Shopping Tips 101

What does the model or motor require?

R/C motors will specify their current limits and battery requirements. These will show up under "Specifications" for the motor or R/C model. Make sure you purchase a compatible ESC.

Where can I find specific recommendations?

The Accessories Needed button on the product webpage will often give ESC suggestions.

What to consider…

Brushed/Brushless: An ESC and motor must match: Brushed motors need brushed ESCs. Brushless motors need brushless ESCs. Some ESCs can run with both options. The description of the ESC will state the compatible motor type.

Batteries: Every ESC you see on Tower Hobbies will specify compatible batteries. If you use LiPo packs, you need a LiPo-compatible ESC. (These ESCs may also be compatible with LiFes, NiCds and NiMHs). When using a lithium battery, the ESC should have an LVC. LVC (Low Voltage Cutoff) will prevent permanent damage to a lithium cell by stopping the ESC from drawing more current from the battery when the battery is getting low. When you see a drop in performance, it is a good indication that the battery is running low.

BEC (Battery Eliminator Circuit): This feature allows an ESC to power the receiver and servos as well as the motor, thus reducing aircraft or vehicle weight to a single battery. They reduce the voltage supplied to an acceptable operating voltage for most receivers and servos. BECs are a common feature of today's ESCs. They will also limit the amperage available to the receiver and servos.

Constant Current: Many brushless motors will list a constant or maximum constant current. Make sure the current rating for your ESC is equal or higher than that of the motor. This ensures that they will operate together properly.

Motor Turns: Turns are often given as a rating for with brushed motors. You will need an ESC that has an equal or lower turn (T) rating. The lower the number of turns, the more powerful the motor.

On-Resistance: Lower numbers mean more efficiency and better performance overall. Size/Weight: ESCs are usually recommended by scale for surface vehicles and Amp rating for aircraft. The two will often have different designs, with surface ESCs having a flat bottom to be installed on to the vehicle's chassis.

Reverse: Most ESCs will have forward, brake, and reverse. Almost all racing competitions do not allow reverse when racing, so having reverse lockout is very important. Reverse lockout is a common feature in high-end ESCs.

Sensored and Sensorless: Brushless motors will come as Sensored or Sensorless. Sensored motors will have a mechanism to determine the exact position of the rotor and apply the necessary power at the correct phase. This translates to greater initial torque when the motor begins to move. Sensorless motors use another process to move the motor, resulting in a slightly slower response.

How much do they cost?

ESCs that offer more battery compatibility, higher current ratings, and programmability or racing features tend to be more expensive.

What does your vehicle or aircraft require?

Your vehicle or aircraft will specify the type, voltage, and/or mAh of the battery best used in the model.

Where can I find specific recommendations?

The Accessories Needed button on the product webpage will often give battery suggestions.

What to consider…

Capacity: The amount of energy a cell can store shown in mAh (milliampere hour). The capacity of the battery determines the run time of the vehicle or aircraft. Capacities can range from 35mAh to 12,000mAh (milliamp hours) and beyond. The mAh will also help determine the physical size of the battery, with a higher mAh battery being larger. Remember, increasing the mAh does give a longer run time, but doubling the mAh does not always mean twice the run time.

Configuration: How cells are assembled. Cells are end-to-end (in stick packs), side-to-side (in flat packs) or split into two side-by-side groups (in saddle packs). In hump packs, at least one cell is stacked on another cell. Lithium cells are typically stacked on top of one another. Vehicles will often specify compatible configurations for the model.

Discharge Rate (C Rating): The discharge rate of a lithium battery. It is a measurement of how fast the battery can be discharged safely. Many vehicles and aircraft will specify a minimum "C" rating to be used with it.

LiPo, LiIon and LiFe: Lithium type batteries are the newest type of batteries to be used in the R/C hobby. They have many benefits versus older NiMH and NiCd packs, from lighter weights to higher capacities and higher discharge rates. They do however, require extra care when handling them and require special chargers. Chargers on our site will specify what type of batteries they can charge.

Matched Cells: Cells discharged at a specific amperage rate and grouped together based on many parameters, including internal resistance. Most command a premium price.

