What Is a Drone?

Military-grade drones may fit in a backpack or they may be nearly as big as a full-size plane and loaded with death-dealing armaments. These drones can cost tens of millions of dollars and have wingspans of more than 100 feet (30 meters).

Although military drones are promoted to the public as bloodless and precise types of war machines, they can be disturbingly deadly. For instance, it's estimated that 2,200 people were killed by drones in Pakistan over the course of a decade, including 400 to 600 civilians.

Consumer and commercial drones offer a happier spin on automated flight. They may fit in your palm and run you less than $100. Sturdier, more advanced models can cost thousands and scream high into the sky — and possibly onto your local radar, which may very well land you in trouble with the Federal Aviation Administration (FAA).

Fire departments, police units and disaster responders all use drones to some degree, assessing harrowing situations, finding missing people and helping fellow humans. Drones are also handy for construction, mapping, wildlife conservation, and pipeline inspection.

There was no history-rattling moment when the first drone went airborne. That's in large part because it's a matter of semantics when trying to determine exactly which historical device qualified as a drone. Was it one of the explosives-laden balloons used in the 1800s? Was it the initial V-1 rockets that the Germans deployed during WWII?

In the early 1900s, military groups used drones, including radio-controlled versions, for target practice. Engineers also developed unmanned aircraft loaded with munitions. These weren't really drones. They were the first cruise missiles, sometimes called flying torpedoes, and not meant to return to base.

During the Cold War, the U.S. ramped up research on drones, hoping to use them as substitutes for manned spy planes. As the Vietnam War dragged on, drones flew thousands of high-risk reconnaissance missions and were destroyed by enemy fire, but in the process saved the lives of pilots who otherwise would have perished.

At about the same time, engineers began equipping drones with real-time surveillance capabilities. With their onboard cameras and unlimited courage, drones could approach enemy lines and document troop movements and strategies without risking human lives.

In 2002, the CIA first used a Predator drone to kill an enemy combatant in Afghanistan. The Predator (more precisely, the MQ-1 Predator), with its spine-chilling name, was one of the first military drones to see widespread action. It was unveiled in 1995 and has since zoomed all over the world — mostly in the Middle East.

The Predator is one of the best-known military drones, but now it's just one of many. Those first strikes in Afghanistan were, as they say, just the beginning.

As the digital revolution has unfolded with its tiny microprocessors and long-distance communications abilities, drones have become more and more useful for military operations. By one estimate, the U.S. military has roughly 11,000 manned airplanes and perhaps 7,500 drones, meaning that a third of the air force is unmanned. For anyone who feared the coming age of automated, sci-fi-type warfare ... well, those days are already here.

The U.S. military has three categories for drones: mini, tactical and strategic. Mini drones are small and mostly used for short-range surveillance. Tactical drones can fly for several hours and as far as 200 miles (322 kilometers) and are used to assess enemy targets. Strategic drones can fly for days and carry weapons.

Some drones use battery power to turn propellers. Newer and pricier versions have full-blown jet engines and can fly more than 500 miles (805 kilometers) per hour, soaring to 50,000 feet (15,240 meters) or even higher. Some drones are autonomous, following preprogrammed routines. Many others require pilots. Those pilots may be on the ground near the operation or they may sit in control rooms, thousands of miles away, guiding their minions by high-speed wireless networking links.

In part, because there's a delay of a couple of seconds from the control room to the drone, crashes do happen. Sometimes pilots push the wrong buttons. Sometimes they misread the flight data they see on their workstation monitors; cameras on the drones simply aren't a substitute for a pilot's real vision and other senses. More than 400 large drones have crashed since 2001, but many disasters have been averted, too. If a communications link is cut, advanced drones are programmed to fly in circles or even to return to the nearest base without human guidance.

Like air traffic controllers, drone pilots have high-stress yet often dull and repetitive jobs, mostly surveilling areas for intelligence and potential targets. Because of burnout, they quit three times as often as regular pilots.

Those who stay receive extensive training in a traditional classroom setting, as well as hands-on training at their computers. They execute endless practice runs and then review their in-flight decisions, attempting to hone their minds to select the best approach to any given scenario, particularly those that involve the use of deadly force.

