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PRO
Turbine Engines

Modelers transitioning to turbine power need to familiarize themselves with the absent-coupling between the engine and the helicopter's collective pitch. In nearly all non-turbine model helicopters, the coupling between throttle and pitch is critical and needs to be carefully setup. Turbines are very different.

PRO-SW   Turboshaft Turbine w/Machined Turbine Wheel  $5,650.00 

PRO5000  Turboshaft Turbine w/Machined Turbine Wheel  $6,136.00 

Turbine models traditionally did not use the throttle channel on your transmitter because the turbine engine speed is completely independent from your collective pitch. The turbine control consisted of a turbine safety switch and a turbine RPM switch (3P switch, slider or dial) which consumed two channels on your radio system.

Classical Matching of Pitch & Throttle Curves

Every modeler that starts out in a glow powered model helicopter initially struggles to setup pitch and throttle curves on their transmitter. The difficulty comes from understanding how the two-stroke engine develops speed and torque as it accelerates. As modelers become more experienced with their engine and transmitter they are able to achieve a very predictable flight response. Those modelers that become proficient may also invest in a throttle governor which connects physically to the engine and will regulate its speed to maintain a fixed rotor-head RPM through all flying maneuvers.

Normal Turbine Operation = Fixed Turbine RPM

In stark contrast, the turbine engine is started and automatically spooled up to an operating RPM with the helicopter's blade pitch in neutral. Once the operating RPM is achieved the turbine will signal the pilot using the auxillary LED and the pilot can lift the helicopter off the ground. Once in the air, the turbine speed remains very constant reacting only to the largest changes in pitch. The turbine's fundamental operation guarantees a constant rotor-head speed which can be fine tuned in the AECU.

Receiver Connections for Jakadofsky RS & PRO Turbine Models

Modelers configuring their first Jakadofsky turbine engine who have previously flown electric, glow or gasoline powered helicopters have a choice in how their turbine is controlled from the transmitter. As demand for Jakadofsky turbines is steadily growing, we believe that a traditional throttle configuration is equally suitable and initially is more familiar to model helicopter pilots. This is detailed in table 1, we however prefer the absent-coupling of throttle to collective pitch and use the configuration as shown in table 2.

Our first configuration shows the traditional receiver setup for turbine models using the throttle channel. The flight mode switch is used as it was intended. Turbine startup is achieved when the flight mode switch is in normal position with the throttle stick at low and the throttle trim all the way down. Toggling the flight mode switch to idle-up signals the turbine to spool up to operating speed by setting a flat throttle curve at 100%. Once the turbine LED signals that the engine is at full speed, collective is added to lift off the model. In terms of pitch curves, Idle-Up 1 becomes the normal pitch curve and Idle-Up 2 is used for aerobatics when additional negative pitch is perferred.

The next configuration shows the absent-coupling receiver setup for turbine models. It is possible to use a 7 channel radio system, however most pilots prefer to make gyro gain setting changes from the transmitter to avoid stopping the rotor-head at each adjustment.

Depending on your transmitter, you may have a choice for the Turbine RPM Switch. In our experience, the a 3 position switch, slider or dial are all suitable. While we do not actively change the turbine RPM during flight in helicopters, occassionally the model is flown at a location that has a different altitude or humidity that affects the engine and its operation RPM can be adjusted. Many factors contribute to what that flying speed should be including fixed elements like the model weight and rotor blade type to variable elements like the air temperature and humidity which change day to day.

Turbine Autostart Procedure - Throttle channel & flight mode switch.

Turbine Autostart Procedure - Absent-Coupling

The turbine safety switch is the only way to start or stop your Jakadofsky turbine engine and can be used at any operating speed. The engine will automatically follow the next procedure during shutdown to ensure the engine cools off to a temperature below 80 degrees to avoid damaging internal components.

Turbine Autostop Procedure - Throttle channel & flight mode switch.

Turbine Autostop Procedure - Absent-Coupling