NiCd (Nickel-Cadmium): The most common and economical type of battery. Each cell is 1.2V. They are most commonly used in receiver and transmitter batteries.

NiMH (Nickel-Metal Hydride): About the same size and weight as NiCd cells, NiMH cells cost more but offer a wider (and higher) range of capacities. NiMHs are also more environmentally friendly, and require neither cycling nor recycling.

Pack: A set of assembled, shrink-wrapped cells that includes a lead (wires) and connector. Commonly used when referring to a battery.

Sub-C Cells: Slightly smaller than typical "C" cells.

Voltage (V): A measure of force. Nominal voltage of a LiPo cell is 3.7V and 1.2V for a NiCd or NiMH cell. More cells = more voltage = more power. All components and models using these batteries will specify the required number of cells needed.

How much do they cost?

Batteries with higher voltages, milliamp hours, or discharge rates will be more expensive than ones with lower voltages, milliamp hours or discharge rates.

Where will you be charging the battery?

You need to consider where you will be charging your batteries. If you need to charge at the field or track, you may only have access to a 12V battery, which means you need a DC-capable charger. If you will be charging at home or somewhere that has a 110V outlet, an AC charger will do. If you will be doing both, an AC/DC charger is the best way to go. Check with the flying field or R/C track to find out what they have available for charging.

What type of battery are you charging?

Many chargers are designed for specific battery types. Some may only charge a certain size. Make sure you have a compatible charger beforehand and don't forget to look ahead. You may need a charger that handles more batteries or different types of packs down the road.

Where can I find specific recommendations?

The Accessories Needed button on the product webpage will often give charger suggestions.

Where can I find specific recommendations?

AC/DC: AC units plug into 110V home outlets. DC units require a 12V battery or power supply. AC/DC units can use both, so you can charge anywhere!

Capacity: How much energy a battery can store, in milliamp-hours (mAh). Chargers will often specify the maximum mAh they can charge.

Battery Types: How many cells can be charged. May be expressed as a range of cell capacities (100-1,300mAh), voltages (1.2-9.6V) or cells (1-8).

Discharging: Draining energy from a cell or battery pack. Regular discharging conditions cells to perform better and last longer. This feature is not necessary for LiPo, LiIon or LiFe batteries.

Charge Current: Current fixed chargers have only one charge rate. Some will have multiple fixed rates. Chargers with adjustable rates allow you to tailor the rate to the battery capacity within 0.1A.

Charge Termination: Older timed units charge until time runs out. Newer peak units charge until the battery is fully charged. This is called "Peak Detection" for NiCd/NiMH batteries and CC/CV for lithium batteries. Some chargers will allow you to adjust the "Peak Sensitivity" of the charger for specific results.

Lead-Acid/LiFe/LiIon/LiPo/NiCd/NiMH Battery types: A charger may be suitable for only one type of battery or for multiple types. Be sure your battery and charger are compatible before use.

Memory: Some chargers have "battery memories." These chargers will store battery information like voltage, mAh, and charge rate for your convenience. With these, you can preprogram your batteries so you don't need to enter the same information every time you charge a pack.

Output Connector: A charger can have one or many output connectors. Some use banana jacks to accommodate adapters to specific batteries. Many have universal connectors for receiver and transmitter packs. Make sure your battery has compatible adapters with the charger you want to purchase. Adapters can be seen in the "Requirements" or "Optional Accessories" on the charger page.

Protective Devices: Many charges have multiple safety features, including "Solid-State Reverse Polarity" and "Current Overload Protection".

Timer: Some chargers have a safety timer function designed to keep the battery from overcharging. Some will automatically be programmed based on the batteries parameters and others can be customized.

How much do they cost?

Charger prices will increase with the number of batteries they can charge, whether they are AC, DC or both, and by how many amps they can charge.

How many channels do you need?

Aircraft radios can easily be categorized by how many channels they can operate. Channels provide proportional movement for a specific aircraft function. This can be the aileron, throttle rudder, or elevator on a basic airplane. Each function will have a specific channel on the radio system. Aircraft for sale on our website will specify the minimum number of channels required to operate the aircraft. Some aircraft will have optional features—flaps for example—and those requirements will also be listed. It is a good idea to look ahead to future models you wish to fly and ensure that you purchase a radio system to suit your needs.

