DO winglets have effect on Vref when landing?

[737Jock]

http://www.avioconsult.com/downloads...%20failure.pdf

When banking, a component of the weight, leads to a side force due to bank angle (Wsin φ in Figure 2), that can re- place the side force Yβ due to sideslip that was required for balance with the wings level. The small bank angle decreases the sideslip angle to a minimum, decreasing the total drag and, hence, increasing climb performance. Side force Wsin φ acts in the centre of gravity and therefore does not cause any ad- verse yawing moments.
Because the side force Yδr, generated by the vertical tail with rudder, no longer has to act against the side force due to side- slip Yβ, but only against the thrust yawing moment NT, the rudder deflection need not be maximal, the airspeed can be reduced until the deflection is again maximal, or the vertical tail can be dimensioned smaller to save manufacturing cost and weight

and weight.
FAR/CS 23.149 and 25.149 allow the engineer designing the vertical tail to use a bank angle of maximum 5 degrees. Reducing the size of the verti- cal tail increases VMCA (for a high enough side force Yδr). FAR/CS 23.149, however, does not allow the vertical tail to be made so small that VMCA exceeds 1.2 times the stall speed (VS). Hence, the verti- cal tail is made just big enough to maintain straight flight while the thrust of the opposite engine is at the maximum takeoff setting, the rudder is maximal deflected and while maintaining a small bank angle as opted by the designer of the vertical tail, usually between 3 and 5 de-

Sorry but I cannot find any evidence at all that VMCA would massively be below Vs in the configuration its actually tested in. And the only reason for that would be the lack of pilots banking into the live engine. Its a crazy notion that basicly would mean the tailfin is way too big, thus weight materials can be saved by making it smaller. While also reducing fuel burn.

Now since they build entire airplanes made from carbon, to save a bit of fuel, do you seriously consider that they would stick on a tailfin that is too big?

I don't really care if its theoretically possible. It would not be economical and adjusted as soon as they notice it.

Sure if you design a longer aircraft based on a basemodel the tailfin could be made smaller (usually they won't), as the arm becomes longer. But the entire idea of super big margins is just ludicrous.