cruise time
let b2= 100 /2 'bunt time
'***************END OF SETTINGS******************************
'*********DO NOT CHANGE ANYTHING BELOW***********************
begin: symbol i=w5
if pin7=0 then testdt
testdt: let w4=dtTEST
init: let m=w4/60
for i=1 to m 'DT Beeper
hookback: high 1
hookbackloop: let i=i+1
if i>=5000 then DT 'DT on towline after 2 min
if i<50 then backpulse
backpulse: pulsout 0,circletowpos
chkhookfwd: if pin4=1 then hookbackloop 'If hook forward jump - hookfwd
hookfwd: high 1
hookfwdloop: pause 20
if i<50 then servopulse 'After hook is forward 1
low 1 'second, power down
servopulse: pulsout 0, towpos
chkhookback: if pin4=1 then hookback
chkpull: if pin5=0 then hookfwdloop 'If hook unlatched, continue
armloop: if pin4=1 then launch 'When hook goes back, launch
pulsout 0, towpos
if i >= 100 then fastg 'after 2 sec, go to glide
launch: for i=1 to b6
pulsout 0, pitchpos
cruise: for i=1 to b1
pulsout 0, cruisepos
bunt: for i=1 to b2
pulsout 0, buntpos
fastg: for i=1 to 250 '5 seconds fast glide
pulsout 0, fastglide
glide: for i=1 to 50
pulsout 0, glidepos
dttimer: for i=1 to w4
DT: high 1
for i=1 to 50
pulsout 0, dtpos
The current rules discussion has reminded me of a conversation many years
ago with John O'Donnell. John was asked what he thought the distinguishing
characteristics of the three FAI classes were. His answer was:
F1A: a tactical game
F1B: all about performance
F1C: trimming and consistency
On thinking about it, I have to agree with him. It would be a pity if future
rules changes were to have the effect of loosing these differences. I'm
certain they are high in the list of the reasons why fliers choose the
classes they fly.
FFN CIAM Proposal Issue?
If an FFN subscriber is coming to the MaxMen 14 rounder, would you kindly
bring the issue with the CIAM proposals? Hard copies would be great.
I would appreciate it.
Rubber for the Champions
I have had a few years experience buying rubber strip (Champion
Rubber) for our models, and also trying to obtain a better source like
Dolby finally did. Almost all of the potential sources lost all interest
when I told them how little I would be able to buy each year. To most of
the big rubber companies, a "small" order is one less than 100,000 lb!
That Ed Dolby was able to find a company willing to make such good
rubber in small quantities (less than 20,000 lb annually) is a miracle.
But John Clapp has more than once told me that the new factory is
pushing him to sell more. They'd like him to double his purchases. But
to do this John would obviously have to double his sales. I doubt that
the factory's profits so far are anywhere near covering the development
costs. The good thing is that this company is far more interested in
giving us a good product than the old factory that made the gray rubber.
What concerns me is the fact that our rubber strip for models is
such a small sideline for this factory. I can't help worrying that they
might someday decide that the airplane strip is not worth their trouble.
Then where would we be?
Clearly the move to lighter rubber motors for F1B is compounding the
problem. We should instead be increasing the weight of the models to cut
down on the performance. But I don't think very many will take this
seriously until it is too late.
[George - Many of us are aware that our rubber supply is somewhat
precarious, like you I worry that the reducing demand could cause
John's supplier to lose interest.
With the rubber we have an delicate balance between the interest
of our hobby/sport and commerical interests. We cannot let
our supplier dictate our rules yet we must
some how cooperate. It is of course possible that another suppler
will come along but we have all heard of other souces that
come to nothing. The current supplier has learnt a lot over the
last 10 years and should they stop producing our rubber
it would take someone else a long time to catch up.
While John is not the person wanting to change the rules, he
must bear some of the responsibility. Since John took over
the business from Ed the energy return and consistancy of
the rubber have both increased. With 20/20 hind-sight
it might have been better to have just concentrated
on consistancy and mechanical toughness rather than increasing
the energy return. In reading between the lines that's what;s
Looking at it from the non competition flyer's point of view
slightly tougher rubber might be better - But I guess
those guys don't buy it in 10 pound
boxes and blow a motor a flight.
Appolgy to Reid Simpson
I applogise for suggesting that Reid's medical problem was caused by
stresses of contest flying. It was not my intention to say anything that
was incorrect, but rather to down play the hospitalization. We all know
from personal experience that our modelling
is rather the opposite and is a relief from the stresses we enounter
in our daily lives.
