Thrust reversal - CONSTRUCTION AND MATERIALS

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Thrust reversal - Turbo-propeller reverse pitch system

CONSTRUCTION AND MATERIALS

Fig. 15-6 Hot stream thrust reverser installations.

20. The clamshell and bucket target doors (fig. 15- 6) described in paras. 9 and 12 form part of the jet pipe. The reverser casing is connected to the aircraft structure  or  directly  to  the  engine.  The  casing supports  the  two  reverser  doors,  the  operating mechanism and, in the case of the clamshell door system, the outlet ducts that contain the cascade vanes.  The angle and area of the gas stream are controlled by the number of vanes in each outlet duct.
21. The clamshell and bucket target doors lie flush with the casing during forward thrust operation and are hinged along the centre line of the jet pipe. They are, therefore, in line with the main gas load and this ensures that the minimum force is required to move the doors.

Fig. 15-7 A cold stream thrust reverser installation.

22. Both the clamshell door system and the bucket target system are subjected to high temperatures and to high gas loads.  The components of both systems,  especially  the  doors,  are  therefore constructed from heat-resisting materials and are of particularly robust construction.

23. The cold stream thrust reverser casing (fig. 15- 7) is fitted between the low pressure compressor casing and the cold stream final nozzle. Cascade vane assemblies are arranged in segments around the
circumference of the thrust reverser casing. Blocker  doors  are  internally  mounted  and  are connected  by  linkages  to  the  external  movable (translating) cowl, which is mounted on rollers and tracks. Because the thrust reverser is not subjected to high temperatures, the casing, blocker doors and cowl are constructed mainly of aluminium alloys or composite materials.  The cowl is double-skinned, with the space between the skins containing noise absorbent material (Part 19).