SEN 678 - 23 Feb 2002
- Category: Archive 2002
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SCAT Electronic News 23 February 2002 issue 678
Table of Contents
More F1E stuff - Davis
Zilberg - Segrave
Coolectors model for sale - Hines
Bonkers Bikers - Edge
Cudos to EV - Achterberg - Achterberg
Twin props - Segrave
More Unoriginal Fan Stirring - Andresen
Benedek-F Strikes Again - Schlosberg
Long motors - Segrave
Twin Motors - Toto in Kansas
Maxmen 2002 - Blackam
SCAT ANNUAL - Coussens
F1C Starter and Box - Clesman
F1C Technology - Coleman
More F1E stuff
I recently read the article by Klaus Salzer about GPS guided F1E and it
brought up some interesting ideas. I thought the letter I'm sending Klaus
would be good for the SCAT news as it touches on many of the aspects and
ideas involved in F1E. I know that you one of the resident FF electronics
experts so I am interested in your opinion about the idea and the
possibilities of modifying your black magic electronic timers to do the
tasks needed? It seems that Klaus has already done the proof of concept and
that development is what is needed. I'm sure there are others out there who
know electronics and my want to get involved? Any suggestions? It may make
sense to publish Klaus article on the SCAT news as well since it is fairly
short? I'll send it to you in a separate e-mail in the hopes that you can
I found your article about your GPS/Electronic F1E very interesting and
helpful. I want to tell you some of what I have been thinking about F1E and
see how it fits with your perception and thoughts. Having only flown F1E for
a year and not in varying enough conditions to really understand the event I
am speaking from a place of ignorant enthusiasm so please bear with me. It
seems to me that one of the limitations of current F1E (and hence a reason
for it's low popularity) is that the number of possible functions, i.e.
Glide straight, circle, DT, based on mechanical timers is limiting. I like
the idea of both the GPS and the ability to do many functions during a
flight, i.e. Fly straight for 20 seconds, do S curves for 45 seconds, fly
straight again, circle for 30 seconds, fly straight again, at the end of the
max turn around and go back towards the launch site and then DT, etc. All of
that should be reasonably done with electronics and GPS. I know for me it
would make the event much more compelling and fun and if that holds true
with others who have not flown F1E then perhaps your ideas hold a key to
increased participation in the event. I think the event hold the unusual
opportunity of combining high tech (GPS and electronics) and low tech (Balsa
and Spruce models home built). This combination hits a chord with me as I
like that combination and it certainly fits that agenda of many of the
Luddites and people wanting to build their own models and still be in
competitive flying. While I do enjoy flying F1A very much I don't like
working with carbon fiber and I feel I am missing something by not building
my own models. As you know, in F1A you either have Carbon wings or broken
wings so there isn't much choice but to buy or do sport flying. So what I
am saying is that I think you are on to something and since I have become
the defacto F1E American flyer I would like to help in pushing your ideas
forward in the hopes that it will gain new flyers in all the countries and
in my efforts to put together a USA F1E team for the 2003 WC. I was
particularly taken by the notion of entering direct GPS coordinates into the
unit rather than simply flying some predetermined compass heading as is now
the case. I also think your RC DT idea has merit and possibilities. It's
used in F1C so it is not outrageous to at least consider it.
What's needed are some off the shelf ready made GPS/electronic timer units
that can be purchased by flyers. In some ways it reminds me of buying a Cox
motor for the balsa power 1/2-A planes I built so many years ago. This is
not so much different than people currently purchasing the steering vane and
magnet ready made for F1E.
One of my other questions has to do with the notion of a front steering vane
rather than using the rudder for steering. Any light you can shed on this
would be helpful. I assume the front vane is more a result of the magnet and
keeping the mechanics simple and putting the weight in the nose? Am I
correct about that or is there some other issue that I am unaware of? I have
copies of some old Aeromodeler articles that show a rudder steered F1E but I
don't recall seeing any at the WC in Poland but I may have not noticed? It
sounded to me like you had your GPS unit in the nose and rudder steering but
it wasn't clear to me?
