Guide To R/C Flying: Quadcopters, Helicopters, and Planes
I'm still relatively new to the world of R/C flying, after quite a few false starts over many years. I was amazed at just how complicated things have recently become, and just how hard it was to get simple answers to seemingly basic questions. Hoping to save others from the horrible frustration of this, I've written this still evolving and expanding document on the topic. Since I am not an expert I may make errors. If you know better, please correct me! I do not wish to spread falsehood!
It would be painful to have to explain at the point I first use a common term, so here are some things you can read or skip over if you already know it.
Control Surfaces: Throttle, Rudder, Elevators, Ailerons
The control surfaces are the various moving panels on the wings and tail that dictate your craft's behavior in flight. If my explanations don't suffice, check out this very good explanation.
If you're not an idiot you probably know that the throttle controls the speed of the engine, and the more throttle the faster the engine goes. Whether you're flying electric or gas more throttle means the propeller blades (or ducted fan) push more air meaning your craft goes faster and/or generates more lift (or the tendency to get the hell off the ground).
Elevators are the horizontal flaps on the tail that cause a plane to point (or pitch) up and down. If you take off from Los Angeles International Airport you can bet the pilot has used the elevators to point the nose into the sky. Both elevators (left of the rear vertical fin and right of it) operate together, moving up or both together.
On the rear vertical fin is the rudder which allows you to control yaw, or the craft's deviation from directly forward motion. Ever seen a dog walking slightly sideways, perhaps because his leash is pulling to one side? The dog is yawing. In flight the rudder's key use is to help make turns more quickly. You can certainly make turns in the air without applying some rudder, but once you start applying rudder you'll quickly realize how much more control you have and how much more quickly you can complete turns. The rudder can also be used when taking off or landing in cross-winds. And on the ground the rudder is useful for turning the craft when you need to taxi pre or post landing.
Most of the work of a turn is accomplished by using one control surface on each wing, together referred to as the ailerons. Making one side's aileron go up makes the other side's go down.
Transmitter & Controller
Radio controlled (r/c) flying would be nothing without transmitters and receivers! Without them we'd be living in the dark times of the control line flying. Mad props go to people who still love that hobby, but for most of us it's just way too limiting.
The transmitter (or tx) is the hand-held controller you use to remotely control your craft. If you've owned an r/c car, boat, or plane you have held a transmitter. To state the relatively obvious, most transmitters have two sticks, two trim buttons or a slider per stick, a number of switches, a display, and a power button.
Frequency (Kenneth, What's the Frequency?)
Transmitters and receivers need a frequency range to operate within and the new preferred frequency range is 2.4 GHz, with digital spectrum modulation. The older system of fixed frequencies (27 MHz, 49 MHz, 50 MHz, 72 MHz, and 75 Mhz) work great until you have other source of interference, often other r/c pilots but also household and neighborhood sources. The new digital spread spectrum does not suffer from this same problem, and even allows (with the proper equipment) the return of important data from your craft to your transmitter (battery level, GPS, etc.).
Most modern transmitters and receivers will operate in the new 2.4 GHz range, so this isn't a feature you really need to look for so much as you need to watch out for the older style.
For more info, check this out.
Modes (Mode 2, Mode 1, etc.)
When people talk about transmitter modes or a particular transmitter having this or that mode they are really just talking about the default configuration of the sticks on the transmitter. Almost everyone uses what is called "Mode 2" which means that the left stick controls throttle and rudder and the right stick controls elevator and ailerons. Since the vast majority of people use only Mode 2 that's what most transmitters support and you don't need a transmitter that supports more than that unless you happen to live somewhere that might be a problem (because perhaps you are going to fly with or be trained by others who fly Mode 1).
A transmitter is described primarily by the number of channels it supports. Channels being the mechanism for communicating commands. One channel is typically used to communicate one attribute. Information about the throttle or up/down position of your left stick requires one channel. While you might think of up-ness and down-ness as two things remember that it can be thought of as just one, degree of up-ness from full down-ness, hence it requires only one channel. Similarly the rudder or right / left position of your left stick requires one channel. Having left and right sticks therefore requires 4 channels.
While 4 channels is enough for the basic flight of most planes, helicopters, and quadcopters, you can quickly imagine the benefit of having other channels to control things like landing gear retraction/extension, flaps (control surfaces to give you additional lift for takeoff and landing), lights, cameras, etc.
