SEN issue 1142 - 11 October 2007

Table of Contents - SEN 1142

  1. Conversations on F1A Foibles and a Wii - from Minnesota to the EoB
  2. Contest at Barron Field - Barron et al
  3. Second thought on Radio DT at Launch - Aram
  4. Ikarus Flying Naked - Woodhouse
  5. More Thoughts on LiPolys - EoB

More Conversations on Hook Switches and other F1A Foibles from the NFFS Forum

Posted by CHE: Fri Sep 14, 2007 1:13 am 
I've used micro switch from the time of the first Bauer timer (1981 ?),
through Koster's Van Wallene, Muticlass, BMT and probably
others and never had a problem. You can get them sealed,
unsealed, and in various colours to meet your need.


Posted by Roger Morrell  Sun Sep 16, 2007 6:19 am   

Post subject: Comment on the Micro Switches
One thing that I forgot to say was that it is very important that the micro
switches be of good quality and designed for low current operation. This
means that the should have gold contacts. On the Magic Timers and any
other electronic timer the current flowing through the switch is only a
few milli amps. For some other applications, including the reset button
on Black Magic I use a simple push button switch. Some people have
tried using these or some thing like them as hook switches. They are not
appropriate. The will not make a good enough contact. The lever on the typical
micro switch ensure that a good mechanical connection is make
between the timer and hook.

Roger Morrell

Posted: by sweepettelee Sun Sep 30, 2007 6:00 pm   

Post subject: Hall effect magnet gap adjustment

A recent problem had a solution I think may be cogent to this discussion.
On a new F1A setup with a new Black Magic timer and Hall effect switches,
I could not get any bunt functions to occur during initial test glides. Surprised
I showed it to Roger Morrell yesterday, who reset the front magnet back
ever so slightly away from the Hall switch...and it worked properly. Very Happy
I had looked at the setup and compared to my other identical bunt timer installations,
but I could not visually tell that was the problem area.

When I asked him, he stated that some magnets have different values
that require gap adjusting
[Who knew? Question ]

[Editorial answer]
Lee - the answer is everyone ! , well you need to adjust the magnet on any reed or hall effect switch. Your's was borderline and was probably moved on your first test glide.  In fact I should have diagnosed the problem right away when you told me that the timer was giving a continuous buzz when you turned it on - indication that the Timer thought the hook was forward  no matter what position it was really in, so the timer was going into the mode to set the d/t time.

Apparently the magnet was too close to allow the switch to recognise when
the hook was back, hence, would not know to start bunt function steps.
Maybe some of you learned ones knew this, but I hope this finds those
with the 'need to know'. Cool

The Leeper    

Posted: by CHE  Mon Oct 01, 2007 12:01 am 

General Lee,

I read you said "I could not get any bunt functions to occur during initial test glides."
Wow, you get your models to bunt when test gliding ! Doesn't this hurt the pup ?

Posted: by DaveEdmonson Mon Oct 01, 2007 9:41 am 

Post subject: Bunt launches    

Even more dramatic than bunt test glides, is to be flying in the wind, and
have the model in a down wind dive that unlatches the hook, and bunts
straight in with maximum velocity! This is not a switch problem.

But on the model that I have had switch problems, found that I was adjusting
the wrong hall effect switch. The switch that starts the program upon release
was passing by the sensor, it would start the program most of the time,
but would screw up ALWAYS on my first big contest flight.

So after setting the switch to remain in contact with the hall sensor after
launch, that seemed to take care of the problem.

Now if I could keep these batteries in these stupid Palm Pilots from going
dead prior to losing the program.

I have about 8 of these Black Magic timers, and 4 Palm Pilots, and 3 programming
cables. Some of the cables work on some of the models, and not others. Some of
the Palmpilots throw out error messages after having the program beamed. Some
just don't work under any circumstance. Most recently a 2 servo unit will
delete part of the launch parameters, and I can't even get at these functions.
Boy you can really waste a lot of time trying to get these units running. Then
I think some of the parameters to set don't even work, like the launch release
settings. I program these out almost instantaneously just to make
sure that they don't have an effect. My next foray into the program
is going to set up a program with 10 second steps so that I can
see what each step is doing, and whether it is really doing it?
There needs to be a better programming connector that
actually works, like on some of the new digital cameras.

