power on stalls - some help would be lovely!
Two penneth worth from an experienced RAF QFI.
"...and let me recover the wingdrop with the rudder."
Please explain how the use of rudder is able to reduce wing angle of attack.
"...and let me recover the wingdrop with the rudder."
Please explain how the use of rudder is able to reduce wing angle of attack.
Lightning Mate
Yes, its a constant struggle to stop people adopting this misconcept, which, to be fair, I think was introduced in the early (RFC) days of aviation when stalling was not really understood.
Actually, yaw does change the relative AoAs of the opposite wingtips by varying their relative foreward speeds, thus increasing/decreasing the horizontal component of the relative airflow.
'Picking up the wing with opposite rudder' is achieved by simply inducing a similar stall and wing drop on the other side! This was developed into an entertaining/dangerous party trick called the Falling Leaf manoeuver, the 'trick' being to catch the reversals before they developed into spins, and I think it is this, more than anything that has perpetuated the misconcept for so long.
MJ
Yes, its a constant struggle to stop people adopting this misconcept, which, to be fair, I think was introduced in the early (RFC) days of aviation when stalling was not really understood.
Actually, yaw does change the relative AoAs of the opposite wingtips by varying their relative foreward speeds, thus increasing/decreasing the horizontal component of the relative airflow.
'Picking up the wing with opposite rudder' is achieved by simply inducing a similar stall and wing drop on the other side! This was developed into an entertaining/dangerous party trick called the Falling Leaf manoeuver, the 'trick' being to catch the reversals before they developed into spins, and I think it is this, more than anything that has perpetuated the misconcept for so long.
MJ
Last edited by Mach Jump; 25th Feb 2014 at 12:41. Reason: Spelling
Thread Starter
Join Date: Aug 2012
Location: Toronto
Posts: 297
Likes: 0
Received 0 Likes
on
0 Posts
a lot of stuff going on here. Appreciate everyone who has taken the time to reply. Some helpful advice, perhaps some misunderstanding as to what I'm asking as well.
For what it is worth, I'm familiar with the "falling leaf" maneuver (at least in theory), this ISN'T what i'm doing or being asked to do.
I think Mach Jump has it spot on "I think that localflighteast understands the above perfectly well, but just can't resist reacting to the wing drop with opposite aileron before reducing the AoA"
I know that the first thing I do is get the plane out of the stall , in this case by getting the nose down (although not too far , done that before as well!)
I just need to stop myself yanking the control column round. I'm looking for physical ways to help achieve this.
I've got a couple of methods I'm going to try.
As for the leaning forward thing. I'm really short. I have to sit quite far forward in order to get my feet on the pedals. If I compound that by leaning forward then any kind of back pressure on the yoke becomes a problem!
Thanks for your suggestions. I'm hoping to get a flight in this weekend so i'll let you know how it goes.
For what it is worth, I'm familiar with the "falling leaf" maneuver (at least in theory), this ISN'T what i'm doing or being asked to do.
I think Mach Jump has it spot on "I think that localflighteast understands the above perfectly well, but just can't resist reacting to the wing drop with opposite aileron before reducing the AoA"
I know that the first thing I do is get the plane out of the stall , in this case by getting the nose down (although not too far , done that before as well!)
I just need to stop myself yanking the control column round. I'm looking for physical ways to help achieve this.
I've got a couple of methods I'm going to try.
As for the leaning forward thing. I'm really short. I have to sit quite far forward in order to get my feet on the pedals. If I compound that by leaning forward then any kind of back pressure on the yoke becomes a problem!
Thanks for your suggestions. I'm hoping to get a flight in this weekend so i'll let you know how it goes.
Join Date: Jan 2008
Location: lancs.UK
Age: 77
Posts: 1,191
Likes: 0
Received 0 Likes
on
0 Posts
Just to clear upa misconception....Local Flight East, the Original Poster, is the party of the Female Persuasion.....not having been contradicted, one assumesher instructor is male. 
one assumesher instructor is male.
localflighteast
Good luck at the weekend. I'm sure you will get the hang of this with a bit more practice, and then wonder what all the fuss was about!
