Which statements about an aeroplane entering ground effect are correct or incorrect?
1) The downwash angle remains constant.
2) The induced angle of attack decreases.
Refer to figure.
The question is asking what will happen to the downwash angle and the induced angle of attack when entering ground effect.
- Downwash angle: When entering ground effect, the proximity to the ground reduces the effect of downwash, and therefore the induced drag. Meaning our downwash angle will reduce when entering ground effect.
- Induced angle of attack: As you can see in figure 1, when entering ground effect the induced downwash will decrease, this leads to a decrease in the induced angle of attack (αi).
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