SEN 665 - 12 Jan 2002
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SCAT Electronic News 12 January 2002 issue 665
Table of Contents
==================
Free Flight: Something for Everyone - Bauer
Building instructions - Segrave
F1C cost - Boutillier
Another Look at Muncie - Ioerger
Desert Challenge - Joyce - Bogie
Desert Challenge 2002 - Bogie
F1C rule changes - Mosely
Glide Testing ? - King
FAI Power is Too High = Mattes
TMOY - Roberts
Motives - Shailor
Geared F1C's - Wright
F1C Height Measurement - Edge
SIFLEET LETTER - Acme
Free Flight: Something for Everyone
====================================
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Free Flight: Something for Everyone
Sorry, but I'm an optimist. I see so much diversity in all the
events, official or non official, that free flight has to offer, that
there is little need to worry and fret over rule changes or the death
of free flight. Pick an event you like - big or small, expensive or
cheap, slow, medium or fast, high tech or low tech, and just go fly
and enjoy the wonder of the thing floating in the air!
Here in the US we have just about every kind of free flight event
there is, and for those in other parts of the world they are still
free to build any type of model they want and perhaps if enough people
show interest some of these other events could begin to be introduced
to some competitions. I'm sure flyers here in the US are happy to
shares rules for and plans for this big variety of airplanes.
We have old timers (slow), nostalgia (medium), AMA & FAI power (fast).
We have big high tech gliders (F1A), and small low tech gliders
(catapult), price ranges from $2000 to $10. We have big, medium and
small rubber, indoor or outdoor, scale or non-scale. The list goes on
and on. Heck, there is even magnetic slope soaring coming to Lost
Hills! You can fly indoor models in your living room, hand launch
gliders or rubber models at a park, or large models on the best fields
in the world. You can travel, or stay at home. My son & I have been
flying 4 inch balsa micro gliders in our house - they weigh 0.1
grams, cost about $0.20 in material, and can do about 10 seconds in a
room. Not an official event, but fun! We also like F1A gliders with
computer controlled timers, servos, gadgets, composite materials,
etc... Each of these extremes is fun in its own way. Sometimes
you're in the mood for one, sometimes the other.
As for F1C, I say leave it alone! Gerhard Aringer already pointed it
out - the top 3 places at the World Champs were separated by only 8
seconds out of 378 seconds, and each model was in a different class of
technology. One was geared, one was a folder, and one was "normal".
All three of these unique models were winners, and some of the biggest
cheers of the contest was for Leonid Fuzevev and his folding wing
masterpiece. Bring on the innovation! This is where is belongs.
This is what these events are about. If someone through his
creativity and hard work comes up with a new innovation that gives his
model an advantage, then more power to him! The challenge then goes
out to the rest of the world to improve on that innovation or come up
with something better! It doesn't matter how many people fly this
event as long as those that are doing it enjoy it. There are plenty
of events for the rest of us. Most of us enjoy watching and reading
about the developement of these models and I believe that the F1C
flyers are very smart and will continue to innovate and work on new
ideas and new gadgets. Sorry, but I think the answer is not to change
the rules, but to go out and build a better airplane...
Finally, the great equalizer in this sport is thermals, or lack of
thermals. It is still possible for a competitor with a very
inexpensive airplane to do well if he knows how to pick air. The best
airplanes in the world still drop like bricks in bad air, and we've
all seen this happen. About 99% of the flying happens when there are
at least small differences between the good air and not quite so good
air. So it is great to see a wide variety of airplanes that can still
compete against each other if they are flown well.
So pick an event you like and go fly. There is something for
everyone. Things change over time. People change, technology
changes. Some free flight events may increase, more may decline, but
that's OK. Just cast your eyes toward Heaven and watch something fly.
Ken Bauer
Building instructions
=====================
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I amtrying to find someone to build the latest version of my twin CdH
"MIG?NON". This is preparatory to publishing the full size plan with these
instuctions in a future issue of Anndre Schandel,s VolLibre, perhaps later
this year. I would supply a plan with full size airfoils and all the
nnecessary details(I hope!) construction requires.
F1C cost
=========
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In last issue of SEN Doug wrote about disinformation, saying
that the extra cost of a geared engine is rather 380-400$
than 750$ as stated elsewhere.
Let's face the reality:
A Nelson 15 +spinner costs 245$. You have to add a prop.
a very good one is available from Alex Mikhailenko (Ru) for
30$ . Total cost = 275$.
On the other side a Hummer costs 790$ + 85$ for necessary prop
tools + ~ 80$ for a McBurnett prop. That is 955$.
