Howto:Implement a Fly-By-Wire System for Airliners
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Objective: Implement a Nasal based fly-by-wire system for Airliners with fly-by-wire and set configuration properties to get desired results.
Background
The Fly-By-Wire system was developed for the Boeing 787-8, but can be used for other aircraft too. As Boeing wanted to give pilots the upper hand, the fly-by-wire systems CAN be disabled and overridden by pilot inputs. If you would like to use this fly-by-wire script for an Airbus Aircraft, you might want to make a few changes to give the fly-by-wire more power.
The whole idea here is to get the pilot's control inputs through a nasal script, and creating custom output properties which are then read by the FDM. To implement this system, you'll need to work with the following files:
- -set.xml
- fbw.nas
- FDM xml file
Note that as the new 787 uses JSBSim, this tutorial will focus on implementing the FBW to an aircraft running with JSBSim.
Functions
The Boeing 787-8 Fly-By-Wire system executes the following functions which help stabilize the aircraft:
- Accordingly adjusts thrust and elevators to maintain lift during turns
- Helps during turns with rudder movement
- Doesn't allow the plane to turn beyond the specified bank limit (customizable)
- Applies thrust and slightly moves the elevators down when closing in on stall speed
- Reduces thrust when exceeding 250 knots under 10000 ft MSL and when reaching Vne above 10000 ft MSL
The Fly-By-Wire Configs can be set/edit from the property tree. In the Boeing 787-8 (new one coming up soon), you can edit the following FBW Configurations from the FBW CONFIG menu in the CDU"
- Fly-By-Wire Status (ACTIVE / DISABLED)
- Rudder Control (ALLOWED / DENIED)
- YAW DAMPER (ACTIVE / DISABLED)
- BANK LIMIT (CYCLE BETWEEN 15, 20, 25, 30, 35, 40)