Amish RakeFight
Registered Loser
- Joined
- Dec 28, 2005
- Posts
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Airspeeds ABOVE and BELOW L/Dmax will increase TOTAL drag.
BELOW L/Dmax, total drag is increased due to induced drag.
ABOVE L/Dmax, total drag is increased due to parasite drag.
Airspeeds at L/Dmax provide the greatest amount of lift for the least amount of drag.
Concerning your question directly, lift is generated (all things being equal) and is a function of, airspeed and AOA. You must compensate with one when the other is taken away in order to generatethe same amount of lift. As you decrease your speed while maintaining altitude, you will need to increase the angle of attack (AOA). By virtue of increasing the AOA you are increasing the amount of induced drag being created. Since you are not creating lift with an abundance of airspeed, you will need to inevitably increase the AOA.
When you increase the AOA, you create a greater pressure differential between the upper and lower part of the wing. Lower pressure on top and relatively higher pressure below. This greater inqueality of the two pressures casues a greater span wise movement of the higher pressure which seeks out the lower pressure above the wing. This air moves outward towards the wingtips where it meets with the lower pressure above the wing and bends the lift vector backward. An easy way of visualizing induced drag is by imagining the wing at an exagerated AOA. While visualizing this, think of the lift as being perpendicular to the wing, not the flight path. If you do this, you'll see that the lift is acting backwards or rearwards rather than striaght up. This rearward pull or dragging, is what induced drag is.
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