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Sep 29, 2010, 02:04 AM
F3B and F3K
RetoF3X's Avatar
Thread OP

A little bit of F3B history

At the Oktoberfest-Pokal the MCM (Modellflug Club München) offered a generous banquet Saturday evening. (Report of the contest, see here: )

Ralf Decker, Martin Weberschock and others surprised us with an outstanding exhibition of F3B models, reaching back to the first world championships 1977 in South Africa.

Among other planes there were:

-A replica of Skip Millers Aquila, nicely built by swedish F3B ace Joakim Stahl
-Ralf Deckers Optima 1-3
-A replica of a Sagitta
-a (original) Dassel
-Ralf Deckers NoName
-Ralf Decker's revolutionary TELE F with variable wingspan (which is now in a technical museum)
-early Caracho
-Estrella (nowadays also an oldie )

The crown jewel was of course the TELE F. Luckily Ralph has charged his batteries, because he had to show the mechanism over and over again. He once gave me the drawings of its mechanism and spar design, this is not a model, it is an engineering marvel (keep in mind that this plane sustained a winch launch in the mid 1980s).

Ralf Decker zeigt den Tele-F in Aktion (0 min 41 sec)

There was also a gathering of world champions:

Ralf Decker: 1983 York -GBR 1985 AUS- Waikerie
Reinhard Liese: 1987 GER- Osnabruck
Denis Duchesne: 1993 ISR- Kefar Sava
Martin Herrig: 2007 SUI- Emmen - 2009 CZE Ivanice

It was a splendid evening and finally I could ask all the questions I had about the early days.

Last edited by RetoF3X; Sep 29, 2010 at 07:12 AM. Reason: link to contest report added
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Sep 29, 2010, 02:18 AM
Registered User
Tuomo's Avatar
How was Ralf Decker's variable wingspan plane flown? Obviously short span is speed, and long span in duration. But how about launch and distance? Was short/long span like on/off, or were the intermediate settings used?
Sep 29, 2010, 02:37 AM
Thermal Wrangler
DrFragnasty's Avatar
Thanks for the coverage Reto.

Sep 29, 2010, 02:44 AM
F3B and F3K
RetoF3X's Avatar
Thread OP
Hi Tuomo

Ralf did not fly it at the worlds, but made a demo of a speed run in Waikerie.
There was some controversy because many believed the limitation of winch power would favour Ralf Deckers Tele F. In order to save the winch regulation change (which made F3B so much more sane and safe) and due to the high empty weight, Ralf used NoName and other planes back then.

The plane could launch with fully extended wings due to its ingenious spar design.

This was the plan:

Launch, duration and distance fully extended
Speed fully retracted

Wing span could in principle be varied for distance. There was a version with flaps, but they could only be used when the wings were extended.

Latest blog entry: thoughts on contest flying
Sep 29, 2010, 04:17 AM
Phil.Taylor's Avatar
Thanks - interesting stuff there - and a video of the legendary Tele-F - amazing

I've just got another piece of F3B history, a "Fletcher"
and I also have a T-tailed version of the "Masterpiece"

Sep 29, 2010, 06:30 AM
Deniable plausibility
Shedofdread's Avatar
Very interesting. Many thanks for posting. As you say, the TeleF is a marvel but the NoName is arguably more significant. One of the first nose cone style fuselages.

Any more Dassel pics?

Sep 29, 2010, 07:52 AM
In F3J size does matter!
roydor's Avatar

I would love to see that spar and retraction mechanism design, could you post it?
Sep 29, 2010, 08:23 AM
Registered User
ron gijzen's Avatar
Originally Posted by Phil.Taylor
I've just got another piece of F3B history, a "Fletcher".
I still fly the Fletcher, but with a V-tail.
It was designed and built by dutchman Frits Donker Duyvis in 1995, who whon the European championship with it.
Design background:

He finished his latest design, the 'Empi' just 2 weeks before the worlds in Ivanice last year and competed with it.
I had the pleasure of assisting him in some windtunnel testing in 2008; it's amazing how much work, determination and money is required to come up with a new, competitive design, especially at the current performance level.
Sep 29, 2010, 08:42 AM
Registered User
I wonder if there are any Spartikus (spelling right?) in existence still? What an awesome model it was, I remember seeing a section of the wing, it was like a fine piece of furniture, maybe we will see something like the Monterey Historics Auto racing, but F3B historics someday, would be cool to see the old and new all flying together.
Last edited by s2000; Sep 29, 2010 at 10:14 AM.
Sep 29, 2010, 09:13 AM
Deniable plausibility
Shedofdread's Avatar
Originally Posted by roydor

I would love to see that spar and retraction mechanism design, could you post it?
Sorry, I can't remember how the spar is arranged but if I remember correctly, it's a sail winch servo that winds the tips in and out.

Just realised this might look like I was crashing someones else's conversation - sorry if it looked like that - not intended. S
Last edited by Shedofdread; Sep 29, 2010 at 11:22 AM. Reason: Ooops
Sep 29, 2010, 10:17 AM
F3B and F3K
RetoF3X's Avatar
Thread OP
Hi Roydor

I have their drawings (CAD) but I am not authorized to upload it.

But this is the scheme: A modified servo (like a winch) is winding an endless loop. You could imagine it as a big 8, the smaller loop of the 8 going around the winch, the bigger one inside the center panel

The big loop in the center panel has two turnaround pulleys. The left and the right tip are connected to the top or the bottom of the loop. Thus if it runs clockwise the belt pulls the wings in, counterclockwise it pulls the wing out.

They had other solutions, but this one was the simplest (it is still hell complicated to build it inside the wingskins).

@s2000: It is the Spartacus, a swiss design. It had a variable center of gravity (in flight) and other innovations. I should have some pictures here, but have to dig them out.

Last edited by RetoF3X; Sep 29, 2010 at 10:22 AM.
Sep 29, 2010, 11:12 AM
Registered User
Hey Reto,

Cody just forwarded this to me. SWEET! I got a kick out of the replica AQUILA . It is quite accurate..even has my address label in the canopy next to USA.(the original went to the Air and Space in DC and the backup at the AMA museum)

The amazing part is I remember all this like it was yesterday. And still competition after all these years...hahahahahaha!

Cool picture of the Dassel, the first moldie to win the worlds..the USA team had it's hands full, flying a Aquila Grande, a Viking, and a Bird of Time against the arrival of technology.

Thanks for recording the fun event!
Sep 29, 2010, 11:25 AM
Daryl Perkins's Avatar
What? No "V-Pigs?" V-ultra won it twice...
Sep 29, 2010, 11:35 AM
Deniable plausibility
Shedofdread's Avatar
Or an Electra? The last one built with technology (foam core and pressed skins) that can easily be reproduced 'at home'.
Sep 29, 2010, 11:38 AM
F3B and F3K
RetoF3X's Avatar
Thread OP
Hi Skip

Now comes the real fun. Second world championship in Amay. What are you thinking in that picture?

Sorry for the bad quality, old pictures, could not save it with the scan.

@Daryl: Simplex, Caracho, Estrella and first Optima, so enough V-pigs were present. And about 120 in the competition last weekend!

Last edited by RetoF3X; Sep 29, 2010 at 11:48 AM.

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