955$ - 275$ = 670$ and not 380-400 as stated by Doug.
This is not disinformation, the truth is 670$.
One can also say that 955$ is 3.47 times 275$.
I am fed up with disinformation.
May I say that I fully support Bob Sifleet's position paper and
that I am much confident in Sandy Pimenoff's action.
Bernard Boutillier This email address is being protected from spambots. You need JavaScript enabled to view it.
Another Look at Muncie
======================
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Hi Roger
I would like to address the denigration of the field at Muncie. I fly
Wakefield there three or four times a year and I prefer it. It is an easy
three minute field if the CDs will locate the flight line properly. With
the prevailing South West wind, all it takes is to fly from up by the hog
barns instead of from the hole down behind the trees. This gives three
minute flights and DT time over AMA property without getting near the
cemetary or the irate neighbors. For some reason unknown to me the CDs like
the black hole in the corner and we sheep like modelers follow meekly along.
Properly used, Muncie is the third best free flight field in the nation
after Lost Hills and Palm Bay and it doesn't have Valley Fever or
alligators, just beautiful mowed grass.
Tom Ioerger
Desert Challenge - Joyce
========================
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Without a doubt, Doug Joyce has developed his canard configuration to a
greater performance than seen to date. The change has been in increasing the
span of the canard surface by maybe half. The climb is the same as before
but the glide is far slower. He is the only one who can fly at Taft without
worrying whether his ship will augur in. No one else seems to have the guts.
Bill Bogart
Desert Challenge 2002
=======================
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The 32nd Dolby Desert Challenge was held at the Taft site on January 6 and 7,
2001, requiring a bonfire for warmth during and after the banquet in the
dark. No wood available at Lost Hills flying site. Fortunately, SCAT has a
mole, Peter Allnutt wintering in Taft, who rounds up great piles of large
pieces of wood no one else can possibly lift.
The contest is a team challenge made up at sign-in time or relayed to the CD.
This year we used two man teams. All six FAI events are offered and no one
entered F1J.
Flying starts at about 1 PM on Saturday, getting in three rounds before the
sun sets, after which the models were put away and preparations were made for
cooking the meat and potatoes on grills and starting the bonfire for the
on-field banquet. A great fire is a real pleasure and a necessity as the
temperature drops down to freezing during the night at this time of the year.
The day quickly warmed up after sunrise. This time, Peter really cleaned up
Taft by finding all the loose lumber, wood, and telephone poles not standing
up correctly. The fire kept us at least 15 feet from the edge of the coals.
There was no problem starting the fire Sunday morning as the coals were
causing metal to glow red and we were able to generate a thermal with the
great fire.
The weather was pleasant with wind up to 5 mph by 10 AM both days.
Temperatures starting at mid 30's F working up to mid 50's.
Fog was lurking the first day, but never showed its white mantle on Sunday.
A note about one of the contestants, A. Nother. He really does not exist,
but his scores are taken from other flyers in the same event in an ordered
random way as a way to let individuals compete
F1A
Brun, P 180 180 180 180 180 180 180 1260
Allnutt, P 180 180 180 167 180 180 175 1242 2502
Smith, N 152 174 180 180 180 180 180 1226
Nother, A 180 180 180 105 78 180 180 1083 2309
Limberger, R 180 180 180 180 180 900
Diez, H 180 180 180 180 146 167 180 1228 2113
Joyce, K 130 132 180 105 78 112 180 917
Kozlyuk, D 91 180 170 180 76 180 180 1057 1974
F1B
Pratt,J 162 180 180 180 180 180 180 1242
Norvall, L 180 180 180 180 180 180 180 1260 2502
Hotard, A 180 138 180 180 173 154 180 1185
Secor, R 163 100 180 81 155 155 155 989 2174
F1C
Joyce, D 180 180 180 180 180 900
F1G
Pratt, J 113 120 120 120 120 593
Norvall, L 120 120 120 120 120 600 1193
Burt, B 120 120 110 120 120 590
Nother, A 120 120 120 120 110 590 1180
White, B 66 120 120 120 110 536
Gorban, E 120 120 120 120 120 600 1136
Hotard, A 120 73 83 120 120 516
Secor, R 120 120 120 120 120 600 1116
F1H
Smith, N 120 102 90 106 120 556
Norton, B 120 120 108 89 97 534 1090
F1C rule changes
=================
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"Except for a moderate power loading increase some 30 years ago"
50% was 'moderate' ??? Be glad if wasn't 'significant' ......
