SEN 809- July 20 2003
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News and Reports 2003
SCAT Electronic News 20 July 2003 issue 809
Table of Contents
==================
Our Rocketry Cousins (for SEN) - Deloach
More on neutral points - O'Connor
Issue #8 of Free Flight Quarterly has appeared - Montes
Ben Coussens - Brush
Sierra Petite........ America's Cup Contest Announcement - Simpson
T-tails for Free Flights...my experience - Helmick
Who knows ? How the Fat Cat got Fat and other tails - Brokenspar
2003 Huron Cup Report
Our Rocketry Cousins (for SEN)
==============================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
In contemplating the current state of free flight sites in the U.S. and the
world (some shrinking, many disappearing) I have been doing some thinking.
Have any FFers or FF clubs ever tried to coorperate with rocketry clubs to
get/use flying sites? The fact is that their site requirements are about the
same as ours. They look for flat, large, unobstructed fields with good
weather. And of course the bigger the better. They even use the same Walston
transmitters and receivers as us. I'm not saying we would necessarily want
to ally with them (or them with us) but our requirements are so similar I
believe it warrants further investigation. I went to the Tripoli (national
high powered rocketry assn.) website and found many clubs and launch sites
within an easy drive of many major U.S. cities. I remember a Texas Cloud
Climbers contest in the mid-nineties at the Allen site. There were some
serious rocketry guys launching upwind of us and we seemed to coexist
adequately.
The reason I brought this up is I was reading an article on the web about
the world's greatest flat piece of earth, the Black Rock Desert near
Gerlach, Nevada. Apparently there was some limited FF use of this
giant-of-giants dry lake back in the early eighties (Ron St. Jean and
friends according to an old Digest). It is public land (BLM), pool table
flat, and about 15 x 25 miles! Currently the California & Nevada Tripoli
group makes use of it for regular launches. So that begs a second question:
has any FF activity taken place at Black Rock Desert recently? It would seem
at first blush to be the greatest FF site in the world, assuming the weather
is good.
This is just a brainstorm. But I strongly believe that out-of-box thinking
such as this will be necessary to insure a healthy future for FF.
Don DeLoach
MMM, Colorado
--For more info on rocketry at the Black Rock Site:
http://www.aeropac.org/--
--The BLM page for Black Rock:
http://www.nv.blm.gov/Winnemucca/recreation/Black_Rock_Desert.htm--
--And www.triploi.org has a state-by-state listing of rocket
clubs--interestingly they are about as numerous (scarce) as FF clubs.--
More on neutral points
======================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Roger
Jonn Barker's fine summary of the aero-modelling lit. on NP calculation was
a pleasure to read.
The following notes may assist anyone interested in the issue.
There is a note on applying Buermann's work in the 1961-62 Aero Modeller
Annual.page 114.
The scale at the bottom of graph B is out by 2 units. It should run from 2
to 16 rather than 4 to 18.
Buermann's original papers can be found on the Thermiksense website.
Formulae that account accurately for the aspect ratio effects on lift
slopes and wing tail interaction, even at low aspect ratios, can be found
in "Aerodynamics of the Airplane" by Schlichting and Truckenbrodt. Here
one also finds guidance on the effects of wake rollup and tail / wake plane
separation.
The main problem for aeromodel applications is the uncertainty of the lift
curve slopes of the
wing and tailplane. Actually it is the ratio that counts which may be why
undercambered TPs
where popular in the past.
A model trimmed to fly close to the stalling point with a tail operating
near its 'ideal' angle can
have a very movable NP which probably goes part way to explaining the
diverse range of
behaviours we sometimes witness.
Cheers
Sean in Melb.au
Issue #8 of Free Flight Quarterly has appeared
==============================================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Roger,
Would it be possible to include the following note in SCAT? Thanks
Sergio
^^^^^^^^^^^^^^^^^^^^^^^^
Issue #8 of Free Flight Quarterly has appeared. The contents of this
issue and previous ones, as well as details of the publication, are
listed in the website:
http://chariot.net.au/~bluejay/freeflightquarterly.html
Issue #8 contains articles by Mario Rocca on VP for F1C, Part 4 of the
survey on F1J engines by Chris Murphy, Erich Jedelsky on Jedelsky wings,
how to trim a contest Gollywock, how to determine variable rib
separation and many others of interest to SCAT readers.
