Boeing is starting flight tests of novel drag-reducing technology on ZA003, one of its initial 787 certification aircraft.
Flight tests of a hybrid laminar flow control (HLFC) are thought to be aimed at proving the viability and benefits of the system prior to it being developed as a mature technology for the stretched 787-9.
Assuming it successfully reduces overall drag without causing a maintenance or operational burden Boeing says HLFC will also be rolled back into the 787-8 fleet.
Tests began in earnest on June 9, the day after the 787 ferried to San Bernardino, Calif from Boeing Field, Seattle where the modifications were completed. The aircraft, originally assigned for the bulk of cabin interior and systems certification work, has been in lay-up since April.
Initial trails are thought to be focused on ZA003's empennage (Guy Norris)
HLFC has never been introduced on a large-scale commercial aircraft before but in experiments has indicated the potential for large drag reduction. The system works by sucking in the surface airflow which keeps the smoother boundary layer attached for a greater portion of the chord. This delays the transition from laminar to turbulent flow, and therefore cuts drag. Depending on the scale of the application, some studies suggest up to a 25% reduction in profile drag is possible leading to 10-20% reductions in block-fuel consumption. For this initial application which just applies to part of the tail section, however, Boeing is setting its hopes on a more conservative 1% drag cut target.
To get some idea of the technology involved, see my earlier blog on the HLFC patent.