Helicopters vs Drones – What’s the Difference
By this time, you’ve probably heard the term ‘drone’ quite a few times. Maybe the first time you heard it was regarding a military vehicle, or maybe not. But by now, the word ‘drone’ means a lot more than it used to. That’s because consumer drones are now available to the public. They’re not just military-grade unmanned aerial vehicles (UAVs), they are the hobbyist’s dream toy and the photographer’s brilliant new tool. What used to be called a remote control (RC) helicopter is now referred to as a ‘drone.’
So what’s the difference between a helicopter drone and the more commonly seen quadcopter drone? And why don’t we see as many helicopter drones in the marketplace? Keep in mind that ‘drone’ is the generic term for a whole assortment of vehicles, so long as they are not manned. A car, a submarine, a sailboat, and a plane could be called drones. A two wheeled robot that operates autonomously could be a drone. BUT, to properly define the two, an RC helicopter is usually exclusively a remote controlled aerial vehicle built with a main rotor and a tail rotor and enjoyed by hobbyists, while an airborne drone is more commonly thought of as a quadcopter, with four rotors positioned in a circle around the body of the machine and built-in autonomous components, and is used by hobbyists and professionals in several industries. The huge difference: autonomy. And what goes hand-in-hand with a vehicle that can fly itself? Vision: an onboard camera. Oh, and the physical configurations are different, too.
While RC helicopters (in the consumer space) are thought of as remotely controlled, mini-scaled aerial toys, drone implies much more than a recreational toy. It implies utility, aerial photography, and enterprise solutions.
The consumer drones more commonly seen are autonomous quadcopters, small unmanned aerial vehicles, or sUAVs) with built-in cameras (or the ability to support such a payload). Military drones are unmanned aerial vehicles (UAVs) that can carry out complex reconnaissance, surveillance, or bombing missions. Why, then, don’t we see a bunch of helicopter drones (two rotors, one horizontal to the body and one vertically set at the tail)? And if quadcopters are better, why don’t we see the military using quadcopters instead of their standard issue two-rotor helicopter? The short answer: simplicity. The long answer involves high-level physics, cost efficiency, and the dynamics of manned involvement with the unmanned vehicle.
Basically, building a helicopter as a downscaled consumer-sized drone is quite a bit more complex than building a quadcopter. Think about it like this: a quadcopter has four tiny little motors with a fan (a rotor, or commonly, a propeller) on top of each one. These engines work independently of each other, and provide varying amounts of power to individual motors to move the quadcopter in any given direction. Need to make a right? The two left rotors are going to work harder to produce roll. Each of these tiny little engines must have full independence from the other. Upscale this design to the size of a manned machine and you’ll need four large engines, four large fixed rotors, and the ability to control them independently. You’ve just added a substantial amount of weight, expense, and complexity to piloting the manned quadcopter.
Helicopter engineering is much more complex from the start. The main, pitch-adjustable rotor needs a mast, mechanics inside the mast, and the transmission in the back. The smaller tail rotor needs to pair with the main rotor’s mechanics perfectly, since the two rotors work in unison to control pitch, roll, and yaw. If there is a discrepancy between the ways in which they ‘communicate’, the machine will be inefficient. Now when you downscale that and try to fit the mechanics of a helicopter into a smaller consumer drone, you’re adding expense and complexity, and expanding the margin for failure.
Quadcopters work perfectly in the smaller version because the parts and mechanics involved are less expensive, more user-friendly, and simpler. Thus you have the modern consumer drone: the quadcopter. Manned helicopters haven’t made the transition to the quadcopter model because of the exact reason consumer drones haven’t adopted the helicopter design: complexity and expense. When you have an actual human in the cockpit, the paradigm changes. An engine the size required for a manned helicopter is absurdly expensive. For a quadcopter, you’ll need four of that size. The mechanics needed to pilot the four rotors independently will require four times the power supply, then four times the backup power supply to keep it in the air. Then, there’s safety. Ever watched a helicopter spiral toward the ground because a tail rotor went out? A rotor goes out in a manned quadcopter, that machine is going mayday big time. Of course, you could mitigate this possibility by adding more rotors and manufacturing a hexacopter or an octocopter, but in the additional engines for a single unit would cause the price to skyrocket.
In terms of flight dynamics, manually controlling four different engines is a lot harder than two. Of course, one could make the argument that if sUAVs can be autonomous, why can’t military-grade manned ones? Obviously, they can, but when you factor in the manual piloting involved, the process becomes a lot more complex. In manned operations, what does complexity do? It creates room for error.
So you have a sort of catch 22 with quadcopters as the logic behind them is flip-flopped when size becomes a factor. At this point, quadcopters, hexacopters, and octocopters are the easiest, most convenient form of consumer drone, and we don’t really expect that to change in the near future.
But can I still purchase a ‘drone’ helicopter? Sure. Is it worth it? Usually not. If you do some research on helicopter drones, or at least the ones that are taken seriously, you’ll notice their price point offers very little in comparison to quadcopters in the same bracket. They’re often harder to maintain, and offer less stability (although in terms of design, the quadcopter design is absolutely less stable than helicopter design, hence quadcopters need stabilization equipment). Because they only have a one main rotor, helicopters have a difficult time supporting gimbals, and require more skill to pilot.
But for the consumer enthusiast, quadcopters aren’t going to take the place of the helicopter. For those who don’t necessarily care for flight autonomy, FPV downlinks, incredible aerial footage, and flight technology that basically allows inexperienced pilots to pick up a controller and pilot a sUAV, the helicopter is going to remain the choice of craft. They’re not going to sacrifice the rule of cool or the authentic experience of learning to pilot a downscaled actual helicopter. There is some possibility that as more manufacturers step up to the plate, we’re going to see more ‘drone’ helicopters. In fact, this is especially true as drones continue to grow in size. Today we have industrial drones that are often hexacopters or octocopters. These are basically big ole’ rigs that can support heavy payloads and fly despite tough conditions. But they’re expensive to make, some being sold upwards of $20k, and there’s a possibility that in those ‘enterprise sizes’ we’re going to see the helicopter model prevail. Why? Because they will be cheaper, more efficient, dynamic, and stable.
To sum it up, basically quadcopters are more common in the consumer drone space because of simplicity and cost efficiency. You can literally attach four rotors to two sticks taped together, strap a flight stabilization board on there, and fly it like a drone. The heart of the structural design is that simple. And, due to the complexity of helicopters, their multiple moving parts, and the expenses and maintenance involved, they are currently less favored in the consumer drone market.
As far as manned operations, we’re not going to see quadcopters replacing helicopters anytime soon. Well, probably ever. Helicopters are arguably the better machine for manned flight. Quadcopters will most likely remain the consumer drone favorite, and helicopters will remain an RC toy, or a manned aircraft. Despite all this, you’ll see a few companies engineering manned quadcopters/hexacopters/octocopters, and a few companies engineering ‘helicopter drones.’
Remember, in the consumer market, the term drone is more commonly associated with a quadcopter that carries an onboard camera and contains some degree of flight autonomy, while a helicopter is usually a remote controlled aircraft flown by hobbyists for purely recreational enjoyment.