SEN 901 - 7 Sep 2004
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SCAT Electronic News 7 September 2004 issue 901
Table of Contents
==================
I have published the announcement... - Pugachenko
44th FAI Invitational Results - Markos
News Flash - Van Wallene
Fw: FFC Daily Event Schedule - Secor et al
interesting video
Glide speed - Ackery
trouiblesome turbulators - SkyKieng
planform - Skykieng
Classic towline rules suggestions - Leeper
Re: SCAT Electronic News 31 August 2004 issue 900 - Moseley
I have published the announcement...
====================================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Dear Modelers!
I have published the announcement " F1A and parts from Moscow for sale "
at SCAT Electronic News 4,15 July 2004 issue 880, 881.
Aleksey Riazantsev and Yury Titov have removed from sale the item
number 3) Servo holder with wheels + Bunt mechanism for e-model of M&K.
Sale of the item was not coordinated with Sergey and Michael.
You may address to M&K to buy these parts, please.
Pugachenko Aleksandr mailto:This email address is being protected from spambots. You need JavaScript enabled to view it.
44th FAI Invitational Results
==============================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
44th FAI Invitational Results. August 28-29, 2004. Muncie, Indiana
F1A Rd 1 2 3 4 5 6 7FO Total
1 Andrew Barron 180 126 180 180 60 180 175 1081
2 Chuck Markos 109 155 180 180 148 180 122 1074
3 Bob Sifleet 151 118 180 112 30 180 100 871
4 Lee Campbell 75 165 57 102 69 180 648
F1B
1 Jim Bradley 180 180 180 180 180 180 180 200 1460
2 Jerry McGlashan 180 180 180 180 180 180 180 1260
3 Bill Shailor 180 171 180 117 180 180 180 1188
4 Evan Simon (J) 180 180 156 180 99 180 180 1155
5 Paul Shailor (S) 180 180 180 180 180 120 102 1122
6 Greg Simon 180 180 180 132 108 180 156 1116
7 Paul Crowley 180 125 180 110 95 180 180 1050
8 Chris Matsuno 127 180 160 86 114 131 141 939
9 David Lacey 147 87 180 115 81 180 149 939
10Joe Friebis 180 102 44 108 96 127 88 745
11Thomas Ioerger 180 180 84 68 119 631
12Fred Blom 90 148 110 118 82 548
13Guenther Nowak 147 140 88 58 60 493
F1C
1 Bucky Servaites 180 180 180 180 180 180 170 1250
2 John Seymour 180 162 180 163 180 142 166 1173
3 John T. Lorbiecki ( 180 180 180 180 100 180 141 1141
4 Gil Morris 180 180 175 108 180 180 1003
F1G Rd 1Rd2 Rd3 Rd4 Rd5 FO Total
1 Thomas Ioerger 120 120 120 120 120 144 744
2 John Shailor (J) 120 120 120 120 120 138 738
3 Greg Simon 120 120 120 120 120 121 721
4 Ed Konefes 120 120 120 120 120 120 720
5 Chris Matsuno 120 120 113 120 120 593
6 George Clowes 91 120 120 74 120 525
7 Evan Simon (J) 120 113 57 120 380
8 Fred Blom 120 120 240
9 David Lacey 99 92 191
F1H
1 Chuck Markos 120 120 120 92 120 572
2 Robert Sifleet 120 120 120 120 63 543
3 Bill Schlarb 82 80 162
F1J/F1P
1 John T. Lorbiecki ( 120 120 120 120 480
News Flash
==========
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Hi,
just got the news from Anselmo that he won the Zulpich Wc competition
and thereby topping the World Cup for the year.
Congratulations to him.
regards,
Allard
Fw: FFC Daily Event Schedule
============================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Hi Roger
In case anyone needs a flyer for the FF Champs it is posted on the Lost
Hills Web site.
Randy
>
The flyer for the FF Champs can be seen at the Lost Hills web site
www.losthills.net. Click on Upcoming events, then on September. Then there
will be a link that says "view the flyer here", that will pop up the daily
schedule.
interesting video
=================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Roger:
Worth a look for SENers?
http://www.sillysot.com/misc/fs14ss.mpg
Glide speed
===========
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I want to acknowledge all those people who have responded to my query
about glide speeds.