How many channels you need in your transmitter is totally dependent on what your craft requires and what you want to do with it. Make sure your transmitter supports at least as many as your craft requires and you'll be fine. If you are starting off with a simple craft and expect to buy something bigger and better down the road you may wish to buy a controller with fix or six channels to accommodate a plane you expect to get in future.
You can't go wrong buying a transmitter with more channels than your receiver has, except for the reality that incompatibility between manufacturer's receivers means that next plane you're lusting after might come with a receiver you can't use with your super expensive 8 channel transmitter.
Cross-Manufacturer Compatibility / Open Standards / Etc.
As far as I can tell there aren't really any standards widely adopted between transmitter/receiver manufacturers, with the exception of BNF (see below). In other words, a 6 channel Spektrum transmitter won't work with a 6 channel Futaba receiver unless it's BNF. I could be way off on this one, I'm just basing this off the fact that every tx/rx company seems to talk about their own standard, and in all the ads I see for kits I always see them specify transmitter brands to match the receiver, instead of mentioning some standard the transmitter needs to support.
[I need to explore this topic more and make sure of my facts.]
The receiver is the generally small (the size of a box of matches) device that goes into your craft and to which the receiver sends its commands. In electric airplanes, helicopters, and quadcopters the receiver gets its power from the main battery, in gas powered craft the receiver generally has its own battery. [I need to check if nitro is like gas and doesn't need a battery for the engine, I assume so.]
Receivers are defined by the number of channels they listen to and what they'll communicate with (either BNF or its manufacturer's current line of transmitters).
Batteries / LiPo / NiCad / etc.
Lipo is the battery type most widely used in today's electric aircraft, delivery power at higher amps and for longer than previously possible. The down side is they are volatile and recharging them must be done with all proper precautions taking lest they burn down your house and kill your family. No joke.
Basic rules for Lipos:
Never charge them unattended. Don't go wandering off!
Only charge them on and around non-flammable things (on top of metal, stone, etc. and not around paint cans, gasoline, etc.)
Always check to make sure your lipo pack hasn't bulged or changed shape! They sometimes swell up and that's the end of that lipo! Do not use it!
Never use a damaged lipo cell!
Never charge them with an unapproved charger
Never charge them with more current than they are allowed
Always make sure the charger is plugged in and turned on before connecting the lipo, otherwise it can short circuit!
Want a BNF, PNP, RTF, ARTF? Seriously, WTF??!?!
One of the most confusing initial things about getting into r/c flying is the different kit types. The vendors all use the acronyms BNF, PNP, RTF, ARTF, etc. but what do they mean????
Bind-N-Fly / Bind and Fly (BNF)
A BNF plane, helicopter, or quadcopter requires only one thing to fly: a BNF transmitter with enough channels. If you've got such a transmitter you are all set! Otherwise you just need to buy one.
Unless it says otherwise, these BNF setups include the assembled craft, whatever battery it needs, a charger for that batter, and a BNF receiver already installed. Just charge the craft, bind your transmitter, and you're off!
Plug and Play (PNP)
A PNP plane, helicopter, or quadcopter requires: a receiver with enough channels for the craft's controllable elements, a transmitter for that receiver, and (very often but not always) a battery and charger for the craft. The craft is assembled, so all you need to do is install the receiver, charge everything up, and you're ready!
Ready to Fly (RTF)
Nothing is needed with an RTF plane, helicopter, or quadcopter. What you buy includes the assembled craft, battery, charger, receiver (already installed), and a suitable transmitter is included. You just open up the packaging, charge and install the batteries, and off you go!
Almost Ready to Fly (ARTF)
An ARTF craft usually includes everything and just needs a few minutes of assembly as a result of the need to package the craft for shipping (e.g., removal of wings).
Kit can mean almost anything, but it usually means you'll need to buy or own some things and you can expect to spend a few hours assembling and possibly testing/adjusting your craft after assembly and before reliable flight.
Kits are a great way to say money if you've got patience, intelligence, confidence, and the components they aren't including in the kit.
