Motor Testing Equality- Independent and Unbiased

[Hexacrafter]

A request to the Forum and Bart.
For the last several months, I have sat back and "watched" the "efficiency claims" and "comparisons" of many about different motors and manufacturers.
I have come to the conclusion that we all need to have some "independent" and "Unbiased" testing performed to publish "real" and "Uniform" test results.
If you look closely at the numbers, statistics and charts published by the different motor manufacturers....there are always specific differences in Voltage used, Prop used, Testing apparatus, ESC, Power source and throttle % ... etc that make the information not really apples to apples. So....
I asked the forum to add motor testing to the Product reviews. All done with the same equipment and by the same person.
I do not have all of the equipment needed to do these tests, and also am currently aligned with specific motor manufacturers (this would be Bias), so I ask if there are any forum member(s) that Bart could appoint to be an independent tester that have the equipment to perform Motor Test Reviews.
My hope is that this will allow the Forum to make motor selections with true apple to apple comparisions and also allow motor manufacturers to post relplies as to how their motor may be a better choice... ie. better bearings, windings, quaility control, manufacturer support.. etc.
At HexaCrafter, when a specific motor is needed, we reach out to the manufacturers we are partnered with, ask for a recommendation and test results and then do expensive and expensive flight testing. I am constantly being asked by clients "what about the XXX manufacturer Model XXX instead". It would be an asset to all to be able to see "fair", "equal" and unbiased test results. Let's all face it.... you will most likely not get this directly from the manufacturers.
I do not claim to be "unbiased" as we have very close releationships with specific manufacturers which we use to provide our clients the best possible manufacturer support we can, but really feel that many of the recent "claims" I have seen posted on the forums are misleading or inaccurate.

Thanks in advance to the Forum & Bart.

 

[jfro]

I think many of us would like that, but I think I don't think it's possible without some major time and money. Too much for any one person to do without being paid.

I think it would be great, but to do it as you describe, it would take a well thought out plan, lots of time, money, and co-operation from motor manufactures. It would also have to be verified, which means doubling or tripling each test on multi motors or from different batches....

 

[Hexacrafter]

To clarify..
I would hope if we can find a "tester", that motor manufacturers would submit motors for "review & testing". They may have to pay for this!
If they have true confidence in their product, why not?

 

[Quinton]

To clarify..
I would hope if we can find a "tester", that motor manufacturers would submit motors for "review & testing". They may have to pay for this!
If they have true confidence in their product, why not?

I have been saying this for a while, however first you would need to set up a standard test that everyone can rely on with the same standards.
Not only would it require motors it would also require ESCs.
One way it could be done is to start a pay for members forum, where each member pays for example $10/£10 or whatever a month and that pays for the equipment needed, however once a motor/ESC has been tested by 1 person it could be sent to the next member for their own tests.
I am not saying it has to be like this, but it would be a sensible way to be able to get access to the equipment required as it would not be cheap, or each member buys a motor/esc and sends it onto whoever wants to test it.
Everyones got a spare motor/esc hanging about so it may not be that expensive to accomplish, but I think it should be a closed membership to begin with to be able to raise the funds to accomplish the testing.

Just an idea

I have already given information on a couple of motors/prop information to the forum using a wattmeter/ thrustmeter, but it gets buried very quickly.

 

[Bartman]

Hi Andy,

I agree and I volunteer for the job. I actually built a motor test stand last year and I've been trying to get around to putting it to work but I've been swamped. KDE sent me some motors and I've yet to do a review on them although they are next in line.

I had asked a while ago for someone to volunteer a U5 or U7 motor to the cause but didn't get any replies.

Things are slowing down here a little bit so I plan to get back to it.

Thanks for the suggestion.
Bart

 

[jes1111]

Andrew - you want volunteers to compile a database so you can gain commercial benefit from it?

 

[Hexacrafter]

No. We use T-Motor & Avroto exclusively. Our relationships with these companies will not be changing.
This is more about the large number of posts which make "claims" of efficiency that independent testing may prove "misleading" or false.
Additionally, many will compare two completely different motor types to make an efficiency "claim".
My hope is to "level" the playing field so that Forum members are not mislead by claims which are not proven independently.
I see alot of "bashing" without solid facts.. I prefer facts.
HexaCrafter will "gain" nothing from this type of independent testing... We engineer our systems with the help of our partners and teams. I trust our partners and their engineers.
FYI... we do not sell motors...
Thanks.
Andrew

Andrew - you want volunteers to compile a database so you can gain commercial benefit from it?

