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Frequently Asked Questions

Question Categories:
Basic Electric | LiPoly Batteries | Speed Controls | Helicopters | Airplanes | General | Shipping & Billing

Basic Electric Questions

How does the Receiver (Rx) get power? The receiver gets its power in one of two ways: from the speed control’s BEC (Battery Eliminator Circuit), or from a separate onboard battery pack, usually a 4 cell, 4.8-volt NiCad battery.

My Electronic Speed Control (ESC) is plugged into the battery channel on my receiver and the servos work, but the motor does not. Why? The speed control needs to be plugged into the throttle channel. With Hitec radios, this is channel 3.

Everything is hooked up according to the instructions but nothing works. Why? Check to make sure your radio transmitter and receiver are on the same channel, and that you are getting power to both. Also, make sure that the connector from the speed control to the receiver is plugged in correctly, not backwards.

How do I install capacitors on my motor? As always, be sure to follow the recommendations in the instructions. As a general rule, a capacitor will solder to one of the motor terminals and "ground" to the case. Most motors will use at least two capacitors: one from each terminal to the motor’s case.

What is "polarity?" The particular state, either positive or negative with reference to the two poles of an electrical circuit.

What does mAh mean? It stands for "Milliamp Hours". "Amp Hours" is a measure of capacity, or the amount of power a battery can hold. 1000 Milliamps per hour equals one Amp hour. Most aircraft batteries use Milliamp hours to measure their capacity.

What do the numbers on my motor mean? It depends on the brand. In many cases they usually give some sort of info for the particular motor. For example, an AXI outrunner uses a six-digit code: 41/30/16. The 41 stands for the Stator diameter. The 30 stands for the length of the permanent magnets, and the 16 stands for the number of winds on the armature, which will also determine the RPM per volt for the motor (Kv).

LiPo. (Lithium Polymer) Battery Questions

My LiPo. pack won’t charge, is it defective? It may be defective. Many chargers will not charge a pack that is below 3 volts per cell, based on the voltage you set for the battery. Check the voltage and make sure it is above the 3 volt per cell threshold.

My LiPo. pack is puffed, what caused this and can it be fixed? Several things can cause a LiPo. cell or pack to puff or swell: (1) Over-charging, amperage set too high. (2) Over-voltage on the charger, cell count not set correctly. (3) Pack was out of balance before use (one or two cells puff rather than the whole pack). (4) Over-use, battery was put under a load that was higher than it’s recommended maximum discharge rate. (5) Over-discharging, below 3 volts per cell.

Can I leave my LiPo. unattended during the charging process? NO! Never leave a LiPo. battery unattended during the charging process.

Where should I charge my LiPo. battery? Charge in a container that can contain a fire.

LiPo. Cautions and Procedures:

  • Always use a battery charger that is compatible with and designed for use with your LiPo. battery.
  • Never charge at a rate (amperage) higher than one times the capacity of the battery pack in Amp hours. Ex. A 1500 mAh battery will need to be set for a 1.5 amp maximum charge rate.
  • Always use a Lithium compatible speed control and make sure it is properly programmed for Lithium battery operation with a 3 volt per cell low voltage cut off.
  • Never discharge a Lithium pack below 3 volts per cell (example: an 11.1 volt 3 cell should never be allowed to drain below 9 volts).
  • Never leave a battery pack connected to a speed control or other electrical device. Some will continue to discharge the pack even with the switch in the OFF position.
  • Always check battery voltage before charging or flying if you are not certain it is within specs.
  • Do not attempt to charge a LiPo. that has been over-discharged and is measuring less than 3 volts per cell. The battery will be damaged.
  • Always recharge after flying, and store the batteries fully charged.
  • A balancer is recommended to keep LiPo. batteries in good shape by matching the voltages of each cell.

    Speed Control Questions

    How do I know which speed control to use? You will need to know approximately how much amperage the motor will pull. You will also need to select a speed control that can handle the voltage you plan to run the motor with. Check the manufacturer’s specs for amp draw and voltages, or contact Tech Support for more information.

    What’s the difference between an "Opto" and a "BEC" controller. "Opto" stands for Optically Coupled. Opto controllers do not have an internal BEC and can handle higher voltages than BEC controllers. An external BEC unit or separate 4.8 volt receiver pack must be used with Opto controllers. BEC controllers generally handle less voltage but have an internal power supply that powers the receiver and servos by using power from the main flight battery.