R/C Flight Simulators
Flying a remote controlled plane, helicopter, or quadcopter in the real world is great, but if you are new to the hobby or new to the type of craft, you're going to crash within minutes, if not seconds! And crashing can (and often does) mean lost time and lost money! In the virtual environment you can crash as often as you like for free! To be sure, flying a virtual model of your real world r/c plane won't be exactly the same, but it will be close enough for your real world skills to develop. Adding to the realism you typically use your actual transmitter with the software, by using an included cable to connect the training port of your transmitter to your computer's USB port.
New r/c pilots must become unconsciously competent in quite a few areas if they are going to keep their crafts safely aloft. Anyone brand new to the hobby can get a plane, helicopter, or quadcopter off the ground but what happens when they begin a turn they don't know how to end, what happens when a gust of wind hits it, what happens when they misjudge the throw of a stick, etc.
The key skills a flight simulator can develop are:
Determining craft orientation at a distance
Reacting to wind
Determining Craft Orientation at a Distance
You can't fly something when you don't know which way it's pointing. If you're mental image of the craft points in the wrong direction the inputs you give it will send it off in completely unexpected directions to which you will likely (as a newbie) respond wholly inappropriately. In a matter of seconds you can go from a pleasant flight to a major, full-throttle crash. Maintaining an awareness of your craft's orientation and re-establishing that awareness when it is lost is absolutely critical. The flight simulator is instrumental in developing this skill. Over time you learn to better detect visual cues that suggest orientation as well as develop minor inputs that can quickly and without confirm or deny your orientation suspicions.
Surely the hardest initial hurdle relates to keeping your control inputs matching the forward or backward orientation of your craft. When things are flying away from you everything is easy, but when it has made a turn and is coming back towards you everything can become incredibly hard. Even if you're doing well for a few moments, any crisis will rapidly send you back to giving mis-oriented commands.
This is not a skill involving logic, so don't make the mistake of trying to intellectualize these mental operations! The more you practice the better you'll get until eventually you are always doing it right! There is no more perfect place to learn this skill than in the simulator!
Initially your stick inputs will probably be much larger in range than is required. You'll drop or raise speed too quickly, you'll begin and end a turn too harshly. That's normal! And also normal is the gradual realization that the art is in the subtle finesse. The slighter and more controlled your movements the more the craft will go exactly where you need it to. While a virtual model is not a real model and while you will need to re-adjust to the real flight characteristics once you get to a field, you can be sure that the understanding of the need for subtlety will be retained.
Reacting to Wind
Flight simulators provide marvelous wind and gust simulation to let you learn to cope with the unexpected.
While helicopters and quadcopters are easy to land, landing a plane (particularly on a runway) requires a lot of skill. The most difficult part of the landing comes during the approach, lining the up for its touchdown. Here again a simulator is vitally useful in letting you get it wrong hundreds of times before you must get it right. Many flight simulator programs have built in landing training routines where it lets you repeatedly perform just the last few moments of flight.
The two commercial software packages I've used the most are Phoenix Flight Simulator ($129) and Aerofly 5 ($199). From what I've read and experience a bit myself, Phoenix is the superior helicopter and quadcopter simulator while Aerofly is the better plane simulator (Aerofly has no quadcopters, Phoenix only has one).
Both feature simularly impressive visuals, though Phoenix seems to default to far poorer settings than your machine can probably do. Make sure you adjust your settings because the improved visuals do make the experience more lifelike.
One very impressive feature of Aerofly is the ability to more dynamically interact with the location from which you are flying. With Phoenix you are fixed in one location at any given field (or scene, as they refer to it). While this isn't a real negative, it quickly feels like an annoying limitation once you experience the ability within Aerofly to switch between multiple locations within flight fields as well as to load several provided "4-D" flight fields which are in fact fully modeled 3-D locations, as opposed to the others which are just panoramas with a slight simulation of depth provided by the ground, and obstacles your crafts can't hit. The "4-D" (I hate that technically incorrect name) scenes have the added benefit that if you are on in the normal r/c simulator mode you can move your own location anywhere within the scene. Also, because it is a real 3-D environment you can choose different camera modes, including the ability to fly along side or behind your plane.
Electric Speed Controller (ESC)
The ESC as used in radio controlled craft performs two primary functions. The first is to act as a Battery Elimination Circuit (BEC) allowing both the motors and the receiver to be powered by a single battery. The second (and primary) function is to take the receiver's and/or flight controller's signals and apply the right current to the motors.
You can read more here.