A lot of us are using the APC 12x6E.
But then you would expect the RPM’s would be about the same.
Some are using 8000 rpm some 9000 or even more.

I fly a cardinal. On a competition we had a lot of wind about 9-12 meter/second.
So I set my motor a bit higher. 9389 RPM
A lot of pilots stayed on the ground or had to much wind so they had to cancel there flight.
I managed to make 2 flights and from about 25 competitors I ended 7. This is an extremely high place for me I think I will never manage this again.

The next competition I had the same settings. My cardinal flew afoul. The speed was way to low on the wingover it came down a bit. I hat to help it in every figure.
No surprise I ended one above the last one.

I use 3 battery's. All battery's give me a lack of power. On the last flight I cleared the data on The CC ICE ESC. When I looked at the data I saw that the Power out was very high and even touched the 100% a few times. Looking at the data I think my time was 5.4 seconds.

When I use the program drive calculator 8000 RPM gives me 73 km/hr. 9389 gives me 86 km/hr. We always say stunt has to fly about 90 km/hr. so 8000 seems to low to me.

I did some testing on the ground.
Prop   Voltage   Current   Watt   RPM   Throttle   Power Out      
APC 12x6   14,5   42,5   614   9097   1,417   100   Castle regulator
               13,67   40,55   554,26            eagle tree   

-Are the above numbers normal?
-How is it possible there is so much variation in the RPM?
-I have almost now power left. I use a AXI2826/10 and a CC ICE 50 does anyone now how much power he has left? And what are your settings?
-Any one any idea why my plane is not performing as at the previous competition. I find it hard to believe all 3 battery's are at the end of the life cycle at the same time.

Greetings Robert-Jan

Hi Igor,

Man you are fast.

I have been testing for 2 evenings.
Changed Motor, esc, battery. Prop’s
Changed the settings. Etc nothing helped.

How far may the voltage drop for 9386 RMP ?
Is any one else running in the same RPM ranges. What are the numbers.

The values from the CC regulator logger seems to be very inaccurate. Certainly the current seems to be way out of range comparing to my Eagle tree. On my first regulator it measures more than 60 Amperes!!!  Although the eagle tree still gives the same numbers as ESC two.


Greetings Robert-Jan

Robert-Jan,
Looking at you static data it is close to what my AXI 2826/10 was running when I found the bearing problem. You might want to check the condition of the bearing. Remove the motor from the ship, hold the bell with one hand and the motor stationary end with the other. Pull out then push in. If you feel the shaft moving the bearings are likely worn. If you open the motor (remove the circ clip from the shaft with retainer pliers to open the clip) and pull the bell end off you will likely see a couple of shiny spots on the stator arms indicating some rubbing of the magnets against them. Check that the magnets are all firmly in place, if any move you can hold it tight against the bell and put a small amount of CA down each side. Clean off the shiny spots on the armature with 400 sand paper just to get it so there are no sharp ridges, also check the surface of the magnets and smooth if needed. You can get new bearing from Boca Bearing in FL. They have a couple types that fit, I installed the hybrid ceramic/steel class 5 ones in mine and reduced the draw by 2amps. I am running the APCE 12x6P with the hub cuff smoothed off and depitched to around 5.5, I fly 5.3 lap time (about 55mph) and typically draw 31.7 ish static amps after the rebuild, prior was 34.5amps.

To do the bearing replacement see the video on the Boca Bearing web site or the Scorpion motor web site. It is pretty simple once you get the circ clip off.

Best,                DennisT

Hello all thanks for the quick answers

@Wynn
I use the tach inside the CC (I have checked this with my hand held tach)

@Dennis
What RPM do you need for 55mph?
Do you also have an RPM for the APC 12x6E (the tractor version)?

@Bob
I use the Rhino 3700 4S 25C. I have 3 of them.

To all
What I don't get is that there is so much variation in RPM in the equal setup's
Why do I need 9380 RPM and other people can fly with 8000 this is a huge difference.
Or has it something to do that the low RPM people don't use governor.

Between the 2 contest I did not change anything. So maybe all 3 battery's are at the end life.
I will try an other test with all 3 battery's parallel.
I will also try to put an oscilloscope on the battery. If the internal resistance is high it is maybe possible that you measure a high voltage.

Greetings Robert-Jan

The question is, what is real voltage when the motor runs, what is KV and I0 (measured).

If you are low on voltage is easy to check, you can either use CC ICE and see if the PWM goes to 100%, or use ESC without governor and siply try maximal rpm, if it goes to usefull maximum, you have problem with setting, if not, you have problem with battery or motor .. you can check it by voltmeter on the battery or emasure the motor KV and I0.