Aerodynamics

Question 1

Explain the following equations: moment, moment index, CG

Answer 1

Moment = Weight x arm, expressed as in-lb
Moment index - Moment divided by a constant such as 10, 100, 1000, etc
CG = total moment / total weight

Question 2

V(x) vs V(y)

Answer 2

V(x) - best angle-of-climb speed, is the calibrated airspeed at which the a/c will attain the highest altitude in a given horizontal distance.

V(y) - Best rate of climb speed, most altitude gained per unit time

Question 3

V(no)

Answer 3

Vno is the max calibrated airspeed for normal ops, or the max structural cruising speed

Question 4

What is empty weight?

Answer 4

Empty weight consists of the airframe, engines, and all items of operating equipment that have fixed locations and are permanently installed in the airplane. It includes optional and special equipment, fixed ballast, hydraulic fluid, unusable (residual) fuel, and undrainable (residual) oil.

Question 5

What is an advantage of a constant speed propeller?

Answer 5

Permits the pilot to select the blade angle for the most efficient performance.

Question 6

The greatest vortex strength occurs when the generating aircraft is __, __, __

Answer 6

heavy, clean, slow.

Question 7

As altitude increases, the indicated airspeed at which a plane stalls [does/does not] change. (For altitudes normally used by general aviation)

Answer 7

Does not change

Question 8

What will an aircraft experience when leaving ground effect? (4 items)

Answer 8

Require an increase in AOA to maintain the same CL, experience a decrease in stability and a nose up change in moment, experience an increase in induced drag and thrust required, experience a reduction in static source pressure and increase in indicated airspeed.

Question 9

Stabilized approach, energy management concepts. (3 items) Describe a short field approach.

A proper landing is usually conducted at:

Answer 9

A proper landing is usually conducted at:
1. A fixed percentage of the stall speed or minimum control speed for the aircraft in the landing configuration.
2. At some value of lift coefficient and AOA.
3. The IAS at landing will not change with density altitude, but TAS will increase with DA.

The values depend on a/c characteristics, but once defined are independent of weight, altitude, and wind.

To accomplish a proper short field approach/landing, the pilot must properly calculate the landing distance given the atmospheric conditions.