SEN 1004 - 21 Apr 2006

SEN 21 April 2006 issue 1004

Table of contents
Buy backs (or re-entry)?? - Lorbiecki
Found at San Valeers Annual - dp
Czepa's 1951 A/2 - Segrave
False start in F1A e-timers
Tiny Altimeter - Gewain
BFMA FFF - Dilly et al

Buy backs (or re-entry)??
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As a drag racer, I compete in what is called bracket racing. One of the latest
things in this style of racing is buybacks. This is when you lose first round,
you pay another entry fee and then get to go back into the race in the second
round. So, you get a second chance!

I was sitting here thinking about our typical contest (this would only be
related to AMA style events) and why not allow buy backs? I would think that
a competitor could fly his three flights and if he was not satisfied with
his results, you could pay another entry fee, CANCEL your first times, and
fly again. This would give you a second chance! Plus, it gets more money for
the contest sponsor. We have a limited amount of flyers anyhow, so why not
give them another chance at an event that they may think is their favorite?

Tell me why this would not work? Don't use the "Well, it has never been done
that way..." excuse. The more I think about this, the more I like it!!

John Lorbiecki

Found at San Valeers Annual
From: "Daryl Perkins"

Hi Roger,

Could you please post on the SCAT news. Someone left their
Streamer pole on
the field at the end of the San Valeers contest. If you are
missing one
please write Daryl at This email address is being protected from spambots. You need JavaScript enabled to view it. I will bring it to
the Big Al's

Regards, dp

Czepa's 1951 A/2
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I dialled up the site given by the 'Leeper' and found a long article
authored by Czepa and Erich Jedelsky, but in German together with a photo of
him holding aloft the ship and a shot of the stab and tail cross section
area fairing. There is also a reduced plan of the ship from what looks like
the old English magazine 'Model Aircraft'. The stab in the plan shows only a
single spar but in the photo of the rear end it has 2 spars. As it is a
milestone in the development of the A/2 glider, perhaps someone could
translate it into English??

Mention of the Aquila reminds me that the Toronto group ALL flew this ship
in the late fifties.They produced them from common jigs as is done(?) in
ther Ukraine or in a factory. It was claimed to do about 2:50 in still
air(!) but this design did not help the fliers as all finished well down
the list at the trials for the 1959 team. But the fuselage was very
vulnerabnle just behind the wing as it was made of a single layer of 1/16"
balsa and often broke during contest flying. Remedies were to move the
junction forward because just at the wing TE there was an abrupt change in
the amount of wood there, from hardwood plus balsa to suddenly just the
balsa. Perhaps extending and tapering the hardwood to the rear of the TE a
few inches would alleviate the problem somewhat so that the stresses are not
concentrated at one point. My thoughts at the time were to change the stab
SECTION for it was 'locking; the ship iinto the glide.and sometimes forcing
the nose down out of thermals with the resulting crash and broken boom (just
behind the wing,you've guessed). At the time, fliers and designers were
trying to obtain the maximum from the stab in the way of lift, hence the
high lifting section. Perhaps a flat bottomed section with a well rounded
nose would be a better choice now. Not kosher vintage/classic I know but
such a change/experiment might further our knowledge of the aerodynamics of
the A/2 glider.

The Montreal Club with 4 very competent A/2 fliers plus supporters went down
en masse to a contest near Boston in around 59-61 as far as I recall to a
military field carved out of a forest, arriving about noon on the Saturday
to find that a NEW flier had built a Spinne(his first model) and recorded
his fifth max as we pulled up!! As it was unlikely that the increasing wind
would abate and the runway was surrounded by trees, we all got back in the
cars and returned to Montreal. with a stop at a hill to flly a hand launch
contest with our A/2s!!

At another US contest,about 1960, I also remember a military man flying his
Spinne but with an all sheeted wing. It flew very groovily with that air of
being a very low drag plane, a kind of silky way of flying.Stab was all
sheeted too, and the ship was painted(?) silver all over. Dan Gregory
(Montreal) also built one all sheeted too and he and I had a great tussle
one very calm and overcast November day in 1960 recording 16 maxes between
us before failing light stopped play .

Mike S

False start in F1A e-timers
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In my recent test with electronic timers I have two
false start in the launching run. The bunt phase start
before release the line ( The model nose down and take
the stable flight just 5 or 6 before the ground).
This problem I have in two diferents models, but with
the same e-timer and the same hook ( mechanical).
Maybe the strike when the latch it is opened can send
a false signal to the hook front switch timer ?
if somebody knows something about this, please tell
Thank you
Hernan Alarcon


for people to help you should say what kind
of e-timer and hook ?

Also you said that you had a false start what does that mean ?

With most e-timers if you start to launch and the timer
unlatches you must launch unless the timer has a bunt
bail out feature ?

Does your timer have one of those ?]

Tiny Altimeter
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I just found a new very tiny altimeter that many model fliers may be
interested in. It is far smaller than any other altimeter I have seen and
it does not need a computer to read out the recorded altitude.

It records the maximum altitude of the last flight and outputs the value
when you wave your finger over the led readout device. The output is in the
form of grouped led flashes that represent the altitude in feet. The Peak
altitude range is from 50 ft to 7000 ft.

The best part is the size and cost. The circuit board is only 0.8 x
0.6inches and the weight without battery is
2.2 gr. Power required is between 3.2V and 12.0 V so a single lithium cell
will run it. The cost is around $40 and they are available from The unit is called "How High".

I have not tried out the unit I have but the Specifications looked so good I
have one and will be testing it as soon as the weather improves here.

Matt Gewain

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Hi Roger,

First, could I add my congratulations, a mite belatedly, on the
thousandth edition of your auspicious organ.

The BMFA Free Flight Forum Report's got a few more to go to equal that, but
our twenty-second has just been published. It's the 2006 edition, and
covers a wide range of topics. As well as papers presented at the Free
Flight Forum in November 2005, there are three extra bonus papers, so the
Report continues the tradition of presenting the theory, practice and
technology of free-flight today, as the following contents list shows:.

Amazing Indoor Sites - Nick Aikman; F1Q - International Electric - Trevor
Grey; A Tail Tilt Adjusting Tool - Russell Peers; Advanced Composites
Don't Have To Be Difficult - Mike Francies; Gadget-Free Discus- Launched
Gliders - Mark Benns; The Effect of Five Airfoils on F1B Duration - Peter
King; British Power - Tony Cordes; Have You Got the Time? - Mike Woodhouse;
Outdoor Free-Flight Scale - Bill Dennis; Promoting a Technical Sport - Nick
Bosdet; Design and Construction of Indoor Model Propellers - Bob Bailey;
Making F1C Booms - Ken Oliver; Predicting Model Flight Dynamics - Ian
Kaynes; Head for Heights - Recording Altimeters - Mike Fantham, Chris Edge
and Alan Jack.

When you buy your copy of the 2006 Report you not only access a lot of
know-how, but you also help our national free-flight teams, as all proceeds
go towards the costs of those who represent the United Kingdom at World and
European Championships.

Prices are as follows:

UK - Pounds Stg 10.00 including postage

Airmail to Europe - Pounds Stg 12.00 " "

Airmail elsewhere - Pounds Stg 14. 00 " "

Cheques should be payable to 'BMFA F/F Team Support Fund', in pounds
sterling only, and drawn on a bank with a branch in the UK; you may also
order by credit card.

Copies are available from : Martin Dilly
20, Links Road,
West Wickham,

or by fax to: (44) + (0)20-8777-5533, or by e-mail to


Thanks to Roger Coleman and TK for thier support of SEN

Roger Morrell