Not all Drone are created equal

[Adamisprimal]

So I have 2 ma1's. While flying them yesterday I noticed 1 Drone is significantly slower. After noticing I switched the batteries around and still the 1 Drone was slower. I then did a test by lifting a 2l bottle with some water in and the 1 lifted about 80g more than the other. I then swapped batteries and got the same result. Do you guys have any Idea what could be causing these differences? Both of the drone have less than 50h flightime.

 

[Yorkshire_Pud]

How do the speeds compare against the Max speed given in the drone's manual or specs ?

I suggest you upload both sets of .txt flight logs AND, if you have them, the .DAT flight logs to here. All of those logs are recorded on the phone attached to the controller.

If you do not have the DATs then ensure that "syncing logs with DJI," is switched off and perhaps also switch the phone's WiFi off, then fly another set of speed tests.

DO NOT do another set of lift tests, I worry that you might cook the motor ESCs doing lift test.

Once you have all 4 logs from the new tests also upload them to here.

Speed is a function of the drones' tilt and any headwind. Ignoring differing headwinds, it might be that the drones are running differing firmwares that set differing tilt limits. Firmware versions might be recorded in the txt flight log or available via that fight log.

With regards to lift capacity, where both drones using the same make of props ? Actually I would go as far as using only one set of props for these tests and moving them from one drone to the other during these tests.

There are reasons I am asking for the DATs but this post is already long enough.

 

[Cafguy]

Stop trying to lift heavy objects with your Drone you are killing the motors. One of the reasons one flys better than the other I suspect.

 

[howardK]

i wonder if there is a slight difference in the pitch of the props?? Perhaps switch them and see what happens

 

[Yorkshire_Pud]

i wonder if there is a slight difference in the pitch of the props?? Perhaps switch them and see what happens

Good question but indirectly covered in post 2 in two ways
a) the suggestion that the same set of props used on both drones during any new tests.
b) the request for the DATs.
Mavic Air DATs seem to be readable and contain motor RPMs. If test 1 DATs are available and assuming any firmware differences do not introduce differing RPM limit then, if the pitches are different, the RPMs during hovers will differ and the lift tests will show the motors at similar Max RPMs.

Attached is the plot of motor RPMs for a Mavic Air

 

[GFields]

Good way to destroy the Air 1

 

[Adamisprimal]

So I appear to have angered some folks here.

Let me start off by saying I am licensed. I am a Drone pilot and have 2000+ logged hours as well as being a level 3 RMT.

I had used the lift test merely to establish if the flight characteristics I experienced were in fact real or just a figment of my imagination.

Of the 2 drones 1 is significantly weaker.

Both drones used the same propellers in the same positions.

Tested both batteries and can see any change.

I might be mistaken but I can only reach 58km/h on the weaker 1. I can hit 67km/h if I descend and put full stick forward in like no wind.

I can say all motors are undamaged and have nothing obstructing them.

Both drones are same firmware version as well.

I am half wondering if the magnets have not lost quite a bit of magnetism and subsequently reduced the output power.

 

[GFields]

So I appear to have angered some folks here.

I don't see anyone that is angered.

 

[BudWalker]

So I appear to have angered some folks here.

Let me start off by saying I am licensed. I am a Drone pilot and have 2000+ logged hours as well as being a level 3 RMT.

I had used the lift test merely to establish if the flight characteristics I experienced were in fact real or just a figment of my imagination.

Of the 2 drones 1 is significantly weaker.

Both drones used the same propellers in the same positions.

Tested both batteries and can see any change.

I might be mistaken but I can only reach 58km/h on the weaker 1. I can hit 67km/h if I descend and put full stick forward in like no wind.

I can say all motors are undamaged and have nothing obstructing them.

Both drones are same firmware version as well.

I am half wondering if the magnets have not lost quite a bit of magnetism and subsequently reduced the output power.

Why haven't you provided the .DAT logs for both MA1s? Looking at the .DATs is the most likely way to answer your question.

 

[Yorkshire_Pud]

So I appear to have angered some folks here.

Speaking for myself, you have not angered me.
My intention was , and is, to try to prevent you risking cooking the ESCs in lift tests. Nothing more, nothing less.

Both drones used the same propellers in the same positions.

Unless you literally moved the full set of props from drone 1 to drone 2 then YOU HAVE NOT used the same props on both drones. For all you and we know one set could contain on or more deformed props. To rule that out you MUST use LITERALLY the same props on both drones.

Of the 2 drones 1 is significantly weaker.

As yet that is unknown.


What is needed is the logs that have been requested and confirmation that you have LITERALLY USED THE SAME PROPS on both drones.

 

[Adamisprimal]

Speaking for myself, you have not angered me.
My intention was , and is, to try to prevent you risking cooking the ESCs in lift tests. Nothing more, nothing less.

Unless you literally moved the full set of props from drone 1 to drone 2 then YOU HAVE NOT used the same props on both drones. For all you and we know one set could contain on or more deformed props. To rule that out you MUST use LITERALLY the same props on both drones.

