Vx vs. Vy

VX and VY are without a doubt two of the most important V speeds that you should understand as a pilot. Here is everything you want to know about VX vs VY.

If you’re thinking about becoming a pilot, then you might have started reading up on different things that you should know and understand. One of those things is V speeds. But let’s be honest, who the heck really knows what all the V speeds are and what they mean? Trust me, you’ll become accustomed to what they all mean with experience, but there are two that you should know like the back of your hand: VX and VY.

VX and VY are arguably the two most important V speeds in all of aviation. VX is the best angle of climb and VY is the best rate of climb. In most cases, VY is used because it gets the plane to altitude the fastest. But if you need to climb more steeply, then VX is the best airspeed to use.

V speeds are one of those topics that really just comes with experience that you’ll gain as you put more and more time into being a pilot. Unlike many of the other factors of flying, V speeds are not something that is just intuitive. You really have to learn what they are. The two most important ones are VX and VY. In this article, we’ll dive into all the nitty-gritty details of Vx vs VY and what you need to know.

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‍What Are V Speeds?

V speeds are specific airspeeds that are required for specific maneuvers. That might sound a bit vague, but that’s just because there are so many different V speeds out there since there is one for just about any maneuver, situation, or condition. Basically, they’re the different speeds that are important for various parts of flying an airplane, such as taking off and landing.

For a complete picture of what V speeds are and why they’re important in a more general sense, check out our full guide on the topic here. Of all the V speeds that you’ll see in that guide, arguably the two most important ones are VX and VY. In fact, you’re almost guaranteed to need to know both of these to pass written knowledge exams and check rides while you’re trying to become a pilot.

So let’s dive a little deeper into this comparison so that you can learn everything you want to know about VX vs VY.

What is Vx?

Let’s start with VX. This is known as the best angle of climb. Basically, this refers to the airspeed necessary to climb to altitude at a very steep angle. Or, in other words, VX is the speed at which you can achieve the greatest vertical gain in altitude over the shortest horizontal distance. In terms of actual airspeed, VX is relatively slow compared to many other airspeeds.

Why is Vx so Important?

The reason that VX is so important is because it’s necessary for avoiding obstacles, such as trees or buildings located near the end of the runway. In these situations, you want to climb as quickly as possible in terms of height vs distance, which is where the best angle of climb comes in.

If you don’t know the proper airspeed necessary for the best rate of climb — i.e. the speed needed to gain the most altitude in the least horizontal distance — then you can either go too fast and cover too much ground, or too slow and risk stalling the airplane. In order to get to altitude in as little ground distance as possible, you have to know VX.

What is VY?

You’ll have to bear with me on this one for a second, because the definitions of the two V speeds are very similar. Rather than the best angle of climb, VY is defined as the best rate of climb. As similar as that might sound, they’re actually two entirely different speeds that produce entirely different results.

With VY, you are getting to altitude as quickly as possible, with no regard for how much horizontal ground distance you’re covering. Even though the angle of climb is significantly less steep than what you climb at with VX, the airspeed is much higher so you actually reach altitude in much less time. That’s where the best rate comes in, since you get to altitude as fast as possible.

Why is VY so Important?

VY is so important because it’s the V speed most commonly used during most normal flights, especially during commercial flights. When you take off, the goal is to get to altitude as quickly as possible to clear airspace, begin the cruise phase of the flight, and turn on the autopilot system to handle the main aspects of flying moving forward. This is where VY comes in.

VX vs VY: Which One is More Important?

With the way you’ll see these two airspeeds compared, and the way we’ve framed it here as VX vs VY, it’s easy to see why you might think that one is more important than the other. But the honest answer is, neither one is definitively more important than the other in all situations. I know that might seem like a bit of a cop-out, but it really is true with this topic!

That’s because in most cases, pilots will fly at VY to reach altitude in the lowest amount of time possible. It’s faster than flying at VX, and is the best rate for climbing that the plane was designed for. But if you need to reach altitude at a steeper angle because, for example, there are obstacles in the way, then you’ll want to use VX. If not, you might not climb at a steep enough angle to avoid them.

VX vs VY: How to Remember Which is Which?

I know it might seem a bit overwhelming right now when you just first start looking into V speeds. But trust me when I say that over time you’ll just get used to all the different airspeeds and you’ll know exactly what they all are. You’ll be talking like a pilot in no time, it just takes some hours at the controls under your belt.

But in the meantime, there’s a good trick to keep track of VX and VY. Recall from above that VX is the best angle of climb. The letter “X” has a lot of what in it? Angles! At the very least, it has more angles than the letter “Y” does. That might seem a bit silly at first, but it really does work and it makes it super easy to remember. The letter that has more angles refers to the best angle of climb. Voila!