Abstract:

ESDU 14005 provides an empirical method of predicting the lift coefficient increment (usually negative, i.e. a decrement) and rolling moment coefficient due to upper-surface spoiler deployment on a wing at subsonic speed with trailing-edge flaps deployed.

The method predicts the additional lift coefficient increment over that obtained when the spoiler is deployed on the wing with flaps undeployed (calculated using ESDU 14004). The corresponding change in rolling moment coefficient due to a spoiler deployed on one semi-span wing panel when flaps are deployed can then be determined. The method of ESDU 14005 is used in conjunction with that of ESDU 14004 to obtain the total lift coefficient increment and total rolling moment coefficient due to spoiler deployment on wings with deployed flaps.

The method of ESDU 14005 applies to plain, single- or double-slotted flaps having flap/wing chord ratio of 0.2 to 0.4 with flap deployment angles up to 60° and the same range of wing planform and spoiler parameters as the method of ESDU 14004. It applies for practical Reynolds numbers and Mach numbers up to 0.29 for wings with or without venting from the lower to upper surface. Sketches comparing predicted data with test data show that in most cases predictions lie within 0.1 for total lift coefficient increment and within 0.01 for total rolling moment coefficient. Some guidance is included on the effect of lower-surface venting which can increase spoiler effectiveness by 30 per cent for flap-type spoilers with large deflection angles. Two worked examples illustrate the use of the method.