Measurements of electric motor performance
Test setup Please note that the measurements on this page are made using homemade equipment.
My scale for instance is a regular digital kitchen scale with 1g intervals.
I have tried to minimize ground-effect by having the propeller approximately 40 cm above the table and by putting the measuring contraption at the edge of the table.
Also my voltage regulator/powersupply is somewhat limited at the current it can supply, as a result the measurements stops a bit early.
Graupner Speed 280 FG 3 gearing
Spped280FG3
Please note that all gear bearings have been replaced with ball-bearings.
Weight of motor and gear: 62 g
Weight of prop adapter: 6g



Graupner slim prop 9-5″
Graupner SlimProp 9-5
Weight of propeller: 16 g

Graupner slim prop 9-5″
Voltage (V) Current (A) Power (W) Thrust (g) Effeciency (g/W)
1.2 0.4 0.5 10 20.8
2.4 0.6 1.4 21 14.6
3.6 1.0 3.6 46 12.8
4.8 1.5 7.2 78 10.8
6.0 2.0 12.0 115 9.6
6.5 2.3 15.0 128 8.6
Total weight: 85 g

Graupner SlimProp 9-5 data



Graupner slim prop 8-4″
Graupner SlimProp 8-4
Weight of propeller: 14 g

Graupner slim prop 8-4″
Voltage (V) Current (A) Power (W) Thrust (g) Effeciency (g/W)
1.2 0.2 0.3 4 13.9
2.4 0.4 1.0 16 16.7
3.6 0.7 2.4 34 13.9
4.8 1.0 4.7 45 9.7
6.0 1.4 8.2 81 9.9
7.2 1.7 12.2 107 8.7
Total weight: 83 g

Graupner SlimProp 8-4 data
Note: There were some resonance around 4.8V, this might be the cause of the lower performance at this measurement point.


Graupner Cam slim prop 8-6″
Graupner CamSlimProp 8-6
Weight of propeller: 9 g

Graupner Cam slim prop 8-6″
Voltage (V) Current (A) Power (W) Thrust (g) Effeciency (g/W)
1.2 0.3 0.3 3 9.3
2.4 0.6 1.3 17 12.6
3.6 1.0 3.5 42 11.9
4.8 1.5 7.2 70 9.7
6.0 2.2 13.0 106 8.2
6.4 2.3 14.4 109 7.6
Total weight: 78 g

Graupner CamSlimProp 8-6 data
Dualsky XM3548CA-4
Data from the manufacture:
Max Power(15s): 650W No. of cells 2...3S LiPo
Max Efficiency Current: 35A
Weight: 165g
Max Burst Current(15s): 44A
Prop. Range: 9x6...12x6
APP .Class 25-32 Class
1080 RPM/V
Motor image
Secret Data:
Unfortunately Dualsky does not seem to be interested in supplying highly useful information like:
Shaft diameter 5mm the length of it 13mm, and yes it can easily be modified for rear mounting as shown on the picture above.
The diameter of the motor is 35mm (35.5mm according to a label on the motor), the length of the can and stator part is 48mm, the brass part holding the non prop end in place is 11mm in diameter and 6mm in height (including a piece of shaft protruding).
It would also be very nice with some pointers with regard to continuous power and current, not to mention static trust and RPM messurements.