This is the .40 5010-810 Brushless Electric Motor from O.S. Motors.

FEATURES: For airplanes using a four-stroke .52 cu in (8.5 cc) engine
          Centrifugal fan design with angled ventilation holes draws air
            through the motor and across the windings and magnets for improved
            cooling
          Two year limited warranty through Hobby Services beginning at date of
            purchase

INCLUDES: .40 Brushless Electric Motor with Backplate, four Phillips Head
            Mounting Screws, 4mm Gold Plated Male Plugs attached to leads,
            three 4mm Female Plugs with Shrink Wrap, Prop Adapter and
            Instruction Sheet

REQUIRES: 90A brushless ESC

SPECS:    Rated Power: 700W
          Rated Voltage: 14.8V
          Rated Current: 45A
          Maximum Current (10 sec): 80A
          No Load Current: 1.8A
          Phase Resistance: 24.5 miliohms
          Maximum Efficiency: 85%
          kV: 810
          Poles: 14
          Shaft Diameter: 0.24" (6mm)
          Shaft Length: 0.46" (11.7mm)
          Weight: 8.3oz (234g)
          Lead Wire Length: 4.3" (110mm)
          Length of Motor Can to Backplate: 1.7" (42.5)
          Diameter of Motor Can: 1.98" (50mm)
          Length/rear of Motor Can to Prop Washer: 2.3" (58mm)
          Prop Washer Diameter: 1.06" (27mm)
          Thickness of Motor Mount: 0.20" (5mm)
          Width of Motor Mount: 2.7" (68mm)
          Height of Motor Mount: 2.7" (68mm)

          Performance for this motor with different props and LiPo cells is as
            follows (all data with 80A ESC):
          Prop Size   Current      LiPo Cells  Wattage   Thrust   RPM
          12 x 8E       51A           4S        857W     3.2kg   10,300
          12 x 10E      54A           3S        680W     1.7kg    7.380
          13 x 6.5E     55A           4S        924W     3.7kg   10,150
          13 x 8E       62A           8S      1,042W     3.7kg    9,930
          13 x 10E      78A           4S      1,310W     3.6kg    9,370
          14 x 7E       70A           4S      1,176W     4.0kg    9,650
          14 x 10E      54A           3S        680W     2.7kg    7,380
          15 x 7E       79A           4S      1,327W     3.6kg    7,900
          10 x 5E       42A           3S        529W     1.8kg   12,200
          10 x 7E       53A           3S        668W     2.6kg   11,500
          11 x 5.5E     54A           3S        680W     2.4kg   11,500
          11 x 7E       62A           3S        781W     2.7kg   10,900
          12 x 6E       66A           3S        832W     2.8kg   10,400
          12 x 8E       75A           3S        945W     2.5kg    9,300

COMMENTS: Nomenclature is defined as follows:
            0MA denotes 0.S. airplane motor
            First two digits are the rotor diameter
            Second two digits are the length of the magnets
            Last digits indicate the kV of the motor

                                                                   jxs 11/07/12
                                                                         ir/jxs