I should know this type of question.

[MikeOH58]

Pretty pathetic that someone going for his com very soon has to ask this question, however, here it goes.

What is the difference between Best Rate of Climb and Best Angle of Climb?

Best rate has to do with the optimal FPM climb, and angle deals with nose up pitch of the airplane during climb?

But which one produces better climb results? And when would you use one over the other?

[bdhill1979]

Vy Rate is over a period of time (feet per minute)
Vx Angle is over a distance (feet per mile)

[MikeOH58]

Thanks bud

[bdhill1979]

Originally Posted by MikeOH58

But which one produces better climb results?

Its really apples and oranges because it depends entirely on what performance the situation demands.

Originally Posted by MikeOH58

And when would you use one over the other?

I like to think of it like this:

Yv is going to get you to your cruise altitude in the shortest amount of time, meaning less fuel consumed in the climb, so since gas cost a bundle, you are going to use Vy the majority of the time.

Vx will get you to your desired altitude in the shortest lateral distance. Out here we have to consider climbing over mountains. I have about a dozen peaks that are within 20 miles of the airport that are above 11000. So Vx is used to ensure obstacle clearence.

[Timbuff10]

Don't forget that they change with altitude too. In the 172 Vy is about 10 kts faster than Vx at sea level. I think around 10,000 MSL or so Vy is slower than Vx.

[Stone Cold]

Originally Posted by Timbuff10

Don't forget that they change with altitude too. In the 172 Vy is about 10 kts faster than Vx at sea level. I think around 10,000 MSL or so Vy is the same as Vx.

There, fixed it for ya...

[Timbuff10]

So they come together and stay the same after you reach a certain altitude and continue to climb?

[ElyJs]

No they come together and you meet the absolute service ceiling. In a 180hp skyhawk somedays its around 12 thousand others around 15 or higher. Usually meets around 63 or 64 knots indicated for me. Also although vX will increase a little, Vy will decrease more then Vx will increase. Want to find vY just find the airspeed thats gives you the highest indication on your VSI.

Best Angle deals with the angle of the flight path relative to straight and level flight

-Jason

[TheAlchemist]

To remember think of the X in VX as an obstacle that you have to clear in the end of the rny.

[MikeOH58]

I understand. For example if you depart an airport, and within a couple miles of your departure heading is say Class D airspace, you are going to want to use Vx, and when above 25, it would prolly be the most economical move to go to Vy.

[bdhill1979]

Originally Posted by MikeOH58

I understand. For example if you depart an airport, and within a couple miles of your departure heading is say Class D airspace, you are going to want to use Vx, and when above 25, it would prolly be the most economical move to go to Vy.

Precisely, and like others are saying, make sure to check your performance charts for the conditions on that day. The examiner asked me about that on my CSEL ride, he wanted me to tell him what climb I would expect that day for both Vx and Vy and plan on going over a mountain five miles from the runway.

[Texasspilot]

Remember the physical aspects too.

A Vx climb will have you at a lower airspeedd and have your engine running at higher temps. Thats one reason not to keep a Vx climb going for longer than needed to clear obstacles.

[moxiepilot]

Barry Schiff explains it pretty well in "the proficient pilot, vol. 1" if your looking for an explination

[GatorFC]

Some more stuff to bake your noodle:

Vy, Best Rate of Climb, is dependent on Excess Power available
(the definition of Power as the Rate at which work is performed is a memory aid I use).

Vx, Best Angle of Climb, is dependent on Excess Thrust available.

Also, here's the quick and dirty from Rod Machado:
Why Vx and Vy Change With Altitude

[barrydb]

Don't forget about the cruise climb! A lot of aircraft have a cruise climb to be used for cross-countries when obstacles are not a factor. The cruise climb is usually a little higher than Vy and will provide better forward visibility for collision avoidance and better engine cooling. Also permits a higher groundspeed so you can get to your destination sooner.