SEN 741 - 18 Sep 2002
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SCAT Electronic News 18 September 2002 issue 741
Table of Contents
=================
Re: "super max" - Gregorie
Polyaccrylic By Mimwax - Wilkinson
Timers Nightmare
Supermax - Bogie
Propeller Research Project - Barker
re Frank - Bryant
Thanks to Mark - Segrave
fuller plast paint. - Wilkinson
Re: "super max"
===============
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> The new rules are created for convenience of the organizers of
> competitions.
>
Don't be too certain about that either: ask somebody who has
programmed the supermax option into a database-based scoring system.
It's not easy.
Maintaining acceptable system performance and avoiding row locking
contention is no joke: the fly in the ointment is the whole-of-event
scan that is now needed to determine how many rounds have been flown
before adjusting scores for dropped flights. This assumes that the
scoring system does not annoy the CD's assistants by forcing them to
tell the system when each round has been flown.
Martin Gregorie
[Martin, contest 'management' is no different from any other
management and often make strategic decisions without IT considerations.
The operational question of flyoff management was the overiding
consideration.]
Polyaccrylic By Mimwax
======================
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Rodger.
I Read A Article That Bob Hanford Wrote In The August
Sept Issue Of The NFFS Free Flight Mag.
It Stated That This Polyaccrylic Could Be Used To Fuel
Proof The Front Ends Of The Gas Models.
Can Anyone Tell Me If This Stuff Is Any Good?
Will It Work As Good As The Epoxie Paint?
Thx Don
Timers Nightmare
================
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Considering building one of these. Do you have any advise to offer if I
enlarge to 72 inches
Thanks,
Peter
Supermax
=========
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The way to get rid of the supermax is to convince your F1 Committee member
that you want it deleted. If enough committee members get the same message,
it would be turned down in the next meeting in March.
The US committee member is Dan Tracy, email This email address is being protected from spambots. You need JavaScript enabled to view it.
Bill Bogart
Propeller Research Project
==========================
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Hi Adam
>From the clear summary of your thoughts so far it seems to me that, with
the help of Bob Langelius, you are well on the way to a thesis already!
I am sure that, in this Internet era, you have all the standard (full
size) references to Minimum Induced Loss (MIL) propellers as inititiated
by Prandtl, Betz and Goldstein. In particular the work of Professor
Larrabee whose design of MIL propellers for man-powered aircraft did so
much to stimulate interest. Larrabee, a model builder himself many
years ago, gave an influencial paper at the 1977 NFFS Symposium and
followed up in 1979 with a further paper giving his design calculations
for a 'Wakefield' propeller. I assume that you are also familiar with
Dr Martin Hepperle's website in Germany which, amongst other good
things, has an on-line design process for MIL propellers.
I have not the energy to check on all the propeller references in the
Sympos - perhaps someone with a good indexing system could do it if
required. To be honest I do not think that most of them would take you
further forward but there are a couple I recollect which may be of help.
First in the 78 Sympo, Professor J Earl Bailey of the University of
Alabama gave results of wind tunnel tests he had made, whilst working as
consultant for the US Army, on propellers for mini remote-piloted
vehicles. Second, in the 1980 Sympo, Don Monson gave a paper on testing
power propellers and considered in detail the use of a control line
aeroplane to obtain results. This would appear to have advantages:
cheap, easy to observe, small flying space required, easy to measure
speed.
A random observation. Would it not be easier for your researches to
power the propellers with electric motors instead of internal combustion
engines?
In England the British Model Flying Association runs a competition each
year in which Universities enter a team of students who have to design,
construct and fly a model airplane that will lift a large payload. The
design calculation are assessed and awarded marks towards a final score.
The weight lifted counts towards the final score but you get no credit
for weights lifted in excess of the design weight. The reason I mention
this is because for the last two competitions the Cambridge Team have
used the most beautiful MIL propellers. These have been designed and
then manufactured on numerically controlled machines in the university
workshops. I know that they did static thrust testing at least so it
may be useful to talk to them. If they would loan one of their
propellers for you to test then that would be something else! I am
pretty sure that I can get a contact number from the competition
organizer if you are interested.
A final thought. I have no personal experience but, if you are testing
on take off performance, I think you might find yourself spending more
time on undercarriage design and ground handling than on propellers. I
would seek advice on this early on.
My best wishes for your project
Regards
John Barker - England
re Frank
========
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Re Frank Zaic.
"
"Through these doors pass some of the worlds Greatest aeromodellers"
I wasn,t in that class,but went in and meet Frank. It was in the early 1950,s.
I was hitch hilking around the world.,model flying between Jobs.
The shop was upstairs in New York and very small.
Frank had just taken up a new hobby,which he refered to as "horse back riding"
Frank Ehling was there and I think he may have worked for Frank.
Although I didnt see anyone buy anything all day. Frank Ehling was
very intrested in Australian birds.
Paul Phecan came in and I had a yarn to him about the "Flying
Aces,Flying Flea"
Which he had designed. I had build one back home in Australia.
Aeromodellers came and went all day,and at the end of that day I had
meet some of the worlds great aeromodellers
Adrian Bryant,
Thanks to Mark
==============
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What a great medium SEN is! An almost immediate response to my query about
sag on indoor model wings from Mark. His comments are interesting in that he
says that sometimes the high point moves rearwards. I remember some time ago
that the indoor airfoils in the pristine state had marked "flap" at the
rear. With the billowing of the film to the rear, this must have increased
the flap effect. This effect makes the airfoill unstable and IPSO FACTO the
ship, which would then require a greater margin of stability and/or a much
larger stab it would seem. With the current use of a simple arc of a circle
as airfoil, the marked flap at the rear has been eliminated. Now the
billowing of the film in flight flap effect is manageable.Another result
seems to be that the camber of the foils has been reduced, although this may
be due also the increasing wing area employed, as lift is a combination of
area x camber. Thanks again, Mark!
Regards
Mike S
fuller plast paint.
===================
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Roger.
I Need Some Fuller Plast Paint.
I Was Told That Someone In Washington Was Selling Some
Of This.
Would Who Ever Is Selling This Please Contact Me At My
E Mail Adress .
Thx Don.
.................................
Roger Morrell