Sergio Montes
Ben Coussens
============
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Ben........we have been watching your expertise in writing
for some time now. You seem to have a real gift here of
expressing yourself to really tell a story in your writing.
We wonder if you might not have this outlined in your
profession for the future? If not, you may think about
it. We have enjoyed, as many have I am sure, your
concepts of free flight special highs and lows of our beloved
hobby.
We just wanted to encourage you to perhaps follow your
instincts on writing and perhaps to be part of your
curriculum for the future, you knows, you could be the
next _____________ (fill this in yourself).
We wish you well at the Nats..............go for it!
P.S. We love your email address! Very interesting!
Allen & Tina Brush
Online catalog: www.inland.net/~abrush
Fly Free Flight For Fantastic Fun!
[Al and Tina
I agree with you that Ben's writing is very commendable. I know
that he has a literary flair - but that is not what is important.
Articles like Ben's and event reports are a very important
part of sharing information about competition FF. We need more
people to write about the different aspects of our hobby/sport.
Let's see some more people follow Ben's lead.]
Sierra Petite........ America's Cup Contest Announcement
=========================================================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Roger,
The following is the contest announcement for the replacement
contest the Sierra Eagles will be hosting in October. I saw in SEN
that SCAT will discuss the status of this contest at a pool side meeting
(Lost Hills Motel 6) this coming Saturday night. I have sent this
announcement to the America's Cup organizers and am placing it in SEN
prior to the meeting so there is no doubt as to the status of the
contest. The Contest is scheduled, sanction has been applied for,
trophies have been ordered. Lets fly!
Roger
SIERRA PETITE
An America's Cup Contest hosted by the Sierra Eagles MAC
October 15-16, 2003
Sacramento, California, Waegell Field
Wednesday, October 15
F1G, F1H, F1J
Round 1 11:15 45 minute Rounds, all Rounds 120 Seconds
Round 2 12:00
Round 3 12:45
Round 4 1:30
Round 5 2:15
Flyoffs start at 3:30 PM. Ten minute rounds with ten minutes between
events. Each contestant that is in the flyoff must provide a timer for
the timer pool for that round. No timer, no can fly. Please bring a
timer and help out with all events.
Thursday, October 16
F1A, F1B, F1C
Round 1 8:00 One hour Rounds, all rounds 180 seconds
Round 2 9:00
Round 3 10:00
Round 4 11:00
Round 5 12:00
Round 6 1:00
Round 7 2:00
Flyoffs start at 3:30 PM. Ten minute rounds with ten minutes between
events. Each contestant that is in the flyoff must provide a timer for
the timer pool for that round. No timer, no can fly. Please bring a
timer and help out with all events.
Entry Fee: $20.00 Open/Senior, $10.00 Junior, per event. If flying two
events, entry fee is $30.00.
First and Second place trophies for Juniors in all events.
Contest Director - Roger Simpson - Phone 916-686-1301, email
This email address is being protected from spambots. You need JavaScript enabled to view it.
This contest is the replacement America's Cup contest for the canceled
Harts Lake, Washington, FAI Challenge. By inserting this contest
between the FAI Invitational Contest that will be flown at Lost Hills on
the weekend of October 11-12, and the Sierra Cup International
Competition that will be flown at Waegell Field on October 17-18, we are
giving the FAI free flight competitors the opportunity to fly in three
America's Cup contests and a World Cup International Competition in a
span of nine days................ further defining "THE ENDLESS
OCTOBER", flying FAI free flight in California................ COME
JOIN US!
T-tails for Free Flights...my experience
=========================================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Dear Mr. Hepcat,
When I made the mistake of building a T-tailed Nordic A-2 for my first
CT model in the mid-'70's, I soon figured out that there was a problem.
The stabalizer was mounted atop a fin approximately 4" tall with a rather
narrow chord, accomplished by having the stab platform cantilevered in
front of the fin, and the DT cord meeting the stab at about 60% back of
the LE. The model was the fab "Schlitzer 2-43", and a drawing was once
published in NFFS Digest.
