SEN-522 December 25 2000 Christmas day

News and Reports 2000 - second half
SCAT Electronic News 25 December 2000 issue 522 Christmas Day

Table of Contents
Towhook Position and Towing Stability: 2 Sympo Articles - Thornbery
Livotto / Canada Cup - Ackery
Kerger's Xmas card
Don Chancey redux - Ramrod250
Thanks - Weinreich
Tow Hook Position - Andresen
Tow Hooks and Weaving - Bogie
Zaic's HooKs - Toto in KS
WC 2001 and Lost Hills Info
For those without Excel... - Hines

Towhook Position and Towing Stability: 2 Sympo Articles
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Allan Brocklehurst, "A Quasi Static Analysis of Model Glider Longitudinal
Towing Characteristics", 6th Ann Sympo of the NFFS (1973), pages 16-20.
Major conclusions are 1. get towhook closer to CG than is typical, 2. CG
position doesn't matter much, 3. the analysis of the problem is complex.

Andrew B. Bauer, "Tow-Hook Position Effects on F1A Glider Steering", 13th
Ann Sympo of the NFFS (1997), pages 15-20.
Major conclusions are 1. stabilizer angular setting on tow approximately
same as glide, 2. vertical position of tow hook high as practical on
fuselage (note Brocklehurst has similar conclusion), 3. hook about 0.2
inches ahead of CG for optimal towing and steering, 4. flaps not useful.

I also recall that there was a re-publlished study of kite stability in
perhaps one of the Sympos, Aeromodeller Annuals, or
Free Flight Forums. I remember it as fairly detailed and done for the
military when kites had military uses for lofting a radio antenna from a
lifeboat. Does anyone know where this was reprinted in the free flight

Livotto / Canada Cup
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Roger ,
You are right, the Canada Cup does now appear on the FAI calender for 2001.
I see now what the problem was, when the calender first came out at the
beginning of the month the Canada Cup did NOT appear on the calender, (it
has since somehow snuck in there ), hence my confusion.
Thanks for the clarification.

David Ackery


Seasoal Greeting

Seasonal geetings to all SEM readers. Thanks for the cards and
greetings that you sent to us, they are very much appreciated.
One of the blessing of SEN and flying FAI classes is that we
get to meet so many great people. The downside is that we never
seem to be able to spend as much time with people as we want to.

Happy Holidays
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To all our customers, friends and supporters

We want to wish you a very Merry Christmas and a healthy and prosperous
new 2001,



Kerger's Xmas Card
A couple of issues back we got an electronic card from Terry Kerger.
I said that I would send it as an attachment, but it turns out
that it is about a 1 MB. So I will put it on the web site.

Don Chancey redux
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More about Don Chancey, for SEN:

I have been in communication with Marilyn Chancey, Don's widow, and I will be
a caretaker of sorts for Don's Free Flight equipment. When the time is right,
I will collect it and evaluate its condition for possible resale to those
interested. I will advise SEN members when it's ready.

Evidently Don did not have life insurance, which has placed a financial
burden on Marilyn, along with the obvious emotional difficulty. Don's
equipment will be sold to help this out somewhat. I will take an inventory
and advise what is available, although much (if not all) will be for
sentimental-value only, since it is 1970s-1980s in vintage.

Don was a supreme competitor, prolific model designer, a wonderful technical
illustrator, and a brilliant craftsman. He was also one of my main mentors in
modeling, and I will truly miss him.

Jim Haught

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I want to John Lorbiecki for the kind words he wrote about me as Digest
editor. It's both as relief and with some sense of sadness that I leave
the post. But it takes up a lot of time and now perhaps I can build more
I'm sure that the new editor, Walt Rozelle,
() will do a very good job. He is an editor
in real life.
Finally I want to thank all of you who supported and contributed to the
Digest over the past 11 years. Without that help and support, there
would be no magazine.

Chris Weinreich

Tow Hook Position
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Happy Holidays to you, Lindy and all the SENers.

Towhook Position:

Interesting discussion. One thing that I never sorted out sufficiently was
vertical position of hook and glider design
on "feel" on the line. Desert Rat series with tip dihedral
was great on the line. In lift it would almost lift the tower
off the ground, while in a downer, it was hard to run fast
enough to keep it on the line.

