On this page, some background information on the development of our LDS linkages shall be given. It was a process triggered by the random shortcomings of the RDS system installed in the series production Freestylers.

Part of these were attributed to the degraded centering performance of the DS3288 servos in many cases. But it was obvious, that the manufacturing tolerances of the metal parts in combination with the large wiper bend angle desired by customers were responsible for occasional excess free movement and return error.

Anyway, a system was desired, that mainly provided more precision around the center position of the flaps (in combination with low actuation forces), high stiffness, robustness, flexibility to mount different servos. This should still come with a sufficiently small height profile to allow realizing an all-internal linkage. Inspired by Jaro Mueller’s system on the Espadita, thoughts went back to a pushrod system. Starting around Christmas 2010, the first prototypes were constructed.

Working principle of LDS-Systems

 

The „Herrig/TUDM“-System

LDS TUD

LDS-Set System „Herrig/TUDM“

 

Reasons that traditionally prohibit an internal linkage with a conventional pushrod design are deformation of the pushrod, slop in the servo output shaft and excess stresses on the flap hinge. All these problems were tackled with the LDS system. Double shear connections avoid flexible bending of the pushrod. Also, the neutral axis of the pushrod was kept as straight as possible to reduce the risk of buckling in case of a crash.In order to keep the bending stiffness high in the area where the rodneeds to be curved at the excenter, this resulted in the special shape. To avoid peeling of the hinge, when accidentally landing with extended flaps, the force from the horn is distributed via a carbon rod over a larger length into the hinge. This way the maximum peeling stress on the peel-ply hinge is drastically reduced. The rod solution is also particularly helpful when retrofitting existing wings.

SAM_8755

max. Wölbklappenausschlag beim System TUDM mit Servo DS 3288

SAM_8749

Einbausituation des Servos. Der Servoabtrieb wird mit Kugellager in der vorinstallierten Rippe gegengelagert

 

The pin diameter was selected thin, to get maximum radius of the horns. Still, just a few mm’s of arm length are possible at the servo – for which a special excenter solution was developed. To avoid bearing of the holes, the horns were made sufficiently wide. The second servo excenter is coupled to the main excenter via the pins, in order to allow it carrying some load as well. A separate bearing support rib prevents the servo output from longitudinal movements, but also reinforces the area of force introduction into the wing. Glued on both sides…

The „Herrig/TUDM“-System is available for Servos DS 3288/JR189HV, MKS 6125 mini/Glider, Futaba S 3150 / S3173SVi and Graupner DES 587.

k-SAM_4008 k-SAM_4004 k-SAM_4001
k-SAM_4000 k-SAM_3998 k-SAM_3996

 

The „Helfrich“-System

LDS Helfrich

LDS System „Helfrich“

 

A little bit in advance, but in close cooperation and with mutual fertilisation, Uli Helfrich developed an LDS system, too. Uli started by modifying normal metal servo horns. But manufacturing with drilling templates was too time consuming. And the tolerances of the servo splines of the horns often left much to be desired…

In the course of time, solutions for the bearing support were simplified. The initially laminated servo frames were replaced by a more pragmatic plywood-GFRP plate solution. Finally, the milled servo horns, enabled by the CNC machine, were the way to go and also allowed a reduction of the part count…
Still, the second servohorn is only coupled via friction from the pressure of the screw, but it seems in connection with the aluminium pushrod this solution works in practice. So far, the two systems coexist – one with a slightly larger focus on control precision under all circumstances, the other with more focus on user friendliness and max deflections.

 

 


logo_logo

Exclusive Dealer in USA

logo F3B-WM

Die perfekte Vorlage: Die FAI-Nummer verrät den Urheber

logo F3B-WM

Gutes Beispiel für eine exakte Handskizze

logo F3B-WM

logo F3B-WM

logo F3B-WM

Vieles ist möglich!

Gewebe

bildinfo

Die ganz besonderen Gewebe lassen wir auf Wunsch von ausgesuchten Spezialisten fertigen......

 

Farben SALPeter

bildinfo

  Die Welt ist bunt!

bildinfo

  Auf Wunsch auch im "Partnerlook"

bildinfo

Franz mit Aspirin 2006 vor dem
Airbus-Hauptquartier in
Toulouse nach einem Gespräch
in der Chefetage über
unsere Leichtbauerfahrungen....

Freestyler in aller Welt

logo F3B-WM

  Freestyler in Asien

logo F3B-WM

  Freestyler in den USA

logo F3B-WM

  Freestyler in Südamerika (Chile)

logo F3B-WM

  ....und am westlichsten Punkt Europas

logo F3B-WM

  ....und "last but not least" in Good Old England!

Kontakt

logo F3B-WM

Franz erreicht ihr telefonisch von 9:00 - 18:00 Uhr unter 0049-37206-489306

Das sind wir

Martin-Herrig

  Martin Herrig

 

Andreas-Herrig

  Andreas Herrig

 

Franz-Demmler

  Franz Demmler

 

Unser Sponsoring

bildinfo

Team Germany F3B2015

 

bildinfo

  FAI-WORLD-CUPs F3B, F3F, F3K

 

bildinfo

  Worldchampionship F3B 2013
  Germany

 

bildinfo

  Worldchampion F3B 2013:
  Team Germany

bildinfo

  F3K Team Germany 2013

bildinfo

  Worldchampionship F3F 2012
  Germany

 

bildinfo

  Trophy "Kap Arkona"
  for FAI-Worldchampion F3F

 

bildinfo

  Worldchampion F3F 2012
  Team Germany

 

bildinfo

  Worldchampionship F3F 2012:
  Stefan Hölbfer / Austria

 

bildinfo

  Worldchampionship F3F 2012
  Team Austria

10 years top-models

logo F3B-WM

  2012: Freestyler 4.3 F3F

logo F3B-WM

  2010: Freestyler 4 F3B/F3F

logo F3B-WM

  2007: Freestyler 3 F3B/F3F

logo F3B-WM

  2007: DLG SALPeter F3K

logo F3B-WM

  2004: Schocker F3B/F3F

logo F3B-WM

  2003: DLG Aspirin F3K

logo F3B-WM

  2000: Freestyler (1) F3B/F3F

HTML-Code für Bilder

bildinfo

Bildbeschreibung