Glide Testing ?
===============
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Anyone interested in joining in with some meaningfull gide testing?
I have been trying to solve some of the problems associated with gide
testing. I have also designed a draft of an Excel Spread sheet that can
collate the results and even draw out airfoil polars directly from the test
data. Excel will make all the neccessary calculations of induced drag et=
c
so you can simply test any wing and get the results at infinite AR. It even=
takes account of the taper ratio of your test wing.
Here is a sample of the main description of the method:
GENERAL DESCRIPTION
1. By using the spread sheet you can calculate the model weight require=
d
for a specific CL and Re No. so that you can use the data from a series of
test glides with a range of CL values whilst keeping the Re No the same.
This gives useful information on the polar of an airfoil at a specific Re
No. which can be kept constant by changing the weight of the model for each
new CL value test.
2. The model consists of a standard F1B or F1G wing mounted on a light
weight stick fuselage with a small and lightweight flat plate stab.
The CG should be at ca 25 to 30% so as to eliminate as far as
possible any lift contribution from the stab. Note that to do this
properly the CG should be varied so as to correspond with the position of the
wing CP, which moves further aft as the CL moves to lower values. This may
be an unnecessary complication, but should be born in mind, at least.
GLIDE TEST METHODS
Method 1. (Simple Glide Test, keeping the same weight, but with the Re
No changing with CL)
First enter the measurements and weight in the relevant cells in Excel.=
Next ballast to a set weight, (and therefore Re No, at optimum glide CL), or=
use a full model weight (e.g. 230gms for an F1B). =
Make a series of glide tests, timing the flight from a known height and
measuring the distance travelled. Several tests should be averaged, omittin=
g
any that seem out of the normal range, or show any excess phugoid
oscillation.
Take the results and enter the weight, height, time and distance in the
spread sheet. Next, make a further series of tests, altering the stab
angle to change the wing CL. At the lower CL's the launch must of course
be faster and the Re No will increase. You should be able to reach CL's o=
f
down to ca 0.3 or less before the model is flying too fast to be practicable=
.
At low CL the glide is steep and fast. You must launch accordingly and be
very quick with the stop watch. As the flight will be very short. =
(Note: The base case in the original program has been estimated only
but shows the necessity to launch the model faster and at a STEEPER angle as=
the lower CL's are approached). =
Method 2. (Advanced Glide Test, changing the weight for each series of
flights to keep the Re No constant, with changing CL) =
NOTE: It is best to have the Excel Program available on a Lap Top whils=
t
carrying out these tests, so that you can keep a check that the data for RE
and CL is consistent with your tests glides. Using the spread sheet, find
the weight required to keep the same Re No for a particular CL test glide th=
e
model, altering the stab angle until the test data gives roughly the correct=
CL in the spread sheet.
Using the same method as above, do a series of tests at different weight=
s
and CL trim conditions..Check on the lap top to see that the Re No and CL ar=
e
reasonably in agreement with the glide test trim you are aiming for, eg Re=
=3D
30,000, CL say 1.0, 0.9, 0.8=E2=80=A6. etc. =
The results will then give a polar of the airfoil at one Re No.
Although this will be rather time consuming, it should give a very good
airfoil polar at one RE NO, and even a series of, RE NOS. =
NOTE: If the Re is kept the same by altering the model weight, it
follows automatically that the glide speed will remain constant regardless o=
f
CL.
THE SPREAD SHEET
When you have entered the required data, (Just Weight, Height, Time and
Distance.) in to the spread sheet, =
Excel allows a value for CD par, calculates CD induced, with a correctio=
n
factor for the wing Taper Ratio, then calculates the actual Re No, Glide
velocity, V sink, CL/CD, CD1.5/CD and a derived value for CDpro (CD 2D).=
It also calculates the actual CL wing. The Spread sheet then automatically
draws a polar for CD pro vs CL. =
NOTE Using the simple Method 1. You can of course easily compare severa=
l
wings at close to their optimum glide CL, to see which wings, turbulators
etc, work best and also how critical they are to slight changes in CL. =
I can email the Spread sheet, a description of the indoor test method and
any other info to anyone interested. I thought this initial work might
inspire someone to think about doing some glide tests and taking part in a
world wide, co-ordinated data base of information. Indoor tests can be wit=
h
quite a limited space if the test method is used and refined in the light of=
experience.
Any thoughts would be welcomed. Isn't it about time we tried to get some
good data on airfoils etc. The tests could also lead to much better data to=
be used in simulation programs. I believe with better data we can start to
use simulations with more confidence, to see where we might look for improve=
d
performance in the future.
