Why Isn't Vx The Best Rate Of Climb?

Say there's a hill a couple miles from the runway you need to clear to stay
alive. You would choose to climb at Vx, the best angle. If the hill wasn't
there you'd climb at Vy, best rate.

Say.. at Vx it takes you 5 minutes to get to that hill (which you clear) by
500'. The hill is 2500' above the runway and you cross it at 3000'. Let's
say that hill is 10 miles from the runway.

If you, instead, climbed at Vy you'd fly at a higher airspeed and get to the
hill in 4 minutes (but crash into the top). If the hill wasn't really
there, in an elapsed time of 5 minutes you might be at 3500' at a point 2
miles beyond where that hill would have been. (12 miles).

So with 5 minutes of climb.. at Vx you cleared the hill and were at 3,000'.
So with 5 minutes of climb.. at Vy (without the hill) you were at 3,500'.

Vx gives you the best angle (to clear terrain) in distance.
Vy gives you the best rate (to get to cruise altitude) in time.

--
Darrell R. Schmidt
B-58 Hustler Web Site URL (below)
http://members.cox.net/dschmidt1/

"RandyL" wrote in message
...
Here is something that I have always wondered about, but have yet to
hear a good explanation for. Vx is the best angle of climb speed for an
aircraft. Vy is the best rate of climb for an aircraft. I can't seem to
visualize why Vx is not the best rate of climb. To my feeble way of
thinking, Vx - the best climb angle - gets you to the highest altitude in
the shortest period of time, no? Why is that not the best rate of climb? I
hope someone can enlighten me on this. I know that there must be a good
explanation, but as I said, I just can't visualize it. Thanks...

Randy L.
--
Remember: Any landing that you can
walk away from, is a landing that you
can be fined, sued, or prosecuted for.