MJ
Join Date: Jan 2001
Location: In the boot of my car!
Posts: 5,982
Likes: 0
Received 0 Likes
on
0 Posts
LocalFlyEast
I still think you are flying in car mode
and reverting to your familiarity with a car instincts especially under stress!
Take a step back and forget the column altogether!
Set the aircraft up for level flight and get it well trimmed so it's flying wings level at a set attitude!
Don't touch the yoke at all but purely use the rudder!
Add gentle pressure and note what happens! Hold a heading using gentle rudder pressure! Now add more pressure and be more brutal! Watch what happens to the T and S and the ball! Watch what happens regarding the nose and the horizon as well as the wing!
Sadly many people hardly use the rudder tending to forget it and concentrating too much on the yoke!
A tip when you fly your steep turns and many won't like this but it's a good exercise trim the aircraft into a steep turn so it takes the pressure off your arms and allows you to fly the turn with gentle finger tip pressure!
You should re trim for every configuration power change!
Why not steep turns!
Consider the harmonisation of all your controls not one in isolation and understand what is happening
Then go back to your stall and don't be afraid to play around to experiment in that configuration too and note what is happening
Pace
I still think you are flying in car mode
and reverting to your familiarity with a car instincts especially under stress! Take a step back and forget the column altogether!
Set the aircraft up for level flight and get it well trimmed so it's flying wings level at a set attitude!
Don't touch the yoke at all but purely use the rudder!
Add gentle pressure and note what happens! Hold a heading using gentle rudder pressure! Now add more pressure and be more brutal! Watch what happens to the T and S and the ball! Watch what happens regarding the nose and the horizon as well as the wing!
Sadly many people hardly use the rudder tending to forget it and concentrating too much on the yoke!
A tip when you fly your steep turns and many won't like this but it's a good exercise trim the aircraft into a steep turn so it takes the pressure off your arms and allows you to fly the turn with gentle finger tip pressure!
You should re trim for every configuration power change!
Why not steep turns!
Consider the harmonisation of all your controls not one in isolation and understand what is happening
Then go back to your stall and don't be afraid to play around to experiment in that configuration too and note what is happening
Pace
localflighteast,
I've come late to this thread. I just want to reassure you that this is a common problem with students. I used to instruct in gliders and almost every new student wanted to "pick up the wing" using the stick. It's instinctive and you have to learn and practice the correct technique until it too becomes instinctive.
My suggestion would be to practice power-off stalls with a higher pitch attitude than normal, so as to almost guarantee a wing drop. Then you have one less control to worry about.
Go slowly as others have suggested and think of it in three steps:
1. Push the yoke forward to unstall the wing.
2. Stop the yaw with rudder.
3. Level the wings with the ailerons.
Then raise the nose while applying power.
If it's any consolation, I should confess to the following. I've been flying for more years than I care to admit and I mostly fly aircraft with sticks. When I hop into a Cessna, I often find I want to "steer" with the yoke, while taxying!
I've come late to this thread. I just want to reassure you that this is a common problem with students. I used to instruct in gliders and almost every new student wanted to "pick up the wing" using the stick. It's instinctive and you have to learn and practice the correct technique until it too becomes instinctive.
My suggestion would be to practice power-off stalls with a higher pitch attitude than normal, so as to almost guarantee a wing drop. Then you have one less control to worry about.
Go slowly as others have suggested and think of it in three steps:
1. Push the yoke forward to unstall the wing.
2. Stop the yaw with rudder.
3. Level the wings with the ailerons.
Then raise the nose while applying power.
If it's any consolation, I should confess to the following. I've been flying for more years than I care to admit and I mostly fly aircraft with sticks. When I hop into a Cessna, I often find I want to "steer" with the yoke, while taxying!
"Yes, its a constant struggle to stop people adopting this misconcept"
That's not the only one either.
