SEN 739 - 12 Sep 2002
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SCAT Electronic News 12 September 2002 issue 739
Table of Contents
=================
Propeller Research Project - Terzian
Need Address and Telephone Number - Simpson
Free Flight Finals voucher and round times - Bradley
glue. - Wilkinson
Indoor wings - Segrave
Junior, to be or not to be - Zeri
The morning super-max - Linkosalo
1960 Nats.
Bulgarian Towhook
Re: SCAT Feedback - Mac the Bigot
Propeller Research Project
==========================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Dear (Sir),
Hi! I am a high school student and am currently working on
a two-year research project on propellers. I found your address in an old
NFFS symposium and would like to purchase some old symposiums from you. I
would like to buy any symposiums with articles relevant to the research that
I plan to conduct, which is propeller efficiency, outdoor propeller tests,
and wind tunnels. Could you tell me which symposiums have articles on these
topics, and can I buy them from you? By the way, if you are interested in my
research, I have included a summary of my plans below.
Thanks,
I plan to test the efficiencies of propellers using several different
methods. I would also like to analyze Andrew Bauer and Jack Norris' work on
the Theodorsen-Betz propeller research by building a Theodorsen-Betz
propeller according to calculations of the computer program, which they sent
to me. (In theory, this computer program will give a plan for the most
efficient propeller possible for a certain RPM, diameter, air pressure,
etc.).
At first, I was interested in performing tests on indoor propellers. In time
though, I realized that performing tests on outdoor propellers would be much
more practical, especially considering the scale of my research. I learned
that there is little, if any information on drag at such low Reynolds
numbers, and that there are many more applications for research on
outdoor-type propellers. I also was made aware that Andrew Bauer and Jack
Norris' computer program does not yield accurate results at such low
Reynolds numbers, however it does for the Reynolds numbers of outdoor model
airplanes.
I have developed the following plan of experimentation with my mentor, Bob
Langelius, a superb indoor and outdoor modeler. I would like to conduct
outdoor flying tests, using an all around ARF fitted with propellers of the
same diameter but of all different designs (including a Theodorsen-Betz
propeller, which I shall build). Power will be supplied by three different
engines: a high torque/long stroke engine, a high RPM/low torque engine, and
a standard task engine. I will then find the best combination to evaluate
the performance of each propeller under certain tasks. The tasks will be
acceleration from a standstill, shortest distance over an obstacle, and
highest overall speed. All of the data will be carefully measured and the
wind velocity will be recorded. Overall, I hope to find the most efficient
propeller for a certain task, and maybe even find a correlation between the
propellers.
In addition to the flying tests, I am considering conducting tests with a
wind tunnel, homemade or not.
Dear ,
Received your request and can help you out in certain areas. First, I no
longer handle the NFFS publication service, however it is available on line
on the NFFS web site at: http://freeflight.org/. Look under the "Store"
category. You should check out the whole web site for other contacts and
useful information.
The Symposiums have been published between 1968 and 2002, however not all
issues are still available.
Also, many of the authors in the area that you are planning your research
receive and read the SEN newsletter (SCAT Electronic News). The Southern
California Aero Team is dedicated to FAI (International Aeronautics
Federation) free flight topics but many readers and members are familiar in
other areas of aeronautical interest and could possibly help you through
e-mail discussions. The web site for SCAT is: http://aeromodel.com/.
You may find that others might recommend either Indoor or Outdoor rubber
designs for propulsion rather than gas engines.
I am hoping that you will receive a lot of assistance from this
communication, maybe even refining your research using different methods.
I have found that free flighters are very supportive in helping each other
out.
Sincerely, Fred Terzian
Need Address and Telephone Number
=================================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Roger please post on SEN
Sometime in the last 3 months I posted an article on SEN telling where to
buy an excellent Epoxy thinner (Copon) that is very compatible with K&B and
Hobbypoxy epoxies.
Today I discovered I had over excelled at cleaning up my backlog of e-mail
and have lost my information pertaining to ordering Copon Epoxy thinner.
Does someone still have that information and would you be kind enough to
send it to me at This email address is being protected from spambots. You need JavaScript enabled to view it..
Thanks, Reid Simpson
[Reid here it is ...]
Source for Epoxy Thinner
========================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
For anyone who is interested in obtaining an excellent Epoxy thinner, please
read on.
As the source for Epoxy paints and thinners as dried up nation wide, I've
found myself running out of thinner faster than the paint.
An excellent thinner that was used by myself and many other modelers since
the 1970s was a brand called Copon. It was for a corrosion control 2 part
epoxy and the thinner was very compatible with both K&B Super Epoxy and
Hobbypoxy. However it is no longer sold in California and this was my
source.
Thru the Web I found that the Copon brand of Epoxy is manufactured in Great
Britain. A query gave me a reply from their representative in the USA, The
following is a quote from Him.
"My name is Dan Schalk and I represent Copon in the United States. We carry
a variety of corrosion resistant epoxies and 6 different Copon thinners. If
you have a product name and number, it would make it easier for me to help
you."
THE THINNER THAT YOU WANT TO ORDER IS THE "SA65 SPRAYING THINNER"
In a follow-up note, Dan replied " A 5 liter can of the material is $60.00
and can be ordered directly from us. We do not have any in stock but do have
a few shipment coming to us this month. If you would like to place an order,
we take Visa or MasterCard and ship UPS. Our number here is 800-578-2772.
As a precaution, please note that this thinner should not be used to wipe
down pre-painted Epoxy finishes. In a conversation with Faust Parker on the
availability of this thinner I brought this up and Faust said "Wow, I'm glad
you told me, I have been using thinners to clean the front ends of my F1C
ships. PLEASE DON'T! I don't want someone to come back to me saying they
have just ruined a good paint job.