As yet that is unknown.


What is needed is the logs that have been requested and confirmation that you have LITERALLYUSED THE SAME PROPS on both drones.

Same props is the same configuration. Lemme get some logs for you all.

 

[Yorkshire_Pud]

Same props is the same configuration. Lemme get some logs for you all.

Well then you have not tested the drones using the same props.
As I said one set could contained deformed props which do not work as well as the props on the other drone.

 

[Adamisprimal]

Well then you have not tested the drones using the same props.
As I said one set could contained deformed props which do not work as well as the props on the other drone.

I only have the 1 set and 1 spare of each. I took the props off off the 1 and put them on the other Drone in the exact same positions.

 

[Yorkshire_Pud]

I only have the 1 set and 1 spare of each. I took the props off off the 1 and put them on the other Drone in the exact same positions.

OK.
Was that what you did in the testing of post #1?

 

[Adamisprimal]

Think these are from both of the drones. So many files to sort through. Rate later today I will do a controlled test with them both and we can then have a looksee

 

[Adamisprimal]

OK.
Was that what you did in the testing of post #1?

I do think that I had my 2 spares on then only switched 2 from the other drone so not exactly all the same props. I have since then used the same props on both drones.

 

[Yorkshire_Pud]

Think these are from both of the drones. So many files to sort through. Rate later today I will do a controlled test with them both and we can then have a looksee

Ok, were 24-10-10_[02-44-38]_FLY041 and 24-10-10_[02-55-56]_FLY006 flown using the same set of props on each drone or different set of props on each drone?

 

[Yorkshire_Pud]

Think these are from both of the drones. So many files to sort through. Rate later today I will do a controlled test with them both and we can then have a looksee

The attached are my crude attempts at looking at the above DATs, @BudWalker may well know better channels to look at.
I have tried to find level hovers so that I can compare motor RPMs during those hovers.
The numbers in the charts show the INSTANTANEOUS values at the chosen moments.
To my mind, if the drones and props are identical then the motor RPMs should be fairly similar in a level hover.

At the chosen moment in 24-10-10_[02-44-38]_FLY041 the average RPM is 12,936.
At the chosen moment in 24-10-10_[02-55-56]_FLY006 the average RPM is 12,016.

To me that seems like quite a large difference, 7.66% based on FLY006 values. However BudWalker would be a better person to judge.

Nor do these appear to be lift tests where I would expect the motors to be going full tilt.
In FLY006 a quick skim suggests that max RPM IN THAT LOG was 18,515.
In FLY041 a quick skim suggests that max RPM IN THAT LOG was 18,551.

To me the above results suggest that either or both,
the drone of 006 is lighter than the drone of 041
OR and thought to be more likely
the props of 006 are more effective than the props of 041

 

[BudWalker]

The attached are my crude attempts at looking at the above DATs, @BudWalker may well know better channels to look at.
I have tried to find level hovers so that I can compare motor RPMs during those hovers.
The numbers in the charts show the INSTANTANEOUS values at the chosen moments.
To my mind, if the drones and props are identical then the motor RPMs should be fairly similar in a level hover.

At the chosen moment in 24-10-10_[02-44-38]_FLY041 the average RPM is 12,936.
At the chosen moment in 24-10-10_[02-55-56]_FLY006 the average RPM is 12,016.

To me that seems like quite a large difference, 7.66% based on FLY006 values. However BudWalker would be a better person to judge.

Nor do these appear to be lift tests where I would expect the motors to be going full tilt.
In FLY006 a quick skim suggests that max RPM IN THAT LOG was 18,515.
In FLY041 a quick skim suggests that max RPM IN THAT LOG was 18,551.

To me the above results suggest that either or both,
the drone of 006 is lighter than the drone of 041
OR and thought to be more likely
the props of 006 are more effective than the props of 041

Looking at motor RPMs hurts my head. And it's hard to infer thrust values. So, I took the easy way:

If we can assume that the 2 MA1s weigh the same and they have identical drag, then the tilt angle can be used to determine thrust. Using tilt/thrust allows us to ignore differences in ground speed caused by winds aloft. Tilt/thrust is also invariant under choice of props and motor performance.

FLY041 and FLY006 are from different MA1s. Both meet tilt angle specs for Sport and non-Sport mode (GPS_Atti mode). The 2 MA1s have similar, if not identical, performance.

FLY041 mostly consists of GPS_ATTI mode. Full pitch forward causes the MA1 to achieve 15° tilt angle; the maximum for GPS_ATTI mode.


The same is true for FLY006 where GPS_ATTI mode is being used.



Additionally, FLY006 has an interval where Sport mode is in effect. In that interval the max tilt angle spec (35°) is met.


@Adamisprimal I gotta ask. Is it possible the difference in performance is due to one MA1 being in GPS_ATTI mode and the other in Sport mode?

 

[Yorkshire_Pud]

I "chickened out" of looking at anything other than simple hovers, I sort of think I wouldn't be able to see anything.
Do you think I am mistaken with regards to the 'effectiveness' of the props used?