I am planning on attaching a servo to a modified MHQ2 quadcopter design (by Hovership) (original files can be found on thingiverse.com) which adjusts the propeller arm +- 12 degrees. Using trigonometry, the extra forward speed we get can be calculated as we know the propeller lift value and the degree of the arm (which is about 30%) I might not be able to test this with a quadcopter but i will be testing the mechanism once i 3d print the additional pieces.
Finished the designs of the prototype to fit the MHQ2 quadcopter on Fusion360. Will 3D print the pieces for test fitting. I might need to change the plans based on this test. There are four different pieces which are two halves of propeller arms and the servo bracket with its lid.