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Do You Want To learn To Fly?
|You Can Learn to Fly an R/C Airplane, Helicopter, Gas or Electric!|
First-time pilots should always seek the help of an instructor. An important part of working with an instructor is making sure that your radio is compatible with standard "trainer systems" or "buddy boxes" (Low cost planes do not have this capability and are a waste of your money). The trainer system allows you to connect your radio to your instructor's, using a cable. You'll still be the one controlling your model, so long as your instructor holds down the trainer switch on his transmitter. But if you start having trouble, all the instructor has to do is release the switch to take over full control of your aircraft. This saves you from crashing your airplane. With your ARCA club membership and your AMA card we will provide an instructor free of charge, you'll learn faster and with more confidence than if you start out and try to solo by yourself. Your plane will last longer too! You do need to have an AMA license in order to fly at any AMA sanctioned field. The AMA license provides the pilot with insurance as well as other nice things. This insurance protects you in case of an accident involving another person or person’s property (like his car etc..). The AMA website where you can get your license is www.modelaircraft.org.
If you are thinking about an Electric R/C Airplane we have information below as well as in our Builders Korner which is called "Getting Started Guide to Electric RC Flying. By Scottwired". This also might be of interest to you.
- How much does it cost? Average cost for a complete (but no frills) beginner package runs around $200-$350.
- How fast does a model go? Trainers usually cruise at 25-30 mph and can land at speeds as slow as 12-15 mph. However, there are also unmodified, off-the-shelf airplanes that can deliver speeds of up to 200 mph!
- How far can a model fly? The range for a modern R/C system is about a mile. But to maintain control, you need to have your model close enough to tell what it is doing. Even a plane with a 5-6 foot wingspan looks tiny at half a mile.
- What happens if I run out of fuel or battery power in flight? Contrary to popular belief, you have control even if your engine or motor stops running. You just glide your plane in for a "dead stick" landing. The radio system has its own batteries for power.
Radio: R/C planes are controlled by a radio system that consists of a transmitter—which stays with you on the ground—plus a receiver, servos, and receiver battery (all of which are "on-board" components, mounted inside your model). Most aircraft radio systems come with everything you need, including a rechargeable battery pack. As mentioned earlier, first-time pilots should always seek the help of an instructor. And an important part of working with an instructor is making sure that both of you use radios with "trainer system" or "buddy box" capability. The trainer system allows you to connect your radio to your instructor's, using a cable. You'll still be the one controlling your model, so long as your instructor holds down the trainer switch on his transmitter. But if you start having trouble, all the instructor has to do is release the switch to take over full control.
Most trainer planes require a radio with at least four channels of control, to operate the throttle, elevator, rudder and ailerons. But not all 4-channel radio systems come equipped with the necessary four servos. Make sure your system has as many as your plane requires.
Aerodynamics: To fly, an airplane's wing has to overcome gravity by developing lift greater than the weight of the plane. Since it can't do that standing still, airplanes use thrust...force directed backwards...to drive the wing forward through the air and generate lift. However, thrust has its own opposition to overcome in the form of drag—the resistance of the air to a body moving through it. If lift and thrust are greater than gravity and drag, you have the potential for flight...and fun.
Wing Location: Wing placement, for the most part, falls into two major categories—high wing design and low wing design. In a high wing design, the weight of the model is suspended below the wing. When the model tilts, the model's weight tries to return it to a level position. As a result, high-wing models tend to be more stable, easier to fly—and natural choices for trainers. A low-wing model is just the opposite. With its weight above the wing, it tends to be less stable—excellent for advanced fliers who want to perform rolls, loops and other aerobatic maneuvers.
Airfoil: If you face the wing tip of the plane and cut it from front to back, the cross section exposed would be the wing's airfoil. The Flat-Bottom Airfoil will develop the most lift at low speeds and helps return the model to upright when tilted. This is ideal for trainers and first-time pilots. A Symmetrical Airfoil's top and bottom have the same shape, allowing it to produce lift equally whether right side up or upside down and to transition between the two smoothly. This is recommended for advanced pilots. Lastly, a Semi-Symmetrical Airfoil is a combination of the other two and favored by intermediate and sport pilots.
Wing Area/Wing Loading: Wing area is the amount of wing surface available to create lift. Wing loading is the weight that a given area of the wing has to lift and is usually measured in ounces per square foot. Generally, a light wing loading is best for beginners. The plane will perform better and be easier to control.
Dihedral: Dihedral is the upward angle of the wings from the fuselage. Dihedral increases stability and decreases aerobatic ability.
Wing Thickness: Wing thickness — measured from top to bottom — determines how much drag is created. A thick wing creates more drag, causing slower speeds and gentler stalls and is ideal for beginners. A thin wing permits higher speeds and sudden stalls — desirable for racing and certain aerobatic maneuvers. Landing Gear Location: Tricycle gear includes a nose gear and two wing (main) gears, making takeoffs and landings easier—ideal for beginners.
Until recently, most R/C airplane models came in Kit form—consisting of a box full of parts, a set of plans, an instruction manual and some hardware. And kits remain very popular. Many modelers enjoy the challenge of putting them together as much as actually flying them. Depending on the kit, however, assembly can take weeks or even months to complete, and also requires a well-equipped hobby toolbox.
For a number of reasons—including a shortage of leisure time—hobbyists are now turning to "prebuilt" models as another way to enjoy R/C flight. Actually, prebuilt planes are great for first-time pilots. Because they come factory-assembled, you KNOW they're constructed well. Many are put together with materials as high in quality as any kit. Because you haven't put your heart and soul into building them, you're less likely to be nervous when flying them. And they let you focus on learning to fly, without also having to learn new model building skills.
