Skidding turns

Yesterday on a short sight-seeing x-cntry I noticed the following
flight characteristic of a 1975 C150: whenever I turned to the left,
especially with low power setting, the ball indicated a skid with no
bottom rudder at all.

Explanations I've seen usually are illustrating the danger of skidding
a turn onto final, at high AoA, the typical scenario being tightening
a turn to not overshoot the runway. The inside wing and the rudder are
pointing toward the ground. The ball indicates skid. The pilot gives
more back pressure -- that's where you can get into big trouble.

But I noticed a substantial ball deflection indicating skid with
neutral rudder (shallow turn, not anywhere near critical AoA, by the
way).

In a left turn it seemed to me to take a fair bit of top rudder to
keep the ball centered. That seems weird to me. It doesn't happen in
the 152 or 172 I fly so I'm wondering if other people have seen this
in 150s (or other aircraft) or maybe the ball indicator has a problem?

I remember during my checkride in the same aircraft the ball showed
substantial skid on a demo approach the DE was doing after I had
passed the checkride. He saw it too and corrected, but the plane's
behavior seemed to catch him off guard as well.

On Feb 19, 9:33 am, wrote:
Yesterday on a short sight-seeing x-cntry I noticed the following
flight characteristic of a 1975 C150: whenever I turned to the left,
especially with low power setting, the ball indicated a skid with no
bottom rudder at all.

Explanations I've seen usually are illustrating the danger of skidding
a turn onto final, at high AoA, the typical scenario being tightening
a turn to not overshoot the runway. The inside wing and the rudder are
pointing toward the ground. The ball indicates skid. The pilot gives
more back pressure -- that's where you can get into big trouble.

But I noticed a substantial ball deflection indicating skid with
neutral rudder (shallow turn, not anywhere near critical AoA, by the
way).

In a left turn it seemed to me to take a fair bit of top rudder to
keep the ball centered. That seems weird to me. It doesn't happen in
the 152 or 172 I fly so I'm wondering if other people have seen this
in 150s (or other aircraft) or maybe the ball indicator has a problem?

I remember during my checkride in the same aircraft the ball showed
substantial skid on a demo approach the DE was doing after I had
passed the checkride. He saw it too and corrected, but the plane's
behavior seemed to catch him off guard as well.

You have a broken rudder bar spring. Cessna's springs regularly do
that and will have the airplane uncoordinated, requiring constant
rudder force on one pedal to keep things centered. The unbroken spring
is pulling on one pedal.
The other, more remote possibility, is a worn nosewheel
centering cam. The nosewheel is the rudder's centering system while in
flight on a Cessna single, with the sprung steering pushrods acting as
system centers. Cessna rudder systems are frequently found badly
misrigged, too, since too few mechanics refer to the maintenance
manuals while fixing them.

Dan

On Feb 19, 9:33 am, wrote:
Yesterday on a short sight-seeing x-cntry I noticed the following
flight characteristic of a 1975 C150: whenever I turned to the left,
especially with low power setting, the ball indicated a skid with no
bottom rudder at all.

Explanations I've seen usually are illustrating the danger of skidding
a turn onto final, at high AoA, the typical scenario being tightening
a turn to not overshoot the runway. The inside wing and the rudder are
pointing toward the ground. The ball indicates skid. The pilot gives
more back pressure -- that's where you can get into big trouble.

But I noticed a substantial ball deflection indicating skid with
neutral rudder (shallow turn, not anywhere near critical AoA, by the
way).

In a left turn it seemed to me to take a fair bit of top rudder to
keep the ball centered. That seems weird to me. It doesn't happen in
the 152 or 172 I fly so I'm wondering if other people have seen this
in 150s (or other aircraft) or maybe the ball indicator has a problem?

I remember during my checkride in the same aircraft the ball showed
substantial skid on a demo approach the DE was doing after I had
passed the checkride. He saw it too and corrected, but the plane's
behavior seemed to catch him off guard as well.

You have a broken rudder bar spring. Cessna's springs regularly do
that and will have the airplane uncoordinated, requiring constant
rudder force on one pedal to keep things centered. The unbroken spring
is pulling on one pedal.
The other, more remote possibility, is a worn nosewheel
centering cam. The nosewheel is the rudder's centering system while in
flight on a Cessna single, with the sprung steering pushrods acting as
system centers. Cessna rudder systems are frequently found badly
misrigged, too, since too few mechanics refer to the maintenance
manuals while fixing them.