 

[fltundra]

No. We use T-Motor & Avroto exclusively. Our relationships with these companies will not be changing.
This is more about the large number of posts which make "claims" of efficiency that independent testing may prove "misleading" or false.
Additionally, many will compare two completely different motor types to make an efficiency "claim".
My hope is to "level" the playing field so that Forum members are not mislead by claims which are not proven independently.
I see alot of "bashing" without solid facts.. I prefer facts.
HexaCrafter will "gain" nothing from this type of independent testing... We engineer our systems with the help of our partners and teams. I trust our partners and their engineers.
FYI... we do not sell motors...
Thanks.
Andrew

T-Motor & Avroto are not even close to the quality of a KDE motor, so why bother testing.

 

[Hexacrafter]

This is what "independent" testing should detemine.
"Opinions" must be supported by "independent" tests.
You may be "surprised" when "facts" about efficiency, thrust, and quality are "Independently" published.
FYI.... We have conducted tests on other mfg. motors....
I am very certain that Avroto & T-Motor will freely volunteer their motors for side by side tests. Bart I will have them contact you.
I think some are misunderstanding this thread.
As mentioned in the original heading: "Motor Testing Equality- Independent and Unbiased".
I have not tried to "hide" my bias....... Hence any "testing" we have conducted would be construded as "Biased".
Photos of test stand from our Partner- Avroto.

T-Motor & Avroto are not even close to the quality of a KDE motor, so why bother testing.

 

[Bartman]

I'm up for it and my test stand will be satisfactory to most everyone I suspect.

We are no longer going to offer comparisons as part of our product reviews. I've had manufacturers offer their positions on performance margins over competitors only to find that they weren't there in my testing. So we'll test, we'll publish what we find, and we'll leave it to the community to decide what is best for their projects.

Bart

 

[Hexacrafter]

Thanks Bart.
I have watched this Forum grow over the years and this will be a great asset to all.
I respect your professionalism and integrity.
Andrew

 

[stevemaller]

In my humble opinion, I believe that only a true, independent professional engineer with no affiliation to any manufacturer or reseller can do this with integrity. In the consumer arena, organizations such as Consumer Reports and others constantly struggle with methodologies and techniques to ensure that their results are impartial, consistent and truthful. In the UAV arena, this is enormously complicated because of the complexity of the systems we're all trying to build and fly. Additionally, the pace of change is ridiculous, and any sufficiently rigorous testing procedure risks publishing results that are invalid as soon as they're released.

But another issue is the subterfuge and confusion around rebranding, rebadging and reselling of motors and other components. It happens in consumer electronics ("house brands" vs. independent vs. OEM white label brands), too. It is a veiled way of deliberately confusing consumers. TV "A" and TV "B" may be identical boxes with a different name. How do I as a consumer know enough to ensure my purchase is the most informed?

And what about support and service? Who stands by for warranty repairs, spare parts, or technical support? Do you have a phone number to call? Do you have to ship things internationally to get them repaired? Do you have requirements for your resellers for their training and suitability to represent your brand?

At the end of the day, many consumers (even some here) are going to go by nothing but thrust and price. But you do so at your own risk. Ask anybody who bought a car based on sticker price and horsepower alone.

The more I do this, the more I value the whole package and the less I look at raw data from questionable, proprietary testing techniques.

#flame_off

 

[Motopreserve]

T-Motor & Avroto are not even close to the quality of a KDE motor, so why bother testing.

Tundra, maybe you were joking??? If not, your response is exactly what Hexacrafter is trying to avoid...unsubstantiated claims with absolutely no data

i love this idea. I have recently built a test stand as well - and will be buttoning up an improved version (that looks to be similar to Avroto's).

The bottom line is that a single person, testing with his own constants, should be able to provide decent analysis via comparison. Even if different equipment would produce differing results, the same test gear should be able to provide us with valuable comparative data that we could use to make choices.

As far as manufacturer warranty, repair, support etc. That is easily obtained by posts here or by reaching out to the manufacturer. At this point I expect nothing, so anything would be better than that!!!!

 

[Quinton]

The bottom line is that a single person, testing with his own constants, should be able to provide decent analysis via comparison. Even if different equipment would produce differing results, the same test gear should be able to provide us with valuable comparative data that we could use to make choices.

There are a few things that you would need to get right and can change.
I did my own tests last year using the following..
http://www.tahmazo.com/products/catalogue/10/137 Thrust Meter
http://www.hobbyking.com/hobbyking/store/__10080__turnigy_130a_watt_meter_and_power_analyzer.html Watt Meter

Now at that time, I did not realise that I would have been also better using a constant voltage from mains power supply to give me exactly 22.2V (or whatever)

I would love to compare my results to someone elses using their setup, and I would also be willing to share motors with them (unfortunately I am in the UK though)
One thing I would like to know is, at what distance do you make the pivot point that sits on your scales and leads to your motor, as booms are different lengths from center plates, would this make a big difference with results?

