power on stalls - some help would be lovely!
Join Date: Dec 2011
Location: Denver/Europe
Age: 34
Posts: 23
Likes: 0
Received 0 Likes
on
0 Posts
Turn Smart - YouTube
This video explains very well the falling leaf maneuver. The wingdrop is indeed prevented by rudder.
This video explains very well the falling leaf maneuver. The wingdrop is indeed prevented by rudder.
This video explains very well the falling leaf maneuver. The wingdrop is indeed prevented by rudder.
What this shows very well is that using the rudder to try to 'pick up' the downgoing wing, without reducing the AoA overall (moving the control column forward) is very likely to induce the opposite wing to drop beyond the first and then you are in a worse situation than you started with.
MJ
Thread Starter
Join Date: Aug 2012
Location: Toronto
Posts: 297
Likes: 0
Received 0 Likes
on
0 Posts
@level flight, I won't be doing them solo because I'm messing them up. Hence the frustration, they are not yet on my list of things I'm approved to do when solo.
@pace - appreciate your comments about treating the controls like a car's but I don't drive so am not convinced this is a major problem.
going to talk over the plan with my instructor and figure out where we go with regard to my next lesson
@pace - appreciate your comments about treating the controls like a car's but I don't drive so am not convinced this is a major problem.
going to talk over the plan with my instructor and figure out where we go with regard to my next lesson
Join Date: Nov 2013
Location: Oz
Posts: 242
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Lightning Mate
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.
...you are preventing the plane from yawing...
YES! If only everyone learned when they did 'Effects of Controls' that the rudder is used primarily to PREVENT yaw, not induce it, they would be much better prepared for all the other exercises, including stalling.
Before the stall though, as the speed is slowing, with some power on, the aircraft tends to yaw in the direction opposite to the top of the prop, as you see it from the pilot's position. This is a yaw to the left in most modern aircraft. This induces a roll to the left as the left wing slows down, and people then try to hold the wings level with the ailerons. This, in turn, causes an out of balance condition as you approach the stall, which will make a wing drop more likely.
People then see the wing drop at the stall as just a continuation of the one that occured as they approached the stall, and they react in a similar way with the aileron. So, you have to recognise that the wing drop at the stall has a completely different cause to the tendency to yaw/roll as you slow down, and needs a different solution.
As you approach a stall, prevent yaw with the rudder. This will keep the wings from rolling due to yaw.
At the stall though, the wing drops because it has STALLED, and you need to UNSTALL IT (move the control column forward) to stop it dropping!
MJ
Join Date: Jan 2014
Location: glendale
Posts: 819
Likes: 0
Received 0 Likes
on
0 Posts
it all boils down to this: don't over control. practice it. little movements
one of the things you need to understand is the faster you are going the less movement you need
and, when you are going slowly, a control input will take longer.
one of the things you need to understand is the faster you are going the less movement you need
and, when you are going slowly, a control input will take longer.
Join Date: Oct 2012
Location: UK
Posts: 681
Likes: 0
Received 0 Likes
on
0 Posts
glendalegoon #11: AT first indication of a stall, push forward (usually just
a small amount, or even the term, ''relax back pressure" is used) on the control wheel
and simultaneously level the wings and add full power
and simultaneously level the wings and add full power
as you also wrote (NB: I added "then" to your quote):
glendalegoon #30: When I taught, I didn't even show it, recover and then
use coordinated aileron and rudder
BPF #18: Say out load " Step 1 stick forward wheel central", do it then say
" Step 2 full power" then do it and then finally " step 3 straight with rudder"
"Roll the aircraft to nearest horizon using coordinated aileron and rudder" would be better.
agbd #36: I also tend to pull power early on as with a major wing drop
you are in an incipient spin
with wing drop. Removing power is part of incipient spin recovery.
The question does arise as to when a stall with wing drop becomes an
incipient spin - most books that I have seen say once the wings have
rolled through 90deg. This seems a little steep to me, and I would probably
say 45 deg. I note you were referring to a PA38 which does tend to
rapidly drop a wing in the stall!
MJ #65: 'Effects of Controls' that the rudder is used primarily to PREVENT yaw
used to prevent further yaw in the stall.
localflighteast #8:
sigh, I waited almost a day before posting this because I had a suspicion the thread was going to
go this way
The best thing would be for you to go through this whole thread with your instructor to see what they think.
NB: Apologies for all the split quotes.
The system keeps on adding the quotation instruction without my asking for it
Join Date: Jan 2014
Location: glendale
Posts: 819
Likes: 0
Received 0 Likes
on
0 Posts
level attitude:
I guess you didn't read that nice FAA document nor the explanation about washout there or in ''stick and rudder'' that I mentioned.
I grow fatigued. I hope others will read the aforementioned information and learn from it.
I hope the mods lock this one up.
I guess you didn't read that nice FAA document nor the explanation about washout there or in ''stick and rudder'' that I mentioned.
I grow fatigued. I hope others will read the aforementioned information and learn from it.
I hope the mods lock this one up.
