Chapter 12 - Polar Drag Flashcards
What is Vmd
Minimum drag speed = where induced and parasite intersect
At what AOA do drag and lift interset
4 degrees
Cd =
The drag produced per unit area and dynamic pressure
Total drag is the sum of
Profile, interference and induced
A stable aircraft is is when
The thrust is set above Vmd, an increase in IAS will be brought back to the original point by drag because it’s on the right hand side of the total drag curve
A unstable aircraft
Is when thrust is set below Vmd, changes to the IAS won’t want to return to original point as it’s on the back of the total drag curve
What are the TEM of being the back of the drag curve
Stall speeds and exceedanses
If you increase mass on a/c what happens to induced, parasite and total drag
parasite doesn’t change because no shape or size difference
induced will increase
total will move up and to the right
Speed neutral is where?
Close to either side of Vmd on the total drag curve. a\c has tendency to neither to return to IAS set or diverge away. because the drag changes are so insignificant
If we plot Drag against TAS at a high altitude what happens to the total drag curve
It move horizontally to the right, because TAS will always read more at higher altitudes, drag will remain the same curve.
What will happen to the total drag curve if the configuration is changed?
It will move up and to the left because parasite drag is increasing
In an EASA exam you may see the equation
CD = Cdp + kCL^2
A mathematical way of expressing CDI is
Aspect ratio
What is the drag polar
Comparing the Coefficient of Drag with the Coefficient of Lift
What is the offset at the bottom of the polar drag graph determined by
The amount of parasite drag the aerofoil has?
