SEN 830- Oct 16 2003
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News and Reports 2003
SCAT Electronic News 16 October 2003 issue 830
Table of Contents
=================
Dads and Model Airplanes - Davis
Livotto Flash
USFFC pictures - Thorkidlsen
Various airfoils and angles - Segrave
Book For Sale? - Stoddard
Colouring ikarex - Morgan
Profili 2 ?
Jason Magill's Address & UK Teams - EoB
Another European Junior site with Pictures - Lorbiecki
Tough Juniors - Ioerger
Profili2 - King
Herm's wonderfully curved plate airfoils - Skykieng
Thanks Roger!! Plus Tom and Amanda.... - Lorbiecki
Dads and Model Airplanes
========================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Today I was thinking about how I got into free flight modeling and
remembered how it came to be for me. I built a Goldberg 1/2A Blazer
that must have weighed two pounds and was painted with green latex
paint. It was one of those kind of models, your first one, that is the
pure definition of a learning experience. No one in my family built or
flew models but my dad was supportive of my hobbies and took me out to
the local boondocks to try to fly the damn thing. I didn't know what
trimming, CG, incidence, or anything else was so we fired it up and
watched it do several loops before crashing onto the roof of the city
bus depot. I learned right then that we needed to go deeper into the
boondocks next time. We headed for home to repair my latex wonder and
over the next few weeks went through the same drill three more times
with the model flying more bizarre each time before it crashed. My
self image was going downhill and somehow my dad had the wisdom to
call the local hobby shop and ask what to do. He got me up early on a
Saturday morning and took me and my latex bag of balsa bits out to a
special boondocks where the local free flight club, SWAT, was flying.
We went over and talked to this great big Texan looking guy, Buzz
Averill, and then he left me there for the day. The rest is history.
Free Flight model airplanes changed my life forever.
I was thinking about all this because my dad died yesterday, one day
after his 84th birthday. I was worried about going to Hungary this
past summer to fly at the World Champs because I knew there was a real
good chance he might die while I was gone. I talked to him about it
and he said go,that he would hang on until I got back. That's how my
dad was, supportive of my fascination with free flight model airplanes
all the way to the end. He did hang on until I got back and several
weeks after that as well. He died at home Monday morning October 13th
in his sleep with his family nearby. I'll never feel a thermal again
without thinking about how he helped me into the sport I love so much.
That's what dads are for and my dad was a damn good one.
Jon Davis
Livotto Flash
=============
F1A - Stamov -Ben Cousssens in 8 man flyoff
F1B - Ghio - Biederon - 4 man fly off
F1C - Verbitsky - Archer - 10 Man flyoff
Fanstastic weather, great contest,
Full results real soon
USFFC pictures
===============
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Hi guys,
Do any of you have any pictures from this years 2003
FF champs that Walt Rozelle might use for the writeup
on the champs for the digest.
We have a completed writeup and tabulated results but
need pictures since I forgot to take my camera.
Appreciate your help or if you know someone that took
some please ask them.
Thanks,
Terry Thorkildsen
Various airfoils and angles
===========================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
I would like to do some experimenting on the large P-30 class and do not
have the Sympo which published Art Ellis' Window Plane. Can someone tell me
what airfoil he used, please? From a photo, it looks like the B6356b but I
can't be sure.
Secondly,in the matter of flying angles. Does the stab always fly at or
close to zero, relatrive to the airstream, all the time?????
Or does the wing always fly at 6 degrees all the time????? It can't be both
so which one is it?
If the former,then trimming raises the wing up to a better gliding angle. If
the latter, then the stab has to be trimmed to give a lower lift(negative)
and allow the wing to glide at its best.
Frank Zaiic published some data from an experimenter showing the wing flying
at 6 degrees but what was the stab angle????
Regards
Mike S
Book For Sale?
==============
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Book For Sale?
I contacted Joe Maxwell regarding his book - "The Secrets of Aids for
Advanced Aeromodelling" and learned that it is now out of print. Does anyone
have a copy they would like to sell to me?
