The Dart Thrower is a simple version of the flywheel mechanism used in pitching machines and battery powered Nerf guns like the Barricade. The principle of operation is simple. Two flywheels are spun in opposite directions by the motor. The gap between the flywheels is slightly smaller the the diameter of the dart, and they will grip it as it passes between. Energy is transferred from the flywheels to the dart, and it goes forward, quickly.
The motor is directly attached to one Flywheel and the other is spun by the interconnecting gears. The gears spin the two Flywheels spin in opposite directions.
Now we have to see how well the Dart Thrower works by testing how far it can throw. I created a stand that grabs the bottom of the motor and holds the it pointed up 30 degree. Its taped to the floor, so it wont move during the test.
I used the Hammerspace workshop floor as a handy premade reference grid. The floor tiles are 12 inches square, and for a bit of added precison, I laid down a tape measure staring at the base of the thrower.
We're going to fire 10 darts from the Dart Thrower, which will give us a good idea for how far it can shoot using out little FA-130 size motor and 4.5 volts.
From above we can see that the darts cluster between 6 and 12 feet downrange. The furthest dart is 147 inches from the launcher and the closest at 70 inches. The average of all the darts is 122 inches, or a little more then 9 feet. Not bad for out tinny little motor.
The Dart Thrower is Sized to use Nerf N-Strike Style darts
Download the Dart Thrower Files From Thingiverse: www.thingiverse.com/thing:534969
FA-130 Size Motor At Pololu: www.pololu.com/product/77