Why inceased power consumption upwind?

[sar104]

I agree, although the rearward moving phase also has less forward drag (backward vector), along with less lift.

Drag is not an independent variable in this situation.

 

[Dronedevices]

Drag is not an independent variable in this situation.

I agree they're tied, less lift less drag, more lift more drag, I was just making the correlation which others might not be aware of.

 

[Dronedevices]

Drag is not an independent variable in this situation.

Another factor which I forgot to mention, when moving forward it also moves away from it's own downward vortex into cleaner air, so the propellers bite into a more stationary mass, even more so as you increase the speed.

 

[Dronedevices]

I suspect you weren't taking advantage of the MotorPower calcs available in CsvView/DatCon. E.g. Motor:Watts:Avg:All is smoothed power signal for the motors. To include the MotorPower calcs go to the menu bar and select DatCon Fields -> MotorPower. The pitch signal shouldn't be too noisy. Here is an example of some data I took when trying to figure out the wind calcs that are done on the Mavic (and other platforms) and then recorded in the .DAT. There are 4 cycles, each with 1) a leg flying away from the HP with full elevator, 2) some rotating to gauge the wind speed, and 3) a leg returning to the HP using RTH. Here is one of those cycles. Outbound has a ground speed of 9 m/s, pitch -9.3 and motorWatts 81. The teal background represents the RTH where ground speed has increased to 10, pitch to -13.5, and motorWatts to 86.

View attachment 30949

That's best looking cycle and is the 2nd out of the 4 cycles. The first 2 cycles are the same path out and back, while the last 2 cycles were a path ortogonal to the first 2.
View attachment 30948

Note, that the ground speed under RTH is always 10 m/s but the pitch and motorWatts varies to meet that requirement.

This data/experiment isn't quite what's needed to answer @Dronedevices 's question. But, it could be a good start.

Thanks to your comment, I went back and looked at the CsvView, this time using the .DAT files recorded on my phone not the Mavic itself using DJI assistant, and the data was much smoother! I also had a chance to fly in stronger winds and there was a 2°-3° change in pitch going upwind as the power went up and the pitch was generally 30° to 33° in the data. This confirms that a 3°change in pitch angle along with fast motor compensations in unstable air does make a big difference in power consumption.

 

[JMF]

I can't believe there are three pages of this, sigh.

 

[Dronedevices]

I can't believe there are three pages of this, sigh.

Thanks for your contribution! Sigh. What if you were able to use 7% less battery upwind in choppy conditions (changing mostly the I in the PIDs so not to use as much power in keeping a perfect flight line).

 

[Dronedevices]

I suspect you weren't taking advantage of the MotorPower calcs available in CsvView/DatCon. E.g. Motor:Watts:Avg:All is smoothed power signal for the motors. To include the MotorPower calcs go to the menu bar and select DatCon Fields -> MotorPower. The pitch signal shouldn't be too noisy. Here is an example of some data I took when trying to figure out the wind calcs that are done on the Mavic (and other platforms) and then recorded in the .DAT. There are 4 cycles, each with 1) a leg flying away from the HP with full elevator, 2) some rotating to gauge the wind speed, and 3) a leg returning to the HP using RTH. Here is one of those cycles. Outbound has a ground speed of 9 m/s, pitch -9.3 and motorWatts 81. The teal background represents the RTH where ground speed has increased to 10, pitch to -13.5, and motorWatts to 86.

View attachment 30949

That's best looking cycle and is the 2nd out of the 4 cycles. The first 2 cycles are the same path out and back, while the last 2 cycles were a path ortogonal to the first 2.
View attachment 30948

Note, that the ground speed under RTH is always 10 m/s but the pitch and motorWatts varies to meet that requirement.

This data/experiment isn't quite what's needed to answer @Dronedevices 's question. But, it could be a good start.