When I was an ATPL instructor it was a constant uphill battle to dispel enormous myths with people who only held a PPL.
A good one was the fact that a wing develops lift because the air over the upper surface has to go faster in order to meet the flow over the lower surface.
Utter b##################s
That's not the only one either.
When I was an ATPL instructor it was a constant uphill battle to dispel enormous myths with people who only held a PPL.
A good one was the fact that a wing develops lift because the air over the upper surface has to go faster in order to meet the flow over the lower surface.
Utter b##################s
Join Date: May 2001
Posts: 10,815
Likes: 0
Received 0 Likes
on
0 Posts
Local another trick I used to do with students was make them fly with a pen across the top of there middle finger trapped by the index and ring finger on the top of it.
Stops muckle fisted abuse of the controls.
Stops muckle fisted abuse of the controls.
A good one was the fact that a wing develops lift because the air over the upper surface has to go faster in order to meet the flow over the lower surface.
Yes. Sometimes we simplify things to a point where they are not really true. Far too big a subject to go into here though. At least people are not going to get into trouble flying the aircraft believing that.MJ
The truth is I don't know what happened in the Tommie - all went so fast. In the Cessnas I'm fairly sure I've been getting to a point where e.g. full right rudder was unable to prevent further wing drop to the left, at which point they show they can bite.
Local another trick I used to do with students was make them fly with a pen across the top of there middle finger trapped by the index and ring finger on the top of it.
Souinds interesting. I'll try that.
full right rudder was unable to prevent further wing drop to the left
MJ
Join Date: May 2001
Posts: 10,815
Likes: 0
Received 0 Likes
on
0 Posts
A good one was the fact that a wing develops lift because the air over the upper surface has to go faster in order to meet the flow over the lower surface.
adgd its any input in ailerons which does it, for the first 2 months demoing stalls I too had a wing drop on the tommy, 200 hours later it suddenly stopped doing it while the students continued to wing drop.
Stops muckle fisted abuse of the controls.
I always made a point, when introducing new students to tandem two-seat gliders, to get them to hold the stick lightly with fingers and thumb, rather than a death-grip. I also checked that lefties were using their right hand, to avoid getting into trouble later in the circuit when they needed to use the airbrakes.
I also showed them how, in the case of the excessively tall stick in a Blanik, to hold it below the hand-grip, so that they could brace their fore-arm on their thigh, to avoid PIOs on takeoff.
.....we didn't hit a single thing you couldn't explain using fairy lift theory
Love to hear about Fairy Lift. It could be just as convincing as some of the other theories, and a lot more fun!
MJ
So, the heavier, or uglier (and especially aeroplanes that are both), the greater account-lightening is required to generate lift.
Pretty much any flying machine fit this:- helicopters, particularly big ones, tend to be particularly ugly so require enormous amounts of account-lightening, whilst gliders for example, which are reasonably light and extremely beautiful, require hardly any account-lightening at-all to fly.
G
Genghis.
I'm sure that's as practically useful an explanation as any other!
Except, of course that the reduction in wallet mass is a function of the square of the ugliness x the weight.
MJ
I'm sure that's as practically useful an explanation as any other!
Except, of course that the reduction in wallet mass is a function of the square of the ugliness x the weight.
MJ
Join Date: Oct 1999
Location: UK
Posts: 3,325
Likes: 0
Received 0 Likes
on
0 Posts
I just need to stop myself yanking the control column round. I'm looking for physical ways to help achieve this.
I've got a couple of methods I'm going to try.
I've got a couple of methods I'm going to try.
First - Unstall the wing with slight (it won't take much) forward stick.
Second - remove any unwanted roll with aileron.
Don't do the second 'till you've done the first.
If it ain't stalled it can't spin.
