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These notes are based on the excellent work of Mike Lynch and Tom Rhodes of the Crystal River R/C Club.
 How does the radio control system work? - As with any kind of radio, a transmitter (held by the flyer) is used to send signals to the receiver (in the airplane). Both are powered by (usually rechargeable) batteries. The radio system can have several channels. Each channel is used to control one airplane function. Servos (one for each channel) are used to cause the actual motion within the airplane to make control surfaces move.
A good beginner's radio configuration has four channels. These channels control ailerons, elevator, rudder, and throttle. Two sticks (like computer game joysticks) on the transmitter give the pilot command of these four controls. With the most common radio setup mode, the right stick is used to control aileron (left/right) and elevator (up/down). The left stick is used to control rudder (left/right) and throttle (idle through full throttle). Like a computer game joystick, the aileron, elevator, and rudder sticks are spring loaded. When you let go, these sticks spring back to the center (neutral) control position. The throttle stick stays where you place it, from idle to full throttle.
Keep in mind that radio control systems can have more than four channels. Other controls for these channels include retractable landing gear, flaps, and even smoke systems. For now, you should concentrate on the four basic controls. Leave the fancy stuff for when you have mastered the hobby.
Within the airplane, servos receive signals from the radio's receiver whenever either of the transmitter sticks is moved. The servos respond according to the motions of the transmitter sticks and cause the control surfaces of the airplane to move in sync with stick movements (through mechanical linkages). Instructors: If an interested person at the flying field has questions about radio systems, be sure to show them on your own airplane.
Other radio terminology:
Trim controls - It is not possible to perfectly set each servo and control surface prior to a model’s first flight. Say for example, the plane tends to climb in a hands off condition. The elevator trim control will give the flyer the ability to trim in some down elevator without affecting the joystick for the elevator. In essence, trim controls allow the flyer to set the radio so that the plane will fly straight and level with hands off the radio. ALL radios come with trim controls for the four basic channels. It is advisable to perform mechanical adjustments to the control linkages such that the plane flies nearly hands off with all trims set in the neutral position. This is a trial and error process that may take several flights. The effort pays off though since trim buttons are easily bumped out of position inadvertently and it can be difficult to estimate the settings if they aren’t close to the neutral position.
By the way, this is another reason that beginners should seek help. It is highly unlikely that a new airplane will behave perfectly with regard to trim settings. A plane that is not trimmed properly can be very difficult to fly (even for an experienced flier). For a beginner, it may be impossible to fly. During the new plane's first flight, the instructor will trim your airplane, and advise you on the procedure to mechanically adjust the control linkages to be centrally positioned.
Servo reversing - It is sometimes inconvenient (if not impossible) to mount the servos in a way to properly control the control surface. In many cases, the servo will come out backwards (left aileron comes out to be right aileron, for example). The feature servo reversing allows you to mount the servos in the most convenient manner, and if one or another comes out backwards, the servo reversing switch for that servo (in the transmitter) can be turned on. Servo reversing is a standard feature on most radios sold today.
Dual rates - Though not included on every radio, this feature allows you to change the responsiveness of your airplane's control surfaces (usually this feature only applies to ailerons and elevator). On high rates, your servos will move full travel and the plane will be quite responsive. On low rates, your servos may only move about 40-60 percent of their total travels. This is a nice feature for beginners, since you can reduce the responsiveness of the airplane, making it easier to fly.
Mixing - This feature allows you to have one control automatically invoke another. For example, the radio can be adjusted to automatically give some aileron movement in response to a rudder command (to make for a smoother turn). While this is a nice for feature experienced flyers, it doesn't help beginners learn to fly. Don't go out of your way to find a radio with this feature for your first radio.
Radio styles - AM versus FM-PPM versus FM-PCM - Generally speaking, the most reliable (and most expensive) radio style is FM-PCM (stands for frequency modulation - pulse coded modulation). Next in reliability and price comes FM-PPM (frequency modulation – pulse phase modulation). Finally comes AM (amplitude modulation). Though almost all of these radio styles are highly reliable, we recommend that beginners purchase an FM-PPM or FM-PCM radio.