Waiting with fingers crossed for luck,
Chris Stoddart
Colouring ikarex
================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
For SCAT
Hi Roger,
Ikarex is a nice covering material (light, tough, not too difficult to apply
- what more do you need...) but if you only have the white colour you really
need to do something to make the model show up against cloud. Light spray
paint like the flower colouring can be useful but I have seen that some of
the Russians achieve a nice dye colour effect. I understand there was some
colouring material that came from Klaus Saltzer but is no longer available.
Does anyone know of good ways of colouring ikarex??
Regards,
Vin Morgan
Profili 2 ?
===========
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Hello Roger,
I wonder if you , Bill or anyone else could let me know where I can
download Profili 2 from please.
Cheers,
John W.
Jason Magill's Address & UK Teams
=================================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Mr SCAT,
Perhaps your global communications network can help me
with an e-mail address for Jason Magill. He sent me a
question but his address keeps on bouncing. Can anyone
help ?
On another subject the UK team trials for Romania 2004
ground to an end this last weekend. In conditions
changing from wind to calm to rain (so just like
Hungary in fact) the results which are subject to
ratification, bribery and various other negotiations
are :-
F1A Mike Fantham, Anthony Ball, Martin Dilly
F1B Russell Peers, Mike Woolner, Keith Chamberlain
F1C John Cuthbert, Stafford Screen, Roger Baggott
(Peter Harris 4th)
The team is a mix of experienced guys and newcommers.
If I remember right, Keith has flown in the Junior team
before and in Glider Martin is new lad bringing a
unique and innovative manner to F1A techniques and
eating ...............
EoB
Another European Junior site with Pictures
==========================================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Sorry I just found this also. This is the main site and also has pictures of ma
ny models. It is interesting to see what the kids over there are flying. These
are the first pictures I have seen of the F1P models being flown in Europe. Enj
oy!!
www.aeroklubpolski.pl/modelarstwo/4me/index.htm
John Lorbiecki
European Junior Champs Scores
==============================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
>From my German friend I have found the link to the Junior scores for F1J/P. It
is:
www.aeroklubpolski.pl/modelarstwo/4me/results3.htm
For F1A it is: www.aeroklubpolski.pl/modelarstwo/4me/results1.htm
For F1B it is : www.aeroklubpolski.pl/modelarstwo/4me/results2.htm
This definately shows the upcoming competition plus the contestant count...
John Lorbiecki
Tough Juniors
=============
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Hi Roger
I think that there has been enough picking on the Juniors. I witnessed
the entire Junior contest on that Sunday before the Nats. The flight line
was truly located in the worst possible place on the field. It is well
known that the turbulence off the trees in the Southwest corner causes
severe problems for experienced modelers. In even moderate winds, picking
lift , Launching a Wakefield, or even controlling a towline model can be
beyond the skills of most Juniors. The correct place to fly from in these
conditions is also well known. It is just North of the hog barns. This
location gives far less turbulence and a longer run on AMA property for the
chase.
I also think that the contest should have been cut off after five
rounds, regardless of the location. At that time , the wind and turbulence
had increased to the point that luck played the largest part in deciding
between a crash, a tow in or a short flight to end in a tumbling landing. I
saw at least $5000 worth of models damaged or destroyed in the last two
rounds. We are supposed to be encouraging the Juniors , not defeating them.
After the disaster on Sunday, some Juniors and their parents who funded the
models will not be back.
Sincerely
Tom Ioerger
Profili2
========
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Dear Mike,
I wholly endorse all of Skyking's advice to you. I have Profili 2, which
includes Mark Drela's XFoil analysis, all in one simple to use package. As Bil
l
says it is THE best bargain around and totally addictive as Bill says. Bill
is correct about the problems at low Re nos but XFoil really does give
probably the best, or at least the most consistant results of any airfoil analy
sis.
Several guys are using it now and would, I'm sure, be only too happy to give
advice on using it. Apart from anything else, you can draw any template in 1/1
scale, to cut ribs and templates with great accuracy, even for elliptical
wings with changing airfoil along the span!!
Peter King
Herm's wonderfully curved plate airfoils
=========================================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
> Re: Airfoils
> ============
> Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
>
>
> Roger,
>
> Obviously someone (actually a lot of sportsmen) didn't read my Airfoil
> article in Sympo??
Yeah, Herm, I just knew you would get bent out of joint! For the record I
read your article (s) in the Sympo. In fact I've got a print-out of one of
them that I ponder on occasion. Lot of good stuff there.
