Fixed Wing vs. Multi rotor ESC's - the Mystery behind ESC's - Discussions

Has anyone seen a good article that describes the key differences between Fixed Wing ESCs vs. Multi Rotor ESC's?

Also how do you identify them as most suppliers do not mention what they are designed for.

Yes I know people use fixed wing ESC's on Quads and vise versa, but I am more interested in learning about the key design and feature differences.

Furthermore, what is people experience using ESC programming cards? It appears Turnigy has one, but there is no such programming card that would work with all types of ESC's

Thanks

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I spent a good amount of time trying to figure out ESC's and the different kinds available etc. and this is what I have learned. Feel free to add things and I will update the post if I missed anything.

There are 4 types of ESC's that have been introduced since their inception:

1. OneShot 125 <---> 4 Khz
2. OneShot 42 <---> 12 Khz
3. MultiShot <---> 40 Khz
4. Dshot;

a) Dshot 150 (150 Kbps - 8 Khz, max update rate)
b) Dshot 300 (300 Kbps - 16 Khz, max update rate)
c) Dshot 600 (600 Kbps - 32 Khz, max update rate)

There are different school of thoughts in the industry but the bottom line is you either use a MultiShot ESC or a Dshot. The Dshot ESC is not supported by all Flight Controllers, therefore one must check and see if their existing FC supports Dshot or not.

Following are the known flight controllers that supports Dshot:

1. Kiss v1.03
2. BetaFlight 3.1 (but not every board)
3. Race Flight.

Go to following list to check the complete list

https://github.com/betaflight/betaflight/wiki/DSHOT-ESC-Protocol LINK

CONCLUSIONS:

1. There is no such thing as a fixed wing ESC vs. a Multi Copter ESC.
2. MultiShot or Dshot are the obvious choices in the future or today.
3. Dshot ESC's do not require any calibration. A big plus.
4. DShot ESC's are expensive.
5. FC must support Dshot.

DSHOT Some known limitations are:

3.1 seems most issues are fixed. Any issues discovered should be in the 3.1.X wiki page now.

All STM32F1 Target do not support DSHOT
Some ESCs that have a signal filter cap may not work until the cap is removed.
Some targets have a DMA conflict between a motor and the LEDs. Some have work-arounds but some do not. If no work-around is listed then disable LEDs and contact the FC designer/support.
No reports of Dshot working for HEX copter.

IT APPEARS THAT PIXHAWK DOESN'T SUPPORT DSHOT AT THIS POINT. There is thread on GitHub LINK

If you want to learn more about Dshot check this link Dshot 101

I don't have a definitive article - but from experience in building both Quads & Fixed wings, below are my observations

Quad ESC's usually have higher frequency rates, more resolution (throttle "steps") and quad specific communication protocols between the ESC and FC.
Quad ESCs do not usually have on board SBEC or UBECs

A good example of a Quad-Specific communication protocol is "Dshot", I've outlined it's major feature sets as it does not use typical PWM signals which sets it apart from regular ESC protocols.

Eliminates the need for throttle calibration.
Unaffected by electrical noise (as the signal is digital)
More steps - 2048, compared to 600-1000 steps from regular ESCs

In a more real world comparative context, a typical 20-60A Turnigy ESC for fixed wing can have a frequency between 8Khz to 16Khz. Dshot can operate up to 37.5KHz.

These feature sets are primarily required because quads need to spin their motors up/down for control, the faster they can do this - the more stable and nimble they become. With the surge of racing quads, which need to be extremely agile these protocols are being heavily developed. A lot of these features are not required on fixed-wing motor/ESCs as they don't need to change speed as quickly all the time.

As far as ESC programming cards go, there is no One-Card-To rule them all as different vendors use different programming protocols.

That's my two cents, if your query was on advanced ESC hardware/chipset design differences, then I'm sure another DIYDrones member would be able to shed more light.

Replies

Sheban May 29, 2017 at 4:05am
I don't have a definitive article - but from experience in building both Quads & Fixed wings, below are my observations
- Quad ESC's usually have higher frequency rates, more resolution (throttle "steps") and quad specific communication protocols between the ESC and FC.
- Quad ESCs do not usually have on board SBEC or UBECs
A good example of a Quad-Specific communication protocol is "Dshot", I've outlined it's major feature sets as it does not use typical PWM signals which sets it apart from regular ESC protocols.
Eliminates the need for throttle calibration.

Unaffected by electrical noise (as the signal is digital)

More steps - 2048, compared to 600-1000 steps from regular ESCs
In a more real world comparative context, a typical 20-60A Turnigy ESC for fixed wing can have a frequency between 8Khz to 16Khz. Dshot can operate up to 37.5KHz.

These feature sets are primarily required because quads need to spin their motors up/down for control, the faster they can do this - the more stable and nimble they become. With the surge of racing quads, which need to be extremely agile these protocols are being heavily developed. A lot of these features are not required on fixed-wing motor/ESCs as they don't need to change speed as quickly all the time.

As far as ESC programming cards go, there is no One-Card-To rule them all as different vendors use different programming protocols.

That's my two cents, if your query was on advanced ESC hardware/chipset design differences, then I'm sure another DIYDrones member would be able to shed more light.
Turnigy Brushless ESC 85A w/ 5A SBEC

Turnigy Brushless ESC 85A w/ 5A SBEC

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