12S power systems ideas and options
- Thread starter Ohio AV8TOR
- Start date
cwojcik
70cc twin V2
When I got the motor in my 10S Challenger, I had to take it apart and file down a burr on one of the stators as it would hit and catch on the magnets when I rotated it. After 20 flights or so it threw a bunch of magnets. Innov8tive offered to replace it, but it was discontinued, and they had no suitable replacements, and the new version of it was not supposed to be available for some time. Then they offered to send it back to Germany for repair, which I told them to do. Roughly two months later I still did not have my motor, but the newer version was available, so I sent them an email and asked for one, which they sent me. At the end of the day I got my motor replaced but it took a long time, and the whole experience left a bad taste in my mouth considering it was one of the most expensive options. I know they dominate the heli scene but I have other favorites for airplane motors.
Aeroplayin
70cc twin V2
One of my flying buddies was familiar with Scorpion from his heli and put one of the bigger motors in his 26% pilot. Didn't last too long -- magnet adhesives -- so I never tried them personally. I was considering one of their big motors, which now come with rotor mounted prop adapters, because it was a Kv I needed that Hacker didn't carry. But the problem with buying psychology is that that one failure is difficult to forget. Fail-safe magnet adhesives, large concentric rear bearings, and large gauge winding wires, are the three absolute must-haves for 3D motors. I will generally take a look at the wire gauge on the coils of a motor I'm thinking about trying, then check out the bearing size if I can, or in the exploded diagram of the motor, and if I see something I like, in a price range that makes sense, I may take the risk. But I have not gotten that far yet with another brand. AXI are nice motors too, but I can get a Hacker or Motrolfly in the same size for less.
Only Fine Helis
50cc
Thanks guys.
Aeroplayin
70cc twin V2
Here is the data I collected from the last round of 12S testing. Thanks to the bunch of you that help out in this process... Enterprise for two motors and a hand full of props, TimmyC and Liberty10 for some data off motors and props I don't have, and Tom K. for helping with the thrust measurements.
This test was to accommodate the 70-74 wingspan class planes, as well as the new 84 inch MXS using the DM5335-195Kv as the power option with 22x10 props. Going to a bigger prop is possible, but more power means more Amps and less flight time, and more than 2-to-1 thrust to weight seems to be enough power for even the power hog like me.
In the charts, you will see the motor listing, along with the labeled Kv, the unloaded Kv (ULKv), the prop information including the weight in grams (Pwt), and then a list of volts per cell (V/S).
I calculated the power values at each of these voltage levels, then highlighted in green the average voltage of the individual tests over a ten second blast at WOT with that specific prop. As a comparison, I also included the measured thrust off the Rapala during the ten second episode. With Tom's help and a new stationary scale mount, I think I have some very accurate and relative values. N/A is not available because I did not test the setup myself and don't have a Rapala reading for it. But I did do the calculations, which are highly accurate.
There is also a calculated RPMs per voltage level, and the RPMs in the green row are the statistical equivalent of the log data representation.
You will also see Amp readings. All values less than 73A are in blue and all values greater than 72.99 are in red. You can interpret this any way you want, but the red is simply an alert that with the 12S setups, this is where I began to see more heat than otherwise. I personally believe that heat and Amps are not joined at the hip, but when you are spinning 20 to 22 inch props on 550 to 700 gram motors to an RPM level that begins to produce 72+ Amps on 12S, you will begin to see an increase in heat versus time that is much higher than if you were not.
HP is calculated from Watt-out, PSPD is pitch speed and Mthrust is the actual measured thrust off the Rapala digital scale. In most instances, they are the statistical equivalent of the calculated thrust (CThrust).
There is a P/CF field as well that will be addressed at another time and deals with load constants and performance values relative to static testing carbon fiber props, composite props, and props with a D/P ratio of 1 or less.
Let me know if you have any questions.
View attachment Prop Comparisons 062214.pdf
This test was to accommodate the 70-74 wingspan class planes, as well as the new 84 inch MXS using the DM5335-195Kv as the power option with 22x10 props. Going to a bigger prop is possible, but more power means more Amps and less flight time, and more than 2-to-1 thrust to weight seems to be enough power for even the power hog like me.
In the charts, you will see the motor listing, along with the labeled Kv, the unloaded Kv (ULKv), the prop information including the weight in grams (Pwt), and then a list of volts per cell (V/S).
I calculated the power values at each of these voltage levels, then highlighted in green the average voltage of the individual tests over a ten second blast at WOT with that specific prop. As a comparison, I also included the measured thrust off the Rapala during the ten second episode. With Tom's help and a new stationary scale mount, I think I have some very accurate and relative values. N/A is not available because I did not test the setup myself and don't have a Rapala reading for it. But I did do the calculations, which are highly accurate.
There is also a calculated RPMs per voltage level, and the RPMs in the green row are the statistical equivalent of the log data representation.
You will also see Amp readings. All values less than 73A are in blue and all values greater than 72.99 are in red. You can interpret this any way you want, but the red is simply an alert that with the 12S setups, this is where I began to see more heat than otherwise. I personally believe that heat and Amps are not joined at the hip, but when you are spinning 20 to 22 inch props on 550 to 700 gram motors to an RPM level that begins to produce 72+ Amps on 12S, you will begin to see an increase in heat versus time that is much higher than if you were not.
HP is calculated from Watt-out, PSPD is pitch speed and Mthrust is the actual measured thrust off the Rapala digital scale. In most instances, they are the statistical equivalent of the calculated thrust (CThrust).
There is a P/CF field as well that will be addressed at another time and deals with load constants and performance values relative to static testing carbon fiber props, composite props, and props with a D/P ratio of 1 or less.
Let me know if you have any questions.
View attachment Prop Comparisons 062214.pdf
Last edited by a moderator:
Aeroplayin
70cc twin V2
Thanks, but it's simple and quick now since I wrote a parsing program a long time ago for this type of stuff, so I only have to change the prop specs and all the data populates the screen. I've been doing this for a while only because I didn't have to take the time to do the math over and over again.
Hey Fellas, I'm about to pull the trigger and purchase the 76" MXS. I was wondering if any of you can share some of your experience. Here are my questions.
1. I live in CA so shipping would be expensive. I'm considering asking EF to ship greyhound because it is only 80bucks. Any of you think this is foolish?
2. I was deciding on the Scorpion 5535-190 motor because I think the motrofly 5335 was too heavy but the 4330 may be a bit underpowered.. The 5535-190 at 3800 watts and 855 grams seems just right, but why hasn't anyone even mentioned it? Also I'm thinking of 21-10 prop.
3. Lastly, what servos would your guys recommend? I like savox, but don't know whether coreless or brushless is better.
Any helpful advice that would prevent me from making a costly mistake would be greatly appreciated.
1. I live in CA so shipping would be expensive. I'm considering asking EF to ship greyhound because it is only 80bucks. Any of you think this is foolish?
2. I was deciding on the Scorpion 5535-190 motor because I think the motrofly 5335 was too heavy but the 4330 may be a bit underpowered.. The 5535-190 at 3800 watts and 855 grams seems just right, but why hasn't anyone even mentioned it? Also I'm thinking of 21-10 prop.
3. Lastly, what servos would your guys recommend? I like savox, but don't know whether coreless or brushless is better.
Any helpful advice that would prevent me from making a costly mistake would be greatly appreciated.