Figure 6.7 Leading-Edge Slots to Increase Clmax on the Stabilator of the F-4E
Example 6.1
A design concept for a light general aviation aircraft uses a canard configuration as shown in Figure 6.8. Both the wing and the canard of this aircraft have rectangular planforms. The aircraft has a mass of 1,500 kg and is designed to fly as slow as 30 m/s at sea level when in landing configuration. At this speed, its cambered main wing generates -1,000 N m of pitching moment about its aerodynamic center. If the maximum lift coefficient for its canard is 1.5, how large must the canard be in order to trim the aircraft at its minimum speed?
Figure 6.8 A Canard-Configuration General Aviation Aircraft Concept
Solution: Note that the pitching moment about the aerodynamic center is drawn nose up in Figure 6.8 because that is the positive pitching moment direction. The actual moment is nose down, since it’s value is given as a negative. In order to trim at the specified minimum speed, the canard must generate sufficient lift so that the net moment on the aircraft measured about the center of gravity is zero. Summing the moments about the center of gravity:
Then, summing forces in the vertical direction:
The dynamic pressure in standard sea level conditions at  = 30 m/s is:
Then, to size the canard so that it can produce the required lift in these conditions:
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