| Ultra-high bypass ratio engines offer propulsive efficiency improvements and potential fuel burn reduction. The associated larger diameter can lead to an increase in nacelle drag that erode the expected cycle benefits. Also, larger engines are likely to be closely coupled with the aircraft. Consequently, compact nacelles are needed to counter these aspects and to translate cycle fuel burn benefits into combined engine-airframe performance. ODIN is to develop design capability and detailed aerodynamic knowledge for installed compact nacelles to operate at off-design conditions such as take-off high lift, windmill and idle. |