You can choose from models with varying degrees of preassembly. The following acronyms are commonly used to identify types of prebuilt planes:
ARF: Stands for "Almost Ready-to-Fly." Most can be completed and flight-ready with as little as 16-20 hours of assembly. Major structures such as the wing halves, fuselage, and tail fins all come entirely built and covered. Average cost for a complete (but no frills) beginner package runs around $100-$150 You simply assemble those sections, install your power plant and radio gear is extra, attach the landing gear and a few other pieces of hardware...and you're done.
RTF: Stands for "Ready-to-Fly." Want a model that's ready for the air as little as 20 minutes after you open the box? Get an RTF. You'll still have to complete a few final assembly steps, but far less than even ARFs require. True RTFs include engine and radio gear already mounted inside the model. There's no easier way to get airborne! Average cost for a complete (but no frills) beginner package runs around $200-$350.
The "size" of a model plane generally refers to the size of engine, in cubic inch displacement, required to fly it successfully. The most popular sizes are 20 (requiring a .20-.36 engine), 40 (.40-.53 engine) and 60 (.60-.75 engine). Many other sizes are available, too, ranging from small, .049-powered craft up to massive, giant-scale models.
Most trainers fall into the 40-size category. That's because 40s are fairly stable, with enough heft to fly well in breezy conditions, but still small enough to be affordable for new hobbyists. Many 60-size trainers are also available, and offer the advantage of even greater stability—plus easier visibility once aloft—both due to their larger dimension.
What first attracts many would-be pilots to the idea of R/C flying is the thought of controlling a blistering-fast ducted fan jet or wicked WWII war bird. And there's no better way to put a quick END to your flying career than to start with such a model. They're simply not designed for anyone who hasn't yet developed sharp piloting skills. Model plane styles are available that duplicate virtually every kind of full-size aircraft. The best ones for the first-timers are, without question, trainers and trainer-like sailplanes. These are specifically engineered to fly slowly and smoothly. They'll keep you out of trouble—giving you time to acquire the skill and confidence You'll need for those jets and war birds.
RC helicopters are model aircraft which are distinct from RC airplanes because of the differences in construction, aerodynamics, and flight training. Several basic designs of RC helicopters exist, of which some (such as those with collective pitch, meaning blades which rotate on their longitudinal axis to vary or reverse lift) are more maneuverable than others. The more maneuverable designs are often harder to fly, but benefit from greater aerobatic capabilities.
Flight controls allow pilots to control the collective and throttle (usually linked together), the cyclic controls (pitch and roll), and the tail rotor (yaw). Controlling these in unison enables the helicopter to perform most of the same maneuvers as full-sized helicopters, such as hovering and backwards flight, and many that full-sized helicopters cannot.
The various helicopter controls are affected by means of small servomotors, commonly known as servos. A piezoelectric gyroscope is typically used on the tail rotor (yaw) control to counter wind- and torque-reaction-induced tail movement. This "gyro" does not itself apply a mechanical force, but electronically adjusts the control signal to the tail rotor servo.
The engines typically used to be methanol-powered two-stroke motors, but electric brushless motors combined with a high-performance lithium polymer battery are now more common and provide improved efficiency, performance and lifespan compared to brushed motors, while decreasing prices bring them within reach of hobbyists. Gasoline and jet turbine engines are also used.
Types of R/C helicopters
Common power sources are nitro (nitro methane-methanol internal combustion), electric batteries, gas turbines, petrol and gasoline.
Mechanical layouts include CCPM (cyclic/collective pitch mixing) in all power sources, fixed- pitch electric rotors and coaxial electric rotors.
Practical electric helicopters are a recent development but have rapidly developed and become more common, overtaking nitro helicopters in common use. Gas-turbine helicopters are also increasing in popularity, although the high cost puts them out of reach of most people.
Nitro (glow fuel)
Nitro or glow fuel helicopters come in different sizes: 15, 30, 50, 60 and 90 size. These numbers originated from the size of engine used in the different models (0.30 cu in, 0.50 cu in and so on). The bigger and more powerful the engine, the larger the main rotor blade that it can turn and hence the bigger the aircraft overall. Typical flight times for nitro helicopters is 7-14 minutes depending on the engine size and tuning.
Recent advancements in battery technology are making electric flying more feasible in terms of flying time. Lithium polymer (LiPo) batteries are able to provide the high current required for high performance aerobatics while still remaining very light. Typical flight times are 4-12 minutes depending on the flying style and battery capacity.
In the past electric helicopters were used mainly indoors due to the small size and lack of fumes. Larger electric helicopters suitable for outdoor flight and advanced aerobatics have become a reality over the last few years and have become very popular. Their quietness has made them very popular for flying sites close to residential areas and in places such as Germany where there are strict noise restrictions. Nitro helicopters have also been converted to electric power by commercial and homemade kits.
A recent innovation is that of coaxial electric helicopters. The system's inherent stability has, in recent years, made it a good candidate for the design of small models for beginner and/or indoor use. Models of this type, as in the case of a full-scale helicopter, eliminate rotational torque and extremely quick control response, both of which are very pronounced in a CCPM model.
While a coaxial model is very stable and can be flown indoors even in tight quarters, such a helicopter has limited forward speed, especially outdoors. Most models are fixed-pitch, i.e. the collective pitch of the blades cannot be controlled, plus the cyclic control is only applied to the lower rotor. Compensating for even the slightest breeze causes the model to climb rather than to fly forward even with full application of cyclic. More advanced coaxial constructions with two swash plates and/or pitch control - common for the big coaxial helicopters like Kamovs- have been realized as models in individual projects but have not seen the mass market as of 2009.
