Rage propellers are designed from the ground specifically for multirotors. Rage propellers are designed to give you maximum control and responsiveness up at speed. Custom Computational Dynamics Software(CFD) was developed to design these propellers. This CFD uses a Vortex Lattice Method to build up the aerodynamics around a propeller. With the known flow field an optimized design is chosen by creating a perfect helical wake airflow; also known as the Betz condition. This results in a blade geometry efficient at a specified design point (speed, thrust, power, flight angle). This blade geometry often takes on a very steep angle near the hub and shallows out as we move out on the blade. Wing tips are added to the end of the blade geometry to improve efficiency by increasing the effective span of the blade while staying constrained to a specified diameter.
Our CFD software gives us an optimized blade geometry that is then modeled. With the model we test strength of the design using Finite Element Analysis (FEA). FEA shows the stress distribution along the blade during given load conditions. From this we change the airfoil geometry either to strengthen the blade or thin it out to lighten the propeller if already strong enough. This results in a strong propeller design that will not break if you hit a gate or mid air collide. Frequency analysis is also done using FEA to figure out the vibration modes of the propeller. Tweaks are then made with the blade and hub attachment to get the first vibration mode to an acceptable level. The blades are offset forward on the hub slightly to act as a swept back wing. During heavy loads this will the blade to flex open shallowing out the angle of attack effectively increasing the stall range. This gives the propeller a more linear feel throughout its throttle curve.
This propeller of the Rage series is the 3x54x4. This is a 3 inch diameter with 4 blades designed to operate at an advance ratio of 0.54. Advance ratio is the ratio of the speed of the multirotor to the tip speed. The propeller has a static pitch of 2.9 inches at 75% radius. Designed to operate efficiently at 50 mph around 60%-70%throttle with a 1407 3600kv - 4100kv motor. Four blades was chosen to lower the moment of inertia of this propeller. This results in the propeller requiring less torque to change speed rapidly; resulting in a more precise and responsive multirotor.