When they score an important victory, these pilots receive medals just like any others, and in spite of the geographical disconnect from their targets, many suffer emotional trauma from the damage their strikes cause.

Not all drones inflict suffering and mayhem. There is an entire range of drones for commercial and private use.

In many places, including the U.S., civilian and commercial drone use is severely restricted by aviation administration regulations, primarily in the name of safety. That does not, however, stop thousands of people from using drones for a plethora of purposes, including videography, sheep herding, product delivery and crop surveying.

If you perform a quick search through your favorite online megastore you'll see that dozens of drones are available. Some are less than $100. Other costs thousands. There are two broad drone categories: fixed-wing and rotary. Each type has its strengths and weaknesses.

Fixed-wing drones can be hand-launched, but often they require a runway or even an unwieldy catapult. They're generally faster and can fly much longer than their rotary brethren.

One option is the eBee senseFly, a fixed-wing drone designed specifically for mapping purposes. Toss it into the air and it follows a preprogrammed route, snapping high-resolution images that are then integrated into maps and 3-D models. It can cover more than 4 square miles (10.4 square kilometers) on a single flight. Farmers are the primary customers, as they can use the drone to optimize their agricultural practices and increase their yields. The eBee can retail for up to $20,000.

The Agribotix Hornet LR is another fixed-wing drone, and like the eBee, it's intended largely for agricultural use. It has a 6.4-foot (2-meter) wingspan and a cruising speed of more than 30 miles (48 kilometers) per hour. It can fly for nearly an hour and a half before it must descend for recharging. Rather than only offering purchase options, Agribotix leases units to customers.

Fixed-wing drones are just a teensy sliver of the commercial and hobbyist drone market.

Fixed-wing drones are fast and fly far, but rotary models are much more common, in part because they're easier to fly and more stable for purposes like photography. If you want a rotary unmanned aerial vehicle, you'll have dozens of options from which to choose.

On the cheap side, for instance, there's the Hubsan Mini RTF quadcopter, which sells for $100 to $200. It's so tiny that it will fit in the palm of your hand. After a 40-minute charging session, you'll get about seven minutes of flight time during which you can make the drone do four-way flips and other stunts. You can also capture pictures on a miniscule 0.3-megapixel camera.

The Parrot AR.Drone 2.0 Power Edition is a quadcopter that sells for $300 to $400 online. This drone features upgraded batteries that offer about 36 minutes of flight time. It comes with a free flight control app that you can load to your WiFi-enabled device, such as a tablet or smartphone, letting you control the drone. It also has a 720p HD video camera that streams video live to your device, giving you a bird's-eye view literally on the fly.

One of the better-known drone manufacturers is DJI, which makes the DJI Phantom series. These drones aren't just for fun — they're intended to give blossoming cinematographers a way to catch amazing high angles without the need for more expensive gear. Some models come with GoPro camera mounts, while others are equipped with onboard cameras of their own.

With all of these flying contraptions zipping around, it's hard to deny that they seem awfully reminiscent of regular old remote-control helicopters and planes. So, what's the difference between those traditional radio-controlled machines and new-age drones?

It has a lot to do with automation and advanced digital features. Whereas traditional remotely controlled devices require constant attention, drones can do amazing things on their own. Program in a GPS location, for example, and a drone can automatically fly itself to that point and then hold its position. Or you can run a so-called "follow me" mode, and the drone will follow you around, tracking you by sensing the signals from your phone.

Modern drones are equipped with a whole slate of similar fun and useful features. Of course, none of those capabilities are worth much if the thing can't get off of the ground.

Even casual observers realize one striking thing about drones — they often have four propellers (but can have anywhere from three to eight) unlike traditional RC helicopters, which have only one main rotor. Drones need extra rotors because they need more stability to pull off their automated functions.

More rotors also mean more lift. Lift, of course, is the push that spinning propellers create beneath a flying machine. The more lift a device has, the higher and faster it can go, and the more weight it can carry. That last part is vital for anyone who wants to attach a camera to a drone. Too little lift means a drone will moan and groan and crash — or maybe never get airborne at all.

