By this point, you should have your SK450 Dead Cat quadcopter frame mostly assembled. The only frame parts yet to be attached are the motor mounts; that’s because we need to attach the motors to the motor mounts before attaching the motor mounts to the SK450 frame. The entire process will involve three steps: attach the prop adapters to the motors, attach the motors to the motor mounts, and attach the motor mounts to the SK450 frame.
So first we will attach the prop adapters to the tops of the motors. The prop adapters are used to affix the props to the motors. Begin by removing the nuts and metal plates from each of the prop adapters. Then, use three of the smaller, hex-head screws to attach each prop adapter to the top of a motor. Then, finally, replace the metal plate and nut. Note that we will wait until later to attach the props.
If I may digress, this actually brings up the most important safety rule for working with quadcopters or any other multirotor aircraft. Never, ever, ever work on your quadcopter while the props are in place and the battery is attached. While the motors are at speed the props are just like blades and can cause horrific injuries when they hit flesh. I am not going to post any images here because they can be very graphic but if you have a strong stomach you can find plenty with a simple image search. Always remove your battery and/or props before doing any work on your quadcopter.
Back to the task at hand. Now that the prop adapters are in place on the tops of the motors, we will attach the motors to the SK450 frame’s motor mounting plates. If you look at the bottom of the motors, you will see four screw holes and a big hole in the middle through which the motor shaft is visible. Now, if you shift your gaze to the motor mounts, you will see the same arrangement of four screw holes surrounding a larger hole in the middle. The mounting holes on the bottom of the motors are not symmetrical, so you will need to rotate the motor mounting plates until the holes line up. Use the Philips screws included with the motors to affix the motor mounting plates to the bottom of the motors.
Now for the last step, attaching the motor mounts (now with the motors attached) to the SK450 Dead Cat frame. There are six holes around the edge of each motor mount, but we will only be using four because the other two are occupied by screws holding on the landing feet. You will probably want to orient each motor so that the wire leads point down the quadcopter arm. Down the road we will work on fastening all the loose wires to the frame. With the motor oriented properly and the screw holes lined up, apply a dab of thread lock to each screw and proceed to attach each motor mount to the SK450 frame.