    What’s the difference between "Brushed" speed controls and motors and "Brushless" speed controls and motors? Brushed speed controls and motors refer to motors powered by Direct Current (DC). Brushless speed controls and motors operate on a form of Alternating Current (AC), similar to house current. Brushed motors use brushes to transfer power to the spinning electromagnet armature that operates in a permanent magnet field. Brushless motors do not have an electromagnet armature, rather the windings stay stationary (stator) and induce their power to move the permanent magnets. In a brushless motor nothing touches except the drive shaft riding on ball bearings, and the efficiency and power are typically much better.

    Helicopter Questions

    All the servos work, but the rotor head will not turn and the light stays red. The throttle trim and throttle stick must be pulled all the way toward you and the transmitter must be ON before the control board will initialize.

    The light on the helicopter flashes red and green and nothing works. Check to make sure the transmitter has good batteries and that it is turned ON. If that does not work, make sure that the radio crystals are plugged in as well.

    I turned my transmitter off and the helicopter goes crazy. Why? The transmitter must remain ON at all times when a remote controlled aircraft is in operation. If you turn it off, you will no longer have control of the aircraft. Follow this rule: the transmitter always gets turned ON first, and gets turned OFF last.

    The tail spins wildly on my helicopter when I try to take off, what do I do? You have one of two problems: either the gyro is defective and needs to be replaced, or the reversing function on the gyro needs to be switched to the other position.

    Airplane Questions

    What does CG or Center of Gravity mean, and how do I find it? Every airplane has a particular center of gravity. This is the balancing point on the main wing where the airplane will balance level. The CG is very important. Shifting the CG fore and aft will change the flying characteristics of an airplane. Every airplane has a CG that is proper for stable flight. Get it wrong and the airplane may not even fly, or will have undesirable flight characteristics. Look for the CG recommendations in the airplane’s instruction manual. It will generally give you a location measured from the leading edge of the wing at the root near the fuselage. Mark this spot on each side and then pick the plane up with your fingertips directly at this location. The airplane needs to balance level. If the tail drops, shift weight forward by moving heavier components like the battery. If the nose drops, shift weight to the rear of the airplane.


    List of common RC Hobby terms and their meanings:

    ARF - Almost Ready to Fly

    RTF - Ready to Fly

    CG - Center of Gravity

    mAh - Milliamp hour

    EDF - Electric Ducted Fan

    15C, 20C, 30C, etc. - Discharge rating of LiPoly batteries. 15, 20, and 30 are multipliers and "C" means capacity in Amp hours. To calculate maximum amp load, divide the battery’s capacity (mAh) by 1000, then multiply by the multiplier. Example: a 1500 mAh battery with a 20C rating will give you 30 Amps max.

    Fixed Pitch - A fixed pitch helicopter cannot change the pitch of it's main rotor blades in-flight. Lift is increased or decreased by changing the speed of the main rotor.

    CCPM - Cyclic and Collective Pitch Mixing

    RPM - Revolutions Per Minute

    BEC - Battery Eliminator Circuit

    Kv - Stands for RPM per Volt

    Amps - Measure of Current

    Volts - Measure of Current’s Strength

    Watts - Measure of Power

    Inrunner - A brushless motor who’s permanent magnets spin inside the electromagnetic stator’s field, they look a lot like conventional brushed motors.

    Outrunner - A brushless motor who’s permanent magnets spin around an electromagnetic stator.

    Shipping and Billing Questions

    Is my part backordered? If you received a confirmation that shows you have a part ordered, but the amount shipped is less than what you ordered or zero, then you have a part that is on backorder.

    How much does overseas shipping cost? Each package is different; most shippers will use dimensional weight to calculate the price. It is best to verify your shipping cost with the Shipping department.

    I see my item in stock online, why hasn’t it shipped yet? Our website updates many times daily, and will immediately update when an out of stock item is received. Your package will be sent out in the order that it was received. In some cases it takes a little while to get them all out.

    All of my items said they were in stock, but I just got a confirmation email that says "0" were shipped. What happened? There was most likely a stocking error. When the shipping department tried to fill the order, none were found on the shelf. The item will be backordered and shipped once we get it.

    You were listing one ETA for a particular item, then I noticed it changed. What happened and when will you really get the item? The dates listed on the website for out of stock items are estimates and are subject to change if the shipment is delayed for any reason.

    I didn’t get a tracking number, or don’t have an email address for it to be sent to. How do I get my tracking number? Not all packages have tracking numbers. However, if you fail to receive the email it may have been stopped by a spam filter. Check this first. If you still did not get it, let us know and we will be more than happy to get the tracking number for you (contact Shipping) and give you a status report.

    I ordered some small parts online but haven’t seen them in a week. Is my package lost? The package is most likely not lost. Give it just a little more time. When ordering small parts with our HongKong Post Office, it can sometimes take a little longer than a regular ground shipment.