SCAT Electronic News 3 Aug 1998
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- Category: Archive 1998
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SCAT Electronic News 3 Aug 1998
Table of Contents
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F1C Grab Bag - Sky King and Koster
Air Sports International - August Issue
Frank Zaic's Birthday - Sal Fruciano
More on Timekeeping - Cenny Breeman
Message from Argentina - Daniel Iele
Weighty Comments from Hermann
F1C Grab Bag
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Sky King and Thomas Koster
Dear Scat Man Morrell:
the following is a most informative letter from Koster. You can judge what will
be of interest to your Scat Web. Thomas and I corresponded a bunch during the
early days of flapper experimentations in the sixties. We also learned early on
that "to live by the bunt can mean to die by it." About the time he won the
W.C. in Denmark I was switching over to the folder concept, and thus naively
plopped into the middle of a quagmire.
According to Thomas's range finder his flapper is getting 17 % higher than
other illuminaries. That is a tremendous differential. Verbitski would have to
use his gearing system to try and close that eighty foot gap. 160 meters is
stunning. In "real" figures that is 541 feet. With an actual 4.6 engine run
that translates to an AVERAGE velocity of 117 feet per second! 460 feet would
be more in line with previous published estimates and that lesser figure still
means a stunning average velocity of 100 fps! These things must be going
faster than suspected at cut-off....but then there is the extra altitude gained
by the bunt to be considered, and that may put things into more reasonable
figures. I'm admittedly throwing up my hands in confusion.
It is interesting that Leonid's "Blazing Pelican" folder is climbing with the
regular ships. It should be faster as his folded wing is quite a bit smaller in
span than the usual folder since he uses extremely large low-angled "tiplets"
that are hidden away inside the wing's undercamber during the climb. It is
difficult to assess the drag of these thick symmetrical sections in actuality.
They look surprisingly good in the wind tunnel and computer simulations, but if
flow separation occurs the pressure drag can be enormous. I turbulate mine as a
manner of course after having made some whirling arm tests. In fact I keep
vacilating in my opinion that the drag is a lot higher on highly cambered
sections during the climb than is usually appreciated.
Koster reports that the folder's glide is merely so-so. Martin Gregorie's
report appearing a few weeks ago indicated that the ship was over-reaching on
trim and was in fact mushing. That would certainly confuse any assesment. Since
Nordics have not yet adopted F1C power sections as their 'foil's of choice I
would still put my money on the plus 6% mean cambers. It does sometimes appear
a crap shoot though with the typical FAI section allowing the plane to zip
along at a higher Re and thus perhaps gaining an edge there. But the flapper
with its high Cl would suffer the same disadvantage as the folder in that
respect. I can't imagine anything else extant having a lower sink rate than a
proper folder.
It seems that the Europeans use the bunt as the engine cut-off indicator...as
our last team discovered to their dismay after recieveing unwarrented overruns
through using delayed bunts. . Something needs to be done in that area for
sure! In any case the folder can be bunted. It would be even more visually
obvious to open the wings at engine cut-off as an indicator-- but the timers
might be confused by all the shattered debris sifting down from the sky.
Thomas gives folders the kiss of death as far as being a competition airplane
is concerned. Interestingly enough Verbitski passed the same judgement on
flappers after his experimentations with such. I like those opinions 'cause it
means a lack of pressure to ban either. My strategic move is now to push to ban
Thomas's engine and prop.
For the record, I will advise Thomas to consider clear Mica Film,dyed for
visability, as an answer to puncture problems. I don't think there is anything
tougher. The stuff may suffer a ghastly bash-in, but a touch of the heat iron
pulls it back to serviceable life. Amazing material....the clear, that is.
With all the preamble out of the way the following is the main menu:
Bill Gieskieng originally wrote to Thomas Køster the following:
> ...Just got my copy of the NFFS symposium report that featured your
> Excalibur as one of the models of the year. Steen's photos were awesome.
> The airplane looks gorgeous and the construction features overwhelmingly
> intimidating to mere mortals. At first it depressed me to realize how
> far behind I am, but after a good night's sleep it inspires me to work
> harder--albeit at a more primitive level.