Small fixed-pitch helicopters need a 4-channel radio (throttle, elevator, aileron, rudder), although micro helicopters that utilize a 2-channel infrared control system also exist; while collective-pitch models need a minimum of 5 channels with 6 being most common (throttle, collective pitch, elevator, aileron, rudder and gyro gain). Because of the normal interaction of the various control mechanisms, advanced radios include adjustable mixing functions, such as throttle/collective and throttle/rudder.
Radio prices vary from $100-$2,000 USD.
Well-known manufacturers of helicopter-specific radio controllers include: JR, Spektrum, Futaba, Hitec, Sanwa(known as "Airtronics" in North America), Multiplex(a division of Hitec)
Radios emit the FM signal in two types of modulation.
PPM is cheaper than PCM and is generally used in low-end helicopters. The lack of a failsafe in PPM makes it more suited to small, less dangerous models. Higher-end radios offer PCM and PPM modulation for better compatibility with all radio receivers.PCM
Pulse Code Modulation. A scheme in which the commanded position for each servo is transmitted as a digitally encoded number. Manufacturers use their own proprietary system to encode this number with various levels of precision (i.e. variable number of bits per servo position). JR use Z-PCM (9 bits, 512 different values: 0 ... 511) then S-PCM (10 bits, 1024 values: 0 ... 1023). Futaba use PCM-1024 and G3 PCM (11 bits, 2048 values: 0 ... 2047). With PCM not all positions are broadcasted at one time (each frame) to save time. The odd numbered positions are sent as absolute in one frame, with the even sent only as differences
from their previous values. The next frame the opposite is done. PCM includes a check sum at the end of the frame to check the signal's validity. Hence, if there is interference and the signal arrives distorted at the Receiver, utilizing the checksum it is able to know if it is the original. In case it is not, a feature called Fail-Safe is implemented to set servo positions to a predefined position, or to hold them at the last valid position.
Pulse-position modulation. A scheme in which the commanded position for each servo is transmitted as the duty-cycle of the transmitted pulses 1 per servo position.
Systems such as FHSS (Frequency-hopping spread spectrum) used by Futaba employ frequency hopping on the 2.4 GHz band instead of the various frequencies in the lower MHz ranges. The advantage is that radios are no longer using a fixed frequency during flight but a multitude of frequencies.
Systems such as Spektrum and JR use the DSM2 DSSS (Direct-sequence spread spectrum) method, where they transmit on a pair of fixed channels chosen when the radio and receiver are turned on. Any subsequent systems would avoid using these channels and continue searching for another unused pair of channels.
With either method many radios can be transmitting at once without interfering with each other. The Futaba systems change frequency approximately every two milliseconds, so even if two transmitters are using the same channel they are not doing so for long. The pilot will not notice any abnormal behavior of the model in the 1/5OOth of a second that they are interfering. This gives one the advantage of turning on a transmitter without regard to channels currently in use by other pilot's radios.
One downside to 2.4 GHz is that precautions must be taken during installation since certain materials such as carbon fiber can mask the signal. In some cases, "satellite" receivers with secondary antennas need to be used to maintain better line-of-sight with the transmitter
Aerobatic helicopter flying has historically followed the Federation Aeronautique International rules, which for helicopters are labeled F3C. These include a predetermined routine of hovering and aerobatics.
An advanced form of RC helicopter flying is called 3D. During 3D flying, helicopters perform advanced aerobatics, sometimes in a freestyle form, or in a predetermined set of moves drawn up by the organizers of the competition. There are a number of 3D competitions around the world, two of the best known being the 3D Masters in the UK and the extreme Flight Championship (XFC) in the USA.
Although RC helicopters are generally used by hobbyists for recreational purposes, they are sometimes used in applications such as low altitude aerial photography, filming, policing, and remote observation or inspection. Some companies make RC helicopters specifically for these uses.
Electric Safety Procedures; The electric airplane prop is dangerous and can easily mangle a finger or cut it off. Don't connect the motor battery until you are ready to fly on the runway or hand-launch. Don't turn on the radio system until you are ready for your flight. Turn off the radio system as soon as possible after the flight. Make sure the throttle is set to off before turning on your transmitter. Many digital speed controls have a function that won't allow the motor to turn until the throttle stick has been in or moved to the low position. Do not make it a habit of testing this function. Motor-on radio checks must be done with the aid of a helper.
There are different electric airplanes, Indoor, Electric Slow and Park Flyer and what we will call full size airplanes. In this group there are planes the size of small to large gas airplanes as well as jets which travel up to 200mph.
Indoor models are typically the smallest, lightest and slowest of the three, usually weighing less than 8 ounces. Many indoor venues impose a maximum weight limit, often 150 grams. Indoor models have very low wing loadings and use the smallest available cells, 50 or 110mAh being fairly usual, as well as specialized, often coreless motors.
Electric Slow Flyers are sometimes regarded as an in-between type, the next level up from indoor models. The term "Slow Flyer" is often used to describe both indoor models and park flyers. They’re basically small, light and slow enough to be flown in a backyard or Neighborhood Park, rather than a standard club flying field.
Park Flyers are generally too large or heavily loaded to fly indoors. They tend to use Speed 280-size motors and up, often geared, and batteries up to about 600mAh. They can weigh anything up to 18 ounces, though they’re often quite large and still have light wing loading. They’re also intended for use in relatively small outdoor areas such as schoolyards or local parks.
Full size electric airplanes can be as large as gas airplanes and weight the same. The EDF jets can reach speeds of 200mph. They require large batteries in the range of 3000mAh and larger with voltages up to 22.2v and beyond.
The comparison between electric motor and gas engine is as follows: 1 brake horsepower = 750 watts. The problem is that electric motors have many more variables than gas engines. In order to determine the performance of an electric motor, you must first answer questions such as how much duration you want, how much power you need, etc. Gearing also heavily influences the comparison.
Brushless electric RC motors
At the forefront of the advance in electric rc modeling is the brushless motor.
