Automatic throttle system in the aircraft simulator

From Flightdeck Solutions

Please describe your system/machine/project. What is the function of your application? Where is your application used?
Our application is a simulated throttle valve for a simulated 737 NG and 737MAX aircraft. The high-pitch lead screws we selected are used to replicate the auto-throttle system in the real aircraft. This system allows the autopilot to automatically move the throttles to control the airspeed. At the same time, a manual control system is possible when the auto-throttle is deactivated. The same applies to manual override when the auto-throttle is activated but a manual control system is still required.

What are the operating/environmental conditions like at the end user's location? What challenges did you have to overcome to adapt to those conditions?
The environmental conditions are typical indoor conditions worldwide. These can be very hot and humid places, as well as very cold and dry areas and everything in between. The biggest challenge in replicating the automatic throttle system was to make it smaller while maintaining full functionality. The real aircraft system is connected with cables that run throughout the aircraft. We had to house the entire system in the part of the throttle above the floor. The next major challenge was to design a system that would allow both automatic and manual throttle control, as well as manual override of the automatic throttle system.

What requirements did the lead screws have to fulfil?
The lead screw nuts and lead screws had to be robust enough to be used in all climate zones around the world over the long term. And they had to be able to be driven in reverse so that the pilots could override the automatic throttle system and control the throttle valve manually.

What alternatives to lead screw drives were considered? 
We considered options such as belt drives, standard bronze-lead nuts and direct servo drive. All of these options were either too large, too expensive or could not be adequately driven in reverse.

Which polymer bearing technology solutions do you use?
We used the dryspin high helix lead screws and nuts in 50mm pitch, supported by 3/8" igus high precision linear bearings.

At which points? How did the products solve your problems?
The lead screws and bearings were used to control the two throttles (one for each engine). The system worked so well that we used a similar system to drive the speed brake lever (to control the simulated air brakes) mounted in the same throttle valve module. The products were the perfect blend of low cost, high reliability, and very simple reverse control. The low costs enabled us to meet the price targets for the simulated throttle valves. High reliability means that we do not need to worry about units wearing out or failing. Simple reverse control means that the lead screws are very easy to turn back, giving the levers the perfect feel and power.