Join Date: Nov 2013
Location: Oz
Posts: 242
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by glendalegoon
I guess you didn't read that nice FAA document nor the explanation about washout there or in ''stick and rudder'' that I mentioned.
I grow fatigued. I hope others will read the aforementioned information and learn from it.
I hope the mods lock this one up.
I grow fatigued. I hope others will read the aforementioned information and learn from it.
I hope the mods lock this one up.
So I reread the part in stick and rudder as you suggested, and I am not sure what you are getting at? I understand the concept of washout, the c172 I fly has plenty of it. It also has differential fraise ailerons, and I get the concept behind that too. Its all to help stop a wing stalling.
BUT, we are talking about when the wing is fully stalled. Perhaps I am missing something? I know that if I use ailerons when stalled in the c172 I fly, then the wing drops and it starts to autorotate. I also know that if I let the controls go, it will recover. BUT, this wont get me past my flight test.
As I suggested earlier, I am guessing that this is to teach to recover in the situation that you stall whilst landing, and in that case you probably want to recover as fast as possible, hence the reason they suggest not using aileron as it may exacerbate the problem. What ever the reason, I am going to ask my FI this very question.
Join Date: May 2001
Posts: 10,815
Likes: 0
Received 0 Likes
on
0 Posts
Fairy lift theory
It centres on the fact that the aircraft flys because there is a load of fairy's on the leading edge which lift the aircraft into the air when blown due to their skirts getting lifted.
So the faster you go the more lift you get from their skirts.
Now stalling is explained by the fact that as the wing angle increases the fairys have to lean into the wind. Once the wing gets to a certain angle the fairys fall over and can't get back up until the angle decreases again.
Its all very embarrassing to admit I defeated the syllabus with lift fairy's theory but the lady did know all the concepts just not the official reason why they did occur. And to be honest if she was happy the reason why you need to decrease the AoA was because the fairys fell over instead of boundary layer detaching and causing turbulent flow its not such a bad thing.
In any case she understood the only way to unstall an aircraft was to reduce the AoA the fact that she thought this was to let the fairy's to be able to stand again is merely a technicality.
So the faster you go the more lift you get from their skirts.
Now stalling is explained by the fact that as the wing angle increases the fairys have to lean into the wind. Once the wing gets to a certain angle the fairys fall over and can't get back up until the angle decreases again.
Its all very embarrassing to admit I defeated the syllabus with lift fairy's theory but the lady did know all the concepts just not the official reason why they did occur. And to be honest if she was happy the reason why you need to decrease the AoA was because the fairys fell over instead of boundary layer detaching and causing turbulent flow its not such a bad thing.
In any case she understood the only way to unstall an aircraft was to reduce the AoA the fact that she thought this was to let the fairy's to be able to stand again is merely a technicality.
. The others were invented by Mr Frise.
Join Date: Oct 1999
Location: UK
Posts: 3,325
Likes: 0
Received 0 Likes
on
0 Posts
Mad Jock - Your Fairey theory still depends on the stude getting the idea that it's exceeding critical AoA (faireys falling over) that causes stalls, not lack of airpeed.
Did she understand about AoA, or was she thinking of the wing angle purely with reference to the ground rather than with the relative airflow? If the former, she might be surprised later in her career to come across flight situations where the wing is vertical, or even inverted, relative to the ground but the faireys hang on in there. Or sometimes only at a slight angle relative to the ground and they all fall over!
Did she understand about AoA, or was she thinking of the wing angle purely with reference to the ground rather than with the relative airflow? If the former, she might be surprised later in her career to come across flight situations where the wing is vertical, or even inverted, relative to the ground but the faireys hang on in there. Or sometimes only at a slight angle relative to the ground and they all fall over!
Join Date: May 2001
Posts: 10,815
Likes: 0
Received 0 Likes
on
0 Posts
Andy the thing which is causing the wing drop is you annoying the aircraft.
This almost always is because your gripping the controls as if your throttling a chicken.
As others have said in a light aircraft there is absolutely no reason at all to have more than thumb and two fingers on the yoke. This will make you control the aircraft using only wrist force instead of using your powerful upper arm muscles. Now this isn't to say that some conditions won't require you to grab it by the neck and use everything you have got. But that is in extreme conditions.
As a famous steerman pilot Brendan in the UK says make love to the sky don't shag it.
Shaggy obviously air flow because that's what makes the skirts lift and fairies stand upright on the wing, why would they lean when they were standing? They would only lean if you were going sideways which you would then apply rudder so the fairies on the tail would pull the plane into flying straight and then they would be able to stand upright again.
Mate it was as enlightening to me with the logic as it is to you. Most of it driven by her. And the logical jumps were worthy of an engineer work things out from first principles. Just unfortunately the first principles she was working from were complete bollocks.
This almost always is because your gripping the controls as if your throttling a chicken.
As others have said in a light aircraft there is absolutely no reason at all to have more than thumb and two fingers on the yoke. This will make you control the aircraft using only wrist force instead of using your powerful upper arm muscles. Now this isn't to say that some conditions won't require you to grab it by the neck and use everything you have got. But that is in extreme conditions.