Dan

On Feb 19, 8:33*am, wrote:

In a left turn it seemed to me to take a fair bit of top rudder to
keep the ball centered. That seems weird to me. It doesn't happen in
the 152 or 172 I fly so I'm wondering if other people have seen this
in 150s (or other aircraft) or maybe the ball indicator has a problem?

Sure you weren't flying a helicopter?

-Robert

On Feb 19, 11:40*am, wrote:
On Feb 19, 9:33 am, wrote:





Yesterday on a short sight-seeing x-cntry I noticed the following
flight characteristic of a 1975 C150: whenever I turned to the left,
especially with low power setting, the ball indicated a skid with no
bottom rudder at all.

Explanations I've seen usually are illustrating the danger of skidding
a turn onto final, at high AoA, the typical scenario being tightening
a turn to not overshoot the runway. The inside wing and the rudder are
pointing toward the ground. The ball indicates skid. The pilot gives
more back pressure -- that's where you can get into big trouble.

But I noticed a substantial ball deflection indicating skid with
neutral rudder (shallow turn, not anywhere near critical AoA, by the
way).

In a left turn it seemed to me to take a fair bit of top rudder to
keep the ball centered. That seems weird to me. It doesn't happen in
the 152 or 172 I fly so I'm wondering if other people have seen this
in 150s (or other aircraft) or maybe the ball indicator has a problem?

I remember during my checkride in the same aircraft the ball showed
substantial skid on a demo approach the DE was doing after I had
passed the checkride. He saw it too and corrected, but the plane's
behavior seemed to catch him off guard as well.

* *You have a broken rudder bar spring. Cessna's springs regularly do
that and will have the airplane uncoordinated, requiring constant
rudder force on one pedal to keep things centered. The unbroken spring
is pulling on one pedal.
* * * *The other, more remote possibility, is a worn nosewheel
centering cam. The nosewheel is the rudder's centering system while in
flight on a Cessna single, with the sprung steering pushrods acting as
system centers. Cessna rudder systems are frequently found badly
misrigged, too, since too few mechanics refer to the maintenance
manuals while fixing them.

* * * *Dan- Hide quoted text -

- Show quoted text -

Hey thanks, I will convey that info in terms of a question to the FBO
and see what they say. I'm sure other pilots have noted this weirdness
as well.

On Feb 19, 12:26*pm, "Robert M. Gary" wrote:
On Feb 19, 8:33*am, wrote:

In a left turn it seemed to me to take a fair bit of top rudder to
keep the ball centered. That seems weird to me. It doesn't happen in
the 152 or 172 I fly so I'm wondering if other people have seen this
in 150s (or other aircraft) or maybe the ball indicator has a problem?

Sure you weren't flying a helicopter?

-Robert

Hah! For my own safety and that of everyone else I hope I'm not
hallucinating *that* bad!

On Feb 19, 5:12*pm, wrote:

Hey thanks, I will convey that info in terms of a question to the FBO
and see what they say. I'm sure other pilots have noted this weirdness
as well.

Remember that the FBO's CFIs are probably flying this plane more often
than solo renters. I would be surprised if the FBO doesn't already
know. Either they are waiting on the part, waiting for the next 100
hours, or waiting for someone to crash as a result of this.

-robert

On Feb 19, 6:14 pm, "Robert M. Gary" wrote:
On Feb 19, 5:12 pm, wrote:

Hey thanks, I will convey that info in terms of a question to the FBO
and see what they say. I'm sure other pilots have noted this weirdness
as well.

Remember that the FBO's CFIs are probably flying this plane more often
than solo renters. I would be surprised if the FBO doesn't already
know. Either they are waiting on the part, waiting for the next 100
hours, or waiting for someone to crash as a result of this.

-robert

The way to find out: push the tail down to raise the nosewheel
off the ground, and see if the rudder centers. If not, one spring is
probably busted.
Be carerful pushing the tail down. The front spar in the stab is
a little light and cracks easily if this is done regularly. 172s are
worse. Much worse.

Dan

* * *The way to find out: push the tail down to raise the nosewheel
off the ground, and see if the rudder centers. If not, one spring is
probably busted.
* * *Be carerful pushing the tail down. The front spar in the stab is
a little light and cracks easily if this is done regularly. 172s are
worse. Much worse.

* * *Dan

that shouldn't happen if you push down on the last two fuselage
formers before the vertical tail, should it?

Be careful pushing the tail down. The front spar in the stab is
a little light and cracks easily if this is done regularly. 172s are
worse. Much worse.

Dan

So _that's_ why the flight school always flipped out when we did that...

Now I fly a plane where the tail is _always_ down. Of course, that makes landing slightly
more challenging...