Landing Technique Question.

Tgrayson is a very smart person and I respect his opinions greatly. However, I would not expect a student to be able to decipher the complex graphs, equations, and concepts that aerodynamic engineers and test pilots use for the determination of certain factors with regards to flying.

I personally believe (and study) the concepts of "scientific aviation" is something that pilots need to study beyond their pilot training. Simple, effective explanations work. I dont need to know the equations for specific concepts. I am not designing an air foil any time soon. But core concepts and their content should be learned and studied correctly.

Pilots are the jack of all trades and the masters of nothing. When I teach or evaluate I dont look for specific, scientific basis for weather, aerodynamics, or similar factors. I look for a core foundation that is in-line with the theorem and an appropriate reference.
 
For My private pilot training my instructor had me do the pitch for airspeed, and power for altitude thing, however my next instructor convinced me (to teach) in a Seminole that aim for your aiming point markers with yoke, and control airspeed with power. I had no problem with short fields after that, and I wasn't a throttle jokey anymore. If you teach your students to adjust airspeed with pitch, then the aiming point markers are moving up and down the windscreen with updrafts and downdrafts, their more of a throttle jokey it seems (after 12 years of instructing he said that method works way better with most students). That's in a Seminole (T-tail), In a 152 I found it dont seem to work as well, because adding power changes pitch (you got to use a combination of both) whereas in a Seminole it dont seem to as much, it just mostly changes airspeed.

Also he taught me in slow flight to do the same (pitch for altitude, power for airspeed) which greatly improved my slow flight. Im a fan of that method even though most pilots I talk to say that wont work because of the "reverse command theory" however it works well with me (at least in a T-tail)
 
subpilot said:
Furthermore, I have yet to have a captain tell me after I got done adding power for being slow "you know son...you were suppose to pitch down to fix your airspeed problem."
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That's because you relaxed the stick as you added power, whether you relized it or not.
 
Pilot2087 said:
Also he taught me in slow flight to do the same (pitch for altitude, power for airspeed) which greatly improved my slow flight. Im a fan of that method even though most pilots I talk to say that wont work because of the "reverse command theory" however it works well with me (at least in a T-tail)
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In the Seminole I can fly slow flight better when I visualize "power for speed method", Most pilots that argue "reverse command theory" never even tried it.
I just started instructing in a 152 which barely has enough power to climb if your low, so it dont work quite as well.
 
Pilot2087 said:
Also he taught me in slow flight to do the same (pitch for altitude, power for airspeed) which greatly improved my slow flight. Im a fan of that method even though most pilots I talk to say that wont work because of the "reverse command theory" however it works well with me (at least in a T-tail)
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You are the first person I have seen mention this on JC. I am with you on your method and I have also had many other instructors tell me the same thing about the reverse command theory in slow flight. I actually took one of these non-believers up to demo how pitch can control altitude and power/airspeed all day long with the stall warning horn going off. He was very impressed and I think that now he is officially in the middle and tells students that both methods work and you have to use what works for you.
 
meritflyer said:
However, I would not expect a student to be able to decipher the complex graphs, equations, and concepts that aerodynamic engineers and test pilots use for the determination of certain factors with regards to flying.
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Of course not. But just because an instructor may not be able to defend everything he says with graphs and formulas doesn't mean that he should be able to make up whatever he wants as an explanation. And many do just that. Not on purpose, but they've had to build their own internal models of aircraft flight because they haven't had exposure to the correct ones. Then they turn around and teach these to students. Whose fault? Primarily the FAA's, due to their failure to provide adequate training materials.

I think almost everyone has heard of the idea that AOA controls airspeed, even those who reject it. If the FAA said in big, bold letters that this would be taught, I'm sure that every instructor would be capable of communicating this concept, without graphs or formulas.

The nice thing is, if the technically-minded eventually become interested in the graphs and formulas, they're in luck, for they exist. However, anyone who starts with the idea that the throttle controls airspeed will quickly become hopelessly confused, because the technical models do not support this idea; they will first have to unlearn everything they know and relearn it correctly in order to move forward. Better to teach it right from the beginning, even if the technical explanations have to come later. (Law of Primacy, you know.)