 

[Motopreserve]

I think nailing down the power supply would be a key factor. I would think the C rating should be taken into effect, but for consistency, an actual aid power supply would be more solid. Perhaps part of a comparative setup would also have to include a few of the same batteries - something reasonable like nano-tech in various voltages. Something like 5000mah in 3S, 4S, 6S? 8S and more is becoming popular - but it seems less so than the 3-6S.

im not sure the boom length eventually used on a build effects the outcome of the tests much. I may be wrong. I thought the key to the triangle-style stand was to have the motor, pivot and hinge all equally spaced.

 

[Quinton]

I think nailing down the power supply would be a key factor. I would think the C rating should be taken into effect, but for consistency, an actual aid power supply would be more solid. Perhaps part of a comparative setup would also have to include a few of the same batteries - something reasonable like nano-tech in various voltages. Something like 5000mah in 3S, 4S, 6S? 8S and more is becoming popular - but it seems less so than the 3-6S.

im not sure the boom length eventually used on a build effects the outcome of the tests much. I may be wrong. I thought the key to the triangle-style stand was to have the motor, pivot and hinge all equally spaced.

The chargery Power supplies display voltage and amps used which would be usefull, although the chargery 1200 would be needed for upto 6s as the others only have upto 15V

I was thinking more in the lines of setups like this..
http://www.multirotorforums.com/showthread.php?13778-Tiger-Motors-U8-28x9-2-props

I asked Ferdiand about it and he said ...

The motor is mounted on an 1m arm, so the distance from the center is 0,5m. On the copter motors are typically 55-65cm from the center (on a quad or X8).

</pre>

 

[Motopreserve]

I might have to rethink my stand. I like that design better to more accurately match a multirotor. It's more simple too. Not sure that it would effect data, but it can't hurt to be have a setup that mimics the MRs more closely. I think most homemade stand designs you find are for plane motor/prop testing.

BART: Do you have any photos of your stand???

 

[Bartman]

it's been posted before, it's called the Tuba-4. the picture might be an old one as it was rebuilt at one point to use 7/8 tubing instead of 3/4. it pivots on a 1/4" steel pin that is supported by bearings so there's no resistance at all in the pivot. clear space underneath makes sure there is no ground effect and the scale under the foot isn't perfect but it's consistent from test to test which is what matters most when trying to gather a bunch of data.

weights above the foot balance out particular motor/prop combinations so the foot isn't too heavy or light on the scale for each test.

amps are measure with a Fluke multimeter, volts are from a power supply and an EagleTree logger displays RPM although I'd live to find a more stable RPM monitor.

EconFly uses an arduino driven board to supply known steps to his ESC's when he's testing them and I'd like to do the same eventually so that I can stop futzing with an RC transmitter. I try to set the throttle according to thrust (as displayed on the scale) and then log the amps/volts. I tweak the thrust using subtrim in the radio as the motor is running so I'm able to get i close but it jumps around a bit during the test. an arduino driven servo signal generator would be ideal, just have to climb the learning curve to make one.

 

[Quinton]

it's been posted before, it's called the Tuba-4. the picture might be an old one as it was rebuilt at one point to use 7/8 tubing instead of 3/4. it pivots on a 1/4" steel pin that is supported by bearings so there's no resistance at all in the pivot. clear space underneath makes sure there is no ground effect and the scale under the foot isn't perfect but it's consistent from test to test which is what matters most when trying to gather a bunch of data.

weights above the foot balance out particular motor/prop combinations so the foot isn't too heavy or light on the scale for each test.

amps are measure with a Fluke multimeter, volts are from a power supply and an EagleTree logger displays RPM although I'd live to find a more stable RPM monitor.



EconFly uses an arduino driven board to supply known steps to his ESC's when he's testing them and I'd like to do the same eventually so that I can stop futzing with an RC transmitter. I try to set the throttle according to thrust (as displayed on the scale) and then log the amps/volts. I tweak the thrust using subtrim in the radio as the motor is running so I'm able to get i close but it jumps around a bit during the test. an arduino driven servo signal generator would be ideal, just have to climb the learning curve to make one.

It would be great to see a co-axial setup on that for comparison.
Does it matter much where the scale point is I am wondering as if you think about it, on a MR the pressure is where the boom connects to the centre plate..or does that not come into it in reality?

 

[kloner]

I'm still waiting for some prop comparisons...... :black_eyed: