Motor Testing Equality- Independent and Unbiased

[Bartman]

hi quinton,

I've run two motors on it and it's actually surprising how much force the 3/4" carbon fiber tubing was able to take!

the scale is made to be exactly as far from the pivot as the center of the motors and it's checked with every motor swap. this ensures the scale is measuring the actual thrust of the motors and not inadvertently applying a factor due to unequal arm lengths (motor-to-pivot vs. pivot-to-scale).

the biggest surprise when i started running it was that there wasn't much prop wash under the tips of the props. maybe an inch to two inches from the tips depending on prop diamter, not much going on out there. or in close to the center. it's all in the middle of the blade for the most part.

 

[Hexacrafter]

Bart,
We tested the Prop wash as well. The interesting part is that the newer CF blades with the "swoop" on the ends actually seem to further force the thrust vector further to the center....
The prop engineers are really doing their jobs....
Andrew

 

[Bartman]

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

omg...every time i shuffle stuff around and see those props you 'loaned' me sitting there in their pretty velour sleeves i give myself a kick in the a$$ for being so far behind in everything!!

 

[Bartman]

Continuing to think about this I'm wondering if anyone out there would like to pick up the testing responsibility. I can supply motors which would be purchased from unsuspecting stores so as to be absolutely sure that we are getting consumer grade gear and not stuff that has been specially prepared for review by manufacturers.

If anyone is interested please PM me.

Thanks,
Bart

 

[Motopreserve]

Continuing to think about this I'm wondering if anyone out there would like to pick up the testing responsibility. I can supply motors which would be purchased from unsuspecting stores so as to be absolutely sure that we are getting consumer grade gear and not stuff that has been specially prepared for review by manufacturers.

If anyone is interested please PM me.

Thanks,
Bart

PM sent!

 

[Av8Chuck]

Continuing to think about this I'm wondering if anyone out there would like to pick up the testing responsibility. I can supply motors which would be purchased from unsuspecting stores so as to be absolutely sure that we are getting consumer grade gear and not stuff that has been specially prepared for review by manufacturers.

If anyone is interested please PM me.

Thanks,
Bart

What equipment would you need and how is the test defined? If you can standardize the test it might be a good idea to have more than one person testing to not only expedite the testing, I imagine this sort of quantitative information would be very helpful with the purchasing decision so there will be an increased demand for it, as well as a good sanity check for those involved in the testing, and could add credibility being an unbiased test.

I'd be happy to help.

 

[kloner]

if there was such a thing as a dyno created, i'm thinking there would be a business created at the end of this thing. like Underwriter Labratories

 

[genesc]

I think a person that is new should do the testing. After all Bart has already stated in many posts that he prefers certain motors.. He is already Biosed..

Gene

 

[SleepyC]

Team Epic have released this 7.4v powered motor dyno that allows you to test brushless motors with out the need of hooking up a speed control. Gives you KV, RPM and amp draw at user set voltage input and there is a mode for testing the function of the sensor to make sure it is functioning correctly. Runs off a standard 7.4V LiPo battery pack, so no big power supply is needed and it is small light and easy to transport to and from the track.

 

[stevemaller]

I think a person that is new should do the testing. After all Bart has already stated in many posts that he prefers certain motors.. He is already Biosed..

Gene

Agreed.

I have a friend who's very RC-savvy, but only a hobbyist (no commercial interest in any products or services), and is also very technically-adept. And this person has the resources to spend the up-front money to get the right gear.
But just like restaurant reviewers who often want to remain anonymous in order to be able to move around at will, maybe this person (or people) should remain anonymous, too.

I already suggested to this person that I could provide a level of indirection so as to conceal their identity (at least to start).
But that may ultimately be unnecessary.

There's also the question of whether the test results should be a paid-for commodity, in order to make sure this isn't a charity project.

Your thoughts?

 

[Av8Chuck]

You'll probably need to have done a lot of reviews for them to be valuable. If you tried charging for this service immediately not sure you'd get that many to sign up. As Kloner has already mentioned, there's a lot of opportunity to test most of the components we use. I'm not sure where the threshold would be, how many different motors and components need to be tested before people would be willing to pay for it. People might also take a wait and see approach to see how accurate the reviews are.

Its probably unnecessary for the tester to remain anonymous and as far as that person being a hobbyist or new to RC's I don't think that's a good idea. As long as the person/people don't work directly for one of the manufacturers so there's no perceived conflict of interest it shouldn't matter. Part of this would be very quantitative, devising the right methodology for testing the components and people will invariably ask for the testers opinion. Even if the tester has a bias for or against a particular product doesn't invalidate the test as long as the test is applied equally and when asked for their opinion they're honest about their bias. Before the Internet that was called integrity.

 

[jes1111]

eCalc is pretty accurate IME, so long as you have the necessary data for the motor. But eCalc can't give any answers for a coax setup, for obvious reasons. And, by the same token, a database of accurate motor/prop data will only be applicable to flat layout MRs.

Just my 2 cents.

 

[stevemaller]

eCalc is pretty accurate IME, so long as you have the necessary data for the motor. But eCalc can't give any answers for a coax setup, for obvious reasons. And, by the same token, a database of accurate motor/prop data will only be applicable to flat layout MRs.

eCalc is a helpful tool, but not at all what we're talking about here. There are so many variables that go into power system testing, and eCalc is just a set of algorithms. That code is right until it's wrong, and you have no idea of knowing. That's exactly why we need some real data about these systems.

 

[soler]

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.

Bart, tell me what you need from a arduino board and I'll write the code, could even add current draw and voltage with a shield if needed.