Product Review: The KK2.1 Flight Controller

Are you a beginner multirotor pilot? Are you looking for a flight controller that will let you get your multirotor up and flying quickly, without days of programming and calibration? Well then the KK2.1 flight controller from HobbyKing is a great option. While it isn’t the most feature-rich or the most mechanically robust flight controller out there, it might well be the easiest to use and the best value for money. For people just getting started with multirotor design, construction, and flying, the KK2.1 flight controller is an excellent choice. However, experienced pilots will likely find it lacking in a few areas, like GPS and brushless gimbal support.

The KK2.1 flight controller from HobbyKing

Let’s take a step back for a moment before diving deeper into this review to cover some background information since, if you are researching the KK2.1, it is likely that you are a beginner multirotor pilot like I was when I first started using the KK2.1. First of all, what is a flight controller? Flight controllers are the metaphorical brains inside every multirotor aircraft. They handle all of the functions related to keeping the multirotor stably airborne and executing commands from the pilot. For an in-depth article about flight controllers and how they control multirotor aircraft, check out A Flight Controller’s View of the World.

Review: The KK2.1 Flight Controller

Flight controllers range in price from $30 to $300 or more. The KK2.1 is at the very lowest end of this price range; you can pick one up for only $30 from HobbyKing. This brings us immediately to one of the greatest benefits of choosing the KK2.1 for your multirotor project. The KK2.1 is one of the most affordable flight controllers on the market right now and it’s affordability makes it a great choice for beginners who are probably working on tighter budget, who don’t want to break expensive parts when (not if) they crash, and who do not require the advanced features available in more expensive flight controllers.

Despite its low price, the KK2.1 is a very capable flight controller. It only lacks a few key features.

Despite it’s low cost however, the KK2.1 is actually an extremely capable flight controller. Just to highlight a few of the board’s most notable features:

• Out of the box, the KK2.1 comes pre-installed with firmware for controlling 20 different types of multirotor. The KK2.1 has eight motor outputs, which means it can control any multirotor with eight motors or fewer (including gimbal motors – more on that later).
• The KK2.1 is equipped with an LCD screen, which is used to display an extremely convenient graphical user interface for programming the controller. In my opinion, this is the best feature of the KK2.1 and it really sets the KK2.1 apart from its competitors. The LCD allows the KK2.1 to be programmed without a computer, or any other hardware apart from a power source. So, you can easily tune your multirotor’s flight performance in the field without any other equipment.
• The KK2.1 has two flight modes, an “acrobatic” flight mode, and a auto-level mode. If your radio transmitter is equipped with at least one toggle switch, you can easily switch between these modes in flight.
• The KK2.1 has build-in camera gimbal stabilization features for servo-driven gimbals (brushless gimbals are not supported). So if you are just interested in using a servo gimbal, you will not need a separate gimbal controller.

The LCD screen on the KK2.1 allows you to easily and intuitively adjust settings, even in the field.

Given it’s very low price, and quite good feature set, the KK2.1 offers excellent value for money, and I would highly recommend beginner multirotor pilots to strongly consider choosing the KK2.1. That said, as you may expect from one of the cheapest flight controllers on the market, there are a couple important features the KK2.1 lacks. Most notably, the KK2.1 does not have an altitude hold feature, and does support brushless gimbals or GPS. Again, these features may not be too important for beginner multirotor pilots, but you won’t have to spend too much time with this hobby before you might well be missing these features.

The first notable feature lacking in the KK2.1 is altitude hold. Altitude hold basically allows the pilot to steer the multirotor without worrying about constantly adjusting the throttle to keep the craft at a consistent altitude. Without altitude hold, a KK2.1 pilot must manage pitch, roll, and throttle, instead of just the first two. This means the pilot has one more control to manage and flying is a bit more difficult. For more information about altitude hold, feel free to read the Common Flight Controller Features post.

Moving on now, as mentioned in the last bullet point in the list above, the KK2.1 does include camera gimbal stabilization features, but only for servo-driven gimbals. Now, again, for beginner multirotor pilots, a servo-driven gimbal is a good place to start. Servo-driven gimbals are cheaper, simpler, lighter, and easier to set up than brushless gimbals. However, the stability and smoothness brushless gimbals can achieve is unquestionably better than servo-driven gimbals. If you are at all serious about shooting high-quality aerial photos and videos, you will need a brushless gimbal. So if you choose the KK2.1, you will also need a separate controller (and probably a separate power source) for your brushless gimbal.

The KK2.1 also has no support for GPS. Equipping a multirotor with GPS technology adds a great deal of navigational and control capabilities. Altitude hold, position hold, intelligent orientation, and return-to-home are just a few examples. Plus, GPS can generally augment the control of a multirotor, making control more precise and crashing less likely.

One last thing about using the KK2.1 versus using a more expensive and sophisticated flight controller if you are a beginner multirotor pilot. It’s not really a benefit or drawback or a feature, its just a comment. I think it is valuable for beginner multirotor pilots to fly with a less advanced flight controller like the KK2.1 because they are less forgiving. This may seem like a bad thing, but flying with more basic flight controllers will force you to actually learn how to fly. Without the hand holding provided by GPS-enabled flight controllers, you will gain a much better understanding, and a better intuition, about the behavior of your multirotor in the air. Then, if you decide to upgrade your flight controller down the road, you will be better equipped to take advantage of more advanced flight controller features. You will probably find a similar sentiment elsewhere on the Internet. This whole last paragraph is, of course, a matter of opinion, but even if you want to take advantage of features like GPS and brushless gimbal support in the future, I would encourage you to start out with a basic flight controller, like the KK2.1.