Happy Painting.
Reid Simpson
Free Flight Finals voucher and round times
==========================================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Blank FAI Stickers and FAI Model Specification Certificate will be available
to anyone who needs them at the Finals, see you Event Director. The FAI
Stickers are on sticky back mylar and can be easily filled out with a
permanent marker. The Event Directors will not fully process, measure
projected area, your model(s) for free.
The start of the contest will be shifted by 15 minutes to start at 7:45 AM.
I neglected to account for the later sunrise from our original plan dates of
Labor Day weekend to the present dates and the rounds times shown in Finals
Bulletin #2 are incorrect. Sunrise is going to be very close to 7:15 AM at
Palm Bay. You can test fly at 7:00 AM without a problem but our program
requires 30 minutes after sunrise.
Jim Bradley, FFTSC Chairman
glue.
=====
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Rodger.
Where might i be able to get some
Rand O Bond Glue?
I Tried The Aerodyne Web Site But None Was Listed.
Also I Need Some Floresent Pigment To Go In The Dope
FOR Spraying On Polyspan Covering.
Thx Don.
Indoor wings
============
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Does anyone know what happens to microfilm on a say, F1D wing, in flight?
Does the sag between the ribs disappear by the lower pressure sucking it up,
so that the top surface is practically smooth? If so, perhaps the same
phenomenon applies to tissue covered wings as well?
Maybe someone has photographed a ship in flight which shows this taking
place? The indoor model I mean.
Regards
Mike S
Junior, to be or not to be
==========================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Dear Mr Scat,
I read with pleasure and interest the recent reports on the successes of
the US junior flyers.
I'm sure it was a great experience to be with them, and probably even
greater to be flying at that level when still so young.
I must confess I envy them a bit, it's more than 35 years that I fly
rubber models, but I've never been a junior !
I mean, I've been younger than now, but at that time in my corner of the
world there was not a clear concept about being a young modeller (I
mean, a person building his models and flying them, just young) or
simply a modeller (again, I mean a person building his models, flying
them, without distinction of age).
So, at the end of the story, I missed a great opportunity, did I.....OR
NOT ?
May I hope to have some support in my quest to regain my lost youth, and
push a little modification in the rules ?
Would a limit age for junior pushed a bit forward, let's say to 55, be a
good idea ?
Advantages: definitively more juniors; a positive effect on the "feeling
young" of most of the flyers; a more than normal recognition that the
people get old a lot later than in the past.
Should this idea meet a large approuval, I could try to push it forward.
With a smile,
Anselmo Zeri
[Anselmo - another approach to being young that seems to work according to
some of my fellow sportsmen's e-mail is to help and fly with young people !]
The morning super-max
======================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
The morning super max is (to my understanding) intended to be flown in the
stable and neutral conditions in the morning. The idea is good, but
somewhat dangerous, as the early conditions may turn out to be rather
variable. This was definately the case in Hungary this year. Someone
commented later that the air was reasonable at the very beginning of the
first round, then again towards the end of the round. In between, constant
sink and missed flights.
This combination of tricky conditions and a max that requires at least
neutral, or rather slightly lifting air for a model to max easily puts
fliers in non-equal position for that round. Flying long maxes in varying
conditions may be ok for championships competitions, where after all team
work is of great importance, and such varying conditions also measure the
co-working ability of the competitors, and the tactical ability of the
team to make all the flights when conditions are favourable. For World Cup
competitions such changing conditions may be catastrofical: with 6 fliers
sharing a round of 55 minutes, it leaves only 9 minutes per fliers, and
with a max of 5 minutes this means a window of 4 minutes to pick up the
air. If the conditions change as they did in Hungary, it is a matter of
choosing the right flying slot to have a chance to max, and even then you
are on the mercy of the other fliers not exceeding their time of picking
the air. In Puzta Cup this was a problem, when flying only to 3 minutes
max on the first round.
I also agree that an extremely difficult round as the first one is most
discouraging to the unlucky fliers missing the max. The remaining six,
with 3 minutes are usually such a nominal task that you can be sure that
your chances are gone - it is just a question of if 5 or 10 guys make
mistakes and drop behind you. Of course it is the same if you drop on any
of the remaining rounds - you're out - but there is a difference. On a 3
minutes round you need to make a bad mistake to be out, but on a 5 minute
super-max round, you may be in a middle of slight sink for 30 minutes, and
need real hot performance to make the fiver in that air.
So I'm slightly against 5 minutes super-max for the first round in
Championships competitions, I think the 4 minutes as it used to be would
be better. And I'm strongly against such a max for world cup competitions
in ordinary summer conditions, where a dead period in the morning, before
the thermal activity starts is the norm. The latter would be possible if
there was enough timekeepers to have only 3 fliers per pole...
-Tapio-
1960 Nats.
==========
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Back in 1960 at the Nas Dallas my first Nats, I met a senior from Calif.
Can't remember his name. He had a high thrust line Satellite. Does anyone
know who this was and if the plans for this ship are around? Just wondering.
Dennis
This email address is being protected from spambots. You need JavaScript enabled to view it.
Bulgarian Tow Hook
==================
Peter Allnutt is looking for a Bulgarian Tow Hook as made by Stoyan Kraev. He
wants the model with the built in micro switch.
Contact Luddite Peter at (1)416 249 0032 or just reply to SEN with
any information.
Re: SCAT Feedback
=================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
SuperMax, oh barf!
I support the idea of doing a survey on the like or dislike of he the
Supermax. I'll be the first unofficial voter and I vote to throw it in the
trash and get rid of it. It is counter productive to what keeps me in the
sport and trying to understand it properly is just about as clear as when
Clinton was trying to explain to the country what the definition of is, is.
Mac the Democracy Bigot
..........
Roger Morrell