Trainer system – Commonly referred to as a “buddy box”. This feature allows the safest manner of flight instruction. We devote an entire discussion later in this set of questions to the trainer system. Please refer to this information. For now, just remember a beginner should not buy a radio that is not set up to accommodate a buddy box.
How many airplanes can fly at a time? - The FCC has allotted 50 frequencies to model aviation. These frequencies are given numbers, ranging from 11 to 60. In theory, this means that fifty planes could be flying at the same time! However, the likelihood of fifty flyers showing up at the same flying field without duplicating frequencies is low. Also, when more than four or five planes are in the air at the same time, it can be quite distracting to the flyers (mid-air collisions, although rare, do happen). For this reason, the NDRCC normally limits the number of planes that can be in the air at the same time to 4 airplanes. On exceptionally busy days, we allow 5 airplanes up at a time but only if each pilot has a dedicated spotter. The role of the spotter is to keep track of other aircraft in the air on behalf of the pilot, paying particular attention to take off and landing activity on the runway. Note that if one flyer turns his transmitter on when another on the same frequency is flying, the pilot of the plane in the air may lose control of the plane. This is why we require frequency control at the field. Instructors: be sure your students understand the rules of frequency control. Anyone that causes a crash by failure to follow frequency control procedures is financially liable for their actions.
How long can they fly? - Depending on the size of the engine and the size of the fuel tank, the range of flight time can be from about 10 minutes to well over 20 minutes. One common recommendation for a .40-sized engine is about a six once fuel tank. This will allow about a 10-12 minute flight.
What happens if the engine quits? - Most planes designed for beginners will glide quite well. In the hands of an experienced flier, a plane can be safely landed even if the engine quits. Of course the altitude and attitude of the airplane at the time of the engine failure has a lot to do with how difficult it is to safely land the airplane. The higher the plane, the more time the pilot will have to plan the landing. (Landings without power are called dead-stick landings.)
How far away can the airplane fly? - The rule of thumb is if you can see it you have control of it! Generally speaking, your radio will have control of the airplane for distances of more than a mile. The higher the plane, the greater the range.
How fast do they go? - This depends on the style of airplane as well as the size of the engine. Trainers will fly at speeds of about 20-60 miles per hour, depending on the maneuver. More aerobatic sport planes can reach speeds of well over 90 MPH. Pylon racers designed for speed can go as fast as 150 MPH.
How high can they go? - As high as you can see them. Again, if you can see it, you have control of it! However, flying fields that are located in close proximity to airports usually have some height limitations. Instructors: be sure to relate any rules related to height and position flying.
Is flying an RC airplane like flying a full-scale airplane? - In essence, yes. You'll have the same basic controls a pilot has on a full-scale airplane. However, full scale pilots that have learned to fly RC airplanes say there is quite a difference in actual flying technique. They say an RC airplane responds much faster than a full-scale airplane. They also say that learning to fly RC can be awkward, since there is no feel for the plane's maneuvers. RC flying requires much more hand/eye coordination since you must respond to what you see.
Is it hard to learn to fly? - This is a tough question to answer. Everyone has a different aptitude level for learning RC. This much is certain. RC flying is hard enough to learn that you will not want to try to learn by yourself. You are not likely to meet anyone who learned by themselves that did not go through several airplanes (or at least several crashes) in the process! Fixing airplanes is not nearly as much fun as flying. If you want to learn to fly with the least amount of problems and expense, join the club and work with one of our instructors. He'll flight test and trim your plane, take off and land for you, give you pointers, and stand close by, ready to take control if you get into trouble in the air. While we can't promise that your plane will never crash, you will have a much better chance of keeping your plane in one piece with an instructor than without one.