We really need to get away from absurdities such as
  1. When power is variable, power controls airspeed; when power is fixed, pitch controls airspeed.
  2. On the front side of the power curve, you power for airspeed; on the backside, you pitch for airspeed.
These "rules" exist because the model doesn't match reality. It's a bit like the pre-Copernicus conceptions of the solar system, where all the planets revolved around the earth; it worked, but there were all sorts of weird corrections that had to be applied to compensate for the fact that the model didn't match reality.
 
Pilot2087 said:
If you teach your students to adjust airspeed with pitch, then the aiming point markers are moving up and down the windscreen with updrafts and downdrafts, their more of a throttle jokey it seems
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There seems to be the idea that these mental models mean that pilots are doing different things. Normally, no. No matter what you thought you were doing, your airspeed changes resulted from AOA changes and your glidepath resulted from changes in thrust or changes in airspeed. Physics works only one way, no matter how you think about it, so I do not accept that you will see much performance difference between the two types of pilots.

However, your general model breaks down if you get low and slow. You need full power and you need to push on yoke to go up.
 
subpilot said:
up to demo how pitch can control altitude and power/airspeed all day long with t
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So if you're trimmed for say, 80 knots, and you advance the throttle slowly and keep your hands off the yoke, the aircraft will accelerate to 100 knots and stay there?
 
tgrayson said:
We really need to get away from absurdities such as
  1. When power is variable, power controls airspeed; when power is fixed, pitch controls airspeed.
  2. On the front side of the power curve, you power for airspeed; on the backside, you pitch for airspeed.
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I find it very frequent that instructors teach power for airspeed and pitch for altitude. The issue I take with it is it simply assumes a surplus of power is always available to the pilot which may not be the case on the back side of the power curve.

I find it much more effective to pitch for airspeed during maneuvers such as slowflight.
 
meritflyer said:
I find it much more effective to pitch for airspeed during maneuvers such as slowflight.
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Yes, that always works. But note that it's "AOA for airspeed", not really "Pitch for airspeed."

When people relate various anecdotes to show how their own technique is superior, I'm reminded of something called the Hawthorne Effect:

http://en.wikipedia.org/wiki/Hawthorne_effect

The idea is that performance often improves when any change is made in the performer's environment. The increased performance isn't due necessarily to the exact nature of the change, but simply due to the fact that some change has been made. The original study showed that worker improvement resulted when lights were brightened, and then they improved again when the lights were returned to their original dimmed state.
 
tgrayson said:
There seems to be the idea that these mental models mean that pilots are doing different things. Normally, no. No matter what you thought you were doing, your airspeed changes resulted from AOA changes and your glidepath resulted from changes in thrust or changes in airspeed. Physics works only one way, no matter how you think about it, so I do not accept that you will see much performance difference between the two types of pilots.

However, your general model breaks down if you get low and slow. You need full power and you need to push on yoke to go up.
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Have you ever tried teaching the other theory to students? I didnt think so, Ive always taught and thought the same as you, until this one instructor was telling me about how I can make it easier to teach by having the student visualizing the Power for Airspeed theory. I started arguing with him.. about reverse command, AOA, etc. He said "Trust me, Ive been teaching this theory my whole life, Reverse command on slowflight is crap. I'll show you." and he did, and I was amazingly convinced, and believe me, I was out to prove him wrong. but like I said it was on a T-tail.

Your on approach, teaching a student to keep the Aiming point markers from going up or down on the windscreen with the yoke, lets say their a little fast, you pull the power while still keeping the aiming point markers from moving.
Now going to your theory, your a little fast so you pitch up, therefore aiming point markers start to move down, so you pull the power. Its doing the EXACT same thing, however when power controls altitude, there is a small delay in height changes, whereas when power controls airspeed there is a small delay in airspeed changes, (Im talking about when a student pilot is flying) so many times I see students adjusting pitch to airspeed, sometimes their in a pitch up altitude at 65, (at 18" MP) sometimes at pitch down altitude (at idle), which means if/when they add power, they have to change pitch altitude too therefore having to readjust the aiming point markers on the windscreen, then they wonder why that sometimes they land 500 feet after their aiming point marker.
my point is that they are both exactly the same thing, there is no correct way to teach it, however IMO students seem to be more precise when they visualize something to aim for, and do it with the yoke, if you learned it the other way, fine, most people will teach the way they learned it.
 