Conversely the Dust Devil types with Vee, taper, sweep and
hook near wing root was always a mystery as to what the air was
like. In still air they seemed to have similar pull and were
between divergence and oscillation.

Any thoughts?

Tow Hooks and Weaving
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In the process of learning tow techniques, it is soon found that, if the tow
hook is too far forward, the model will weave left and right alternately.
Moving it back a little cuts down on the weave. Farther back, the weave
steadies out. Farther yet to the rear will cause the model to peal off to
the right or left without any return, hopefully not bashing itself.

It is not a mechanical thing at all. Purely dynamics - lateral-directional
dynamics due to wing dihedral, vertical tail volume and moments of inertia.

Best position is found by trial and error. Turn the model upside down, place
a screw driver under the hook and lift it up. If the rear of the fuselage is
down maybe 8 inches, it may be ready to start testing for a straight tow
position. Moving the CG with weight can cause unwanted pitching motions.

Bill Bogart

Zaic's HooKs
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Dear RowanMast,

The definitive article on the towline stability of gliders is to be found in
the 1957-58 issue of the Zaic Yearbooks. (Naturally!) It seems that the
Brits did a paper on the stability of kites and towed gliders and it was read
and abstracted by J. K. Querman. It can be found on p. 113 of that yearbook.

It goes into the phenom of oscillation when the towhook is too far forward
and divergence when it is too far aft. If a given design is stable on tow,
there is a region between these two extremes where the glider may be towed
stabily. However, on some designs the two regions overlap and there is no
satisfactory location of the towhook.

Jim O'Reilly

WC 2001 and Lost Hills Info

I have recieved some request for Lost Hills and World Champs
Info. Some people have tried to reserve at the Lost Hills
Motels to find they are full.

This is not the offical position by any any means but ...

As with any World Champs the organizers will provide an
accompdation package for teams and offical supporter. Details
of this will be coming out soon.

The AMA has reserved 50% of the rooms at the hotels
at Lost Hills for the offical teams. These will be
allocated when people make reservations. They have also reserved rooms
at Buttonwillow that will be used after the Lost Hills
motels are full.

Modellers from other countries have already reserved rooms. That
is probably the reason why it is hard to get rooms.

Lost Hills Motels

Days Inn 14684 Aloma St Lost Hills, CA (661) 797-2371
Fax: 661-797-2021
Motel 6 14685 Warren St Lost Hills, CA (661) 797-2346
FAX: (661) 797-2976

This bunch is at Buttonwillow - about 20 miles further

Buena Vista Motel 428 E Front St Buttonwillow, CA (661) 764-5722
First Value Inn 3810 Tracy Ave Buttonwillow, CA (661) 764-5207
Super 8 Motel 20681 Tracy Ave Buttonwillow, CA (661) 764-5117
Motel 6 20638 Tracy Ave Buttonwillow, CA (661) 764-5153
Good Night Inn 20645 Tracy Ave Buttonwillow, CA (661) 764-5121

Seaching on the Web gives accomodation at -
Mc Kitterick
Sanat Margarita

all with 25 miles of Lost Hills ! but I do not know of
anyone who has used them - Reviews from readers ?!

Just a little further is Baskerfield and Taft.

Super 8, Motel 6 and Days Inn all have national reservation
numbers - but I do not know what they are.

Unfortunately because of all the other things that I have to do
I cannot help people make their travel reservations.

For those without Excel...
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Since it seems several readers have difficulty opening files from Mr. Perkins
& others, which are Excel format, I can open the documents on the NFFS
website @, select "National Cup" from left column, then
pick the document you want to open. It will come up in
pdf format which requires=
Netzip's "Download Demon"(freeware I believe).
It is condensed quite small, but the magnifying glass icon will blow it
up to visual size.
Maybe this will help other SEN readers.

NOTICE TO Norm Smith, you should go to KOI loaded for Bear! Good Luck!

Merry Christmas to All and to All, a deesen pasa(or some such Hebrew saying!).

[Lee there is some issue with getting the very latest on the the
NFFS site. I assume it taakes some time to get it converted to
PDF etc - that is Bob Perkins asked be to get the latest up
as qickly as possible.

In addition when downloading from the SCAT web site sometimes
the file name garfed up. So when you look at the
attachment and it says it is Xmas.gif - for example -
but when you come to save it it gives some bizzare file
name. Replace that name with the one you first saw e.g. xmas.gif
in this example.]

Roger Morrell