How long does it take to learn to fly? - Like the previous question, this is tough to answer. It depends upon the student's aptitude. It also depends on how often you practice. The more often you practice the shorter the time it will take to master. You know the saying, "If you don't use it, you lose it!" It truly applies to RC flying. If you only fly once a week, it may take quite a long time. You'll be struggling to remember what was learned in the last session. Some people solo (fly by themselves for an entire flight) in as little as two weeks of practice (every day for several flights). Others make take the whole flying season to learn to fly. Yet others may take more than one flying season. With a good instructor, even the learning stage is fun and rewarding. So this period should seem to go quite quickly, regardless of how long it takes.
What is the best size for learning? - Generally speaking, the smaller the airplane, the less expensive it will be. Unfortunately, the smaller the airplane, the less stable it is and the worse it handles in the wind. Here are the approximate engine sizes as well as the approximate wingspan and weight of several standard classes of RC airplane.
| Engine | Wingspan | Weight |
| 0.049 | 35" - 40" | 1 lb. - 2lb. |
| 0.20 | 40" - 50" | 2 lb. - 3lb. |
| 0.40 | 60" - 65" | 4 lb. - 5lb. |
| 0.60 | 60" - 65" | 6 lb. - 8lb. |
| 0.90 | 70" - 75" | 9 lb. - 10lb. |
| 1.20 | 80" - 85" | 10 lb. - 12lb. |
Keep in mind that all size RC airplanes perform nicely on calm days. We recommend starting with an airplane large enough to handle our typical wind conditions. This means a .40 or .60 size airframe.
What's the hardest part of flying? – Take Off and Landing. Your instructor will first teach you how to keep the plane in the air, making simple turns. Then you'll progress to flying figure eight patterns. Once you can keep the plane in the air by yourself without any problems, you'll learn to land. Finally, once you have mastered all other phases of flying, you'll learn how to taxi and take off.
How much wind can there be? - Experienced flyers can fly (sport planes) in winds well over 20 MPH. However, the more wind, the harder (and scarier) it is to fly. Beginners won't want to fly in winds much over 8-10 MPH until they have mastered the first step of learning how to fly. Crosswinds may be particularly difficult for the beginner and your instructor may ask you to wait for a better day.
What about flight simulators? – The flight simulator software available today is very realistic and an excellent investment for beginners. The student can log many times the number of flight hours on the simulator than is possible at the field in a given period of time. This investment is virtually guaranteed to rapidly improve your hand/eye coordination and accelerate your learning curve. The use of this tool may shave weeks or months off of the time it would ordinarily take to achieve solo certification.
What makes a good trainer plane? - Here are some qualities that contribute to making a good trainer plane:
High wing design - You'll notice that all trainer recommendations we give are high wing airplanes. This is the most stable design (even for full-scale airplanes). Since the body of the fuselage is below the wing, the plane will nave a natural tendency to right itself after a turn.
Flat bottom or semi-symmetrical wing - Flat bottom wings are best for stability, which is helpful when learning. However, planes with flat bottom wings are not very maneuverable. Once you do learn to fly, you will eventually want to learn how to do some aerobatics. Flat bottom wing designs perform poorly when it comes to aerobatics. Semi-symmetrical wings have a slight curvature to the bottom of the wing. They are not quite as stable as flat bottom wings, but they do allow moderate aerobatics.
Rugged design - It’s almost a guarantee that your first plane will get knocked around quite a bit. You'll want to be sure that it can take some minor bumps and bruises. But be careful here! When a plane is designed to be rugged, it usually sacrifices some of its flying characteristics. There are a number of planes on the market that claim to be almost indestructible, and they almost are, but they sacrifice good flying characteristics to be able to make this claim.
Should I build a plane from a kit or buy an ARF (almost ready to fly)? - This is totally up to you. If you enjoy working with your hands, by all means, build your own airplane. You can save a little money (but not much) and you'll have the satisfaction of flying something you built yourself. Also, you’ll have the plans to the airplane in case you have to do some repairs after a crash.