I talked with Tower Hobbies today and they told me that I have to
use their Balsarite with Micafilm. Does this sound right to you? I think
you told me that it can be applied with just ordinary contact cement.
Straighten me out on this. Thanks, George
[George - Ihave have used Balsarite , because I like spending money,
I have also used contact cement. I prefer Balsarite because it
is easiler to apply ... other comments ?]
Answer to Peter Kings Boeing 777 water over wings!
I'm currently designing a home for a former air force fighter pilot Dave
Hayes (nickname is "fireball", long story behind that) who is now a pilot
for Northwestern Airlines. He lives in Oxnard but his main base is Minneapolis.
Here is what he said about Peter Kings note about water washing over the
wings of a 777 as he flew into Tel Aviv. Take it away Dave.....
"I don't know exactly the air conditions of the flight therefore I'm only
speculating on what this could have been, but I'm 99 44/100's % sure it
was a natural phenomenon related to the relative humidity of the air
mass the aircraft was in and the compressibility and expansion effects
of the air flowing over the top of the wing. There are no liquid
emitting systems on the wing structure of the 777.
If the corrected outside air temperature (OAT) was less than -10 degrees
C, then the crew might have had the wing antique system on. That
system takes high temperature bleed air off the later stages of the engine
compressor section and vents it to small holes along the leading edge
of the wings. This system acts similar to a Boundary Layer Control
(BLC) systems found on some high performance jet aircraft. BLC systems
are usually employed to emit a layer of bleed air over the wing to help
form a better more uniform layer of boundary layer air over the top of the
airfoil surface. It has the secondary effect of causing the engine
to have to work a little harder, that is it will be a little up a little
higher on the power curve and therefore a little more responsive to
throttle inputs. BLC systems are on a few Navy fighters, the
F-8, F-4 and F-14 and enhances their power response performance in the landing
configuration, which is particularly critical around the ship.
Anyway, as the aircraft continues to climb and the temperature continues
to decrease, the corrected OAT goes below -10 degrees C and the wing
anti ice is no longer required. When the aircraft was on its descent it
may have encountered the same conditions and thus the same effect was observed.
The high temp air coming out of the leading edge combined with the
outside air and the lower air pressure along the top of the airfoil,
may have set up a condition where there was considerable condensation
generated. The Mediterranean in the summer time acts as one large air
mass with a high relative humidity. There are also times when
the vector of wind combined with the aircraft's speed vector can produce
differing effects on each wing, but usually the aircraft's velocity
vector is so much larger than the wind's that it is muted, but under
just the right conditions of wind, temperature, humidity, aircraft
speed, and fuselage blanking he may have observed something unique."
There you have it! Direct from a guy who should know. If any of you
2001 World Champs
Date sent: Mon, 14 Feb 2000 12:58:23 +1100
From: chris greenwood
Subject: 2001 F/F World Championships
>From Chris Greenwood, Secretary Model Aeronautical
Association of Australia
It is with regret and embarrassment that I have to advise
that Australia is unable to host the 2001 F/F World
The field that was to have been used has been made
unsuitable by the Navy's erecting an antennae farm on the
site. The availability of the accommodation was also placed
in doubt through a review of policy by the University - the
current three semesters might become two. The availability
of the accommodation could not be confirmed until December
A successful attempt was made to find an alternative venue
and accommodation; a field was found at Narrandera with
accommodation at Yanco. However, because of dissent with the
Australian Free Flight community, the necessary support of
the organisers was not forthcoming.
I hope there is sufficient time for another host country can
------- End of forwarded message -------
In response to the request posted last week I am supplying my source
code for the latest version of stamp based timer I am using in my F1A's.
I think witht he notes it should be possible for most to follow the logic
and see how easy it can be to use the stamp as a timer. I have also
included my board layout in Autocad format and a list of materials
to build my complete timer from Digi-Key. (800) 344-4539. Please do
not send me complaints about my choice of formats. I have worked
two years developing this material and am giving it away for the
furtherance of the sport. you can do a little work if you have an interest
in following along with the process. If there is some interest I will try
find time to do a layout drawing to further simplify the process for
someone who wishes to try building their own timers. These documents
were originally to form the basis for an article on timers but my time has
been too limited to finish. Possibly if there is interest I can find more
I encourage all to build and program their own electronic timers. Otherwise
you will never be sure what really goes on in their. And frankly I do
not like to rely on magic to make my planes fly. ---Ken---
The files below will be sent in a separate e-mail
(See attached file: Kk03new.bas)Source code for timer quotation marks start
(See attached file: stamp1brdRevA.dwg)Board layout
(See attached file: Parts List.xls)Parts listing