SCAT Electronic News 30 November 1999
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SCAT Electronic News 30 November 1999
"SCAT - 40 Years of FAI Free Flight Competition"
Table of contents
=================
DT stab angles - Watters, the Luddite
Science News - Bogart
FAI records - Tribe
F1C and Cut F1B - Andresen
In answer to Phil Uden - King
What's the problem - Editor
Swiss results? - Hines and Nuttgens
Looking for - complete result list Eurofly-Bern 1999 - Bellen
Dust - Dukie
Patterson Question - Fitch
DT stab angles
==============
Roger, can anyone give me some info on shallow stab angle DT? What happens with
angles less than 40° which I have always used? Has anyone any test
info/experience on this? Do you you get into a progressive repeated
stall, leaf fall, or does the stall damp out? What happens with a F1B
at 20°, 25°, 30°? Any info out there?
Thanks for any help,
Old Luddite, John Watters
[John , personally I always go to making it steeper - I just want
to get down, but someone might have some advice for you. It certainly
does depend on the type of airplane.]
Science News
============
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
In the November 20, 1999 issue is a rather long article on wearable
computers. Apparently, troops in Kosovo are using this scheme to talk with
locals. The computer translates the speech of the local and sends the
message in English to the trooper. The article can be found in
www.sciencenews.org. This site gives full copies of what it presents in a
weekly magazine mailed to my home.
[ Bill, sounds just what the true international sportsman needs,
or maybe even for communicating with the shepherds at Lost Hills]
FAI records
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Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Regarding the comment on F1C speed records, try looking at the FAI site,
records,aeromodelling and just wonder!
F1B speed 187 km/hr !!!, Rubber driven Helicopter 144km/hr !!!, etc.
Perhaps the FAI interpretation of F1B is not what we understand.
Regards,Peter Tribe
[Peter , this one I can answer, though Ian Kaynes would be better.
I seem to remember something a while back in FFn discussing this. The
FAI rules are not for a F1X model as we fly it . F1B for eaxmple is
any rubber model for record purposes. The discusion was
if this was relevant ]
F1C and Cut F1B
===============
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Roger,
About 50 yr ago Eugene Stiles set the F1C speed record @ Plymouth Internats
right there in the Brokenspar back 40. There can't be too many Stiles' that
fly F1C so maybe Hardy can get the inside scoop from his flying buddy
Charlie Stiles. Not sure if ROG is required but I think Hardy's on to
something as F1C's do about 100km/hr UP and FAI CL record is about 300km/hr
dragging lines that are the majority of drag.
Hardy. go for it. Put a long prop on that F1C, point & shoot. Good luck
finding official timers & camera people.
Really like the Wakefield suggestion removing area restriction as calcs many
moons ago showed a Coupe built to 40gr Wakefield dimensions but Coupe weight
would have the duration of a 40gr Wake!
Hope Bob White doesn't find this out or he'll convert his big twin-fin to
Coupe and improve his Americas' Cup standing.
I think that after a few people figured out how to make a 12'span to the
20/200gram rule you'd see some real performance until the rubber supply
dried up from lack of demand (due to small motors) unless it really drew in
more fliers.
H
In answer to Phil Uden
======================
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Dear Phil
Great to see you writing to the SCAT page!! How are you ?
I ran your ideas through the simulation and this is what I got, (For a full
gadget, AA type model). I ran the following cases, all with 200gm
airframe and 20gm motor . The motor was 26 strands of Tan 2 and the Motor
run was ca 30secs using a standard AA prop. (600mm Dia)
Wing Area (dm2) Duration (sec)
CASE 1 16.0 (Normal) 231
CASE 1 17.0 234
CASE 1 18.0 238
CASE 1 19.0 241
It seems the wing area does not make that much difference. (bare in mind
that 200gms Airframe plus 20gms of rubber results in a model 10gms lighter,
(220gms), than a regular F1B, (230gms if you can get it down to weight !!)
All models reached about 195ft ca 60m on the climb with a delayed prop
start of
0,4 secs and a launch velocity of 16m/sec.
I would hasard a guess that a non gadget model would be down by about 5 to
10% depending how good the modeller was.
In fact it looks like quite an interesting idea except it would make current
models rather obsolete. I do like Coupe D'Hiver, for the very reasons
Phil mentioned but I would, personaly, still prefer the rules left alone or
go down to 30gms of rubber and maybe a 220gm airframe.
Thanks for all the interest shown in our simulation program. I have
already had about 10 enquiries about getting the simulation and have done my
best to send out copies by internet. Aram Schlosberg asked me about an
F1A sim. I have now updated this and it is available to interested parties
for trial use. Aram has already sent me some really helpful and
penetrating feedback and I hope those who recieve copies will try to do there
bit, as far as they are able, to do likewise and help in the development of
the simulation. I hope it is at least a basis from which a much better and
fuller tool can be developed. My hope is that it will become, in time and
with your help, a complete and reasonably reliable way of simulating
(optimum) performance. As I see it, the biggest help in developing the
program will be collating it with as much data from real flight and wind
tunnel testing, that we can collect. The most helpful data may well come
from systematic glide testing that people have done or will do !! For
anyone thinking of doing serious glide testing, the area where we badly need
data, is the effect of Re No on typical glider airfoils at RE = ca 40,000
down to RE = ca 10,000. The area between 10.000 and 30,000 is not only
one where airfoils change dramatically in efficiency, but the very area where
we have the least reliable data.