Where can I find specific recommendations?

The Accessories Needed button on the airplane/drone webpage will often give radio suggestions.

What features to consider…

ATV: Adjustable Travel Volume. Also referred to as End Point Adjustment (EPA), ATV lets you preset the maximum travel of a servo to either side of neutral. Allows you to tailor control outputs to your flying style.

Dual Rates: A two-position switch on your transmitter that makes the controls more or less sensitive. The lower rate is good for beginners who tend to over-control their models.

Exponential Rate: Also referred to as Expo. Offers servo travel that is not directly proportional to stick travel. Control response is milder below half-stick, but becomes increasingly stronger as stick travel approaches 100%. Great for aerobatics and trouble situations.

Mixing: Allows simultaneous operation of two or more channels from a single control input. A feature for intermediate-advanced fliers which simplifies routine flying operations and makes more involved maneuvers possible.

Model Memory: Many transmitters can store specific information like dual rates, trims, and end points within the radio, allowing you to save the information for each aircraft. The more aircraft you have, the more memories you'll need. Don't forget to plan ahead!

Servo Reversing: Allows you to change the direction of servo rotation by flipping a switch. Eases servo mounting and increases assembly flexibility.

Trainer System: Allows an instructor to link his/her radio to a student's radio via a cord, and to take control of student's craft in-flight by flipping a switch.

For more features, please check out this complete R/C radio glossary – https://www.futabarc.com/techsupport/glossary.html

Compatibility

Many radio system manufactures like Futaba offer different 2.4GHz system protocols. Always check to see if your transmitter and receiver are compatible. If purchasing a Futaba radio, check out their compatibility chart to make sure you're getting the correct equipment. https://www.futabarc.com/receivers/fhss-s-fhss-compat.html

What is S.Bus?

The innovative Futaba S.Bus system lets you unleash your flight system's full potential and cut down on cable clutter at the same time. It uses digital serial data communication technology to transmit control signals between your receiver and servos. A single S.Bus cable can carry signals to as many channels as your transmitter can handle. You no longer have to worry about plugging in the wrong servo to the wrong channel, because each servo knows what channel it is dedicated to in advance. Check out this page for more info. https://www.futabarc.com/S.Bus/index.html

What is Telemetry?

Some radios systems have a feature called telemetry. Telemetry allows the users to see important data from the receiver, such as remaining battery voltage, aircraft altitude, aircraft speed, and many others. Check the tech notes of the model for this feature.

How much do they cost?

R/C Radio systems will increase in cost based on how many channels they support, how many models they can store, and what specific features are available to them.

How many channels do you need?

Surface radios are also called "pistol-grip radios," as they are held similar to a pistol. They can easily be categorized by the numbers of channels they are capable of controlling. The most basic R/C vehicles require 2 channels: one for steering and another for throttle. The number of channels they control are often stated in the name of the radio. The Futaba 3PL is capable of controlling 3 channels, whereas the Futaba 4PX can control 4 channels. Many vehicles require more than 2 channels. Some R/C crawlers require an additional channel for the control of a winch or dig unit. R/C tanks also need additional channels to operate the turret and other scale features.

What features to consider…

Each radio on our website will tell you the features it has in the "Tech Notes" tab.
ATV/Adjustable Travel Volume: Also referred to as End Point Adjustment, ATV lets you preset the maximum travel of a servo on either side of neutral. This allows a racer to shorten or lengthen a car's steering and throttle range to suit his/her driving style .

Dual Rates: A feature on your transmitter that makes the controls more or less sensitive. The lower rate is good for beginners who tend to oversteer their model.

Curve (Throttle/Steering): An adjustment to the response of your steering or throttle based on the relative position of the trigger or wheel. This is typically used for racing.

Exponential Rate: Also referred to as Expo. Offers servo travel that is not directly proportional to wheel travel. Control response is milder below throttle, but becomes increasingly stronger as steering travel approaches 100%. Typically used in competitive racing or practice.

