Jetdktr

My Feedback: (21)

With all the manufacturers , mail orders places, Hobby Shops, and internet selling their own electric motors with their own markings and spec numbers has anyone made up or is there a list or chart that tells which motor is equivelent to another. I like what EFlight has done with their larger motors ie 10,15,25,32,46,60,90,110,160 that is like glow motors. But everyone else is xx-xx-xxx or xxxx/xx/xx.
It would be nice with all the motors out there to know what the, say an Eflight 32 is the same as in an Axi or Atlas or rimfire etc. or any other motor: Axi to Atlas or rimfire and visa versa

elf232

Are you saying chart the strength of an electric motor versus its equal in nitro engine?

cyclops2

Almost impossible. Because the same sized motor comes with many different magnets, # of magnets, pole qualities, shaft sizes, wire winds, wire gauges. It is truly endless in the 22XX- size.
Fuel engines NEVER have so many options in any size.
Even car, boat and plane in the same size.

Rich

Jetdktr

My Feedback: (21)

ssorry maybe I overstated my question. What I meant was ,say an EFlight outrunner 450 is approx the same as a Axi whatever or a Rimfire whatever. Or say an Axi ??? or an Atlas ??? is equivelent to a ?? size nitro motor!

cyclops2

Electric motors of the same size can be wound for either 1000 rpm or 6000 rpm at 1 volt. The prop has to change wildly to prevent overheating the electric motor.

Fuel engines have very few props for any engine size. Let me restate. For SPORT FLYING.

cyclops2

I honestly believe it would be a hopeless pile of data.

Edit... We have a real need for our motor calculators.

No one has ever suggested a nitro engine calculator.

Jetdktr

My Feedback: (21)

I dont believe it would be a hopeless pile of data and I Dont want a nitro engine calculator. I used Eflight as an example. Their 46 outrunner will fly a 40-50 nitro airplane. EFlight just made it easy for their larger motors. Here is kind of what I mean:

size : AXI ??? = AtlasXXX = Rimefire ??? = Ripper xxx = HiMaxx/xxx = eflight = all these are approx equivelent
next size : Axi ??? = Atlasxxx = Rimefire??? = Ripperxxx = HiMaxx/xxx = eflight = all these are approx equivelent
and so on and so on

For example: If I have an a/c and it recommends a rimfire motor and they (seller) is out of rimfires, what axi, atlas , eflight, or whatever motor would be equivelent to the rimefire that is recommended. I know the different brand of motors wont be exactly the same, just looking for very close equivelents.

Every brand out their on a chart would be almost impossibe to do I know, but I guess a random selection of some of the brands available or the best sellers would be a start, and as new motors come out you could add it into the appropriate spot. Sorry for the confusion

cyclops2

OK.

I misread your to me, 2 different questions.

1 was a equivalent Nitro to electric motor. Same watts & RPM as the nitros ratings.

Other was, electric motor to another electric motor in ability.

Simple !

Ask Dr Kiwi. He is the best .

Rich

-pkh-

My Feedback: (2)

If you are trying to find electric motors that are similar, just compare the specs:

1) motor type (inrunner or outrunner)
2) physical size
3) max power rating (continuous)
4) max amp rating (continuous)
5) Kv rating (RPMs/Volt)

If you want an off brand motor that will be similar to a name brand motor, be sure the specs listed above are similar, and you will have a close match. If you need a direct or "drop in" replacement, then you have to worry about matching mount screw locations, shaft sizes, etc. Off brand motors may be more cheaply made and less efficient, so you may find you get less performance out of them with the same power input, but that's the price you pay if you're looking to save some $$$. For example, HobbyCity.com has several customer reviews posted for their motors, and they are mixed. Some are quite happy, others say that the motors don't perform as well as name brand motors and are more cheaply made (break easily).

Hope that helps!

Jetdktr

My Feedback: (21)

Thanks for all the info guys. PKH has it , a comparision, my original question was is there a list or chart out there that has those specs for a group of brands of motor for one size and then specs for a group of motors for the next size larger motor and so on and so on. I guess the question comes due the way the manufactures spec out (or label) there motors.
ie:
Himax - HC5018/30
AXI- 5320/28
EFlight - 450 outrunner
NeoDym - Neo400
Hacker - BL50
I have no idea if these are any where close to each other. If they were they would be grouped together. The next size larger would have for example the same brands that are equivelent, and so on

Thanks again,
Jim

PS who is DR KIWI

onewasp

I think this is the kind of thing you are looking for.

http://innov8tivedesigns.com/Scorpio...ison%20Web.htm

Hardly complete and I can't attest to its accuracy but it is the only thing I have found to date.

Jetdktr

My Feedback: (21)

BINGO!!!!!!!! THATS WHAT I AM TALKING ABOUT!!!!!!! THANK YOU FOR THE LINK!!!!!!!