When you finally get a model flying decent with one of the
electronic timers, and only need to change the DT time,
then they are great.
Dave Edmonson, proprietor
F1A, B, G, H, J, P-30 models and supplies

Posted: by Peter Brocks Mon Oct 01, 2007 9:50 am   

Post subject: Hall effect magnet gap adjustment    


I do not understand why some electronic gliders use Hall effect switches
that have to be powered with an extra line and are also susceptible to
malfunction by magnetic dirt. Is a subminiature Cherry switch not much
simpler and accurate?


Peter it is not necessary to understand this - it is a religous question, i.e. one of belief !  You are obviously of the same belief as CHE- that good quality mechanical switches are good. Stamov and M&K follow a different religion.

From my F1E experience I know that magnets of different composition
have different magnetc values (Gauss). I built me a Gaussmeter which
shows that a Neodymium magnet is stronger than an AlNiCo magnet. Also,
an AlNiCo magnet will lose its remanence (magnetization) over time
while a Neodymium magnet does not unless you heat it up.



Posted: by CHE Tue Oct 02, 2007 1:28 am    


I simpathise with your problems. I use BlackMagic timers in some models
but find the Multiclass timers more reliable. These were originally
produced in Denmark and the development sponsored by F1C flyers
(Koster and Nyhegn) and so tend to be ultra reliable. The main
difference with ALL other timers is that the programs (ie servo
times and angles) are held in the timer and the interface just
interogates the parameters. This way you are not using any
software in the interface unit to send data to the timer and even
just dissconnecting the cable will ensure any changes are loaded. I
have never had any data errors using this timer. The big downsides
are the timer's size, weight and cost.

The timer is now made by Christophe Bachman in Swizerland but it
seems harder to influence the development than before. In comparison,
the nice thing about the BalckMagic timer is that the development
is continuing to follow the idea of the flyers wherever practical.

I've never used Hall effect switches mainly because of the concerns
over battery life. With Li-Poly batteries this problem diminishes
but I now read about the adjustments problems. Instead I've used
some very high quality switches (sealed, waterproof) and some less
so including the Cherry types and all have worked OK. Lord Magic's
comments about gold contacts are important however.


Posted: by sweepettelee Tue Oct 02, 2007 9:34 am    


I read you said "I could not get any bunt functions to occur during
initial test glides." Wow, you get your models to bunt when test gliding !
Doesn't this hurt the pup ?[/quote]
Well CHE, I did NOT handglide the 'pup' UNTIL I ran the functions thru
to the glide step.
But you knew that, oh Literal one. Razz
The Leeper

Posted: by Roger Morrell Wed Oct 10, 2007 2:18 pm   

Post subject: Switches and programming     


the choice of switches is the made by the individual flyer. There are 3 kinds
in common use and all have thier plusses and minuses.

Setting up a reed or hall effect has the problems Lee mentioned. You have
to get the magmet in the right place. It turned out in his case it was just
on the borderline of working or not.

A halle effect does require power but this is not really a concern with
modern batteries. It has the advantage of having no physical contacts in
the switch to get damaged.

Mechanical aka Micro switches must be the kind for low voltage low current
with gold contacts.

On the connector and versions of Pilot

the Palm IIIex is clearly the best .

To work with a M series palm the timer must have a resistor. there are
some timers without that resistor and I will fir it to any 2004 or
later timer that does not have it. Check with me first.

the Little magic timers as used by a number of people including
Stephanchuk and Burdov have a more robust connector. The is a proto
type of the 2008 model Black magic undergoing field testing that
has this connector. This connector is also used for charging.

I have considered a number of different devices for programming
the timer, including Pocket PC, Lap tops, Nintendo, and of all
of these the palm is still the most cost effective and the most
robust for field use. We are looking at using an IR connection
to 'solve' the cable problem.

Many of the cable problems are caused by people making thier own
cable with bad solder joints. If required Pierre Brun will make
customer cable for people that do not have the DB9 connectors
in the middle. Typically Pierre does very good work.

I have considered making a programmer box similar to that used
by the multiclass timer, but a device with a more modern interface
would be roughly equivalent to baking my own PDA - clearly more
expensive that using a off the self or off e-bay product.

The multiclass has a very simpler user interface when compared with
the Palm and that is always a possibility.

