By Jordan Bullock CFI, FO B737
As you’re learning to fly, you progress through various stages. With this progression, your instructor’s verbiage towards you as a student changes. For example, your CFI might say, “Hey, on this one, give me a steep climb out”. Eventually, this turns into, “Climb me out at Vx”. Each aircraft’s POH or manual has a page specifically dedicated to that aircrafts V-Speeds. So, what are they?
V-Speeds: What Are They?
Each V-speed (and there are many) is technically a specific speed for a specific maneuver in a specific configuration. While that’s a mouthful, it essentially boils down this: The speed at which you should conduct the defined maneuver. Much simpler. Of course, the configuration matters and has implications, but you’ll naturally figure that out based upon the maneuver.
So, what does the “V” stand for? Most people assume it’s ‘Velocity’. That works. However, technically speaking, it stands for “vitesse”, a French word meaning “rate” or “speed”. Like many aviation terms, we borrow from the French! There are many different types of V-speeds (over 30). If you absolutely need to know what they are, feel free to check out CFR 14 Part 1. There you’ll find all of them. Below, we’ll take a look at some of the ones you should know as you work through your training, but we will refrain from getting into the speeds associated with Mach as those pertain more to Jets!
Vr: Rotation
This is undoubtedly the very first speed every aspiring pilot learns. The rotation speed. The FAA defines this as, “The speed at which the pilot makes a control input, with the intention of lifting the airplane out of contact with the runway or water surface.” Simply, it is the speed at which you takeoff. But what does the term ‘rotation’ have to do with lifting your nose off the ground? Without getting too in-depth with aerodynamics, when a plane is conducting a takeoff, the pilot is pulling back on the control column to pitch the nose up. This when the plane begins to rotate along its longitudinal axis.
One last thing to note here is that the FAA specifically states that Vr cannot be less than V1, which is your stall speed. Outside of basic aerodynamics, this is a safety measure taken to ensure most aircraft have plenty of energy at and shortly after takeoff to avoid stalling out.
Stall Speeds
Stalls are immediately dreaded by every fresh faced student pilot. It’s natural. It’s the first time their aircraft stops being fun and starts getting serious. To new pilots, a stall can feel like their plane stops flying. But what speeds are associated with stalls? Let’s look.
While it’s true, you can theoretically stall at any speed, each aircraft has speeds related specifically to stalling. VS1 is the stall speed in a clean configuration. This you’re configured with no flaps deployed or landing gear (if you have retractable landing gear) out as well. On the airspeed indicator, this would be the bottom of the green arc.
Then you have Vso. This is the important one. Vso is the stall speed in the landing configuration. So, flaps are deployed for landing and the gear (if retractable) is out. On the airspeed indicator Vso is known as the bottom of the white arc.
Vy & Vx
At the start of training, pilots are often taught to climb out by keeping the nose just slightly above the horizon. As pilot’s progress they learn to climb out at Vy. Vy is the best rate of climb speed. This speed will give you the greatest altitude gain in the shortest amount of specified time. Eventually, most pilots almost always climb in Vy, whether its after takeoff or when changing altitudes. But what if during takeoff, you wanted to avoid a tree line at the end of the runway? Well Vy wouldn't be the best climbing speed. That’s what Vx is for.
Vx is the best angle of climb. This gives you the greatest altitude gain in the shortest amount of distance. At a slower speed than Vy, your nose pitch attitude will be more aggressive. By climbing out at Vx, you ensure that you can avoid the tree line or whatever obstacle awaits. There is an argument to always climb out at Vx. Why? Well it gives you the most altitude, thus the most cushion room if things get hairy, for example an engine failure. Whether or not you climb out at these specific speeds or you just keep the nose above the horizon, practicing and being proficient in Vx and Vy climbs will undoubtedly make you a better pilot.
Va: Maneuvering Speed
The last speed we’ll discuss is Va, maneuvering speed. I’ve seen the lack of understanding this speed in various levels of pilots. Maneuvering speed is the speed at which an abrupt and full deflection of any of the primary flight controls could result in substantial aircraft damage. In short, making full deflections at this speed or worse, above it, can end tragically.
In the ACS (Airman Certification Standards) for each rating the required maneuvers to be demonstrated are laid out. For most maneuvers, the FAA leaves the airspeed for which the maneuver should be completed at up to the manufacture. But with one small caveat. It states, “… or if one is not available, an airspeed not to exceed Va.” This indicates that almost every maneuver will be below Va. Pair that with the risks of exceeding the maneuvering speed and its probably the most important V speed.
Conclusion
Understanding V-speeds demonstrates a knowledge that the pilot not only understands basic aerodynamics, but they show an understanding of operating their aircraft. Knowing the operating limitations and procedures of the aircraft you’re flying ensures good pilotage and keeps the blue side up!
By Jordan Bullock CFI, FO B737
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