Q. 11/23/04

[automan1223]

Know your V's


24. A02 PVT
After takeoff, which airspeed would the pilot use to gain the most altitude in a given period of time?
A) VY.
B) VX.
C) VA.

[Texas Armadillo]

b. I think of X as X-treme.

[automan1223]

That is a good way to keep an answer, with so many derriatives it is easy to get confused, I just remember the other question which is Vy, I think "Y" for yo-yoo, as in fast on the string. Dont ask.

Jonathan

[iconnary]

I'd say A (Vy).

Vy gives best rate of climb, or otherwise put, most altitude gained over shortest period of time.

Vx gives best angle of climb, or otherwise put, most altitude gained for least horizontal distance traveled. This is used to clear obstacles at the end of runways (short field takeoff stuff).

An easy way to remember this is to visualize a 2-D graph with a vertical Y axis and a horizontal X axis. With Vy, the emphasis is on the vertical Y axis, giving best gain on the Y axis (altitude). With Vx, the emphasis is on the horizontal X axis, giving shortest distance traveled on the X axis for most gain on the Y axis.

Va is maneuvering speed.

[Texas Armadillo]

Oops, you're absolutely right. Vx is the most climb in the shortest "distance" not the most climb over "time". I didn't read the question correctly.

[ventana7]

I remember it because the X forms angles, so Vx is best angle of climb.
Rob