Reading about the issues that people have is very important to me.
People have been using Black magic timers for about 15 years now
and most of the features are as the result of user feed back. We
use the timers in a vary harsh environment, often with wiring
that is not up to the standards of construction observed in the rest
of of the airplane and sometimes with people not really undertsanding
how to get the best out of them. But they still work pretty well.
The magic timer program is aimed at resolving these issues.

Roger Morrell

The Magic Timer person This email address is being protected from spambots. You need JavaScript enabled to view it.

Posted: by CHE  Thu Oct 11, 2007 12:08 am   

I read from the timer magician that :-

"I have considered a number of different devices for programming the timer,
including Pocket PC, Lap tops, Nintendo"

Wow ! What a great idea ! Can we have a Wii interface that allows
you bunt perfectly each time and to steer your model to the thermal
and, and, and ....................

Nurse arrives to sedate CHE.

Thought by Roger Morrell

CHE - sedated at last !  success!!

Contest Schedule at Barron Field, Oct 20-21
From:Andrew Barron [This email address is being protected from spambots. You need JavaScript enabled to view it.]


Here is an event schedule for the Skyscraper and FAC contests in Wawayanda, New York, Oct 20-21. For directions to the field and additional details see the contest calendar portion of the website

National Cup and America's Cup JrPlus
FAI, AMA, Nostalgia, SAM

October 20 and October 21, 2007

Barron, Ford, and Shuback Fields
Wawayanda, New York

FAI EVENTS: Saturday, October 20:
F1G (small rubber), F1H (small glider), F1J (small power), F1Q (electric).
Five overlapping ninety minute rounds beginning at 9:30, 10:30, 11:30, 12:30, and 1:30.

Sunday Morning, October 21: [Awards at 3:30pm.] F1A (glider), F1B (wakefield), F1P (power) America's Cup Junior and F1C Seven overlapping ninety minute rounds beginning at 7:30, 8:30, 9:30, 10:30, 11:30, 12:30, 1:30.  First round max 240 sec (weather permitting); subsequent round maxes 180 sec.

Saturday, October 20: 9am--4:30pm. [Awards at 4:30pm.] Hand Launch Glider, 1/2A Gas, Payload, ABC Nostalgia, Mulvihill, SAM Old-time Rubber (combined), Classic Towline.

Early Sunday: Dawn Unlimited.  Meet with event director at 7am.
Launch Window 7:15-7:30 am. Each flier is to make prior arrangements for a timekeeper.

Sunday, October 21: 8am to 3:30pm. [Awards at 3:30pm.] Catapult Glider, 1/2 A Classic, 1/2 A Nostalgia, P-30 Rubber, Pee-Wee 30 Power, ABC Classic, E-36 (electric).
SAM Old Time Ignition (all SAM ignition classes combined).

Contest director: Aram Schlosberg, This email address is being protected from spambots. You need JavaScript enabled to view it., 718-479-0478.
Field use representative: Art Ellis, This email address is being protected from spambots. You need JavaScript enabled to view it. 203-453-1850.

Turn in scores between each flight. Open fliers pay $25 ($10 field use fee, plus $15 entry which covers unlimited number of AMA, NOS, SAM, and FAI events). Juniors and Seniors pay $15 total ($10 field use plus $5 entry). Fliers are encouraged to bring cell phones to facilitate communications and retrievals.

Contest Directors, Tom Hallman 610-395-5656, John Houck 610-488-6235. Entry $20. ($10 of it is for field use fee).
Events marked * may be flown either day.
Websites: for events and for directions.

Saturday, Oct 20, 9am-5pm: *FAC Scale, *Peanut Scale, Embryo, No-cal, Fiction Flyer Mass Launch, Oldtime Plan/kit Scale, Golden Age Racers Mass Launch, WWI Mass Launch.

Sunday, Oct 21, 9am-3pm: *Jumbo Scale, *Power Scale, Modern Age Civilian, Dime Scale, WWII Mass Launch, Modern Military Mass Launch, Golden Age Scale, Flying Horde, Harvey Wallbanger Award.

Andrew Barron and CDs Aram Schlosberg and Tom Hallman =============================================================

Second thoughts on radio instant launch
From: Aram Schlosberg [This email address is being protected from spambots. You need JavaScript enabled to view it.]