As a famous steerman pilot Brendan in the UK says make love to the sky don't shag it.
Shaggy obviously air flow because that's what makes the skirts lift and fairies stand upright on the wing, why would they lean when they were standing? They would only lean if you were going sideways which you would then apply rudder so the fairies on the tail would pull the plane into flying straight and then they would be able to stand upright again.
Mate it was as enlightening to me with the logic as it is to you. Most of it driven by her. And the logical jumps were worthy of an engineer work things out from first principles. Just unfortunately the first principles she was working from were complete bollocks.
Join Date: Nov 2013
Location: Oz
Posts: 242
Likes: 0
Received 0 Likes
on
0 Posts
This almost always is because your gripping the controls as if your throttling a chicken.
But suffice to say, the 2 finger approach does not really work when you are forcing the plane to stall. Its clearly is not interested in stalling!! A little force is needed to pull it up into a stall, especially when you have full flap deployed.
When we were doing incipient stalls the other day, a bit of power on, pull up to stall, it wing drops regardless of what you do.
Thread Starter
Join Date: Aug 2012
Location: Toronto
Posts: 297
Likes: 0
Received 0 Likes
on
0 Posts
Mad jock
"the thing which is causing the wing drop is you annoying the aircraft.
This almost always is because your gripping the controls as if your throttling a chicken."
Totally guilty as charged with this as well. I'm working on the finesse but it isn't coming easily. Hey at the start of all this , many , many lessons ago I managed to pop a knuckle out of joint I was hanging on so hard!
But it takes a mere puny female like me a fair amount of force to get the control column back enough to properly stall the plane. So finesse isn't exactly the first thing on my mind.
"the thing which is causing the wing drop is you annoying the aircraft.
This almost always is because your gripping the controls as if your throttling a chicken."
Totally guilty as charged with this as well. I'm working on the finesse but it isn't coming easily. Hey at the start of all this , many , many lessons ago I managed to pop a knuckle out of joint I was hanging on so hard!
But it takes a mere puny female like me a fair amount of force to get the control column back enough to properly stall the plane. So finesse isn't exactly the first thing on my mind.
Join Date: Oct 1999
Location: UK
Posts: 3,325
Likes: 0
Received 0 Likes
on
0 Posts
As others have said in a light aircraft there is absolutely no reason at all to have more than thumb and two fingers on the yoke. This will make you control the aircraft using only wrist force instead of using your powerful upper arm muscles.
That aeroplanes fly well on their was demonstrated on TV recently. Griff Reece Jones was out and about in the Brecon Beacons and got a ride in a K13 glider. The instructor, before handing him control, said "clap your hands". He did, and so did the instructor; "see, it flies perfectly well without either of us controlling it. So only use very gentle movements on the stick".
Join Date: May 2001
Posts: 10,815
Likes: 0
Received 0 Likes
on
0 Posts
Honestly I have had little 50kg imp girlies manage to get the yoke back using 2 fingers and thumb. Its not so much that you using only those fingers its the fact that you not balling your fist round it. So if your fingers arn;t strong enough use three finger s and thumb but still have the centre of pressure on the fingers while they can move and not in a fist.
So its just a flexing of the fingers which is pulling the yoke about not a physical movement of your whole arm. And rotation is through the wrist not by moving your shoulder.
So its just a flexing of the fingers which is pulling the yoke about not a physical movement of your whole arm. And rotation is through the wrist not by moving your shoulder.
Join Date: Oct 2012
Location: UK
Posts: 681
Likes: 0
Received 0 Likes
on
0 Posts
I guess you didn't read that nice FAA document
if intended for students, I think it is dangerously ambiguous.
Since the basic cause of a stall is always an excessive angle
of attack, the cause must first be eliminated by releasing the
back-elevator pressure that was necessary to attain that angle
of attack or by moving the elevator control forward
of attack, the cause must first be eliminated by releasing the
back-elevator pressure that was necessary to attain that angle
of attack or by moving the elevator control forward
Using the ailerons requires finesse to avoid an aggravated
stall condition
stall condition
in a stall is when (due to washout) the inboard section of the wing has stalled,
but the outer part hasn't and, even then, excessive aileron input will stall the outer
part of the wing, leading to wing drop. With an already dropping wing the critical AoA
will already have been exceeded and any use of aileron will only make matters
worse - more roll & more yaw (= possible spin as localflighteast indicated in
her original post).
Finesse comes with experience. Students are taught to recover from stalls
instinctively - using a method that always works.
In Europe (certainly the UK) and, it sounds like, in Canada any candidate who uses
aileron when the aircraft is still stalled will be asked to repeat the manoeuvre and, if
they still do it, will fail that part of the test.
decrease the pitch attitude by applying forward-elevator pressure
to break the stall, advancing the throttle to increase airspeed, and
simultaneously maintaining directional control with coordinated
use of the aileron and rudder
to break the stall, advancing the throttle to increase airspeed, and
simultaneously maintaining directional control with coordinated
use of the aileron and rudder
There should be no ambiguity: unstall the aircraft - then ailerons
may be used.