Get the right speed control for your electric model airplane.
The main number you need to look at is the maximum continuous current rating. This will be in amps.
It is okay if the current rating of the electronic speed control (ESC) is higher than you need. In fact, it should be a little higher than needed. If it is a lot higher, however, then the speed control will weigh more than necessary. It will probably also cost more than necessary.
Instead of listing the maximum continuous rating, many manufacturers prominently mention the burst current rating. This is the number of amps that the speed control can handle for only a few seconds. Some pilots like to rely on this higher current rating during a take-off, for example. If you are just starting out, it is best if you never exceed the maximum continuous rating.
How can you tell if the manufacturer is talking about the burst or continuous rating? There will be clues in the product description or label. If only one number is to be found, it is almost always the continuous rating. If two numbers are given, the higher one will be the burst rating.
The battery elimination circuitry (BEC) is a feature that most speed controls have. It is a voltage regulator that supplies 5 or 6 volts of steady power to the radio system components like the receiver and servos. It is very handy because it avoids the need to carry a separate receiver battery.
Almost all BECs that come free with speed controls use linear voltage regulators. These are relatively inefficient. Do not use them with more than a four cell battery pack.
A few speed controls have so-called switching voltage regulators in their BECs. They are more expensive but can handle any number of input battery pack cells. Warning! Unless the speed control clearly labels their BEC as switching, you have to assume that it is linear.
Some speed controls do not contain the BEC circuit. They are called optically (or opto) isolated. Normally, these speed controls can also handle a higher number of battery pack cells. If you are a beginner with a park flyer, there is no need to mess with this type of speed control.
Feel the Heat
Speed controls get hot! Give them plenty of cooling air. Keep them away from sensitive electronics, like receivers.
Over the years, speed controllers have gotten much better at protecting themselves from overload conditions. If they sense imminent damage to their electronics, they typically now shut off the motor for a few seconds. In the past, they would just burn up.
If all you have is a park flyer with a three cell battery pack, you almost never have to worry about changing the programming of the speed control. It will come from the factory with sensible defaults.
You could change the programming using your transmitter. Trying to make sense of all the beeps and bops just drives me nuts, however. A much better way to do it is by investing in a programming card. Changing any setting will then be dead simple. The only downside is that you need to buy a different programming card for each type of speed control.
Do not mess with the motor timing! Chances are, the default value will be fine. If you do change it, then carefully measure the motor RPM before and after. You could easily make it run worse than when you started.