Fly-by-wire system will replace naval helicopter’s hydraulic actuators, reduce weight and cut support costs

AgustaWestland has revealed the design changes required to integrate a developmental helicopter electro-actuation technology (HEAT) fly-by-wire system recently selected as part of a £750 million ($1.3 billion) upgrade to the UK Royal Navy’s EH101 Merlin HM1s.


To form part of the Lockheed Martin-led Merlin Capability Sustainment Programme, the HEAT upgrade will replace the EH101’s four hydraulic actuators – which provide control inputs to the aircraft’s main and tail rotors – primary and secondary hydraulic systems and mechanical control runs, while retaining its conventional cockpit controls.

The modified aircraft will receive maintenance-free brushless electric motor actuators – three for the main rotor and one for the tail rotor – linked to the cockpit by four motor lane control units. The aircraft will also be equipped with two BAE Systems-supplied fly-by-wire flight-control computers, fibre­optic cabling and two new generators, each capable of producing a power output of 10kVA.

Benefits of the actuation upgrade include a 40kg (88lb) weight reduction over the current system, in addition to slashing the multi-mission platform’s support costs, says AgustaWestland.

The upgrade will also expand the aircraft’s flight envelope, improve operations in adverse weather conditions and reduce pilot workload, it says. “HEAT is a generation ahead of any other helicopter fly-by-wire system,” says Martin Fausset, the company’s EH101 programme director.

AgustaWestland last year conducted successful tests of HEAT components using a ground rig at its Yeovil site in south-west England. Carried out under a development programme jointly funded with BAE, Claverham and the UK Ministry of Defence, the ground-rig tests assessed the components’ performance, durability and environmental qualities and studied the effects of vibration, radiation and lightning strike, the company says. Ground tests will continue until a flight-test campaign begins in late 2006.

The HEAT system will equip at least 30 of the RN’s Merlin HM1s from 2010, and is also being offered as an upgrade for current and future production examples of the EH101 and potentially to the UK’s Future Lynx utility helicopter, says AgustaWestland.


Source: Flight International