SCAT Electronic News November 25 1999 - Thanksgiving Day
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SCAT Electronic News November 25 1999 - Thanksgiving Day
"SCAT - 40 Years of FAI Free Flight Competition"
Table of Contents
=================
Patterson Patter
Looking for Guy Menano
Photos from the U.S FF CHamps - Terzian and Weinreich
Closet Luddite - Goodnow
Date Change - Bogie
Cross-Section - Andresen
Mk 35 Simulation program - King [and Kaynes]
AmCup F1B - Parker [and Coussens]
Patterson Patter
================
I thought I would never see it - Dan Tracy on a Motor Bike... how strong
was that wind ? What next Dan without a tie ? or that cloth cap on
backwards ?
Congrats to CD Leath for not wimping or buckling to pressure to reduce the
max to 2 minutes. I flew at the very end of round 6, just before the
contest was suspended. I was watching the wind speed to see when to launch,
the high was 25 mph and the low 13.5. I think I got away on a 14, my
timer saw me all the way til I D/T'd and I ended up about a Km from Hwy
46. Plenty of room! I did have to use my retriver to find it as I
lost it while chasing.
The wind did drop to permit the 7th round to be flown, many people
had left by then. I was there because instead of packing up I was
answering questions about electronic timers.
Results will be out soon, but the F1B [Batiuk/Jensen] and F1C
[Joyce/Gutai/Simpson ?] ties need to be resolved.
Brian Van Nest did beat Hector Diez in the two man F1A flyoff
on Monday morning. Jim Parker, the other person who was clean dropped
round 7 and ended up third. Fourth and fifth [or vice versa] were Peter
Allnutt and Steven Coussens.
For the F1B trimming expert .. my F1B with a fairly tight nose up
spiral climb which is great in calm weather was not optimal
in the wind. When the plane turned down wind with it nose high it
seemed to get in a vacumn and tail slide out of the sky. Fortunatley
it tail slid into good air that kept it up for the requisite 3 minutes,
but it is somewhat disconcerting to see all that altitude fall away.
Good to see another junior out in F1B, Phillip Scheiman who did not
do quite as well as he had in the last event but aquitted himself
well in the difficult conditions.
Looking for Guy Menano
======================
I need to contact the young F1C flyer Guy Menano -
if you get/read this please e-mail This email address is being protected from spambots. You need JavaScript enabled to view it.
Photos from the U.S FF CHamps
=============================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Roger,
Chris Weinreich (NFFS Free Flight Digest editor) has made an appeal for
photos from the FF Champs at Lost Hills. Could you see if any of the local
SEN subscribers could help him out with photos they may have taken during
the three days of flying? Thanks.
Chris Weinreich [This email address is being protected from spambots. You need JavaScript enabled to view it.]
Fred T.
Closet Luddite
==============
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Gee I have been a "Luddite" for years and didn't even know it. As I fly
Nostalgia I build with balsa and tissue {Is Polyspan allright? I will go
back to silk or double covering if I have to.} Also I have been known to use
carbon fiber where no one can see it.Is this OK with the ruling body? As a
plus to my membership, if I am allowed to be come a full time member, I have
destroyed several miltifunction corbon fiber,fiber glass models I sinerely
hope you will consider me for membership in your august body.
Thermals
B. Goodnow
Date Change for Desert Challenge
================================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Desert Challenge dates are now one week later - Jan 8,9.
Bill
Cross-Section anyone ?
======================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Roger,
Previous to 1954 there were cross section rules for both Nordic and
Wakefield. These have advantages over weight as performance limiters since
they do not adversely affect the durability of the model and the size hole
it makes in the ground or a skull.
I still think the answer isn't less performance, but rather fewer, longer
maxes early in the AM.
Chief Luddite White keeps lobbying for return of the wingtip & prop ROG.
Noone listens to him either. Maybe now that he has GPS and shortly RDT,
people will start to listen to Bob. His balloon trick per Bogart seems to
work fine and is preferable to more weight too, also.
Mk 35 Simulation program
========================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Dear SCAT readers,
Maybe this will be of some interest to F1B and F1G flyers.
The Ian Kaynes / Peter King. Performance Simulation Program has now
progressed to the 35th Version !!! It is available for anyone prepared to
try using it. Of course it is still in a long process of development and the
parameters are continually up dated as info comes in from real experience on
the flying field, new wind tunnel data, etc etc.
However, what might be of more use to those without the time and
inclination to use the program is the fact that I am prepared to run
simulations for interested parties and publish or send the results.
The type of areas that seems to give the most reliable, comparitive, results
are as follows:
Effects, on performance of:
1. Model Weight
2. Rubber Weight
3. Aspect Ratio or (Limited Span cases) This incudes the effect of RE NO.
5. Prop Dia and Pitch, (I am trying to improve the simulations for actual
design of props, i.e. Doring, Andriukov etc. but am not yet happy with
the results).
6. Motor length (No of Strands)
7. General Layout i.e. Moment Arm, TP size, CG position, Static Margin etc.
(NOTE. I can also get quite good approximations of resultant Decalage).
8. The effect of Temerature on Rubber Power and Sinking Speed.
9. The effect of Elevation, (Height above Sea Level), on the sinking speed
and Climb
Height.
