In all powered forms of Radio Control Modeling, the operating temperature of the main driving motor or engine is an important factor to consider for longevity and performance. Depending on the load or conditions the motor/engine must face will determine the correct operating temperature.
The operating temperature for a gas, nitro or electric motor/Engine has different characteristics and impacts on overall performance. We will now look into these separately.
Electric Operating Temperatures
In all electric powered models can be found 3 main components. These commonly are the motor, ESC, and Battery. Each component has different heat characteristics and specific operating temperature ranges.
Electronic Speed Control
The general maximum temperature for an ESC ranges from 60C (140F) to 74C. (165F) In general the lower the temperature is, the safer or more reliable your system tends to be. Higher quality ESC’s will tend to be able to operate on the higher end of the safest maximum range.
A LiPo battery tends to be the odd component of the 3 main components in an electric system. The reason being is the LiPo battery does not perform its best at colder conditions. However, the LiPo Battery does still have a maximum recommended temperature. This maximum recommended temperature is 60C. (140F) It is recommended to have your LiPo at temperatures above 21C (70F) for optimal performance. Many racers will target higher start off temperatures.
The motor is critical in the sense that the correct temperature range is followed. It is recommended to keep the motor as cool as possible for optimal performance. As temperatures increase, as does resistance. If the motor were to get too hot, possible magnet demagnetization may set in. This will permananetly damage the motor magnets.
The maximum recommended motor temperatures range between 60C (140F) to 75C. (165F) A water cooled motor should stay on the lower end of this range and a higher quality motor may achieve a higher value. Keep in mind it is best to keep the motor as cool as possible for maximum reliability and performance.
Gas and Nitro Engines
Gas and nitro engines operate best within a specific range. The internal temperature of an internal engine has a large impact on the thermal efficiency of the engine. A nitro engine temperature range typically exists between 82C (180F) and 115C. (240F)
A Gas engine operating temperatures typically exist between 100C (212F) and 155C. (310F)
It is critical to understand that the operating temperatures should not be used as a tuning tool. They are just more of a reference point and to not alarm you if you are experiencing higher temperatures than you thought was safe. Use these temperatures as a guide. Keep in mind that operating temperatures will change through the course of one tank of fuel.
Measuring Thermal Temperatures
To measure thermal temperatures, it is best to use a Temperature Gun. This is the most popular tool that is in use. They can range in price from about $20USD and up depending on brand ect. The second way to determine temperatures is to use a loggin device. Many small logging devices on the market are able to keep a log of temperature vs time. This is a better way for determining temperatures over a long period of time as this better represents the data.
On an internal combustion engine, this reading should be at the plug boss. On an electric component the highest reading found should be recorded. This may exist in multiple locations that build heat.