On the other hand, if you don't enjoy building, or you wish to get in the air as quickly as possible, there are several excellent flying ARF airplanes on the market (some of which we highly recommend). Keep in mind that, even with an ARF, there is still some work to do. While the wing halves, fuselage, and tail section are complete, you do have to final assemble, mount the engine, and install the radio. Most ARFs come with excellent instructions (since they assume beginners are purchasing them), and you can be in the air in about 10-12 hours of building time. The VRTF (virtually ready to fly) designs can be assembled in as little as two hours with no special tools.
Plane and engine size - 40 size trainers offer the best compromise in stable flight and economy. If cost is not a concern, 60 size trainers tend to be substantially more stable than 40 size trainers (especially in higher winds). Difference in total price between a 40 vs 60-size setup is typically less than $100.
When it comes to engines, you should buy a product with a proven track record of reliability and ease of use. Talk to experienced flyers at your field to get recommendations. OS, Thunder Tiger and SuperTigre engines are among the most common name brand engines at our field. All have excellent reputations and most of our experienced pilots will be very familiar with the initial setup and operation.
As far as power, select an engine that is in the middle or top end of the recommended range for the airframe. As a general rule, it is best to err slightly on the overpowered side. As you begin taking off, a good strong engine makes the procedure much easier. If your plane barely has the power to get off the ground, taking off can be quite a challenge. This extra power is also very handy when practicing approaches and for gaining altitude fast. Additionally, once you have learned to fly, a good strong engine will be needed for your next (sport) airplane.
What is the trainer system? (IMPORTANT!!) - Imagine you've just built your airplane and you bring it out to the field for the first time. You get together with an instructor and he test flies your airplane and trims it out. Now it is going to be your turn. Your instructor takes off again and gets the plane up to a safe altitude and hands you the transmitter. If you’re like most beginners, you’ll have the plane on its back almost immediately (beginners have the tendency to over-control the plane). Your instructor quickly grabs the transmitter back from you and rights the plane. Then he gives you back the transmitter. You get about 3 more seconds of practice before he has to grab the transmitter again.
This passing back and forth of the transmitter is very cumbersome, error prone, and downright scary. In the beginning, when you are just trying to keep the plane in the air, passing the transmitter will suffice. But as you get better, and you begin to do maneuvers closer to the ground (like takeoffs and landings), you'll want a more fail-safe method of instructor control.
Typically called a buddy box, the trainer system allows you to connect a slave transmitter with the master transmitter via a cable. Once set up properly, the instructor will take the master transmitter and give you the slave transmitter. He'll get the plane in the air and when ready, he’ll simply press a button and you'll have control. If you get into trouble, he releases the button and he has control again. No more passing transmitters. The trainer system will dramatically improve your odds of learning how to fly without crashing even once (especially as you begin taking off and landing).
Note that the trainer system connector port is not equipped with all radios. Most older AM style radios, for example, do NOT come with this port and those that do typically are not compatible with our modern FM systems. You should plan on buying a current model Futaba, Hitec or JR FM transmitter.
Pre-flight inspections - Beginners to RC flying vary dramatically when it comes to building skills. Some are building their very first flying model and find it quite challenging while others may have built other types of flying models and find it rather easy. The kind of airplane has a lot to do with how difficult it is to get into flying condition. ARF's tend to be rather easy, requiring little more than final assembly while kits can be much more challenging. Additionally, correctly installing radios and engines can be somewhat difficult, even for ARF airplanes.
For these reasons, we insist that all beginners have their planes checked for air-worthiness prior to starting flight training. Instructors will check for problems that need to be corrected. Common mistakes that must be corrected before the plane can be flown include having servos activate control surfaces in the incorrect directions (easily fixed by using servo reversing), not placing foam rubber around the receiver for padding, not properly gluing wing halves (on ARFs), not correctly gluing hinges, and improper center of gravity point. Keep in mind that these are but a few of the many things that can cause an airplane to crash, and the instructor must be on the lookout for many more.
Additionally, there may be things an instructor finds that may not cause the airplane to fail (yet) but should be repaired in the near future. For example, certain control surface hardware (clevises, control horns, and linkages) works better than others. An instructor may be willing to help a beginner today, but ask that some things be changed before further help will be given.
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