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BR710 RECEIVES JAA CERTIFICATE

On August 14, BMW Rolls-Royce received the certification of the European JAA for its BR710 engine. According to Albert Schneider, Managing Director of the Dahlewitz based company, this is the most important milestone in the six-year history of BMW Rolls-Royce.

The BR710 has been chosen to power the new ultra long-range business jets Gulfstream GV and Bombardier Global Express. BMW Rolls-Royce is the only supplier for this market segment. The new turbofan will also power the updated Nimrods of the Royal Air Force, beginning in 2002, and the more powerful version BR715 will power the McDonnell Douglas MD-95.

The JAA certification of the engine is a reason to celebrate for all employees and marks the end of a four-year development program with 5000 hours of test runs, including a ten-month flight test program with the Gulfstream GV. The BR710 program was launched in August of 1992. Only one year later the core engine accomplished ist first test run. The first run of the complete engine was done in September of 1994 and the first flight was made with a Gulfstream GV in November 1995.

However, the development of the new turbofan was not free of problems. In the beginning, the specific fuel consumption (SFC) was eight to ten percent above the specifications. According to chief engineer Reginald J. Moore, the efficiency of each component was evaluated and improved, air leaks eliminated, leading to a reduction of the fuel consumption to the desired numbers.

Another problem was revealed during a fan bird strike test, when the engine was shot with four 0,7 kg birds, resulting in the rupture of a fan blade. After the angle of attack of the fan blades was reduced by one degree and the series production blades were used, another bird strike test was successfully accomplished.

The beginning of the flight tests revealed another small problem. In idle condition, the engine generated a so called combustor rumble, caused by incomplete burning of fuel in the combustion chamber. Even though this is not harmful the noise is a nuisance. The problem could be eliminated by reducing the spray cone angle of the fuel injection nozzles.

The last milestone in the certification process was a 150 hour continuous operation test, which the BR710 accomplished in record time between June 3 and June 21 this year. The following disassembly for evaluation by the certification authorities showed all critical parts in immaculate condition and resulted in official JAA certification. The next milestone in the program is the first flight of the Bombardier Global Express scheduled for September this year. In December, the engine will enter service in a Gulfstream GV.

From page 62 of FLUG REVUE 9/96.