There's a reason that most consumer drones don't get much more than 15 to 20 minutes of flight time, and that reason is related to power. Drones need batteries to power their props. A couple of lightweight rechargeable batteries suffice for a short amount of time in the air. Adding more (or more powerful) batteries is a great idea ... until you realize the extra weight they add can reduce overall flight time.

As power flows from the batteries to the rotor motors, the propellers begin to spin, and it's the spin of each prop relative to the others that changes altitude and direction. Rev up the rotors and they'll generate enough lift to overcome the force of gravity, zipping the drone higher and higher.

If you want the drone to tilt on one side, two of the rotors will begin spinning faster on one side, creating more lift. In doing so, some of the upward lift becomes more of a sideways force, causing the drone to move forward or backward. In the same manner, different prop speeds will spin the drone.

Obviously, you don't have to think through these processes as you're flying your drone, otherwise you'd probably crash it every 10 seconds. Drones are loaded with accelerometers and gyroscopes that help them maintain their orientation in space. These instruments detect linear acceleration, tilt and other directional cues to keep them from dive-bombing the ground — or worse — unsuspecting bystanders.

Many drones also have integrated GPS so the machine "knows" where it is. Command the drone to hover in one small space and it will do so, fighting a breeze if necessary.

To input your commands, you need a controller, typically one that uses 2.4 gigahertz radio waves. Many drone controllers look just like RC controllers of yore — that is, a boxy unit with two thumb joysticks and a collapsible antenna. Others rely on a combination of 2.4 gigahertz signals and WiFi, and they may pass on an old-school controller for one that looks more like a gamepad. They may even rely on a control app on your smartphone or tablet.

The act of flying consumer drones ranges from pretty easy to fiendishly difficult. Cheaper drones are budget-friendly but may be so difficult to fly (and so delicate) that they're broken before you can figure out how to make them travel in a straight line. Pricier drones often have some automatic functions, like landing assistance, that help simplify some of the harder and riskier portions of flights, easing you into your new role as a pilot.

Drones are the stuff of dystopian nightmares. They're used for surveillance at home and abroad, raising privacy issues everywhere. They can carry weapons and can kill people from thousands of miles away while the operator sips coffee in a temperature-controlled office.

Yet drones are a dream come true for many commercial enterprises. Farmers can better monitor fields and livestock. Construction engineers can much more easily see their projects from every angle. Drones can offer new perspectives on real estate, move cargo and deliver packages.

By one estimate, drone technology could create more than 100,000 jobs in the next decade. And they could boost the economy by billions and billions of dollars as they spill into sectors of engineering, computer science, commercial contracting, videography, forestry, and, of course, the military. All of these disciplines will require experts in fabricating and flying drones — and commercial drone pilots could make good money.

Colleges, such as the University of North Dakota, are increasingly offering degrees for piloting drones in anticipation of the drone explosion. Students train on simulators as they build up their flight hours, but in many cases, they can't fly actual drones as part of their coursework. That's because before drones can truly take flight, they'll have to surmount legal and regulatory hurdles. At present, the FAA limits what drones can do in American airspace — even if you're practicing through a college program.

Hobbyists must keep their machines flying lower than 400 feet (122 meters) and at least 5 miles (8 kilometers) from airports to prevent conflicts with manned aircraft. In spite of those rules, the FAA has documented dozens of near misses from people who violate regulations, and any of those instances could have potentially caused serious damage to an airplane and endangered lives. Those kinds of problems complicate the government's ability to integrate commercial drone usage on a larger scale.

Still, Congress has directed the FAA to find ways to regulate drones, particularly commercial drones, in ways that will help harness these technologies for the economy. In the meantime, drone technology continues to evolve much more quickly than any single organization can track. Hobbyist drones are getting cheaper and more capable by the month, and more and more manned military craft are being replaced by enormous, powerful and deadly drones.

If you were waiting for the day of the drones to arrive, realize this — that day has already come. Drones, for good or bad, will be a part of our culture for many years to come.