Traditionally, electric powered models have used standard DC 'brushed' motors. In these, as part of the motor's operation, carbon brushes press against a spinning commutator and this causes friction. This unwanted but inevitable friction puts extra strain on the motor and makes the motor less efficient. Also, the brushes wear down with use and so need periodical replacement. These are the two big disadvantages with brushed motors.
Gearing allows a motor to turn a larger prop at lower rpm. This allows the system to produce more thrust while drawing the same number of amps. The trade-off is that top speed is reduced, which makes gearing suitable mostly for slow-flying aircraft. Sport electric planes are usually run with a direct drive system.
While such motors do work well, a brushless motor uses electronic circuitry and powerful magnets to do the job of the brushes/commutator system and no revolving parts ever touch each other. As a result there is no friction and therefore much greater efficiency, meaning a huge increase in power - brushless motors can be up to 300% more powerful than their brushed counterpart, and they also do away with the issue of periodical brush replacement.
There are two types of brushless motor used in radio control modeling; the inrunner motor and outrunner motor. The inrunner motor is closer to a brushed motor in that the body remains stationary while the permanent magnets and shaft spin within the fixed stator. Inrunner motors, although much more powerful than brushed motors, are still limited in their torque and usually need gearing when used in an airplane or helicopter.
Outrunner brushless motors are different because the permanent magnets are attached to the inside of the motor casing, or 'can', and it's the can that rotates around the fixed stator. When you see an outrunner in operation you will see the outer can spinning. Outrunners generate more torque than inrunners and are very suitable for larger models, and a gearbox is often not necessary as the torque from the motor alone is sufficient.
Inrunner brushless motors, generally speaking, are more suited to swinging a smaller propeller at higher RPM whereas outrunners are more suited to swinging a larger prop at lower RPM.
As with most things electronic, brushless motors carry a rating system, in this case known as a kV rating. The kV value is the RPM (revs per minute) of the motor per volt fed to it. For example, a 2500kV motor powered by a 7.4V Li-Po battery pack will give 2500 x 7.4 = 18,500 RPM with no load.
Motor constants are Kv, Io and Rm.
Kv = Speed / Voltage: With the motor shaft in a drill press running at a known speed, measure the voltage at the motor terminals. So if the speed is 6000 rpm and the voltage is 3V, then Kv = 6000/3 = 2000 rpm/V
Io: Simply run the motor with no load (no propeller) and measure the current taken. You can use almost any voltage, because the current does not vary with voltage. However, the motor will still be turning at the rpm defined by V x Kv.
Both Kv and Io should be measured with the motor neutral-timed. For most can-type motors, this is where they are fixed. If you do have a motor with adjustable timing, you can try (carefully) adjusting it as you measure Io. It will be neutral-timed when Io is at its lowest value.
The speed of electric motors is controlled by speed controls. Traditional mechanically operated controls have been replaced with much more effective Electronic Speed Controls (or Electronic Speed Controllers), or ESCs, which plug directly into the model's receiver throttle slot instead of being linked to a servo, as a mechanical one needs to be.
Whereas mechanical speed controls varied the amount of volts entering the motor, ESCs allow the maximum volts through but at varying rates depending on the throttle stick position. The micro-processor in an ESC opens and closes tens of times a second to let the current pass.
ESCs for brushless motors are different to ones for brushed motors, technology-wise, and this is an important factor to consider when upgrading your model; never use a brushless motor with an ESC designed for a brushed motor.
Brushless electric motors combined with Li-Po battery packs and ESCs are the ultimate combination for power when it comes to electric RC.We have an article in our Builders Korner which very good for the beginner, it is called "Getting Started Guide to Electric RC Flying.By Scottwired".
Model planes can use several different types of power sources. Electric models carry battery-powered motors to turn the propeller. Gliders or sailplanes ride on thermal air currents (some also have electric motors for quick launching to great heights). Most R/C models, however, are powered by glow engines.
The most economical are basic 2-stroke engines with brass bushings supporting the crankshaft. For a little more power, you might choose a 2-stroke that uses ball bearings to support the crankshaft. The ball bearings also extend the life of the engine, so you can continue using it to power future models. The cost, however, is nearly twice that of a bushing-equipped engine.
Finally, there's the 4-stroke glow engine—slightly less powerful than 2-strokes of the same size and higher priced, but offering more torque, swinging bigger props, using less fuel and sounding much more realistic.
The Academy of Model Aeronautics in its efforts to make R/C modeling safer by reminding everyone that there are specific reserved channels for aircraft and surface (car/boat) use. Why separate channels? In today’s crowded urban areas, it is not uncommon to find R/C cars (75 MHZ) being run within radio range of a model aircraft (72 MHZ) flying site. Without channel separation, the possibility of interference would always exist. Most of the crashes that have occurred were caused by people unknowingly operating on an improper channel and they were also unaware that any R/C flying was taking place in the area. Remember that our Broadcast Channels were granted to us by the FCC and we are able to obtain and keep our R/C exclusive channels thanks in part to the excellent safety record of R/C modelers. In other words, this channel system is not just an AMA guideline for members; it’s the law of the land that applies to all R/C users. So please, be aware of the aircraft only/surface only channel system. The model you save just might be your own.
Mode 1 / Mode 2
Refers to the stick configuration of an aircraft transmitter's control sticks. Mode 1 has the aileron/throttle on the right stick and the rudder/elevator on the left. Mode 1 is popular in Europe and Asia. Mode 2 is the USA standard and has the elevator/aileron on the right stick and the rudder/throttle on the left. Almost all radios used in the USA, Canada, Central and South America are Mode 2.
