515 Spin Semi Symmetric Spin Main Blades 400-2-515
For these blades we are using an asymmetrical air foil. These blades are producing lift at an angle of attack (pitch) of 0 degree already. They are specially developed for pilots who like to fly helicopters with a fuselage and who aim for extended flight times.
How can longer flight times be achieved using the same equipment and our asymmetrical blades?
Energy is saved due to the asymmetrical air foil, since it produces lift at an angle of attack of 0 degree already. The low angle of attack produces less drag compared to symmetrical blades and less energy is needed to rotate the blade. Furthermore the chord of the blades has been increased, decreasing the aspect ratio, and reduces the circular wing loading by not changing the wing span. Furthermore the center of gravity of the blade has been shifted more to the outside, forcing the angle of the longitudinal axis of the blade the rotation axis to decrease. All these factors are allowing using less rpm for fl ying operations. Less energy is used; less wear and tear on all moveable parts and longer lifetime of the helicopter are other side effects as well.
Since the center of gravity of the blades has been shifted to the outside and the angle between the longitudinal axis and the rotation axis of the blade has been decreased, the stability has been increased, enforcing the straight and level flight. This stability supports the modern flybarless systems. But the pilot still using the paddle head will enjoy more stability too. Despite the common view of several pilots, asymmetrical blades can be used for flying rolls, loopings, inverted, etc. Setting up the system, it should be notice that for setting up the system not only the power curve should be reduced, but that the individual gear in the transmission should be changed too to get better results. This is especially required if battery driven motors are used.