- Winglets and ailerons can be an effective way of slightly increasing the efficiency of existing rotor/blade designs, which are not optimal (i.e. optimal solidity ratio, airfoil camber, chord length and angle of attack matched to an efficient motor, which results in maximum airflow with minimal energy consumption).
- Some manufacturers that use dated rotor designs have decided to take this approach (winglets and ailerons/flaps) to increase rotor efficiency mostly because investing in a complete redesign of the fan is cost prohibitive to them. Fortunately, Hunter was able to use lessons learned in the fan industry to design an optimal rotor that is directly matched to highly efficient DC direct drive motor. Instead of winglets (or ailerons/flaps), our blades/airfoils utilize a “sweep” at the end, which, through our tests, have proven to be much more effective than a winglet.
In reference to ailerons, the addition of an aileron to a fan blade/airfoil actually serves the similar purpose of a flap on an airplane (ailerons are used to change an airplane’s direction/roll). Flaps are used to both increase the surface area of an airplane wing and also the velocity, therefore overcoming inefficiencies of the wing design. In terms of an airplane, this inefficiency is due to the fact that an airplane wing is designed to optimize lift during flight at high speed. The flaps are utilized during landing because the wing (as- is) is most efficient for flight and not very efficient for creating lift at slower speeds. Using the flaps during the landing makes it easier to land the plane at slower speeds. Similar theories apply with fan design. If a manufacturer is using an aileron (flap) as part of the design, just as the winglet, it would be indicative of inefficiencies in the rotor/blade/airfoil design.