72 MHz Frequency (Channel Number)
Like all radio equipment, an R/C system broadcasts its signal at a specific wave rate and this is known as its "frequency". Just as commercial radio stations that you listen to each operate on their own frequency, so do R/C transmitters. There are several different frequencies to choose from and these are now referred to in the R/C industry by "Channel Number". This channel number is easily confused with the number of control channels used in the model but the two are quite different - the channel number that your transmitter broadcasts on (e.g., channel 26 or channel 50) refers to its frequency, not the number of model features it can control. If there was only one R/C frequency or channel number available, only one person in any given area could operate their model - just as if there were only one TV channel, you would only be able to choose one show to watch! By having a number of different channels available, many models can fly at the same time. Many old fliers are switching over to 2.4 GHz, so old 72 MHz transmitters are selling cheap. What use to sell for $200 - $400 is now selling for around $50. These transmitters work great and are a cheap way for a beginner to start in the hobby.
AM: (72 MHZ) Stands for Amplitude Modulation which transmits by a variation in the amplitude of signals; it is subject to interference more than FM.
FM: (72 MHZ) Stands for Frequency Modulation which transmits signals by variations in frequency, reduces the risk of "glitches" due to signal interference.
PCM: (72 MHZ) Stands for Pulse Code Modulation uses binary code to digitize the signal, providing the most accurate signal possible.
One of the most exciting new breakthroughs in hobby radio technology is the use of 2.4GHz. The Spektrum system does not actively use timeline sharing -- it appears to be solely Frequency division (grabbing sole ownership of two frequencies and denying any other Spektrum transmitter the right to use those frequencies). In this respect it's little different to a smart synthesized 72MHz system that checks what channels are free before firing up then chooses the quietest one and uses it. Of course the Spektrum also only uses a small percentage of the available time on its chosen channels so other systems could (in theory) slip into the gaps without having too much effect but no two Spektrum 2.4GHz systems will share frequencies with each other in the way that Futaba or XPS do. The Futaba FAAST uses both time division and frequency division by performing pseudo-random frequency hopping -- meaning that it not only transmits in short bursts like the rest but also keeps constantly changing its frequency so as to dodge interference and reduce the effect of other signals.
Radio Receivers (Rx)
The radio unit in an airplane or vehicle which receives the transmitter signal and relays the control to the servos.
This effective method of training allows two transmitters to be connected by means of a trainer cord. The instructor can pass control over to the student's transmitter so that he can fly. If the student gets into trouble, the instructor can regain control instantly saving your airplane.
Note: Be sure to check your radio instructions for proper connection and for compatibility with other radio systems.
R/C Radio Systems Features and Control Channels
The first thing you need to decide is how much you want your model to do. For each control function, you need one channel of control. The usual uses for control channels are:
One Control Channel.....Rudder
Three Control Channels....Rudder or aileron, elevator, throttle.
Four Control Channels....Rudder, aileron, elevator, throttle.
Five Control Channels....Rudder, aileron, elevator, throttle, flaps or retracts.
Six Control Channels....Rudder, aileron, elevator, throttle, flaps or retracts.
When you have more than 6 control channels, you can add such features as bomb drops, dive brakes, parachute drops, sliding canopies or other operating parts to your model. The most common number of control channels used on a powered aircraft model is 4. Four-channel control gives you full acrobatic capability and will enable you to fly most airplane models.
A servo contains an electric motor and is the "muscle" that moves the rudder, elevator, or other control surfaces. For each channel of control, you need a servo. Most 4 or more control channel radios come with 2-4 servos. There is a wide variety of servo types depending upon their intended use. If your 4-channel radio only comes with 3 servos and you wish to fly a "full-house" airplane (one that has 4 controllable features) you'll want to purchase one additional servo.
This feature allows you to reverse servo rotation. If a channel operates opposite of its intended direction, a simple flick of a switch corrects the problem.
Adjustable Travel Volume (End Point Adjustments)
ATV allows you to preset the maximum travel of a servo to either side from its neutral position. Such settings help tailor control action to suit your flying or driving style.
Exponential Rate (Adjustable Rate Control)
This feature smoothes responses between stick and the controlling servo movement.
Two control channels can be coupled together so that they move together when only one control channel is activated. Many 1/4 scale models require a combination of aileron and rudder to turn. Mixing does this electronically at the transmitter. V-tailed models, where the two halves of the V-tail must move not only together but independently, are another use of control mixing.
Electronic Speed Control:
Electronic speed controls replace the mechanical speed control and servo providing enhanced power efficiency and precision. In addition, they are lighter which improves the performance of some electric models.
Connect the servo to either a pushrod or cable. Adjustable servo arms are available for some radios which can be made shorter or longer.
Most manufacturers offer servo plugs that are compatible with their radio systems. This allows you to adapt other brands of servos to your radio system or repair damaged plugs.
Servo Extension Cable:
(Aileron Extension): These cables simply increase the distance between a servo and the receiver. Note: Very long servo leads may cause radio interference. Chokes or radio noise traps may be required.
Y-Harness: Two servos can be plugged into one channel with a Y-harness. The two servos will then operate simultaneously. It is most often used in areas where the strength of one servo is not adequate. An example of this would be the ailerons and elevator on larger airplanes.
A dual rate switch on the transmitter can reduce the amount of servo travel. This makes the controls less sensitive. The aileron and elevator control channels are the most common channels with this feature, although some radios will also have a rudder dual rate switch. Select low rate, and an over responsive model can be made easier to control. Since beginners tend to over-control the model, low rate can also tame their models.
The original rechargeable cells are Nickel Cadmium ones, abbreviated to NiCD or 'nicads'. These are used less and less nowadays and have been succeeded by Nickel Metal Hydride (NiMH) and Lithium-ion Polymer (Li-Po) cells.
NiCDs are the least powerful of the three and cadmium, the type of metal used inside the cell, is extremely toxic - these two reasons alone are enough not to use NiCD cells these days!