Peter King
FAI Power is Too High
=====================
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Hey FAI Power Fliers
I am sitting back here in Missouri building Zeeks and AMA Gas models =
while reading all this stuff about the too high costs and too high =
performance of F1C models. It really doesn't impact me one way or the =
other but would like to see the event prosper. There is one very simple =
way to restrict the performance of the engines. For years many auto =
racing organizations have required orifice plates on the intakes of the =
engines to keep the horsepower hence speed of the cars within the safe =
limits of the speedways. Use of a similar approach, restricting the =
maximum venturi diameter, could be used in F1C without immediately =
obsoleting anyone's engines or planes. It is also a super easy item to =
check on the field to ensure compliance.
I recognize that with time the engine designers would redesign their =
engines to regain a portion of the lost performance but if you all =
really want to control performance it seems like the obvious approach =
while still allowing innovation in engine and airframe design in all =
other areas.
Bob Mattes
TMOY
====
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Dear Roger
So far, I have not received any nominations from the rubber contingent =
for the 2002 Symposium Ten Models of the Year. Time grows near fellow =
flyers, so please get those nomination packets in soon so our highly =
qualified committee has something to do.
Please follow the packet format requirements found on the NFFS website, =
or get a hold of me if you have questions.
I must go out to my shop now to design and build a sure rubber winner =
for 2002.
Mike Roberts
Chairman TMOY
2435 53rd SW
Seattle, WA. 98116
ph 206-937-2740
Motives
=======
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Motives...
So let me get this straight.
The motive behind attempting to ban gears is not that performance is too
great, but that the proponent wanted to buy a couple, but couldn't get the
models before this coming October.
Maybe the order should have been placed earlier.
Bill
Geared F1C's
============
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I've been reading all the fuss over the geared F1C's in scat for it =
seems like weeks now. I've only just started flying F1C in Australia =
and fly a conventional model with foil wings. It's being made out that =
you now need a geared model to have any hope winning a competition; =
maybe I'm being naive but it seems to me that if I have a good day with =
my conventional model, and you have a bad day with your geared model, =
I've got you.
No matter how good (or almost how bad) a model is, if you put it in good =
air you max, and if you put it in sink you don't. The picking of lift =
therefore seems more important to me than the model. I agree that the =
price of geared F1C's is a bit steep (especialy over here with a =
conversion rate the wrong way around) and for me they are out of the =
question. But don't forget that there are other factors such as poorly =
set timers, bad launches and gremlins in the high tech components which =
will bite you at the worst possible moment.
I'm just going to have to rely on picking good air, launching straight =
and hoping for the best.
When does the difference in the models really matter? in the flyoff? =
I've just had a vintage model (pre 1954 plan) flight of over 45 minutes =
on the weekend in a flyoff; what flyoff time do you want?
We'll thats about all for now, I think I'll go for honing my flying =
skills rather than my typing skills.
Peter Wright
F1C Height Measurement
======================
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Mr SCAT,
The discussion on gears in F1C is running apace with significant differences in
the alledged performance advantages. I have seen comments in SEN to the effect
that :-
1) A geared model gets to the same height as an ungeared model on a 5 second ru
n in about 4.6 seconds
2) A geared model is only a few seconds better in overall duration than an unge
ared model
and more recently :-
3)A geared model in 5 seconds gets to the same height as an ungeared model on 7
seconds
I find these statements somewhat inconsistant - what is needed are facts.
I understood that there are a number of US flyers with lazer rangefinders capab
le of measuring F1C climb heights. Would anyone like to publish the comparison
between geared and ungeared models on the same run in SEN ? If the data isn't a
vailable (and perhaps even if it is) then I further propose that measurements a
re made at the MaxMen contest in February. Anyone willing to take this up ?
I appreciate this isn't a simple process. To get good data you would need to pe
rform a number of measurements on the same model and record the engine runs. Yo
u also need a resonable sample of models, both geared and ungeared - even with
different engines. Without this information I don't see how the current "discus
sion" can sensibly proceed.
Chris Edge
SIFLEET LETTER
===============
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I think Mr. Sifleet has stepped way over the line... Has this person
become so enlightened that he thinks I can't do my own thinking Should
I look to him the next time I want to build a new F1C model Gee
maybe I could have him balance my checkbook
It's real simple If I don't have the money I don't buy
it............... And Most Important I don't Whine about it One
more thing Get your facts straight Sifleet! Ron @ acmeaero
...............
Roger Morrell
