Absolutely right. Much better described than by myself. Cheers. Ps, it worries me that this falacy is in nearly all the pilot theory study books.

Im thinking that it is a thing as it explains what happens at the top of a stall turn where airspeed is zeeo

Thanks, glad to hear that!

When yawed to the left, but as you say maintaining a steady direction flight - so if I understand your question correctly, the aircraft is flying diagonally forward - ie the 'heading' (the direction the nose is pointing - is a bit left in your example) is different to the 'track' the direction of travel or path of the airplane through the air. The relative airflow is coming from the direction of travel, ie slightly side-on from the right of nose. Easy to visualise with a pen or pencil. So what you have is that the relative airflow to the left wing is being partially obscured by the body of the aircraft whereas the right wing isn't. So in this case the inner part of the left wing, the root and inboard portion of the wing obscured from the relative airflow isn't generating lift because there is no airflow over it, but further out towards the tip, the wing continues to generate lift as the fuselage isn't shielding the wing from the airflow this far out on the span. In contrast, the right wing has clear access to the oncoming relative airflow, so its generating lift across the full span. When AOA (alpha) is increased beyond the critical angle of attack, the tips (OK this is for swept wings) stall first. So in the case of the left wing it is generating no lift at all (its fully stalled), whereas the right wing is still generating lift inboard of the tip. So the right wing is generating lift and the left wing isn't. The resulting moment causes the aircraft to roll to the left.

They do yes

Interesting point.

Heres my take on that. Every action has an equal and opposite reaction. So if you have a free gyro, sure push on it and it moves as if youve pushed it at a point 90 degrees in the direction of rotation. The gyro feels really rigid to you where youre pushing it. I know this as i repair gyro instruments. However this breaks down if you get gimbal lock on the 90 degree axis and all of a sudden there seems to be no more rigidity whatsoever. Its a really weird sensation, but it is whats commonly referred to as toppling in aircraft gyro instruments or sometimes called gimbal lock An aeroplane makes the prop a non free gyro to some extent. So while there are gyroscopic forces generated its not anything like a free gyro So if you have a high angle between the relative airflow and the crankshaft axis i would expect that the downgoing blade would tend to pull the aircraft forward more than the upgoing blade. In a clockwise from pilots view rotation, ie lycoming/continental/rotax id expect this would also give you some pitch up moment. For a gypsy/russian radial it should also be pitch up. So in my low wing plane, a sudden application of power at a low airspeed should get some pitch up but this would be countered by the prop shaft being above the centre of gravity. It might be different if i do the same from slow inverted flight. Maybe ill give that a try

Good call laurie. I have to agree with you. Flying line astern formation also demonstrates this. Flying echellon and about 1/2 a wingspan out, you get a very strong roll into the lead from the aircraft wake though, and you can clearly see that vortex in smoke

But at the top of a hammerhead, whats that left yaw? I suspect its slipstream spiralling, at the much lower forward speed

@@davefoord1259 if truly vertical its the normal torque effect dominating once airflow over the controls is lost. If not quite vertical its good old P effect. It's for these reasons that aerobatic aircraft normally have a preferred direction of yaw at the top of the stall turn (hammerhead). Some types will happilly go one way, but trying the other way is difficult and/or requires much earlier rudder input before all the non-slipstream airflow is lost. Depends on the type and direction of prop rotation, power available etc.

And in formation flying it is absolutely critical to be able to understand, visualise and be ready for the effects of wake and wingtip vortices from other aircraft.

@@lauriejones3198 its not torque right at the top, thats trying to roll you not yaw you. Aileron position is a good guide to the right time to kick the rudder. and its not p factor as aoa is zero and prop is perpendicular to chord line. I think it is slipstream at that point