Guy Norris/LOS ANGELES
BFGoodrich and Raisbeck are studying a plan to tackle Stage 4 noise requirements for the Boeing 727 by combining the former company's "Super 27" conversion with Raisbeck's aerodynamic modification package.
The Super "Plus" 27 would meet the stringent noise requirements by combining the improved take-off characteristics of the Raisbeck LEAPS (leading edge advanced performance system) package with flat rated, lower noise settings on the Super 27's Pratt & Whitney JT8D-217 engines.
"We are not in a joint venture. We are investigating the potential of how to meet Stage 4 on the 727, and this seems to be one way" says Raisbeck Commercial Air Group president, and chief executive James Raisbeck.
The package would include a combination of reduced leading edge slat deflection on take-off and landing, reduced flap deflection for approach and landing, and flat rating the engines on take off to reduce sideline noise. Raisbeck says the aircraft has a typical maximum take-off weight (MTOW) of 86,500kg (190,500lb), and a maximum landing weight (MLW) of 170,150kg. "By flat rating the -217 engines about 3%, limiting the leading edge slat deflection by 11í, limiting landing flap deflection to 28í, and adding the Raisbeck external mixer to the centre engine, Stage 4 is met with no trade-offs", says Raisbeck.
The MTOW is expected to be reduced to 83,000kg, but MLW would stay at 70,150kg. Raisbeck adds that these are "not bad operational weights for an aircraft that started out in 1963 as a Stage 1 727-100, and whose wing design has never been changed". By fine tuning the LEAPS modifications, which increase lift over drag on the 727 by around 11%, Raisbeck believes the MTOW reduction could be less than envisaged. If studies prove positive, and the furore over the adoption of new noise levels in Europe is resolved, Raisbeck says the Super 27 could be re-certificated to Stage 4 as the Super "Plus" 27.
Source: Flight International