Thankyou, all the replies were most helpful.
Especially Bill Gieskieng and Peter King.
Bill has generously shared his experiance with Profili, and Peter King
provided his formula for calculating glide speed,
V = sq root of { ( weight in kg x 9.81) devided by (0.5 x rho
x wing area in sq dm x CL) }
where
V = m/sec (thankgoodness for the metric system)
rho = air density = 1.225
CL = 1.0 for F1B
>From this I get the following Renolds numbers for a Wakefield on the
glide,
Chord - dm Rn
1.15 37493
1.1 35863
1.05 34233
1 32603
0.9 29343
0.8 26082
0.7 22822
These numbers are lower than what we would like, (especially at the
tips), and much of this falls into the murky area where we are told
that airfoils are starting not to work very well, and computers have
difficulty figuring out what is happening. But despite this our models
are able to fly, and do so very well. Struggling to better undestand
this is one of the many interesting challenges we have.
cheers
David Ackery
trouiblesome turbulators
=========================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
A few SCATS back I ventured an opinion that, judging from Profili2,
turbulators in the usual forward positions were detrimental. However I
found "invigorators" at around 65% of the chord to be helpful on my
airfoils in that they increased their usable range at lower Cls.
Seems I left a gap in my trials.
Sergio Montes countered my findings with the fact that turbs at 40% gave
outstanding results.
David Ackery replied as paraphrased below.
The effect of turbs in Profili is very interesting.
I will normally use turbs at 5%, since this is conventional wisdom and
accepted practice. However, prompted by your discussion, I am prompted
to reconsider.
As a benchmark I ran B6356b at Rn = 30K with turbs at 5%, 15%, 30%
, 40%, and it keeps getting better as the turb moves back (after 40% it
starts to get worse). These results I don't understand. Is the
accepted wisdom of the last 50 years wrong?
So, what are we left with? Stick 'em and try 'em?
A fly in the ointment may be that Profili assumes that the transition
takes place where the turbulator is predicated in the program. It may be
that it takes a period of travel before a tripped flow actually
transitions..(.if it does at all in actuality) So, to achieve a
transition at 40% it may take a trip device placed some distance
"upwind."
That's just a guess. I confess haven't the slightest clue.
B G
planform
=========
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
To clarify Manuel's comments below, I had mentioned in SCAT that there
was evidence that for low Re a rectangular planform with tips tapered
for the final 20% had some advantages. Somewhat the same observation is
to found in Martin Simon's book on Model Aerodynamics.
The surprising findings were mentioned some time ago on the Xfoil
discussion group, and the material backing this up was available on a
web page. I went looking for it recently but couldn't find it.
In any case the advantage from changes in the planform would be minor
and hardly discernable by casual observation. The main point to me is
that I would not be hurting performance by using a generally
rectangular wing....it certainly makes for ease in construction, even
if it lacks in desirable elegance.
Bill G
Classic towline rules suggestions
=================================
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Hi Dave,
For the most part I agree with your discussion of Classic towline.
My exception is that the 'time on tow rule' is useless and self-policing.
The intent of the event, as I have understood, was to not allow circle
towing or bunt launches.
Simply saying 'No circle towing or bunt transition allowed' would suffice.
Don't even charge an attempt, as going to get it and refly seems penalty
enough.
I have no problem with 'BOM Rule' either way.
It was never enforceable anyway.
Just ethics and guilt were involved for each individual to decide what to do.
BTW, I purchased a 'Tropik' Nordic kit from Lars Larson.
He flew his in the Scania Cup this July and did well.
It is very nice and I will build it this winter.
It was good to see you and congrats on your NATS results.
Ciao,
Lee
Lee Hines
Re: SCAT Electronic News 31 August 2004 issue 900
==================================================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
This is a multi-part message in MIME format.
>Trying to get hold of Graham Knight regarding the 2005 Sympo,
This email address is being protected from spambots. You need JavaScript enabled to view it.
Eliminate BOM in Classic Glider?
Forget it - it's bad enough having it restricted to A/1 and A/2 designs
only, as it is .....
.........................
Roger Morrell
