posted 05-15- 11:23 AM               

So, at some point during the landing approach, you go from a "descent" where the p-factor is not very noticeable, to an overall "positive" AOA, at which point the p-factor becomes significant again. This would not necessarily be "gradual" if your roundout and flare requires a large enough change of AoA.

Just a guess. Props are weird. Could just be that as you slow down and bring up the nose, the rudder gets "blocked out" by the fuselage and you "suddenly" need more rudder to achieve the same amount of control you had a second before.

Was it windy?

posted 05-15- 02:19 PM            

Props are weird indeed, no doubt about it. There are many things that causes the effect. The extra pull from the downgoing part (right hand side) of the prop is one thing. A minor, but perhaps noticable effect, is also that the prop is one huge gyro. The slip-stream from the prop is yet an effect that may be part of it. All of which I think should be more or less proportional to the AoA.

One thing that came to my mind as a possibility (really guessing here) is that when I reduce the RPM (fixed pitch prop) rather suddenly, the prop may stop pulling and instead be a huge airbrake. As I raise the nose to maintain altitude and reduce airspeed, there comes a more or less sudden moment when the prop starts pulling again. There's only one detail that says this isn't the case... there was no right yaw or roll the moment I reduced the RPM... (none that I remember anyway.)

Windy??? The airplane moves relative to the air around it, so what does wind matter? Or did you mean gusty? If so, no, there was a light wind, around 5-10kt, but no gusts worth speaking of. When keeping cruise speed, it was like following a string in the air.
_
/Bjorn.

PS. Did my first landing yesterday! Woohoo! Worked great. Sims like this one where FMs is a major thing has helped a lot. Tomorrow will be about 1 hour of touch and go's. Phiew!

posted 05-15- 06:46 PM               

For instance, the plane will ALWAYS "weathervane" into the wind, unless you prevent it from doing so by "slipping" where you bank into the wind and align the fuselage with the runway using the rudder (a pretty standard technique for crosswind landings).

If you fly a relatively "stable" approach, you're holding your speed pretty closely, and you'll have your controls "set" and (maybe) even trimmed to hold your desired crosswind corrections in. Then, as you bring the nose up to land, all that changes

As you flare, the engine and fuselage will block some of the airflow from the rudder, and the rudder will also become less effective due to your speed decreasing from the increased drag of the higher AoA on the wings. So if there is any wind, it will weathervane you worse as you flare, unless you proportionally increase the amount of crosswind controls you're holding. This would tend to be somewhat "gradual" tho...

Hehe of course, if that was your FIRST landing, then we may be on different pages as to what "gradual" actually means

If you did the first one right--just keep doing it that way. Eventually you won't even notice the yaw, because you'll feed the rudder in as you flare...

posted 05-16- 05:08 PM               

But that's a total guess The only Piper I've flown is the Seminole, and that has counter-rotating props like a P-38, so not much yaw unless you start doing engine-out work...