Mixing: Allows simultaneous operation of two or more channels from a single control input. A feature for intermediate-advanced drivers, which simplifies driving operations and makes cornering or accelerating easier.

Model Memory: Many transmitters can store specific information like dual rates, trims, and end points within the radio allowing you to save the information for each vehicle. The more vehicles you have, the more memories you'll need. Don't forget to plan ahead!

Rechargeable/Dry Batteries: Some advanced radio systems come with rechargeable batteries for your convenience. Others require "AA" batteries and must be supplied by the modeler. All rechargeable systems also include the proper wall charger (110V AC).

Servo Reversing: Allows you to change the direction your servo rotates by the flip of a switch. A nice feature that can save you the frustration of having your servo turn the wrong way.

Compatibility

Many radio system manufacturers like Futaba offer multiple different 2.4GHz system types. Always check to ensure your transmitter and receiver are compatible. If purchasing a Futaba radio, check out their compatibility chart to make sure you're getting the correct equipment. https://www.futabarc.com/receivers/fhss-s-fhss-compat.html

What is S.Bus?

The innovative Futaba S.Bus system lets you unleash your surface system's full potential and cut down on cable clutter at the same time. It uses digital serial data communication technology to transmit control signals between your receiver and servos. A single S.Bus cable can carry signals to as many channels as your transmitter can handle. You no longer have to worry about plugging in the wrong servo to the wrong channel, because each servo knows what channel it is dedicated to in advance. Check out this page for more info. https://www.futabarc.com/S.Bus/index.html

What is Telemetry?

Some radios systems have a feature called telemetry. Telemetry allows the users to see important data from the receiver such as remaining battery voltage, battery or engine temperature, motor current, and many others. Check the tech notes of the model for this feature.

How much do they cost?

R/C Radio systems will increase in cost based on how many channels they support, how many models they can store, and what specific features are available to them.

What to consider...

Analog Servos: Lowest in cost. They will generally have lower torque and speed compared to digital servos. They are used in many RTR vehicles and in sport RTF aircraft.

Ball Bearings (BB): Bearings in the servo help them last longer, run smoother, and faster than bushing servos.

Brushless Servos: 30% faster than brushed digital servos. These servos use brushless motors which offer faster, smoother response and more torque.

Coreless (Motor): Improves resolution for smoother operation (than cored motors).

Digital Servos: Superior to analogs in speed, precision, smoothness, centering, holding power and often torque. They will cost more and draw more current from your battery.

Gears: Molded plastic gears cost less. Metal gears are stronger and more durable. You will often find metal gears in high torque servos.

Programmable/S.Bus Servos: Allows programming of most (or all) parameters. See "S.Bus" below.

Torque: The torque value of a servo is often measured in ounces per square inch or "oz-in." It measure how much force the servo can apply to a surface. Larger planes and vehicles will require higher torque servos.

Transit Time: This is measured by how quickly a servo can rotate a specified number of degrees, often shown as "0.11 sec/60°". This means the servo rotates 60° in 0.11 seconds. Slower servos are more forgiving; faster servos excel at swift, strong response.

Voltage: Servos will have a specific range of voltages at which they can operate. The "Specifications" on the product page will show a servo's voltage compatibility. If none are specified, the servo will likely handle 4.8-6V. Make sure you system is set up to allow proper operation.

What is S.Bus?

The innovative Futaba S.Bus system lets you unleash your surface system's full potential and cut down on cable clutter at the same time. It uses digital serial data communication technology to transmit control signals between your receiver and servos. A single S.Bus cable can carry signals to as many channels as your transmitter can handle. You no longer have to worry about plugging in the wrong servo to the wrong channel, because each servo knows what channel it is dedicated to in advance. Check out this page for more info. https://www.futabarc.com/S.Bus/index.html

Get the servo you need…

There are so many servo choices that it can be hard to find the best one for your application. Check out the Futaba Servo Wizard below to make choosing a servo easier. https://www.futabarc.com/servos/servo-wizard.php

How much do they cost?

Servos will become increasing expensive as they get larger, have more torque and speed, utilize features like digital transmission and S.Bus technology.
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