On a little different topic I am thinking of promoting an F1E world cup
contest in Lost Hills next year between the Issacson FAI contest and the
MaxMen World Cup contests in February. What do you think about it and do you
have any sugestions? Norm Furutani who administers the Issacson contest
would include F1E in his contest as well so we could have two back to back
F1E contests a few days apart and then the MaxMen for those who may want to
fly the other FAI events. I did some scouting around the truly lost hills
nearby the not so lost hills free flight site and I can assure you there are
hundreds of perfect sites within an hour of lost hills. Work needs to be
done to secure them but I have a year to do that. There are several sites
that RC slope flyers use nearby as well and they may be good F1E sites
although I did not have time to see them last week.
Last but not least, what can we do to push forward with the GPS/Electronic
timer module? I'll send this e-mail to several others who may be interested
and have electronics skills. If we can come up with a unit that works I
would be willing to underwrite some of the development costs in hopes of
spurring on the event. I think it is a perfect adjunct to current FAI free
flight events and compliments rather than competes with them. It's a good
fit and the skills and thrill of freeflight overlap all events.
Hope to hear from you soon,
Igor Zilberg was originally Russina, at least he flew with the old CCCP team
in Wiener Neustadt in 1969 where he placed 3rd behind Loffler and an
Austrian(cna't remember his name!). He has emigrated to West(?) Germany and
flew wiith that team in Lost Hills. Perhaps Wantzenriether or Andre Schandel
can help with his addess. Wantz at 2, rue de la mairie, 57810 BOURDONNAY
FRANCE. He speaks French,German and understands English and can write some
too. Same goes for Schandel. Wantz's email address is
tack, surely the only real test of long motor runs is in the white heat of
competition? Simulations like theory can only indicate where a likely avenue
may lead to higher performance so that it could be investigated. Like for
instance, height tests by DTing the ship at the end of the motor run and
timing the descent. Note:ALL ships descend at very close to the same speed
according to George Xenalis, 10ft/sec. As an example, Blackam's flight at
the 2001 MAXMEN DTd at 7.05 and landed at 8.30. That's 1.25 or 85 seconds.
He said it was VERY high at DT. Rightly so, as 85 secs at 10ft/sec equals
[as an observation Ziberg did well in the Canada Cup - I do not know
how many times he flew the loong model. But I did see him fly it in the
World Champs at the same time as Blake Jensen. Zilbergs model floundered
in difficult condiftions and did not max. Blake's conventional model did.]
Coolectors model for sale
FOR SALE: The Original"Big AL 97"
Own the F1A bunter that I designed, at the urging of
Don Zink, to be the modern composite updated version
of Anders Lepp's great AL-33 glider.
It is in fine condition & in flyoff trim for the next time you maxout!
Reliable M&K components are used(mechanical system).
"Price: $500 OBO"
Contact Lee Hines, 949 645 4850
What a great MaxMen contest ! In particular I thought arranging the wind and
rain for us Brits was really nice, shame there was no snow or else we could
have gone curling. Now, about those bikes.
Despite the CD's best efforts, there are still idiots out there who are risking
the injury of competitors by their actions. I guess us glider flyers can
forgive the brain fade that causes our towlines to be driven over but I
wonder what the reaction would be if any of us ran accidentally through
rubber stooges or starter boxes ?
I sadly can envisage someone getting injured soon. Just consider this scenario.
A glider flyer is stretching his new steel line prior to a flight when a bike
comes through. You can imagine the rest; the biker gets taken out and the flyer
looses his fingers. Would the insurance cover the personal injury if the CD ga
ve everyone a warning as George did ? I doubt it.
Just think about it next time .....
while not wishing to start a polymic , what ever that is - there were a
couple of glider flyers who did on more than one occaision tow thru the
F1B flight line. Seeing the person did it more than once, I assume that
it a deliberate stratey to benefit from the thermal activity generated
by the hot air from certain F1B sportsmen!]