A week ago I floated the idea of using a radio signal to release a glider's
line. The currently available RDT technology can easily achieve it and
floating off a model in a powerful thermals or while kiting is a low risk 
Another premise I was using is that towing is a special situation, between
earth (the helper) and sky (the instant the line drops off the hook). The FAI
sporting code specifies that RDT can only be used once for a non-reversible
dethermalization during FLIGHT, and applying it to towing as well is a matter
of deduction - since towing precedes and is not part of the officially timed 
Even of the radio signal was restricted to trigger off an instant release -
and not be expanded to other functions such as straight tow, circle tow, 
OLA trajectory listed in Allard's reaction, a radio instant release has very
undesired consequences.
Suppose for a moment that radio instant release was allowed. Then fliers
would simply launch their models with the line, and press the button to
release the line if the model was in good air. In bad air or following a poor
launch the flier would simply let the line dangle under the model until it
DTed  (a standard e-timer bailout feature), tangled itself or simply landed -
granting him/her an automatic and completely undeserved attempt.
In short - a good technical idea with unexpected consequences.
Even if radio on-off signals are specifically barred from towing, a loophole
is still available. 
While towing, the control over the model is done through the hook - by
pulling it forwards and downwards - depending on the angle and the line's
tension. These hook moments, in turn, can control the rudder and wing
wiggler and the stab through wires or servos.
We definitely do not want to allow an e-timer any autonomous functionality.
For example, guide the model in a particular direction (which is what Allard
might have been alluding to in his OLA reference).
Suppose that the model has an on-board directional sensor, and that the
prevailing wind direction could be recorded just before the helper released
the model. The e-timer could be programmed to guide the model in the
preset direction as soon as the towhook's tension was above a certain
threshold for say 2 seconds. Models would no longer veer off to the right
or the left during OLA!
E-timer's active control during the tow and flight requires feedback from
on-board sensors. I'm not advocating that sensors, such as altimeters,
not be carried on-board - by that they be independent of the e-timer.
The benefit of floating this idea indicated the need to tighten up the FAI
sporting code covering to towing.

Ikarus  Flying Naked
From: Mike Woodhouse

Is this naked flying compulsory? If so will it be warm? Are the spectators and ladies expected to participate?

I'm looking forward to a warm summer!

Michael J Woodhouse, Norwich, UK.
Free Flight Supplies has secure internet credit card facilities.
All mail to: - <This email address is being protected from spambots. You need JavaScript enabled to view it.> web site: - <>

on 10/10/07 5:37, This email address is being protected from spambots. You need JavaScript enabled to view it. at This email address is being protected from spambots. You need JavaScript enabled to view it. wrote:

> Friday, August, 8th  2008  EUROPE COUPE / German Youth Champs F1H, F1G
> 14 - 19”00   5 rounds F1H
> and F1G
> 19“15              Fly-off
> or  Champagner Fly-off
> 21 “00          
> Naked-flying

Editor's Comment - I did notice this reference during the preparation of the previous SEN, and initially wondered who would ask the question ... should have known!

More Feedback on Li-Polys
From Chris Edge

I have now flown models with a single 400mAH iPod Nano replacement battery and have found it works perfectly (Multiclass timer, single servo, no servo movement on tow) as some have suggested. In terms of servo speed all I can report is that the model bunts perfectly whilst I'd expect changes of 0.05s on cruise/bunt times to have an effect. Two models have been flown in this configuration and both show the same characteristics. The conclusion therefore is that a single Li-Poly running at this voltage makes no difference to servo speeds with a single servo model. Of course the downdraughts don't know that you've gone to all this trouble and suck your model down just as fast ....

Testing on two and three servo models has still to be performed. I have, however, been told about a 'third way' - first way is one cell, 2nd way is two cells and a regulator. This uses a voltage booser of which a particularly cute example can be found here :-
This example boosts the battery output voltage to 5v (from a nominal 3.7v) but with a proportional loss of battery current. This approach will be tested at some stage but I hear from sources in europe that this is the preferred method by some flyers.

Such batteries are capabile of running all the electronics and mechanism one would require. Accordingly I'm now working on a system that, once the model has landed, it determines where it is (via GPS) and extends feet to enable it to walk back to the flightline, picking wild flowers en route.


Roger Morrell