It's actually easier to avoid inadvertent aileron movement if you are flying an aircraft with a stick, but you have to go with what you've got
It's actually easier to avoid inadvertent aileron movement if you are flying an aircraft with a stick, but you have to go with what you've got
Join Date: Oct 2012
Location: UK
Posts: 681
Likes: 0
Received 0 Likes
on
0 Posts
Hi localflighteast
Firstly, since you say:
Then please don't:
Power On Stalls, from level flight, in a C172 with approx. 1600rpn will give
a slightly higher nose attitude at the point of stall than Power Off Stalls.
Is this what you are doing? Or are you using the power to pull the nose up
very high prior to the stall - leading to things happening very quickly, and
hence you trying to react too quickly and doing the wrong thing?
The "Nose Drop" from a Power On Stall is more evident than from Power Off.
Just ease the Control Column forward a little (plus add power if doing a
standard stall recovery) to ensure that both wings unstall, without
bothering about aileron or rudder (just ignore any wing drop at the stall).
The aircraft will now be in a perfectly good flying condition and any bank
can be rectified by usual aileron input coordinated with rudder.
I think the point of all of this (including Test Standards) is to confirm
no aileron input is used whilst the aircraft is stalled/close to the stall - it
is not to show use of rudder in a stall.
If you are going to use rudder in the stall then you need to understand why:
1) If, for whatever reason, one wing stalls before the other then the
aircraft will roll towards that wing (greater loss of lift on one side).
2) A stalled (or more stalled) wing generates more drag than the other, so
the aircraft will also yaw towards that wing.
The use of rudder, in a stall, is not to try and "lift" (secondary effect) a wing
back up, it is for its primary effect of yaw and only sufficient needs to be
applied to prevent further yaw of the aircraft. You have to accept that, with
a wing drop no stall recovery will result in an, initial, wings level attitude.
The use of rudder in the stall is simply to minimise the "unusualness" of
the unusual attitude you will be in once recovered.
There is probably one phase of flight where you already use rudder without
aileron - and that is the last phase of landing where you may need constant
small rudder inputs to keep the nose of the aircraft pointing straight down
the runway.
Be conscious of this your next few landings and, if it is true, then you know
you can apply the same to stalling.
Firstly, since you say:
I think I almost span it once because I was stupid
airwork dual and then the next couple of lessons I go up and do them solo
Power On Stalls, from level flight, in a C172 with approx. 1600rpn will give
a slightly higher nose attitude at the point of stall than Power Off Stalls.
Is this what you are doing? Or are you using the power to pull the nose up
very high prior to the stall - leading to things happening very quickly, and
hence you trying to react too quickly and doing the wrong thing?
The "Nose Drop" from a Power On Stall is more evident than from Power Off.
Just ease the Control Column forward a little (plus add power if doing a
standard stall recovery) to ensure that both wings unstall, without
bothering about aileron or rudder (just ignore any wing drop at the stall).
The aircraft will now be in a perfectly good flying condition and any bank
can be rectified by usual aileron input coordinated with rudder.
I think the point of all of this (including Test Standards) is to confirm
no aileron input is used whilst the aircraft is stalled/close to the stall - it
is not to show use of rudder in a stall.
If you are going to use rudder in the stall then you need to understand why:
1) If, for whatever reason, one wing stalls before the other then the
aircraft will roll towards that wing (greater loss of lift on one side).
2) A stalled (or more stalled) wing generates more drag than the other, so
the aircraft will also yaw towards that wing.
The use of rudder, in a stall, is not to try and "lift" (secondary effect) a wing
back up, it is for its primary effect of yaw and only sufficient needs to be
applied to prevent further yaw of the aircraft. You have to accept that, with
a wing drop no stall recovery will result in an, initial, wings level attitude.
The use of rudder in the stall is simply to minimise the "unusualness" of
the unusual attitude you will be in once recovered.
There is probably one phase of flight where you already use rudder without
aileron - and that is the last phase of landing where you may need constant
small rudder inputs to keep the nose of the aircraft pointing straight down
the runway.
Be conscious of this your next few landings and, if it is true, then you know
you can apply the same to stalling.