Cudos to EV
Well, I was reading how the French got a proposal on the agenda at the CIAM
meeting in March to ban the gear. Since we are currently in a rule freeze
period till I believe 2005, it seemed odd to me that this could happen. I
have been informed that the only loop hole around this is on a safety issue.
This is what we believe is now the ploy to try an circumvent to rule policy
set down by Mr. Pimernoff and the CIAM. The rule freeze was designed to help
create stability in the F1 events and for the most part has done what was
So here we go again!! Enter Evgueny Verbitsky!!
Well, to the French or should I say one Frenchman,
as for the safety ploy, the vibration problem has been fixed!! EV. has
figured out a way to replace the steel bobbin with hard rubber and the
vibration problem is gone!!!! As I was informed the gear now has "LESS
VIBRATION" than direct drive engines. I guess all Mr. Boultiere now needs to
do is to change the wording on his proposal to ban direct drive models and
fully approve gear engines as they are now deemed the safer of the two
styles currently available.
For statistical purposes they can use the last Max Men contest. Four(4)
direct drive model crashed and only one gear model! Guess direct drive is 4
X more dangerous than the gear!! I call for a ban of direct drive for a
Scared me right to gears!!!!!!!!!!
Hopefully, Mr. Pimernoff and the General Assembly will see this proposal for
what it really is and not even address it. I am sure they have many more
important issues to deal with on their agenda, and do not need to waste
valuable time on this ploy trying to circumvent the rules that have been put
in place to stop frivolous proposals!!
Since safety is not, I repeat, is not an issue; I guess we can all, who
choose to, start playing with their gear stuff. For your gear engine,
mounts, ect. call Doug Galbreathe and Evgueny Verbitsky. They will be glad
to help you get the products you are looking for!
PS> Do it for, if no other reason, safety!!!!!!!!!!!!!
inspiration for the MIG?NON came from Czech Lubomir Koutny's MIG-DIs, a
scale model of a Russian fiighter. In correspondence, he said that the ideal
scale model is a TWIN with props turning up in the centre, quote "which
reduces the induced drag"!!!! At the time, some years ago I did not see why
this could be so ,thinking that perhaps the sentence had lost something in
the translation. But Andresen's comment has illuminated Koutny's
assertation, which seems to be only logical now. I had noted that some other
scale planes ALL had the props turning UP in the centre and All climbed to
the LEFT, too. It was only when I was in a position to try b oth rotations
as well as direction of climb that I noted something about the difference
about the direction of rotation. Up in the centre produced a much
faster,higher climb than down in the centre. As I said, the difference
compares with putting the prop on backwards but even more so relative the
the normal prop direction. Mike S.
Re the Bronco OY-10. what diameter are the props(each) and what is the span
of the model, please.(This as an addenda to my earlier message,Roger)
Can you tell me where I can download a plan for a model Canard aeroplane =
More Unoriginal Fan Stirring
Frank Ehling set the rubber helicoptor record 50yr ago with twin RH props on
the tips of a LH rotor. It had the advantage of being affected little by
differences in tork in the 2 motors.
Later the Turboprop OV-10A Bronco used contra-rotating props that turned UP
in the center. This was done to oppose the tip vortices from the wing and
reduce the induced drag. Sounds like the phenomenon that Mike Segrave
Again nothing original, just reporting.
Benedek-F Strikes Again (a resend...please use this version)
Reading the second issue of the new Australian "Free Flight
Quarterly", I found the following passage in Richard Blackam
report about winning the third place at the last WC.
Richard is describing the 10 minute max early morning flight of
"Spirit 25", made in windy conditions with a strong wing shear at
about 40 meters. Alter 6:30 minutes the model "unfortunately
... struck the wind sheer layer and picked up a little stall, which
rapidly became a severe stall and had the model down in at
less than 7 minutes." (I can attest to that, as I happened to be
one of the timers.)
On the opposite page, there was a detailed plan of "Spirit 25"
with full size Benedek 6456-F sections (without attribution).
The wing has four panels, with a tip section flattened out a bit.
(Washout information is absent.)