Nickel Metal Hydride cells (NiMH) have 3 or 4 times the power capacity than an equivalent-sized NiCD and are commonly used in electric rc models, both in the model itself and the transmitter. NiMH cells don't suffer from the so-called memory effect that NiCDs do and so can be charged regardless of their present charge level - nicads should always be fully discharged before being recharged.
The disadvantage with NiMH cells is that even with their relatively high internal resistance, they still have an internal self-discharge rate when they're not being used. For this reason, it's always a very good idea to charge them before heading out to the field, as they will more than likely need 'topping up'.
The lithium-ion polymer battery packs (Li-Po) is one of the most recent major development in wet cell technology and these alone have drastically transformed the face of electric rc flight. They will hold a charge for months without internal discharging. They have a very high capacity relative to their size and weight, and deliver much longer run times and higher power than NiMH or NiCD packs.
Disadvantages of Li-Po battery packs are that they can be a potential fire hazard if charged incorrectly, and the cost is considerably more than their NiMH cousins although this is something that will improve as the technology becomes more common. But the advantages in performance of using a Li-Po battery pack in an electric rc model far outweigh this cost.
Top-end Li-Po powered electric rc aircraft are now beginning to match the abilities of nitro powered aircraft in terms of speed and flight times. That was an impossible idea just a few years ago!
The lithium-iron Phosphate (LiFe) is a new battery pack.
A123 is another battery pack of the future.
Charging your cells & battery packs
It's very important to pay close attention to the charging requirements of your wet cells.
If you've purchased an RTF electric rc model, then the chances are that an appropriate charger is included in the box. If not, then invest in a good quality peak detection (PD) charger if you use NiMH cells in your model (shop for chargers). PD chargers prevent over-charging, and the associated damage to the cells.
If in doubt, speak with the person you are buying from and tell him/her exactly which cells you have and which connectors are used on the battery pack.
Charging NiMH cells is a straightforward process, so long as you take the time to calculate the optimum charging time given the capacity of your cells and the charger output. This is a simple calculation, the battery capacity in mAh (milliamp hour) is divided by the charge rate of the charger, in mA (milliamps). Charging information may also be displayed on the cells themselves - for example, "7h-110mA" tells you that the cell should be charged for 7 hours at a rate of 110mA.
However, charging Li-Po cells is a different story altogether and it's imperative that you charge them with a charger meant for Li-Po cells. The whole charging process is different for lithium polymer battery packs, and packs can explode when over-charged, creating a fireball - you don't want this happening in your hobby room while you are out in the back yard! (Do a search for "Li-Po battery fire" on YouTube to see what can happen).
On Li-Po packs you may often see the words "Do not charge above 1C"... This means that the pack must not be charged at a rate that is greater than it's capacity. For example, a 1000mAh battery should be charged at a maximum rate of 1000mA, or 1A. Charging the same pack at 800mA, or 0.8A, would be the same as charging at 0.8C. Charging a 2200mAh pack at 0.8C would mean charging it at 2200x0.8=1760mA, or 1.76A, and so on.
Charging a Li-Po pack above 1C greatly increases the risk of a fire, or at the very least can cause irreparable damage although it has to be said that as Li-Po technology is developing more and more packs that can tolerate a 'higher C charge' are becoming available.
'Trickle charging' is a term used to describe a method of very low-current continuous charging to compensate the cell's natural discharge rate, thus keeping the cell topped up so long as it is connected to the charger. Many fast battery chargers automatically switch over to trickle charging once the main fast-charge has completed.
Capacities, voltage & other ratings
All cells have a capacity and the value is expressed in mAh, or milliampere-hour (also often seen as milliamp hour).
Think of this capacity as "how much gas is in the tank"; the higher the capacity, the more work the cell can do over a given time period. The mAh value represents, theoretically, how much current will flow from the cell over an hour eg a 600mAh cell will give 600 milliamps over one hour, or 1200 milliamps over half an hour, or 300mAh for two hours etc.
Logically, the longer you want to play between charges, the higher the capacity of the pack needs to be.
Ratings when connecting multiple cells
When individual cells are connected together to make a battery pack, there are two methods of connection - in parallel and in series.
By wiring cells together in parallel, the positive terminals connect to positive terminals and negative to negative. The end result is an increase in total capacity but the voltage remains at the level of just one of the cells.
By wiring cells together in series, the positive terminal is connected to its neighboring negative terminal. This results in the total capacity staying at the level of each individual cell, but the overall voltage is increased to the value of all cells added together.
For example, 7 x 600mAh AAA cells wired in series to make up a battery flight pack do not create 4,200mAh flight pack - the pack's capacity stays at 600mAh, but the voltage becomes 7 x 1.2V = 8.4V.
Conversely, 7 x 600mAh AAA cells wired in parallel will result in a 4200mAh 1.2V pack.
Battery packs for rc models have their cells connected in series, with the exception of larger Li-Po packs....
Li-Po cell & pack ratings
Li-Po battery packs have a different rating system and can have cells wired in series, then wired in parallel to an identical set of cells. This gives the best of both worlds - the higher voltage from the cells wired in series, plus the higher capacity from the two sets of cells being wired together in parallel. It's this combination that helps make Li-Po battery packs perform so well.
The nominal voltage of a single Li-Po cell is 3.7V, compared to the 1.2V of a NiMH cell, so Li-Po battery packs can be bought in increments of 3.7. For example, 3 cells connected in series will give a 11.1V pack, 4 cells a 14.8V pack and so on.
Li-Po battery packs are rated with S, P and C values. For example, a '3S' pack will have 3 cells wired in series, while a '3S2P' pack will have those same serially-wired 3 cells connected in parallel to an identical 3 cells.
