SEN 675 - 12 Feb 2002
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SCAT Electronic News 12 February 2002 issue 675
Table of Contents
=================
Isaacson Winter Classic
Missing Stuff
Lost Jacket at Lost Hills - Davis
Where is Joe Klaus - Lorbiecki
Where is Art Ellis - Brush
F1 Rules Proposals - Bogie
Twin props - Segrave
what is F1e - Stiles
LONG MOTOR RUNS ?? - King
Isaacson Winter Classic
=======================
Full results will appear , real soon now.
But in short ..
F1A - Hines
F1B Andriukov a
F1C Johannes R
F1H Stoev
F1G Ruyter
F1J Menanno
F1E Brocks
Gollywock White
P30 Thompson M
Great weather, great flyoff, great turnout, World Champions
abounded. Great burgers cooked by chef Wolfgang Weiler
and the Furutani Brothers. For those who have trouble Norm is the one
with glasses, brother Alan reported intersting conversations with
people hed had not met before. Also thanks to Casey and Emily for help
with flyoffs, food and scoring.
Missing Stuff
=============
There are a couple of articles that have not been published - because
they need work and I'm very busy at this time. They will appear
in due course, after the MaxMen.
Lost Jacket at Lost Hills
==========================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Hi Roger,
Please post this on the next scat newsletter.
Lost Windbreaker jacket
Lost a navy blue Patagonia windbreaker jacket at Lost Hills during the
Issacson contest. Please bring it to the Max-Men contest if you find it.
Thanks
Jon Davis
[Jon , I think the F1E mule ate it]
Where is Joe Klaus
===================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
I recieved an email from a gentleman in Alaska asking about Kustom
Kraftsman(ship?). I think it was owned by Joe Klaus. Made the fine
thread needle valves for TeeDees and modified engines. The gentleman was
interested in either getting in touch with him and finding out the
whereabouts of any stock that was remaining from the business. Does
anyone have any info I could provide him?
Thanks
John Lorbiecki
Where is Art Ellis
==================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Does anyone know the whereabouts of Art Ellis from Ct. For two months I
have emailed him and sent snail mails with no response. Did Art move? Does
he have a different snail mail address? If any one is in reach of him,
please tell him we need to talk with him.
We are worried that something has happened to him as he is not getting any
of our mailing. Thanks.
Tina Brush
Star*Link, Flite Tech, Bob White
Online catalog: www.inland.net/~abrush
F1 Rules Proposals
==================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
There are two on the list.
A rewrite of the rules for the launch period for F1B allowing winding before
the start of the round. USA
A rewrite of the rules restricting gearing to direct drive only. France
Bill
The gears are F1C , I Presume ! - darn, I was looking to that as
a 30gram solution ! :-)]
Twin props
==========
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Twin prop diameter i.e., each one, to equal the swept area of a single is
approx. 70% of the single.(20" = 14" for the diameter of each of the twin
props). As shown before, the 12" diameter with chord of 35mm at the 70%
radius has an advantage of 35 x 1.5 over a prop of 18" dia. with a chord of
40mm at the same 70% radius. BUT, there are TWo props, so the advantage is
twice that. We are talking Reynolds Numbers here of course. So we end up
with 35 x 1.5 X 2 = 105 vs 40 x 1 = 40 (RNs). As mentioned before the 12"
twin props turn at a rate 50% faster that the equivalent 18". Taking the
current FB props to be 600mm dia., the a twin equivalent would be 600 x 70%
= 420mm dia. Next, using the data Mike Woodhouse gave in his article in
Freeflight Quarterly for turns(on 28 strands of 1/8" of between 450 and 480,
this reduces to 400 to 427 for 30 gms. Then, dropping down to 26 strands,
max turns become 522 to 557. Thhat's for a single prop. BUT, were dealing
with twins, so we split the 26 strand motor in two = 13 strands. Difficult
make up so we will reduce this to 12 strands 1/8". Max turns is now 1600 to
1707. Divided in two for the twin props, this equals 800 to 854. Now asuming
that the props still turn at l.5 times the norm of 10 turns/sec we get a run
of 2/3 x 800 to 854 = 53 to 57 secs. Wow!!!even longer that most runs of
40gms!!! Into the bargain, fast turning props have less "slip" and are much
less prone to stall and drop you out of the thermal. There are other
advantages too. You can use a wire saddle attached to your wrist which locks
the props and as you throw the saddle is retained on your wrist, the props
start on the ship leaving oyur hand and away the ship goes. A whole new
world!! Perhaps the only critical point is that the props MUST turn up in
the centre and the ship MUST climb to the LEFT. Repeat, to the LEFT.
Additionally, you don't need auto rudder of autostab, at least not on a
Coupe! What do you say?
what is F1e
============
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
I would like to know what F1e is about. Is there anyone selling
complete models that are trimed and ready to fly. charlie
[Charlie - you missed it a Lost Hills last weekend - Motor bikes are
out, a mule is required and baggy rapper pants are de rigeur for the US Team]
LONG MOTOR RUNS ??
==================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
I have always had serious doubts about the use of very long motor runs in F1B
and other rubber classes. I ran some cases in my simulation program and
here are the results, for what they are worth. Note the simulation is based
on very high performance 35gm models, downgraded to 30 gms of rubber. It
seems that the top 35 gm models are now capable of attaining 7 mins plus.
The absolute results are not that important, it is the general trend that
matters and that seems to be pretty much against runs of longer than ca 55
secs, however you run the figures.
30gm F1B
No of Strands Run (sec) Height (m) Duration (secs)
24 57 99 369
22 61 96 360
20 73 90 359
18 89 80 346
16 111 59 294
14 132 24 206
13 152 0 125 (Note
the model lands with
turns on)
There are two points to make here:
1. I allowed a slight decrease in prop efficiency for the longer runs, due
to adverse Re No effects on the slow running prop. This made very little
differnce to the general trend however.
2. When you add a 0.2 m/sec downdraft to simulate rather bad air, the two
longest runs now both land with turns on. In fact the results here are not
what I expected as the general drop in percentage terms is roughly the same
for most of the motor runs. I believe there is a bigger penalty than that
due, to the fact that these are optimum climbs and the effect of not
attaining the optimum climb angle may well penalize the long run more than is
shown here. See below:
No of Strands Run (sec) Height (m) Duration (secs)
24 57 88 226
22 61 84 223
20 73 75 219
18 89 62 209
16 111 37 182
14 132 0 127 (Note
both flights land with
13 152 0 77
turns on)
Peter King
.....................
Roger Morrell
