Various other nations have worked on stealth helicopter technology. During the 1980s, British company Westland Helicopters undertook a top secret research programme towards developing a stealth attack helicopter.[16] Being based on the Westland Lynx, the proposed design was internally designated WG 47; its configuration included a faceted fuselage with internally stored weapons, twin canted tail rotors and the routing of engine, environmental and cooling system exhausts into a side-exiting infrared suppressor.[16] It featured a tandem cockpit, the glazing of which was specifically angled outward to eliminate optical glint towards the horizon. The programme was concluded during 1987.[16]Westland's stealth helicopter research subsequently influenced its other programmes; the NHIndustries NH90 was one such beneficiary via the application of stealth profiling techniques into its fuselage design.[16] The AgustaWestland AW159 Wildcat, an advanced development of the Westland Lynx, also incorporated several stealth features, such as infrared exhaust suppressors; such devices have been installed on other platforms by the company, including the AgustaWestland Apache.[17][18] Such measures augment the effectiveness of its defensive aids suite, which includes missile warning sensors and countermeasures dispensers.[18]