Many people who haven’t used a Vertiq motor/ESC module before have questions regarding our published thrust data. Admittedly, our data is formatted a bit differently than that of most other motor manufacturers. There are two aspects of our data that can be explained by our modules’ unique configurability and controllability.

“Why is there not a throttle column?”

Before answering this, it’s important to note that all Vertiq modules support three different “Throttle Modes”: PWM Mode, Voltage Mode, and Velocity Mode, which can be configured in our GUI, IQ Control Center. Here’s a breakdown of each mode, and more detailed information on each configuration can be found in our documentation.

PWM Mode

In PWM mode, a 75% throttle command is interpreted as “Command 75% of supplied voltage.” This is the most common way throttle commands are interpreted in the industry, and typically what other motor manufacturers mean by their “Throttle” columns. We discourage the use of PWM mode on Vertiq modules for two reasons.

First, during flight, the supply voltage from the battery will naturally vary. For example, a 12S battery is 50.4V to start, has an average of 44.4V during operation, and is low at 38.4V. So the same 75% throttle could change from the motor commanding 37.8V to 28.8V from the start to end of a mission, which means you'll need to command a higher throttle as you fly to hit the same levels of thrust. This method of throttling is not consistent.

Second, your throttle may not naturally map well to the module-propeller pairing and could cause your propulsion system to overheat. For example, if you run a large propeller that hits the motor module’s continuous torque limit at 36V Commanded Voltage and battery voltage is 48V, throttle commands over 75% in PWM mode could generate too much heat. Vertiq ESC’s have a temperature sensor, and we’ve developed a model to estimate the temperature of the coils themselves. Because of this, our modules are able to derate before hitting temperatures that would damage the motor/ESC.

Note: PWM Throttle Mode is separate from PWM communication. Although we advise against it, PWM Throttle Mode can be used with any communication protocol that your Vertiq module supports (hobby, CAN, UART, etc.).

Voltage Mode

In Voltage Mode, a 75% throttle command is interpreted as “Command 75% of the user configurable max voltage”. In other words, throttle can be mapped to specific voltages. In the above example with a large propeller, you could set max voltage to 36V so that you’re never exceeding the continuous torque limit of your motor. Also, since 36V is below the battery’s low point (38.4V), the motors will perform the same throughout the entire flight, regardless of battery level. A 75% throttle command in this example will always command 27V (36V * 0.75), regardless of battery voltage. A 100% throttle command in this example will always command 36V.

Velocity Mode

In Velocity Mode, a 75% throttle command is interpreted as “Command 75% of the user configurable max velocity.” In other words, throttle can be mapped to specific velocities. Velocity Mode is conceptually very similar to Voltage Mode, but uses actual motor rad/s instead of voltage. In this mode, the module operates as a closed loop controller, applying the voltage necessary to maintain the commanded velocity. If max velocity is set to 500 rad/s and the module receives a 75% throttle command, it will command the appropriate voltage to maintain a velocity of 375 rad/s (500 rad/s * 0.75). We recommend operating your Vertiq module in this mode for the best performance and response times.

Conclusion

With this context, the reason we do not show throttle percentages on our thrust data is because "throttle" can mean different things for different users; “75% throttle” can mean 37.8V at full battery or 28.8V at empty battery in PWM mode, it can mean 27V if you set a max voltage of 36V in Voltage Mode, or it can mean a slightly different voltage in Velocity mode.

Most other manufacturers use PWM on a full battery, and they display the data in 10% throttle increments. We display our data in increments of 1V or 2V, eliminating the variable of a depleting battery supply voltage that frequently makes others’ data confusing.

If you do need to make a comparison to another manufacturer’s data, divide our commanded voltage by supply voltage to find the equivalent to "fraction of battery."

“What does the color coding mean?”

Vertiq publishes our thrust testing data with the “State of Operation” both listed in the last column and indicated by the shading of a given row. “State of Operation” indicates whether or not the torque and thrust for a row of data can be sustained continuously or if it can only be achieved for a short period of time before getting too hot. The three different “States of Operation” are Continuous, Continuous*, and Intermittent.

Before understanding the color coding, it’s important to understand the concept of Vertiq modules’ continuous torque limits.

Continuous Torque Limits

Vertiq runs tests to determine the continuous torque limit of all of our modules. We define the continuous torque limit as the amount of torque in Nm that the module can operate at in airflow (spinning a prop) for 10 minutes continuously, reaching a steady state temperature that does not damage the motor or ESC. Torque levels above this limit are achievable, but cannot be sustained without the module getting too hot and derating. There are many variables that affect cooling (mounting surface, ambient conditions, airflow from propeller, etc.) and would in turn affect this continuous torque limit. You can read more details about our specific testing setup here. Each Vertiq module’s continuous torque limit is on its datasheet, which can be found on the module webpage. Vertiq’s add-ons and different module configurations affect the continuous torque limit. Different configurations’ effects on continuous torque limits are also listed on a module’s datasheet. The Default and Pro configurations have the same continuous torque limit. The Performance Kit has a higher continuous torque limit due to its increased airflow.

Once continuous torque limits are defined, we’re able to color code and list the state of operation on our thrust data. Now, we can explain the three different “States of Operation”.

Continuous State of Operation

Continuous State of Operation, which is indicated by blue shading, means that a row’s amount of torque and thrust can be sustained with a standard Vertiq module without any of our additional add-ons. We refer to this as a “Default Configuration”.

Data points in these blue rows are below the Default Configuration’s continuous torque limit. This means that under normal operating conditions, you can run the module at these velocity/torque/thrust levels without overheating.

Continuous* State of Operation

Continuous* State of Operation, which is indicated by blue and yellow striped shading, indicates that the row of data is sustainable only when using a Vertiq Performance Kit. The Performance Kit includes a blower fan rotor attachment, which improves airflow and cooling for the module. This improvement in cooling increases the module’s max continuous torque, which is why rows where the module is being pushed harder are only continuously sustainable when using a Performance Kit.

Data in these rows should not cause motor or ESC overheating when using the Performance Kit. However, data in these rows should be considered intermittent (not sustainable) when using any other configuration (Default of Pro).

Essentially, if you’re using a Performance Kit, you can plan and design around being able to sustain these levels of thrust. If you’re using a Default or Pro Kit, however, do not plan to achieve these thrust levels for more than a short burst as your module will begin to overheat.

Intermittent State of Operation

Intermittent State of Operation, which is indicated yellow shading, indicates that the row of data is not sustainable regardless of your module’s configuration. Depending on external factors, you should be able to burst up to these levels of performance, but you risk your modules overheating and derating. We do not recommend designing your vehicle around this data, and we only include it to show what is possible for a short burst in case of emergency or an aggressive maneuver.

“Why does the data from this test suddenly end?”

If thrust data for a given motor/prop combo suddenly ends (results cut off before the Commanded Voltage equals the Supply Voltage), it means the module got too hot and started to derate during our test. This is more likely to happen when a propeller is oversized for a module.

A good example of thrust data ending “early” because a module derated can be found here. In this test, you would expect the Commanded Voltage to step up until it equals Supply Voltage (48V). However, at the 38V Commanded Voltage step, the module began to derate. This is why we excluded that step, and there aren’t any higher steps to include because we end our test when derate occurs.

Vertiq takes pride in publishing honest and realistic data. If the goal is to produce a high performance and reliable aircraft, we encourage our customers to build in factors of safety into their vehicle. For the propulsion system, this means only using a motor-ESC-propeller combination that can continuously achieve the required max thrust.

Understanding Vertiq Thrust Data