Making Turns with rudders
The limiting bank angle will depend on a large number of things, speed and airframe being the major ones. If you are teaching PPL studes then 30 degrees might be appropriate. If you are on instruments I assume you're familiar with the formula for R1 bank angle. Anything else can be found in the standard FI manuals.
Yes, crosswind is "max demonstrated" and not a limit. It is perfectly possible to operate beyond max demo with a range of techniques, including differential thrust.
HFD
Yes, crosswind is "max demonstrated" and not a limit. It is perfectly possible to operate beyond max demo with a range of techniques, including differential thrust.
HFD
My boss smacks my head for using rudder in the Duchess
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They are guidance, but not actually limiting.
But be very wary of ignoring the guidance published in the manufacturer's flight manual or POH. If you prang the aircraft because you deliberately chose to disregard the official advice then the insurers won't pay up and their lawyers will be after you real quick.
In general terms, control inputs are made either as a reaction to a cue, in this case an observed yaw or slip ball deflection, or in anticipation of a predictable response. In a well coordinated turn the rudder input should be coordinated with the aileron input such that no yaw occurs. If the yaw due to aileron is excessive such that a significant adverse yaw rate is generated rudder free the there may be an advantage in 'leading with rudder' because less rudder will be needed because it is only the yawing moment due to rudder that needs to be countered and not also a yaw rate that needs to be stopped.
If an aeroplane has low static directional (weathercock) stability then at a constant bank angle rudder will be needed into the turn to keep the slipball central but this is a different aerodynamic requirement to that for opposing aileron induced yaw.
In aeroplanes that have low aileron power but strong lateral stability (dihedral effect) it may be optimum to use rudder to generate sideslip and thus a rolling moment in the direction of turn in addition to rolling with aileron. This is not a coordinated turn but a specific technique for some aircraft. And then there is the F4 above 17 units AOA ....
If an aeroplane has low static directional (weathercock) stability then at a constant bank angle rudder will be needed into the turn to keep the slipball central but this is a different aerodynamic requirement to that for opposing aileron induced yaw.
In aeroplanes that have low aileron power but strong lateral stability (dihedral effect) it may be optimum to use rudder to generate sideslip and thus a rolling moment in the direction of turn in addition to rolling with aileron. This is not a coordinated turn but a specific technique for some aircraft. And then there is the F4 above 17 units AOA ....
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But be very wary of ignoring the guidance published in the manufacturer's flight manual or POH. If you prang the aircraft because you deliberately chose to disregard the official advice then the insurers won't pay up and their lawyers will be after you real quick.
It is worth noting that this requirement must be met without unusual pilot skill - so it must be easily achieved. So if a pilot can apply extra skill, and accept a more intense crosswind, without being negligent, they can be confident that they are not exceeding a limitation of the aircraft.
If in doubt, fly the approach. If you can maintain the runway centerline down final, landing should be within you skill. If you cannot maintain the centerline, and smooth control of the aircraft, you should not attempt to land on that runway in those winds.
Modern flight manuals /POHs are written in a particular format, with a distinct limitations section, which is limiting, approved sections, which are obviously approved, but may not be limiting, and unapproved sections, which are or information. It's wise to be familiar.
For those wanting a very good treatise on the aerodynamics of Cessnas, I highly recommend: Cessna Wings for the World, by Thompson. It will tell you what you want on know about using the rudder in a Cessna.
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So after four hours of plowing snow from my apron and runway, and sweeping off my 150, I rewarded myself with a flight today. It's a straight out of the box 1975 150M, with a Horton STOL kit.
When I rolled into a rate one turn, with the objective of not exceeding rate one, to a 30 degree bank, the ball would be more than one ball out by the time that the 30 degree bank angle was achieved, if I did not apply pro turn rudder within two seconds of applying the aileron. If I lead the turn by one second with rudder, or the application of rudder and aileron were simultaneous, the turn could be co ordinated by modulating the rudder which had been applied. Leading with rudder did un coordinate up the turn, though leading with aileron would.
The STOL kit on my 150 does affect these characteristics, so I would agree that not all 'planes are the same. But this is the characteristic of one of mine.
When I rolled into a rate one turn, with the objective of not exceeding rate one, to a 30 degree bank, the ball would be more than one ball out by the time that the 30 degree bank angle was achieved, if I did not apply pro turn rudder within two seconds of applying the aileron. If I lead the turn by one second with rudder, or the application of rudder and aileron were simultaneous, the turn could be co ordinated by modulating the rudder which had been applied. Leading with rudder did un coordinate up the turn, though leading with aileron would.
The STOL kit on my 150 does affect these characteristics, so I would agree that not all 'planes are the same. But this is the characteristic of one of mine.