>
> I hope you have the time to do Excalibur proper justice with some
> serious flying.
>
> Please pass along my best to Steen.
>
> Bill Gieskieng AKA This email address is being protected from spambots. You need JavaScript enabled to view it.
>
> Hi Bill.
> Good to hear from you again. I just came from vacation and saw your e-mail.
> I haven´t seen the NFFS Symp. myself - but glad to hear that it came out
> right
> The model isn´t right however. The Pre-preg-covering foil isn´t good
> enough. It is actually too stiff on a too soft core - gives structural
> problems in hard landings. So my new model has a build-up wing with
> carbon/kevlar D-box and a lot of carbon capstrips in the flap itself. Weight
> comes out pretty good. Covering material is a problem though. I have used
> mylar 1/2mill - but holes comes pretty fast in the covering in landings
> etc. What are you using now. There are a lot of covering materials in US
> that I am not familiar with - do you know of any good ones ?
> I flew the new model at the European Champs in Portugal recently. Very
> tricky weather - so I actually dropped two flights - on otherwise 7 perfect
> climbs. With my new rangefinder (Bushell - laser) I did check a lot of
> climbs at the champs. Ken Faux, Stafford and Verbitski usually had between
> 130-140 meters attitude. The russian folder (Fusiev) : 3 recorded flights
> with
> 148 m as the highest - two flights of 138 and 140. I had only two
> recordings on my own model - both 165 meters ! So it isn´t bad at all.
> Folders : Fusievs model is facinating - I truely think it is fantastic -the
> way it is made and trimmed. It accelerates good in the beginning but stops
> acceleration quite early and settles. My measurements tells me that it
> doesn´t get any higher than the normal models. And there is no reason to
> assume that it has a better glide. It didn´t seem so. A bigger problem is,
> that the model doesn´t bunt after the engine stop. It is a real problem for
> the timekeeping. The concept is great and interesting - but hardly the way to
> go to be competitive.
> Right now I have wild plans for a new model. New molds for the complete
> front-end and a new type of hinges for the flap (the new idea is always the
> best - god knows I must have been through all possibilities). I will inform
> you about that later if you are interested.
>
> Right now I have a new design-drawing program called SolidWorks. It is
> difficult but GREAT. You can draw a cowl for the engine - and have the
> mold milled directely as female molds !
>
> Good to hear from you - keep in contact.
>
> Your friend
> Thomas
[Editorial Note]
Alexander Andriukov also uses SolidWorks at Aerovironment and likes
it very much.
He finds it much faster than AutoCAD to do drawings of his model parts.
Air Sports International - August Issue
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Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Dear Friends,
The August issue of Air Sports International netzine is now on-line.
Apart from carrying the usual articles/features we have in-built a new
feature in this issue. You will now be able to download the August issue on
to your hard disk and view the netzine off-line. You can down-load the
August issue by clicking on the 'OFF-LINE' button on the cover page.
Detailed instructions are given on the site which opens up on clicking the
"OFF-LINE' button.
The netzine is available, as before, at:
http://airsports.fai.org
Do write in your comments.
Atul Dev
Editor-in-Chief & Publisher
Air Sports International
This email address is being protected from spambots. You need JavaScript enabled to view it.
Frank Zaic's Birthday
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Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Roger,
on our return trip from the 'composite' seminar, Ann and I took the
opportunity to visit
with Frank and Carmen Zaic, on the occasion of his 86th birthday. We are
pleased to report that Frank and Carmen are both in good health and good
spirit. But seem to have lost contact with many of their friends, and current
aeromodel events.
I urge our worldwide friends, some who know Frank personally, others through
his Zaic yearbooks to drop Frank a belated 'happy birthday' message at 16915
Kinzie,
Northridge, ca. 91343,
during our visit, Frank related the story of thework he did with naval Lt.John
Alden in the early thirties in creating our A.M.A. organization. Frank was the
first employee, edited and published the first issue of model aviation
magazine, along with the work required to turn out his yearbooks.
Sal Fruciano
Timekeeping (again)
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Hi Roger,
The last few weeks everything has been said already about the problems
associated with timekeeping.