> Lift coefficient depends on mean camber.
That ain't exactly true. Lift coefficient is much more dependant on the
angle of attack. A thick bi-convex section -- with even negative mean
camber-- can still lift a bunch.
>
> Thickness adds drag (and potential strength, stiffness and sometimes
reduced
> drag at low lift).
Well, yes. But "thickness" can have beneficial results even at high lift.
>
> Cambered plate is ideal shape for many model applications
That's like saying that wings achieve their manifest destiny on airplanes.
The problem with highly curved plates on non-indoor ships is that the flow
on the bottom behind the nose separates and that creates high drag even at
useful glide Cl. An example of this performance defect is to be found even
on the most famous curved plate of all;. The Go 417.
A solution to this quandary is the much-maligned Jedelsky section, i.e., the
front 50% of the undercamber is changed to a flat bottom that leaves the
remaining 50% as a curved, flap-like plate. That addition of thickness on
the bottom better accommodates the natural airflow and makes the curved
plate a more practical.item.
I had always thought of the Jedelsky sections as basically a simplistic way
for a beginner to quickly put an undercambered airfoil on an ugly model.
Wrong! ( except for the model bit...they were ugly) I got a different take
on this airfoil approach after reading a re-print of an Jedelsky article
from the seventies that Sergio Montes offered in the last issue of his
fabulous "Down Under" Free Flight Quarterly. ( This email address is being protected from spambots. You need JavaScript enabled to view it.)
There is no time here to go into all the benefits, but one in particular is
interesting. Unlike most airfoils The Jedelsky has a very smooth stall. In
fact it doesn't stall in the sense of losing lift...In wind tunnel testing
by Althaus the drag just goes up and up.
One of the great features of Profili2 is that one can run an airfoil up and
down and see the pressure distribution and just how the streamlines behave
... and misbehave. It soon becomes obvious that changes in the bottom
surface do have an effect -- not only on the bottom but also on the topside
flow. This is not surprising since any change in the pressure field
registers ahead of the airfoil and influences the incoming path of the
approaching streamlines. One drawback of the simple Jedelsky bottom is the
discontinuity at the 50% join. The abrupt change generates drag. This can be
fixed by some judicious fairing at that point. One thing to keep in mind
is that running the straight bottom back further than 50% does cause a
marked deterioration in the good qualities...the shallow join-fairing
mentioned above does not have that negative effect..
I'm not advocating that one simply grab one of the stock Jedelsky foils off
the shelf but rather use the principles outlined to good advantage in
fine-tuning a design.
> End of story,
Yeah, that just about sums it up! Billous G
> H
Thanks Roger!! Plus Tom and Amanda....
======================================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
It is because of people like you Roger that allow people like us to vent, voice
opinions, or try and help those that frequent this posting site. It is fun to
read what others are doing as well as having a place where experts can answer t
he various questions that always crop up. Thanks!!
As far as the question on F1P/F1J....At the upcoming WC I understand that the m
ax will be three minutes, with a 7 second engine run for J and a 10 second run
for P. As far as people flying a P model in the "states" in F1J, you need to us
e a 7 second run, as F1P is NOT an approved event per AMA.
Amanda, don't feel bad! John (the kid) absolutely destroyed an F1C model (on hi
s 5th max!) when he hit the stab on his reversed hat, causing the model to atte
mpt to fly parallel to the ground. Didn't work....Engine and timer ended up 4 f
eet from the rest of the wreckage. Wings destroyed, front end destroyed...Saved
the tailboom and stab...
We are pulling for you Amanda, keep the faith. Remember it is only a sport, but
like any sport there are highs and lows. Remember and celebrate the highs, and
forget, but learn from, the lows. Even the best have problems (right Joe and T
om!!) but they continue on. We hope to see you on the team. If not, you still d
id well....
Thanks again and back to the building board. We need to come up with the model
that will push John to that number one spot at the World Champs in France. Stil
l haven't decided which way to go, but we will have one F1P with a flat bottome
d wing (all carbon) and another with an undercambered section. Come on spring!!
(already 38 degrees in Wisconsin).
John and John Lorbiecki
.........................
Roger Morrell