THANKS ONEWASP!!!!!!!!!!!!

Jetdktr

My Feedback: (21)

Want to thank onewasp again for the electric motor comparison chart. Actually had to use it today. One of my Electrify aircraft recomended a Rimfire motor (both Great Planes products). I did not have a Rimfire. Went to the chart and found out that I had an EfLight equivelent on the bench.

cyclops2

That is a USEFULL chart !!!!!!!

Thanks.

cyclops2

Dr Kiwi is a complete motor man that can give Thrust MPH cells & opinions.

jalank

Here is another chart with comparison specs for a wide range of electric motors.

http://progressiverc.com/Brushless_Motor.html

lbarnes

I too was trying to get data that would tell me what motor equals another. Since I am always looking for the best deal at the cheapest price.

I was very confused, what I did figure our was the KVr rule. I found that the higher the Kvr the higher the RPM and current draw.

I fly airplanes, not ducted fans. I played with the T-28 and wanted to kick it up a notch. I measured the stock motor and went shopping. Hobby king was my first place I went to (now please dont tell me how BAD this place is, because I know). The Turnigy motors were a good place to start. Prices low and specs looked good.

After ordering a 3542-1100kvr and some 40A ESC I waited (forever) for them to arrive. When I got the parts I mounted it to the T-28, and fired it up. Wow, was I suprised at the added performance over the stock.

My first flight I fried a 40A ESC. I thought well they were cheap enough so I tried another. I also fried that one too.

Now i was [:@]

I sent back the ESC's they replaced them and off I went again. When I fried the 3rd one, I stopped and tried to figure out what I was doing wrong.

I purchased a Watt's up meter, hooked it up and I was shocked at what I discovered.

I was drawing over 40A with a motor that was advertised to draw about 35A. Well I soon learned that the size of the prop and the Kvr are very important things to balance out.

I was trying to swing a larger prop than I should have done.

My point is that you need to know what you got and what your trying to do. Fine tuning the motor, ESC, prop and battery will get you the best results.

With a watt meter you can fine tune the motor by using different props. My set up for testing is a Watt's up meter, digital scale and a range of different props.

I set up a new motor in the following way:

1. I have a 2x2 wooden block that I use to mount the motors to.
2. I reverse the prop and motor direction to push in the opposite direction (pusher mode).
3. Hook up my test bed to the watt's Up meter, receiver and transmitter.
4. I experiment with changing the props , measuring the thrust developed and Amp draw with that combo and change out until I get what I want.

Now That I have done this, I now have 2, T-28's that have motors (one 1100Kvr and 1000Kvr) that make them rockets. I got a 36Oz plane with 60Oz of thrust and draws 38A/27A of current on full throttle.

One swings a 11 x 5 and the other swing a 10 x 7.

Hope this helps someone else.........

Just my $.02 worth


Larry

-pkh-

My Feedback: (2)

Unless you are using the exact power system (prop, motor, ESC, battery) spec'd by the manufacturer (for which the max current is known), you MUST get a watt meter (or ammeter) and check the current. Even with pre-determined power systems, it's best to check it with a meter to be sure. Amp specs on motors are just to show max and/or most efficient current levels for the motor. If you overload or stall an electric motor, you can pull much more current than the motor can handle.

When comparing motors, look at the Kv, max power, and max current specs. If those are similar, then so are the motors.

jmohn

It would be nice if the different motor manufacturers used similar comparisons to define their motors.

Max amps
battery cells (voltage)
RPM
HP (with xyz prop)
Watts (with xyz prop)
etc.

I think Eflite does the best with this so far. The way they label the motors to compare them to equivilant glow engines was a good way to get people to convert, but it's not needed now and is inaccurate as most of the motors I have used produce more power than the glow equivilant.

Still a much better way to make it easier to convert to electric for people.



Jeff

Dr Kiwi

Any attempt to get an exact match of IC versus electric is doomed to failure because, of course, just like electric motors, not all IC motors are equal! There is a somewhat useful "crude rule of thumb" which says watts = cubic inches x 2000... but that probably only applies to run-of-the-mill IC motors... the rule of thumb would say that a .15 = 300W (might be about right for a lousy OS.15), but my MVVS .15 is rated for 0.7HP = 500W. What about some high end .15 with a tuned pipe .. it could well produce >1HP... so are we going to push an E-flite Power 15 to 750W... I don't think so.

jmohn

At least if they provided a range of output (watts or HP) for the motors for a given prop and voltage you could compare them with other motors. Like when you are considering a purchase of a new car. They provide you with HP, mileage and torque so you can figure out how it compares to other cars out there.

The Eflite motor information is still a good way to go since they actually test them in planes and tell you how the motors performed with x prop and y voltage. Maybe they should all you a standard computer model to test them on?


Jeff