Technofan will supply to NHI the ventilation system of the avionics bay, the ECS and the cooling unit of the RAGB (Remote accessories gearbox). This cooling unit deserves a special mention as it was not in the original specifications. Originally, the NH90’s RAGB did not have a cooling unit; but Eurocopter began to revise this decision during the development process. And in August 2002, the manufacturer contacted Technofan and several other competitors, to propose a cooling unit. This unit will limit excessive oil temperatures rates especially encountered during “hot and high” operations.
The remote accessories gearbox (RAGB) taps part of the engine’s power to drive a number of helicopter auxiliary systems, including hydraulic and electric generation. In other words, it is totally different from the main gearbox, which drives the rotor.
For Alain Berger, Sales and Marketing Manager, the program deadline is very short:
“as this equipment was not originally scheduled, we have to develop it and qualify it at the same time. The first set will be delivered to NHI during the summer. Thirty more sets have to be delivered to NHI before the end of 2003”. The other challenge was the weight aspect. Technofan’s RAGB cooling system calls on composite materials and a very compact design of the fan-heat exchanger assembly. The system comprises an air-oil heat exchanger, which draws in outside air and blows it over the exchanger. This cooling unit weighs 15% less than the ordinary solutions.