EC 135 ACT/FHS (D-HFHS)

Flying helicopter simulator

The ACT/FHS ‘Flying Helicopter Simulator’ is the world’s frst helicopter to have a fly-by-light control system. The scale of applications of the FHS includes training of test pilots and trials of new open and closed-loop control systems up to simulation of the flight characteristics of other helicopters under real environmental conditions. The FHS is equipped with two engines, a bearingless main rotor and a Fenestron tail rotor as standard. Fly-by-light control is a system in which, as opposed to a fly-by-wire system, the control signals between the operating devices, the flight guidance controller and the actuators for rotor blade control are transferred optically via fibre optic cables instead of electrically. In addition, there is also a mechanical emergency control system. The advantages compared with electrical data transfer are the high transmission bandwidth, high reliability, as well as low weight. The fly-by light flight control system consists of a quadruple-redundant computer system and is designed such that the stringent safety criteria of the European aviation authorities are fully met.

The cockpit layout provides seats for a safety pilot, the test pilot and the flight test engineer. A comprehensive equipment line-up with sensors and systems for on-board data recording and processing is used to record the data from the flight tests. The FHS differs from the standard Eurocopter EC 135 helicopter due to the following modifcations: optical and electronic FBW/FBL flight control system; on-board computer system that enables simulation of the flight characteristics of other – actual existing or virtual – aircraft; and a modular experimental system that consists of flight-control computers, data measurement and pre-processing systems, displays and additional equipment and controls in the cockpit. In future, the FHS will be fitted with instrumented rotor blades with a rotor measuring system.

Deutsches Zentrum für Luft- und Raumfahrt (DLR)
Barbara Milow · E-Mail barbara.milow@dlr.de