I suspect you weren't taking advantage of the MotorPower calcs available in CsvView/DatCon. E.g. Motor:Watts:Avg:All is smoothed power signal for the motors. To include the MotorPower calcs go to the menu bar and select DatCon Fields -> MotorPower. The pitch signal shouldn't be too noisy. Here is an example of some data I took when trying to figure out the wind calcs that are done on the Mavic (and other platforms) and then recorded in the .DAT. There are 4 cycles, each with 1) a leg flying away from the HP with full elevator, 2) some rotating to gauge the wind speed, and 3) a leg returning to the HP using RTH. Here is one of those cycles. Outbound has a ground speed of 9 m/s, pitch -9.3 and motorWatts 81. The teal background represents the RTH where ground speed has increased to 10, pitch to -13.5, and motorWatts to 86.

View attachment 30949

That's best looking cycle and is the 2nd out of the 4 cycles. The first 2 cycles are the same path out and back, while the last 2 cycles were a path ortogonal to the first 2.
View attachment 30948

Note, that the ground speed under RTH is always 10 m/s but the pitch and motorWatts varies to meet that requirement.

This data/experiment isn't quite what's needed to answer @Dronedevices 's question. But, it could be a good start.

I hate to add anymore to this post, but I don't see a way to view different flights in CsvView at the same time, except by converting the .pml files and viewing them separately. Which program would you recommend for converting the .pml files to a different format such as JPEG, or am I completely missing something? Thanks in advance!

 

[BudWalker]

I hate to add anymore to this post, but I don't see a way to view different flights in CsvView at the same time, except by converting the .pml files and viewing them separately. Which program would you recommend for converting the .pml files to a different format such as JPEG, or am I completely missing something? Thanks in advance!

Well, one of us missing something. If you want to view different .DATs at the same time then you'll need to run multiple copies of CsvView.

The .pml file contains the info necessary for a saved SigPlayer. That's Player Markup Language. So I don't know what it means to convert a .pml to JPEG which is an image. ???

If you want multiple SigPlayers then select the Empty SigPlayer multiple times and populate each appropriately.

If you want to include a SigPlayer in a post then click the "Copy to System Clipboard" on the Sig Player menu bar, go to the post and Ctrl-V. You could also Ctrl-V into some app that could produce a JPEG.

 

[Dronedevices]

Well, one of us missing something. If you want to view different .DATs at the same time then you'll need to run multiple copies of CsvView.

The .pml file contains the info necessary for a saved SigPlayer. That's Player Markup Language. So I don't know what it means to convert a .pml to JPEG which is an image. ???

If you want multiple SigPlayers then select the Empty SigPlayer multiple times and populate each appropriately.

If you want to include a SigPlayer in a post then click the "Copy to System Clipboard" on the Sig Player menu bar, go to the post and Ctrl-V. You could also Ctrl-V into some app that could produce a JPEG.

Thanks that answers my question, I guess I was too caught up in converting files and forgot about the existing image output.

 

[Flyin2low]

Maybe DJI has really smart engineers who designed increased power to be delivered while flying into the wind at max tilt angle and minimum ground speed.??????

 

[sar104]

Maybe DJI has really smart engineers who designed increased power to be delivered while flying into the wind at max tilt angle and minimum ground speed.??????

However, for constant-altitude flight, motor power (or motor thrust) and tilt angle are not independent variables because the vertical component of the thrust (thrust x costilt) plus any aerodynamic lift must be equal to the weight of the aircraft.

 

[Dronedevices]

Well, one of us missing something. If you want to view different .DATs at the same time then you'll need to run multiple copies of CsvView.

The .pml file contains the info necessary for a saved SigPlayer. That's Player Markup Language. So I don't know what it means to convert a .pml to JPEG which is an image. ???

If you want multiple SigPlayers then select the Empty SigPlayer multiple times and populate each appropriately.

If you want to include a SigPlayer in a post then click the "Copy to System Clipboard" on the Sig Player menu bar, go to the post and Ctrl-V. You could also Ctrl-V into some app that could produce a JPEG.

Thanks again for all your help! We have been using CsvView's signal data with pitch being critical for the development of our patented attachable aerodynamic arm covers and wings, which reduce power consumption by 15% and 40% respectively on the Mavic series (contrary to some forum posts).