The Benedek-F section has the novel feature of a very flat
back upper surface, which suddenly dips downwards, towards
the trailing edge, at about 90%. Clearly, this unique feature
is the culprit!
In contrast, the standard wing section gradually transitions
from its highest point to the trailing edge. The gradual curvature
change together with a partial separation of the upper
boundary layer effectively morphes the wing's stalling. Indeed,
models almost never exhibit the vicious stall behaviors of full
scale planes, were one wing can suddenly stall, with profound
Evidently, the unique F-section kink seem to anchor the
upper flow as the angle of attack increases. But, at a higher
incidence, or as the speed drops, the upper flow will
suddenly detach, to a point much further upstream. In other
words, there is a flow discontinuity causing the wing to stall.
The flow discontinuity is manifested as hysteresis, which implies
that the wing's angle of attack has to drop considerably before
the upper airflow re-attaches. This has been noted by
Dieter Althous (Profilpolaren Fur Den Modellflug, vol 2) who
recorded a considerable hysteresis at a 35,000 Reynolds number
A Wakefield with a Benedek-F section and a tip chord of 85 mm
is flying dangerously close to this region. It is also evident that
such models, particularly in WCs, once disturbed, quickly develop
a full blown stall pattern. This is another personal experience -
having dropped the first round at a WC many years ago, flying a
Nordic with a F-section.
There is no doubt that the F-section has an excellent still air
time performance. But models with this section should be kept
locked in the box if there is any evidence of either turbulence or
Here we come to the most intriguing idea. The outstanding still
air performance of the F sections is due to their flat upper back
section with the kink just before the trailing edge. This feature can
be incorporated in other high performance sections as well.
My conjecture is that an a F-modification might increase the true
still air performance of a section, at the cost of adding hysteresis
if the model ever got disturbed. In a sense, one might increase the
performance by 5%, but loose 50% if the model get disturbed.
(The numbers are selected to make the point.) Kind of a Faustian
Based on Mike Woodhouse's data from Freeflight Quarterly#2, which gives
turns on 28 strands of from 450 to 480. the turns available on 20 strands
would be from 745 to 795. If the data from Peter King is taken as "real
life", the the run on 20 strands is 72.2 secs. Thus the run is substantially
FASTER that is the norm of 10 turns/sec so the RN will begreater , not the
same as indicated by another correspondent to SEN. Itis allso said that the
height loss is ONLY 40 feet!!!! which is equal to the difference in the
motor runs if we asume that the sinking speed is 1ft/sec which seems to be
what King is using in his calculations or slightly greater. So it will be
more advantageous to use the POWER of the thicker motor to get altitude as
it will be less affected by gentle down, the bane of long motor runs. They
may be OK for most of the flights during a contest but when they encounter
only slight down, the look on the face of the flier of complete DISGUST as
his ship bites the dust at less than a max or very much less thasn a max
would be a sight to behold!!!! Mike S.
If a twin motored model has identical props, identical motors identically
wound (at the same time, of course!) and symmetrical warps, it isn't going to
care if you turn it left or right. On the other hand, any violation of the
above provisos may cause the thing to chase its tail. (You DO wind them
simultaneously don't you!)
Now, the subject of ascending inboard tips vs. descending inboard tips
introduces a whole 'nuther source of heartburn! If both inb'd tips descend
together you have a case of two "friendly" engines. (Note that we have
slipped into the man (person?) carrying arena here.) If you lose the right
engine, the left one is the one which turns the conventional direction and
its torque reaction and "P factor" will tend to roll or yaw the aircraft to
the left, while its LH offset tends to yaw it to the right.
Conversely, if both engines have tips ascending in the center you get two
adverse engines. Losing the LH engine causes LH roll from torque and LH yaw
from thrust offset and "P" factor.
Consider the Lockheed P-38 of WW II. It started out in life with descending
tips in the middle. To solve a persistent buffeting problem the direction of
rotation was reversed during the development phase and resulted in an
aircraft that required full pilot attention at low altitude and airspeed.
