The advantage of the coaxial rotor is that, in forward flight, the lift provided by the advancing halves of each rotor compensates for the retreating half of the other, eliminating one of the key effects of dissymmetry of lift : retreating blade stall.
22.
Because the advancing blade has higher airspeed than the retreating blade and generates a dissymmetry of lift, rotor blades are designed to " flap " lift and twist in such a way that the advancing blade flaps up and develops a smaller angle of attack.
23.
In this case, dissymmetry of lift and blade flapping could cause the rotor disc to tilt aft . With full forward cyclic control already applied, the rotor disc might not be able to be lowered, resulting in possible loss of control, or the rotor blades striking the tail boom.
24.
A helicopter with a conventional rotor layout has a theoretical top speed of, after which it suffers from dissymmetry of lift . Some designs have successfully created hovering and high-speed aircraft, including the Bell Boeing V-22 Osprey tiltrotor that can fly at and the Sikorsky X2 compound helicopter that flew at, but both made significant aerodynamic compromises to hovering efficiency or range.
25.
For instance, while a simple amide addition study with relatively small substituents gave an \ alpha _ { FL } of H " 50?in solution, the crystallographic value determined for an enzymatic cleavage of an amide by the serine protease subtilisin gave an \ alpha _ { FL } of 8? and a compilation of literature crystallographic \ alpha _ { FL } values for the same reaction in different catalysts clustered at 4 ?6?( i . e ., only slightly offset from directly behind the carbonyl, despite significant dissymmetry of the substrate electrophiles ).
