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50% Bücker 133 Jungmeister

wingspan: 3,30 m
length: 3,00 m
height: ca. 1,2 m
weight: 24,6 kg

Fiala / Valach VM-250 R5
FALON beechwood vintage style 32×18
Hacker / Ditex EL-3214S
JETI duplex CB-220
2x JETI duplex RSat 2
1x JETI duplex RSat 900mHz
Hacker / TopFuel 3x 2400 2S
EMCOTEC premium wires

VIDEO (J. Benz):


KARAT biplane build report

I am very happy to see one of the best builders we have in F3A building on of my planes and giving aeromodellers around the world the chance to follow each step he makes.
Isaac Najary from Israel writing in famous american RC-UNIVERSE forum a detailed report of his KARAT biplane building.


Thank you very much, Izzic! I am very excited to see the result 😉

Acrostar mk2 XL repair

Unfortunately a clubmember crashed my Acrostar and damaged the gear, the gear frame, the wing support, the landing gear covers wheelpants and cowling.
I thought about building a completely new Acrostar or just fix the fuselage.
I decided to do the second option and took some pictures during this process…


My message with this post: You don´t have to throw it away immediately 😉

Acrostar mk2 XL UPDATE!!!

The delivery of series product of Acrostar XL has started and here are some additional tipps / information.

The wing tube which is included in the kit, was changed due to my wish. More specifically the wall thickness has been enlarged to get a stronger tube. The new tube is also used by the manufacturer for another airplane. So It could be possible that you need to cut the tube around 10mm.

I recommend to modify the tail wheel as shown on the picture. Just one washer and no lock-nut between the bracket  and the wheel.

If you use long servo arms, it is useful to install the ball link below the servo arm. Otherwise the ball-linkage will touch the servoarm if you have big deflections.


I recommend to tape all control surfaces with flexible, transparent surgical tape.
The result is a much better effect of those functions.

Acrostar mk2 Testberichte

Kurz vor Jahresende sind zwei tolle mehrseitige Testberichte vom Acrostar mk 2 in deutschen Fachzeitschriften erschienen.
Ralph Müller hat den Acrostar für die FlugModell Ausgabe 02/2019 getestet, Nils Brückner für den Branchenprimus FMT Ausgabe 01/2019.
Beide Autoren berichten ausführlich über den Bau, mögliche Modifikationen, aber auch das Original oder die unterschiedlichen Antriebsvarianten.

Beim Test der FlugModell ist mit mir ein kleines Interview zum Acrostar, seine Geschichte und wie es weiter geht, dabei.

Beim Test in der FMT hat Nils Brückner den Cockpitausbau näher beschrieben und sogar über die FMT einen PDF-Plan zur Verfügung gestellt, den Link zur FMT-Website gibt es hier!

Beide Testberichte sind absolut lesenswert- vielen Dank euch Beiden!

Nun danke ich allen Besuchern meiner Website und wünsche einen guten Rutsch und alles Gute für 2019!

Robin Trumpp

Tolles Bild von einem stolzen Acrostar Pilot: Bendix Bode

KARAT biplane kit

Die first part sets for KARAT biplane have arrived and go straight to their customers.
But before I would like to show you some impressions.
The weight of all plane parts incl. battery plate, servo plate, motor plate, landing gear and pants is around 2150g.

Prices and delivery time on request or via our distributors.

Precision Aero Products

Tipp for ULTRAmate by C. Oppliger

 Christian Oppliger from Switzerland tested ULTRAmate and has a tip for all who want to push the limits of that plane a little further.
Many thanks for the information and your help!!!


Hi Robin,

I programmed 2 mixers:

  1. Ailerons —>Throttle 8%
  2. Elevator —> Throttle 8%

Due to the high control effect of ailerons and elevators I added a mixer to this functions of 8% throttle. So the control surfaces are better flown on and the effect of them is higher.

That also means, that the plane with full deflections not brakes down that much and flies more dynamic and in extreme maneuvers even more stable. The reason for those mixers is coming from the F3P-scene where they use it actively to keep the speed constantly during rolls. I tried it in 3D models as well and found it very helpful, especially when the planes have very big control surfaces like ULTRAmate.

Best regards

RT Eraser V3 EPP: Airplane of the year 2017!

After 5 years and in 3rd version our design distributed by the Hacker Motor GmbH won the price airplane of the year 2017 in the category slowflyer.

RT Eraser V3 EPP was voted by the authors of famous FlugModell magazine.

At the international toy fair in Nuremberg Hacker got the diploma and the medal for this amazing award.

We are very proud of this achievement and hope that it was not our last award for airplanes designed by Robin Trumpp.
The future we plan bigger, more valuable and more beautiful, that´s what I can tell you already.