As well as the 'C' charging recommendations talked about earlier, 'C' values are also given to a Li-Po battery pack to determine the cell's discharge capability. Two ratings may be given on a pack, a continuous and burst rating; for example, a pack may be labeled as 2200mAh 15/25C which tells us that it can handle a continuous 33A discharge (2200x15/1000) or a burst of 55A (2200x25/1000). The 'industry standard' burst rate is a 15 second time limit.
The continuous C rating also lets us know how long the current draw can be sustained, theoretically. A 2200mAh 15C pack can deliver 33A for 1/15 of an hour, or 4 minutes while a 2200mAh 30C pack could deliver 66A for 1/30 of an hour, or just 2 minutes - lots of power, but no time to enjoy it! Of course, the reality is that higher rated packs will run for longer because you wouldn't be running them at the limits.
To determine the flying time or duration of a battery pack in minutes:
- Duration = 60 X (capacity/1000) / current
- Therefore, to calculate the duration of a 1700mAh pack for a 30-amp draw:
- Duration = 60 X 1.7Ah / 30 amps
- Duration = 3.4 minutes
There are several different battery chemistries that all require different charging techniques. The basic method is using the wall charger that comes with the radio setup. It generally charges the battery at a low rate, about 50ma to 60ma (ma- milliamps – thousandths of an amp). To get a full charge you take the rated capacity of the battery plus %30 more (i.e.: 600ma + 180ma = 780ma). Divide the calculated capacity by the charge rate of the charger to come up with the amount of time needed to get a full charge (i.e.: 780ma / 50ma = 15.6 hours or rounded up to 16 hours). If you are serious into electric flight you really need to get a good charger and maybe a cycler. You will also need a watt meter so that you will KNOW what your electric setup is actually doing. Without the watt meter, you are only guessing and stand a good chance of destroying your batteries, esc and maybe your motor too. The watt meter can also tell you how much current your servos are using which is handy in making sure you size your power system properly in a standard radio setup.
Connectors and wire size are important in any electric power setup and even the standard servo/receiver setup in wet power airplanes. The more torque a servo uses, the more current it will use. This also means sizing the wire harness, switches, and connectors appropriately. Using a wire gauge too small can cause voltage sag and some receivers don’t like that. They may reset or cause temporary loss of control.
NOTICE: LIPO Battery Warning
Read the directions and follow them. These batteries can be dangerous if mistreated, even if they are NOT mistreated. They can explode and burn. Always store them in a fire proof container like a steel ammo box or lipo safe charge bags. They have been known to spontaneously explode and burn. Houses have burned down, cars have burned and airplanes have burned when charging lipo’s in the airplane. Always remove the lipo battery when charging.
Regardless of whether a model comes in kit form or prebuilt, some building tools will be needed to make it flight-ready. These include such common items as a hobby knife, T-pins, screwdrivers, pliers, sandpaper, masking tape, and perhaps a drill. Building a kit also takes some specialized equipment like covering tools. Follow the Accessories Required links for the plane you choose to see a list of the tools needed. R/C model building adhesives are also required, and differ from the white glue and model airplane cement you may have worked with in the past. Cyanoacrylates are commonly used. These are glues specially formulated for working with wood, which provide a range of curing speeds—giving you as little or as much time as each assembly step requires. "Thick" Cyanoacrylates also help to fill slight gaps between parts. Modeling Epoxies are two-part adhesives, consisting of a resin and a hardener. At steps where very strong bonds are critical, a plane's manual will often recommend epoxy. The resin and hardener must first be mixed, then applied to the surface—so mixing cups, mixing sticks and inexpensive, disposable epoxy brushes also come in handy. Check out our Builders Korner web page for building tips. Your flight instructor or any club member will be glad to answer any questions you may have.
There are many normal modeling tools like knives, wrenches, abrasive paper, etc. that are useful. You can get started in electric flight with very few specialized tools. There are a few, however, that will make life so much easier that you’ll soon wonder how you ever did without them.
Here are a few useful tools:
- Soldering Iron:This is essential for general wiring. If you only have one, it should be around 25W. If you’re going to make your own battery packs, a larger iron will help, preferably at least 40W and maybe up to 100W.
- Multi-Meter:Buying an analog meter isn’t worth it. You can get a simple digital multi-meter for very little from stores like Radio Shack. If you can get one that will read DC current up to at least 20A, that will be helpful (or see Wattmeter below). But even the simplest will let you measure voltages accurately, so you know what‘s going on in your power system, and will also provide a way of checking continuity so you can make sure all your wiring is intact.
- Wattmeter:This device simultaneously measures and displays voltage and current and will also show the total energy used. It’s very much like the displays on most good chargers, but with the great advantage that you can put it anywhere in the circuit and so measure exactly what is happening. It is unbeatable for finding out (rather than guessing) what current you are using and how the battery voltage goes down as the current increases. It will also allow you to measure your own motor constants, which is very useful if you want to experiment with odd (perhaps cheap surplus) motors.
- Crimp Tool:Depending upon what type of connectors on which you decide to standardize, you may find it worth getting a crimping tool. The one I use is quite expensive, but makes it so much easier to fit the connectors and makes a much better joint than a soldered joint.
- Tachometer:A good tachometer is very useful if you want to do some investigating of electric power sources. Even the most basic of motor parameters involves knowing the speed at which the motor is rotating.
- Digital Scales:All planes fly better if the airframes are light, and this is especially true of electrics, where the power package makes up such a high propo rtion of the overall weight. It’s probably most important to get scales that can weigh small amounts fairly accurately (down to 1/10 ounce), since you’ll be saving weight wherever you can. Some of the best value to be found is the used postal scales that are sometimes available. These will be fine, unless your ambitions lie in the direction of very small and light indoor models. Since the lightest of these have a total flying weight of well under an ounce, you will need jeweler’s scales.