In my opinion there is very little we can do immediately, so the best thing
that remains for the moment, is to ensure that we get the be timekeepers
available. And these happen to be the fliers themselves. These are also the
people that complain about the timekeepers, but we do not want to do the job
ourselves. We are always busy; retrieving for somebody else, watching,
chatting.
Maybe I am a bit hard on this, but let me illustrate: In a couple of weeks
our club is organising the Bilzen International contest .
(http://ping4.ping.be/cenny_breeman/BI/Bilzen_International.shtml Formerly
the Pampa Cup in Helchteren, Belgium)
So far I have received 30 entrees from which only 3 indicated that they were
willing to help us out with timekeeping. We do ask for it specifically on
the entry form ! And believe me, the ratio has always been like this in all
the previous years.
Why not volunteer for timekeeper on the other day of the contest when you
are not flying ? The organisers would love it.
Don't misunderstand me. I do not believe that the problems will be
completely solved by it and I am not against any change that can improve the
situation, but it is the best we can do so far and we can do it tomorrow.
Regards,
Cenny Breeman
Priestersweg 3
3621 Rekem
Belgium
(+ 32 (0)89-721144
Fax + 32 (0)89-721144
Email This email address is being protected from spambots. You need JavaScript enabled to view it.
Message from Argentina
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Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Hello Roger:
A couple weeks ago I read a message regarding the posibility of running an
American F.F Championship, in the same way the European Championship are.
That is, bi-annually in alternate years with the World Championship.
In South America we run, also bi-annualy, the South American Championship
(all Model Airplane classes, F/F, R/C etc.),
This is a country team event, that is run in parallel with what we call the
Panamerican Championship, an individual open event.
For F/F there are different poles for country teams and individuals.
We propose to explore the possibility of running a F/F only Panamerican
Championship.
We estimate that only three countries in America are able to send full
teams: U.S.A, Canada and Argentina. Partial teams may come from
Brasil,Chile, Uruguay and Mexico.
If run the way I mentioned (parallel country team/individual), an
acceptable concurrence may be expected.
Country Team members qualify for both Panam competition and Open
International, individuals for Open Int. only.
This could be an World Cup event. (Ask Ian Kaynes).
If we further advance discussing and polishing this idea , Argentina would
make the formal proposal of hosting that event for April or May of year 2000
in Embalse,Cordoba.
Daniel H. Iele
Presidente
Federacion Argentina de Aeromodelismo.
Weighty Comments from Hermann
-----------------------------
Roger,
Some comments re 30 July 1998.
Attempts: Originally the delayed flight was introduced for power models
flying unlimited flight time to not penalize the competitor if a gust
caught the ROG launch etc. It was thought that any flight less than
double the engine run was adversely affected by some act of God & should
be given another chance. Now with models capable of 1.5 to 2.5 X the max
it makes less sense as anything less than 180 has obviously been
adversely affected. Based on this it makes more sense to use 179 sec as
an attempt limit than 20 sec.
LIMITING PERFORMANCE: Why is added weight always suggested as a
performance limiter?
Often it is claimed to level the playing field. Nothing could be further
from the truth.
In F1A added weight plays right into the hands of the athlete as it helps
the bunt.
In F1B the rubber becomes even more critical.
Heavier F1C's would make a gearbox actually useful and variable pitch
almost mandatory.
In all cases, as was pointed out, models would be adversely impacted by
impact. In addition, the weight would eventually be turned into thinner,
longer, truer wings so much of the performance would be regained.
So the bottom line is that models would be harder to fly, there would be
more emphasis on atheletic performance and power sources. They would
also be more breakable. Do we need this?
Bob White has a simple cure, at least for F1B, resurect the wingtip &
prop ROG.
Actually, the F1G, F1J approach of low weight, low power and no size
restriction seems to work fine in practice with simple models being
competetive with the high techs.
If any changes are implemented with the idea of limiting performance, I
hope they are thoroughly analysed for consequences (now that would be
refreshing).
Does anyone really think F1A, F1B and F1C are too light?
Thanks,
Hremann Andresen
.............................
Roger Morrell
