TriBelle The Innovative Helicopter

Dr. Sieghard Dienlin (right) and Stefan Dolch (left) with TriBelle and the InterEx Querdenker-Pokal 2002 (InterEx Unconventional Thinker Cup 2002)


Remarkable Features Overview


Philosophy a pleasure to fly

Stubenfliege and Mouse have set a world-wide standard in their class. This successful series is continued with TriBelle. All three models obey the maxim: "Pure fun flying." Their designs are reduced to the essentials with high quality construction.

TriBelle is fundamentally new and revolutionary. It is the first helicopter with three hingeless rotors, no mechanics, and self-stabilizing flight characteristics.

Great effort was put into pre-production design. Ideas, concepts, design simulation, test stand trials, again and again new variations. Then, test flights, test flights, test flights. A fantastic model which we never tire of flying. It is full of innovations. Many are not obvious at first glance; and some innovations are not seen in close observation, only in hindsight. Your pleasure in flying TriBelle is a unique experience.


Ingenious Steering

TriBelle steering maneuvers are performed by manipulation of the revolutions of the three rotors, thereby eliminating servos, linkages, moveable rudder or elevator, rotor hubs, and many of the parts which make a normal helicopter expensive, difficult to fly, susceptible to interference, and to require intensive maintenance.

TriBelle is the worldwide first and only model with this ingenious steering device (patented design). It is based on an invention by the Solar Plane Pioneer, Dr. Sieghard Dienlin, who has placed the marketing exclusively with Braun Modelltechnik.

Altogether there are three steering functions:

The following table shows the functions in detail:

Control stick

Rotor Reaction

Effect on Helicopter



All rotors increase speed (rpm)



All rotors decrease speed




Rear rotor increases speed

Flies forward, accelerates


Rear rotor decreases speed

Flies backward, decelerates

Roll and Yaw


Right rotor decreases speed, left rotor increases speed

Turns to the right


Left rotor decreases speed, right rotor increases speed

Turns to the left


Flying Characteristics harmonious, wide range capabilities

TriBelle is well suited for both fixed wing aircraft pilots and helicopter pilots. The positive characteristics of fixed wing aircraft and helicopters are combined.

Fixed wing aircraft pilots describe the flying characteristics so:

TriBelle flies like a 3-channel slowflyer with no minimum speed and, also, full rudder effect in the hovering mode. TriBelle has a much wider speed range and can negotiate a more narrow circle than a slowflyer.

Helicopter pilots describe the flying characteristics so:

TriBelle flies like a conventional helicopter. One need not worry about the tail. The hover flight is very quiet. Further advantage: unlike normal helicopters, the model is self-stabilizing in flight. Once trimmed in level flight, TriBelle flies, calm conditions presupposed, hands off and maintains its course. TriBelle flies clean circles, with little need for intervention by the pilot. TriBelle is thus unusually easy to control.

The extraordinary handling characteristics are the result of the integration of high-grade components. The ingenious geometry, with skillful design of weight/mass distribution, and the clever electronics with piezo gyro stabilizer.


Superb flying performance

TriBelle is trimmed to supreme effectiveness. Unlike the conventional helicopter, all rotors contribute to lift. Rotor thrust is not hindered by a voluminous hull. The geometry of the rotors, (with a low loading of only 8 grams / sq. dm.) is the principal cause for outstanding flight performance. Here, lightweight construction pays off. The rotors are particularly notable, at a diameter of 370 millimeters, they weigh only 7 grams.

TriBelle hovering power requires only 15 watts (at weight configuration of 280 grams). With fast loading capability of the NiMh battery pack (6 cells Sanyo Twicell 750 mAh), flying times of approximately 13 minutes are achieved. Special lithium ion battery pack extends performance to approximately 1 hour.

Through the nominal applied voltage of 7.2 volts, different battery pack accumulators can be used: 6 cells NiCd, 6 cells NiMh, or 2 cells lithium ion.

The thrust reserve is considerable. The maximum thrust totals approximately 500 grams, about double the basic configuration weight. With it TriBelle can move nimbly. TriBelle has flown well with an additional payload. The total weight should not exceed 350 grams in consideration for the handling characteristics.


Long service life

If you don't have mechanical linkages and parts, they can't become broken. TriBelle's rotors are maintenance free.

Occasionally it is reported that the motor commutator is worn after only a few hours of operation. How long the motors serve depends on many factors: supply voltage, current, clock-frequency of the speed controller, application of a choking coil in the motor control, duration of full-power periods, etc. Unfortunately some cheap motor assemblies are sold as first quality parts.

After more than 70 hours flying time of TriBelle, no defects were found neither in the motors nor in the gearings. This high level of stability is achieved by: high frequency controllers with choking coil; highest quality motors driven at moderate supply voltage near maximum efficiency; highly efficient rotors; consistent lightweight construction with the maximum workmanship quality. All this make TriBelle a reliable operational helicopter.


Mechanical Construction - with a love of detail

The structure is manufactured entirely of carbon fiber reinforced epoxy. This material simultaneously gives TriBelle incredible light weight and strength. In the air TriBelle is indestructible. She survives many hard earth and floor crashes without damage.

The carbon fiber epoxy finish and color of the structural tubes, the battery cover, the rotors, and the fin prove handsome to the eye. The location of the electrical wiring within the structural tubes eliminates the "cable salad" one often sees in even a quality model.

The soft whir of the slowly turning rotors is another aesthetic pleasure. At only 1200 revolutions per minute the high-grade gearing is barely audible. A cheaper engineering decision would have insulted our ears.

The battery pack is mounted in front by a unique connection system. In a crash, the battery pack is ejected. This limits damage possibilities to the helicopter.

The elastic feet of TriBelle protect the craft and the floor. Flights landing on a parquet floor mars neither the craft nor the floor. TriBelle has a sturdy stance, with its feet located at the base of the motor housings. This places them at the greatest distance apart and furthest from the center of gravity. A training stand or undercarriage, an accessory offered for many conventional helicopters, is not necessary.

The fin is detachable. If one disassembles the rotors, TriBelle is very compact. It packs in a volume of approximately 660 mm x 535 mm x 150 mm. It then fits easily in your vacation luggage.


Genuine Assembled Model

TriBelle is delivered as fully assembled, ready to fly model. Rotors, steering electronics, and fin are assembled at the factory. Every craft is tested for performance. When you receive your unit, you take it from its freight box, screw Rotors on, place the receiver, put on the fin, insert the battery pack hardly anything to do to get TriBelle ready for take off!


Technical Data


Weight [grams]

Model structure with hood and fin


3 corless motors with inline gearbox


3 rotors


Steering electronics




Battery pack 6 cells 700 mAh Sanyo Twicell NiMh





Scope of supply for TriBelle (order number 130)

Fully assembled, ready to fly model, test-flown.

Equipped with: 3 coreless motors with inline gearbox 1524-12, 3 carbon rotors 370 mm, steering electronics with 3 high frequency controllers and piezo gyro stabilizers. Operating instructions.


What else is required?

6 cells 750 mAh Sanyo Twicell NiMh battery pack with special connecting system (order number 502).

Charging cord with plugs (order number 510).

Computer radio transmitter with at least 4 channels and 2 freely programmable mixers; receiver (preferably PCM) with at least 4 channels and Graupner or Futaba plug system; battery charger.


Last update: 12/02. Errors and changes reserved.

Andrea Braun Modelltechnik - Lagerhausstrasse 105 - D-67061 Ludwigshafen - Phone and Fax 00 49 621 56 71 52

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