Once your aircraft is chosen, built and covered, there's only one thing left to do...fly it! To do that, you'll need what we refer to as "flight line equipment"—such as fuel, a fuel pump, engine starting equipment and a few other basic tools. Except for the fuel, most flight line supplies are one-time purchases. You can use them throughout your modeling career, with as many different models as you fly.
Most modelers go to the field equipped with the following, all stored in a "flight box" for easy transport:
- 12V Field Battery—to supply power to the power panel
- DC Charger—to recharge the 12V field battery
- Glow plug clip—an electric device that gives your engine's glow plug the initial heat it needs to burn fuel
- Fuel Pump—to move fuel from your gallon can or jug to the plane's fuel tank, available in hand-crank or electric-powered styles
- Glow fuel—for a model engines carries a percent rating, which indicates its nitro methane content. For trainer aircraft, 10% or 15% is recommended. Use a good quality fuel with a blend of castor oil and synthetic lubricants to protect your engine. Avoid "cheap" fuels, which sometimes attract moisture and cause engine parts to rust.
- 12V Electric Starter—a device for quick, easy engine starting, powered from the power panel (a small wooden dowel or "chicken stick" can also be used).
- Miscellaneous Tools—including a 4-way glow plug/prop wrench.
- Glow plugs and propellers —it's always a good idea to carry extras...without a spare; you might be forced to stop flying early.
Generally speaking, you need equipment that is very similar to what other RC flyers require. There are only a few primary components: radio, battery, charger, speed control, motor and, of course, the aircraft. The amount of accessories you purchase are up to you, but most pilots typically buy things like a soldering iron, flight box, volt/amp meter, etc.
Swap Meets are buyer/seller events where RC enthusiasts go to sell their RC stuff that they don’t need to get money to buy more RC stuff that they want but don’t need. This is a great place for new people into the hobby to get started cheaply. Here you can buy a ready to fly airplane for half price or less of a new one. You can get all sorts of stuff from nuts & bolts, spinners, props, wheels, engines, kits, transmitters, receivers, ARFs, and many other things needed for the hobby. When you go to a swap meet for the first time, take your Tower Hobby catalog with you. That is your bible for pricing RC stuff that you are looking for or at. Remember you are trying to buy the stuff for ½ price or less as listed in Tower Hobby. Most all of the RC Clubs in Texas have one swap meet each year. We try to list their swap meet on our front page or in our Builder’s Korner. In our Builders Korner there is a link to every RC Club in Texas for you to surf to see when their swap meet is.
ARCA has a swap meet each year on the last Saturday of October, click here for information on our Swap Meet.
This is a great article. My son Bailey and I have been working with Edwin Smith learning to fly. Edwin is a great instructor. Very patient, easy going and makes learning fun. Bailey did his first solo flight 2 weeks ago all due to the great coaching from Edwin. If you want to learn to fly, contact the club and join in the fun.
I had an interesting conversation with a newbie friday at the Jet Rally. He had already bought a plane from Banana Hobbies that was described as a trainer. When he showed it to me, it turned out to be a foam motor glider with an off brand transmitter that claimed to be buddy box capable. He was dismayed when I told him what he bought was basically a toy RC airplane. It turns out the transmitter trainer port was proprietary and NOT compatable with any standard buddy box the club uses. Another problem is the plane is really only going to get you used to finger movements and flying slow. In my opinion, he would still need to upgrade to a standard trainer as a next step. As I see it, if he wants to still use this plane, he has two options. Option 1 - Find another transmitter exactly like the one he has and a buddy cable to work with it. I looked on Banana Hobbies web site and didnt see that available. It doesnt mean they dont sell it, it just wasnt obvious. Option 2 - Buy a new standard radio, remove the old receiver and install the new receiver and use the new radio. I would be able to buddy box him with our equipment. Another option, Option 3 - sell all that stuff and get a standard trainer combo. My preference, I believe he would learn more about true aerodynamics and bypass the toy airplane step. There is a difference between airplane drivers and airplane pilots. This is why I prefer a newbie to talk to us first before buying any equipment. There is a lot to consider when entering the RC sport and learning how to fly. Talking with us ahead of time gives us an idea of how serious you are. Just trying it out, or have always wanted to and diving in whole hog, or dont know and want to try it out on the cheap first. We have different ways of dealing with each scenario. Save yourself some money, talk to us first.
Just joined this site. I haven't joined the AMA yet but plan to, and also ARCA. Is there any specific time I could meet someone and discuss getting started. I definitely want to make this a serious hobby. It just looks like too much fun. I can't stop watching YouTube clips. Advice on meeting up would be greatly appreciated. Thanks again for the help.
I recently hooked up with three of the trainers at ARCA (Edwin Smith, James Mathenia and Tom Bath) and I can't say enough about them. All three went out of their way to help me. I had some experience with "toy" planes from Harbor Freight but these guys have definitely helped me take it to the next level. What a great group of people. I would highly recommend joining ARCA if you are serious about RC Airplanes or Helicopters. It can be a very expensive "attempt" at a hobby without the proper instruction. Don't be one of those people that spends good money on a plane, takes it out to a park that is probably too small by themselves and wrecks it within a few weeks, days or even hours. Annual club and AMA dues are nothing compared to the cost in damages a trainer and a good airfield will save you! Thanks to them my 6 channel Parkzone P-47 is up and flying instead of in pieces. Thanks guys.
Hey, would anyone be available at the field next week? I know that the Old Kingsbury event is going on, and James will be out of town for it. (I've been training with him lately.)
It's been hard to get to the field since I've been using my spare time to fix the car, but I'd really like to practice again soon. The weather looks great next week. I have Thursday, Friday, and Saturday off. Is anyone free those afternoons? (っ •‿•)っ