NOTE.
The Program now has a semi iterative analysis, (using 'SOLVER'), of the
relationship between Glide Velocity, CD, CL and RE NO. e.g. CL (at Max
CL1.5 / CD) , which is effected by RE NO. then effects Glide velocity which
in turn can change the RE NO again. This then also effects the CD and the
CL/CD. The new version allows for this.
I have also, recently been working on the effects of Airfoil Geometric
Parameters of the Wing.
i.e. Max Camber, Max Thickness and even Position of Max Camber. This is a
tricky area to pin down but I am now getting results quite close to what we
would expect in practice. This is an area where feed back is specially
useful, of course and I have already had some useful info to help improve the
modelling of these effects.
The 'BASS' MODELS
The program has been tuned to use, as a basis of comparison, the following
models:
F1B
Andriukov's AA30 . (Estimated mean Still Air Performance ca 350secs. Climb
Heighty ca 300ft at 150ft Elevation and 17deg C ) You can argue with this
but the important thing is the comparative performance, when we change a
model etc.
F1G
My own Linda Mk 8 (14.5dm Wing, 500mm prop.). I am fairly convinced that
this will do ca 175secs, Climb Height ca 135ft. in the same atmospheric
conditions as above.
One of the problems we have had is: To get good results for Climb Height. I
have used the CD in the prop calcs to tune the results. This has meant
using much higher values for CD (Prop) than are probable. We think the
reason for the discrepancy is the fact that the simulation is based on an
Optimum climb angle and a straight flight path. Neither of these things are
correct in practice !! We are planning to revert to more reasonable
values for CD and to:
1. Increase, substantially, the Model drag during the climb. Side Slip,
Inertia effects and even Prop Wash are probably quite heavy on drag when the
model is turning during the climb. (One thing we discovered was that, to
reduce the climb height you have to increase the model drag by a surprisingly
large amount to make a difference.)
2. To change some of the climb speed and angle results in the climb analysis,
to more closely approximate the models inability to fly long at the Optimum
Climb angle due to it's constantly trying to adjust to a lower and lower
Torque, etc.
I have also done simulations on all the other main FAI classes, but the
for the latest Versions I have rather concentrated on F1B and F1G. If there
is any interest I will try to bring the Simulations for F1A, F1C, F1J. F1H
and Open Rubber up to date, using all the new parameters. Time permitting of
course.
One final note:
Do not expect to make any dramatic advances in performance by using
simulations. I have 'tuned' all the data to try to fit what we already know.
Most FAI models are more or less at the limit of their 'potential'
performance already. They just need good rubber/engines and perfect
trimming. Where the simulation may help us is in developing models designed
for future Rule changes. However the simulations can prevent quite a few
fruitless design ideas being attempted. For example, I had a theory that
a 'Flapped' F1B would gain a lot extra on the burst and reach a substantially
greater altitude. I quickly droped the idea, for better or worse, when a
quick simulation showed a height increase of less than 0.2 m. !!!
Sincerely yours
Peter King
[Peter - you did not say where to get it ? Did you want to put
it on the SCAT Web Site ? ]
AmCup F1B
=========
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Roger,
The F1B competition is very close this year. The Patterson results with the
George Batiuk and Blake Jensen tie adds more suspense. I have triple checked
the contest results, bonus points and math totals. I discovered 2 errors. I
did not add the 5 bonus points for the 18+ entrants to the Intercity contest
results. This had no effect on the top 5 because Paul Crowely's corrected
score of 20 points was still lower than his two other scores at Muncie (per
the AmCup rules). This will help Paul if he ends up in a tie. The second
mistake was in my Excel formula which gave Al Brush 1 too many points. His
correct score is 103.
Here are the correct scores. The second score in parenthesis is the flyer's
fifth next highest score which would be used to break any first place ties
(per the Am Cup rules). The scores in the brackets is the score the flyer
can improve upon by flying at the King Orange.
I'll be doing the same for the other events but I don't believe them to be
as critical as the hotly contested F1B race. Please put this in the SEN so
these F1B flyers can figure out all the possibilities and decide if they wish
to fly to Palm Bay and test their fate with the Y2K bug.
As usual, if anyone has any corrections or wishes to have the EXCEL 5.0a
results via e:mail, please have them contact me at This email address is being protected from spambots. You need JavaScript enabled to view it..
Crowley, Paul 104 (20) [16]
Sessums, Herb 103 (23) [25]
Brush, Al 103 (21) [22]
George Batiuk 85 (11) [22]
Ghio, Walt 71 (0) [0]
Woods, Dick 71 (13) [15}
Should George Batiuk win the Patterson, he will drop 11 points and add 30 for
a net total of 104 with a tie breaker remaining (11), the score he can
improve upon at the KO remains [22].
Tom Coussens and I have decided to extend the 45 day tie break rule so George
and Blake can decide the winner of the Patterson in the most Sportsman like
way. We have extended the 45 day rule in the past and even this year. We
will however strictly enforce this rule in 2000. We will also propose an
AmCub rule change to clarify the current rule to the SCAT membership for vote.
Thermals, JIM
.......................
Roger Morrell
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