Sincerely yours
Peter King
email address... This email address is being protected from spambots. You need JavaScript enabled to view it.
What's the problem
===================
Editor
There are certainly less participants in F1B than a few years ago
but I'm not certain that what Phil suggests is the reason.
I think that long fly offs in thermal conditions can be solved
by a solution similar to that suggested by Aram Schlosberg. That
is capping the max at say 7 minutes or even less under thermal, windy
conditions. This is based on the premise that the model will either
get a thermal and make the max or otherwise get a downer and
drop. It's significant to look at the results and see that under easy
thermal conditions most sportsmen make the maxes. This is a reflection
of the standard of the contestant and no rule change is going
to make any difference. A heavier or less powerful model is still
going to make the thermal. Of course there will be some who
drop because a slightly better thermal will be needed, but
probably not very many.
When it comes to complexity there are people who like the
complexity of the models. However a complex model does
not guarantee sucess. The best example of the
success of the simple model is Klaus Salzer, there are
others too who do well simple models. Jin Brooks stated that
he considers this thermal picking ability important
for his success, I don't remember if Jim flys simple
model but many of his fellow Canadians have been very sucesful
without gadget models. One of the reasons
however why some people fly multifunction models is because
they find them easier to fly and trim. There is no question
that it requires a lot of skill to get simple model
to fly like Klaus or Bob White. Sometimes I think beginners
think they need a more complex or expensive model than is required.
Their time is probably better spent getting flying experience
and learning about picking air. Maybe they want instant success
and see applying money to the problem and getting a top of
the line model the answer, ...which we know is certainly not
the best route for a beginner.
I think the problem we have is that part of the appeal of the F1B
class is the power and the ability to control it. Any move to restrict
this reduces the appeal in some people's eyes.
One other factor is that I was talking to John Clapp the other day
and he was talking about reducing the energy of the rubber. Reading
between the lines and listening to other modellers talk many have complained
about the fragility of some recent batches. How they are sensitive to
temperature etc. Some of us who test every motor and have rubber
from many batches have a reasonable idea what to do with different
conditions. However I'm sure that John has got complaints about rubber
breaking, so the simple solution is to make it a bit more durable.
The 'only' downside to this is that the rubber does not have so
much energy.
I always thought that John should send to each person who proposed
the 25 gram motors some of that stuff that even the Taiwanese toy guys
rejected. Unfortunatelu John takes to much pride in treating people
fairly and in turning out a good product to do that.
So eventhough some people think we have a problem, I'm not
sure if we have really zeroed in on it yet.
Roger Morrell
Fw: Swiss results?
==================
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Hi Rog. If ansgar did not send this to you, here 'tis, to add to the =
bit you spoke of.
Lee
----- Original Message -----
From: Alla Nuttgens
To: Lee Hines=20
Sent: Monday, November 29, 1999 2:39 PM
Subject: Re: Swiss results?
Hi Lee,
it was beautiful in Switzerland - not my flying ( 240 180 118( good air
- I doesn't understand , why model came so wquick down) 180 183 ( in 10
m in a tree near the river ), but on Monday after the contest the
weather and the sightseeing trip to a 2000m hight viewpoint of Rigi with
the roundview over the famous Swiss Alpes. After arriving at noon , we
are sitting on a bank in the sun and enjoying the last sunny holiday
with snow on the mountains around and some fog in the valleys and
Bavarian Kingsweather ( blue sky with some clouds) . After half hour the
fog and clouds were coming from the valley so quick and close the view ,
that it was a magic adventure to stand on the top in snow and big fog
and see nothing. This was an experinece for us, how quick weather
changes can happen.
So to the contest: I wasn't on Saturday there for F1B and C, I came in
the evening and see, how Evgeny Verbitsky clean his F1C - "Boat" from
water. What has happened: In a test flight for the fly-off, which was
planed for next morning, he landed exacly in the small river and the
quick running water with some was moving his gear -model top and down
and crashed both wings completly. Only the part of the wing until the
wing joiner was resting at the fuselage. The tailplane was full of
fresh swiss water. Oh my dear -how terrible aeromodeling can be.
I have less time, because we have our 50th anniversary of regional
Aero-.Club and I have to organize a lot of thinks.
Sorry - later more.
Ansgar
complete result list Eurofly-Bern 1999
========================================
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Dear Roger,
I am looking for a complete result list of the f1a of the Eurofly- Bern =
1999.
We had to leave home early, so we couldn't get one. Can you help me? ( =
On the FAI. web are only the first 25 in f1a)
Many thanks in advantage.
Best regards, Win Bellen
[I'm sorry we do not have those results]
Dust
=====
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Roger
Brokenspar's records would never be approved, because they can't process
dust, the model has to be complete in order to process it. Hardy's research
on the VIMD has been nearly completed and he is moving on to better things.
Thx
Dukie
Patterson Question
==================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
How interesting to find out that the last round was flown, after many people
had left. I don't think I'm the only one who understood flying was over for
the day and that there would be a flyoff at the Max Men.
So how many otherwise maxed-out flyers got eliminated by this move?
[Jerry, there were only two maxed out flyers in the 7 round. I think
that until the 6 round about 6 or 7 people were clean.]
............
Roger Morrell