There is a persistent rumor about that Jim Brooks has a fleet of
conventional-turning Wakes in his back shop for use when he travels to the
Can anyone tell me what the max structure was for the Maxmen? It looks
like (from the results) that the round 1 max was in excess of 7 minutes?
If so, I think we have a developing fairness problem... More on that if
all flights were 3 minutes. It appears that thr tardiness with which the FAI
made the announcements about the super-max etc caused some confusion.
To this end they decided to make the first round 3 minutes
and the 8thout the extended max. But the Sunday weather did not permit
a longer max.]
Southern California Aero Team
Bissonette-Mirage Field ? Lost Hills, CA March 9 and 10,
An America's Cup Contest
Saturday, March 9 Sunday, March 10
Open Events: 8:00 AM to 3:00 PM Mini Events:
8:00 AM to 1:00 PM
Seven 1 hr rounds 3 min. Max
Five 1 hr rounds
2 min. Max
? F1A Nordic - 4 min. 1st Rd. Only F1G Coupe
? F1B Wakefield - 5 min. 1st Rd. Only F1H A-1 Glider
? F1C Power - 5 min. 1st Rd. Only F1J Power
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"
? Catapult Glider
? Hand-Launched Glider
Fly-off schedule will be announced at the close of Round 7.
Mini Event Fly-off schedule will be announced at the close of Round 5.
Entry Fees: Juniors welcome! Contest Director:
$20.00 for First Open Event Award for Junior Tom Coussens
$5.00 for additional events High Time! 25442 Via Dona Christa
(18 or younger in 2002)Valencia, CA 91355
$10.00 per Mini-Event
$10.00 for Cat. Glider &
Juniors are Free!!
Awards in all events!
AMA and Lost Hills Field memberships are required. Sign-ups at the field.
Record Seekers: The current F1A , F1C and F1H Open AMA
Records have been set at this contest in years past! Make
history at the SCAT Annual!
F1C Starter and Box
I am looking for an easily transportable engine starter. A boxed type
would be nice or plans for any version are acceptable.
An observation on geared engines or folding wings.
I am just getting back into flying F1C, F1J and AMA Power. I had
problems with cataracts and flying power was not practical with "dirty
windows"cataracts. I had the lenses replaced so my eyesight is again
excellent. I hope this admission of replaced lenses doesn't cause some
idiot to go to FAI to get lens surgery banned.
The geared engines are impressive at a glance, but as yet don't live up
to any perceived advantage. Why ? Propellers are not yet doing all they
could, and in fact are causing new problems in F1C. About 10% of the
time they fold with one blade against the engine cowl. This cause air to
flow over the right wing panels, reducing lift and making the model to
turn tight to the right. This effect can cause a model that should do 8
to 10 minutes, assuming the climb and transition were good, to barely
make a 3 minute flight. Not good for any flyoff round. Verbitsky uses a
small extension on his hub which reduces but does not eliminate the
problem. He is also using a hard rubber insert between the prop and the
metal insert through which the prop pin is inserted. This eliminates
some of the "shake" caused by the gear backlash most evident when the
engine is coming up to speed. As yet, the proper size, shape and pitch
have not been determined. I have not seen Fuseyev's folder enough to
come to any conclusion other than like geared engines they create new
problems in timing of the transition functions, and also creating more
"stuff" to go wrong. We are all tryin to think of a fix. So far a
Montreal stop seems impractical due to lack of room in the geared hub
and the speed at which we are turnig the engine. Som esuggest folding
the prop blades forward, also technically tricky.
I am willing to try both gears ( I already own a VE and a G.K. Hummer)
and folders. I will experiment with some 1/'2 A and F1J models to see if
I can get a folder/flapper to work consistently. " Viva New TechnoIogy".
I will not run with my tail between my legs making false accusations to
the FAI. An action that I see as extraordinarily cowardly when the dope
doing the screaming has ordered folders while griping about gears. To
those people I have but one observation: "It is better to keep one's
mouth shut and be thought a fool than to open it and resolve all doubt".