Pilot2087 said:
Have you ever tried teaching the other theory to
students?
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Of course not. It's based on a misunderstanding.

Pilot2087 said:
Now going to your theory, your a little fast so you pitch up, therefore aiming point markers start to move down, so you pull the power.
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No, no, and triple no. :)

Let me say this clearly:

Angle of attack and pitch are not the same.

Pilot2087 said:
you pull the power while still keeping the aiming point markers from moving.
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What you're doing here is increasing your angle of attack. Why? Your power reduction tends to steepen your glide angle; When you pull back on the yoke, you keep your pitch attitude the same. Your angle of attack is the difference between your flightpath and where your nose is pointed.

Your control manipulation and mine are identical.
 
tgrayson said:
Of course not. It's based on a misunderstanding.



No, no, and triple no. :)

Let me say this clearly:

Angle of attack and pitch are not the same.



What you're doing here is increasing your angle of attack. Why? Your power reduction tends to steepen your glide angle; When you pull back on the yoke, you keep your pitch attitude the same. Your angle of attack is the difference between your flightpath and where your nose is pointed.

Your control manipulation and mine are identical.
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I agree that your control manipulation is the same, what Im trying to say is that I taught both ways, I found it easier for a student to visualize height with yoke, airspeed with power. maybe its because they are used to cars or something. ever have students that sometimes they are dragging their plane in on final, sometimes they got a high pitch, sometimes its low, thats because their pitching for airspeed, try teaching them to aim for markers with the yoke, and their problem will be solved... trust me. Im all about Pitch Altitudes! not necessary AOA altitudes.

When were in cruise we teach that yoke controls altitude, power controls airspeed, why switch it it around on slowflight and landings?
 
Here's what an aircraft looks like in a descent:

pitch1.png


The difference between the flight path and where the nose is pointed is the aircraft's angle of attack. I'm assuming angle of incidence is zero, for simplicity.

When you pull power back, the flight path angles down. If you pull back on the yoke to keep the nose pointed at the same place, you end up with a larger angle of attack:

pitch2.png


I've exaggerated the angles for clarity.
 
Pilot2087 said:
I found it easier for a student to visualize height with yoke, airspeed with power. maybe its because they are used to cars or something
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May be easier, but it's a dead end, and you're stuck with different rules with power off flight.

Personally, my goal isn't to make things easy on myself, but to give a student an accurate as possible understanding of how an aircraft flies. If there are some initially difficult concepts to acquire, then so be it. That's what teaching is all about.
 
tgrayson said:
May be easier, but it's a dead end, and you're stuck with different rules with power off flight.
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hmm power off flight, I hate when I get students from other instructors that as soon as I pull the power they pitch for an airspeed, First thing I do is cover up the airspeed indicator have them fly a "Pitch altitude". Might be just my style of flying. I dont know, I got my Private pilots license from a Bush pilot who who has different techniques then these modern day instructors.
 
Pilot2087 said:
hmm power off flight, I hate when I get students from other instructors that as soon as I pull the power they pitch for an airspeed, First thing I do is cover up the airspeed indicator have them fly a "Pitch altitude". Might be just my style of flying. I dont know, I got my Private pilots license from a Bush pilot who who has different techniques then these modern day instructors.
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You're doing the exact same thing. Best glide results in a particular descent angle. And best glide occurs one particular AOA. Since your pitch attitude = flight path angle + AOA, there is one pitch attitude that results in best glide.

Regardless of whether or not you permit your students to look at the airspeed indicator, there is an airspeed and it's clearly controlled via the yoke, since that's all you've got. The addition of a power plant doesn't change that.

Pilot2087 said:
I got my Private pilots license from a Bush pilot who who has different techniques then these modern day instructors.
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Maybe, maybe not. We all share the same physics, so his techniques aren't likely to be all that unique. Regardless of what your technique is, it can be taught using conventional and correct aerodynamics. If it can't, then the technique can't work. :)
 
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