Copyright © A. Filippone (1996-2001). All Rights Reserved.
High Speed Aerodynamics

Strakes and Canards


The strakes are small wings placed upstream a main wing, that are used to modify the downstream vortical flow. A typical application is in agile aircraft (e.g. fighters). The strakes are one of those examples where the interference can be largely beneficial both from the aeodynamic point of view (lift) and control (effects on rolling and bending moments, see below). Similar effects can be achieved with a long leading edge extension (which makes a smooth wing-body combination).

Figure 1: Strakes

Flow Separation and Vortex Dynamics

Vortex formation (and buffeting) on a wing is a direct consequence of the strakes. The vortices have a well defined and nearly steady structure in a wide range of angles of attack.

Effects on Loads and Moments

Typical lift and rolling moment coefficients are shown in Fig. 2 and Fig. 3 at two different transonic Mach numbers.

Strakes Effect on CL Strakes Effect on CL
Figure 2: Lift characteristics

Strakes Effect on CMx Strakes Effect on CMx
Figure 3: Rolling Moment characteristics

Related Material

Selected References

  • Peake DJ, Tobak M. Three-Dimensional Interactions and Vortical Flows with Emphasis on High-Speed Vehicles, AGARD AG-252, 1980.

  • AGARD AR-82. The Effects of Buffetting and Other Transonic Phenomena on Maneuvering Combat Aircraft, 1975.
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Copyright © A. Filippone (1996-2001). All Rights Reserved.