Watford,
Above, you said: "Vmca (Minimum Control Speed in the Air) is unaffected by bank, or anything else come to that, it is an absolute figure for each aircraft and can be found in the Flight Manual/POH/etc." This statement is not quite correct.
Vmca is in fact affected by bank angle and a number of other factors including CG, weight, power output, windmilling propeller etc. Vmca is related to controllability rather than performance. Banking ‘five degrees towards the live' results in a ‘slip' causing the relative airflow to pass over the fin at a greater angle of attack. This results in improved control effectiveness. (A lower speed for the same rudder deflection). Vmca will therefore be lower with bank than with wings level.
During certification under FAR 23 the FAA stipulate as an option, a maximum bank angle of five degrees. Obviously the manufacturer will accept this parameter to enhance his product.
Bank angle will also improve performance quite markedly. An early experience with a 400 series Cessna almost resulted in my demise following an EFATO on an obstacle cluttered flight path. My training had been along the lines of wings level, ball centred and I was not impressed with the climb performance. A later endorsement introduced the bank technique and I regret not being told of it earlier. However, many Australian training manuals were of British origin and made little point of the subtleties contained in Section 3 of American POHs.
Interestingly, whilst five degrees assists with control, about half that angle provides optimum performance (Vyse/Vxse). The shallower bank angle reduces slip or skid and minimises form drag.
I look for maximum use of the trim controls thereby easing the workload in achieving optimum bank angles. I have also found that some turbine aircraft with more sophisticated yaw dampers may be more accurately controlled by disengaging the yaw damper and re-engaging with the required rudder input.
Regards
------------------
dragchute
email:
[email protected]