There were two issues with the model, the most important being that while
circle towing, the sink rate was phenomenal. My conclusion was that with
the towline attached, the increased sink rate caused the wing wash to be
onto the stabalizer. A certain Nordic-flying Boeing engineer said the
wing wash would be downward, but let us remember that a glider is
continually sinking through the air column, even as that air is rising
(thermal). Very unlike an airliner in powered flight mode. My solution
was to add a stab "kicker", which worked ok up until the auto timer start
was invented. The zoom launch wasn't good due to this extra incidence.
The second issue was that the model had a peculiar rolling axis in
turbulence. My observation was that the roll axis was slanted upward
toward the stabalizer , resulting in a nose down pitching as the model
flew through turbulence, also resulting in yawing. This cannot improve the
glide ratio! At that time, I was pretty avidly doing a lot of calculations
when designing gliders, and "the numbers" would have been pretty standard.
Also, the wing had short main panels and long, light tips, so the problem
was not "heavy wingtips". It rode lift pretty well despite the peculiar
rolling, but the CT was strictly bad news, and I would not recommend a
T-tail for a towline glider or any other FF type. Thermally,
Steve Helmick
Who knows ? How the Fat Cat got Fat and other tails
===================================================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
the speciiified tire pressure for the Fat Cat ?
On the tire it says...do not exceed 36 PSI to seat the bead.
That's not runnig pressure.
I remember 5 PSI.
RSVP
(,,,where's my manual ? )
Brokenspar
( This email address is being protected from spambots. You need JavaScript enabled to view it. )
2003 Huron Cup Report
=====================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Huron Cup Report 2003
The 3rd annual Huron Cup opened at 2:30 on Saturday afternoon after a
long wait on the part of Dick Wood, Tom Ioerger and Bob Sifleet. The
hope for improved conditions was fruitless, so the mini flying began in
weather alternating between periods of rain with lower wind and no rain
with increased wind. All three entrants performed commendably to achieve
the following scores:
FIH: Bob Sifleet 557
FIG: Tom Ioerger 510
Dick Wood 461
As the contest ended about 5:30, the air was full of F1A gliders being
checked out for the coming 7 rounds. By about 6:30 the rain was no
longer in evidence, but the wind was on the increase. It was decided to
begin the F1A, B & C rounds at 7:00 am Sunday.
Conditions were perfect Sunday at 7 and round 1 began on time with 5
minute maxes for F1B & C and 4 minute for F1A. At the end of round 2, a
wind shift made it necessary to move to the north west part of the field
for the rest of the contest.
Strong life and drift took four models over a strip of bush and into the
adjoining airfield in round 5. All were recovered. No models left the
field in the other rounds.
Prize giving took place at about 3 pm. Each competitor received a Huron
Cup certificate with his name and place. The first, second and third
placers received engraved glassware.
Sorry there are no pictures with this report, gentlemen; my faithful
photographer was house-hunting this weekend.
Jerry McGlashan
Scores
F1A
Bob Sifleet USA 180 (+60) 180 180 180 180 180 180 1320
Chris Lenartowicz CAN 180 (+60) 180 180 150 180 180 180 1230
Igor Fradkin USA 162 180 180 180 112 180 180 1174
Tzvetan Tzvetkov USA 180 (+53) 125 165 180 151 180 180 1161
Omer Erguner USA 180 (+56) 180 101 180 180 134 180 1135
Aram Schlosberg USA 180 (+60) 180 165 180 180 0 72 957
Leslie Farkas CAN 180 (+30) 169 108 84 180 71 145 937
Victor Sokolov CAN 122 159 97 179 71 80 128 836
Todor Boiadjev CAN 0 0 180 180 180 71 180 791
F1B
Bob Biedron USA 180 (+120) 180 180 180 180 180 180 1380
Dick Wood USA 180 (+104) 180 180 180 144 180 180 1224
Tom Ioerger USA 180 (+120) 180 143 180 180 180 180 1223
F1C
Andrei Kirilenko USA 180 (+31) 180 180 180 180 180 180 1291
...................
Roger Morrell
