Pulling it too soon....

Wait, I'm under the impression that pitch does not necessarily = AoA. AoA is defined as the angle the chord line of your wing makes with the relative wind. Pitch is the angle the longitudinal axis of your airplane makes with the ground, right?

Oh, sorry, I just looked back and saw that you're talking about this in the context of the takeoff roll only, and I guess that would make them the same. But, for future reference, it's best to qualify statements like that every time you make them - not everyone may go back and read previous posts.
 
Oh, sorry, I just looked back and saw that you're talking about this in the context of the takeoff roll only, and I guess that would make them the same.
It still doesn't make them the same as they are not the same.
 
Wait, I'm under the impression that pitch does not necessarily = AoA. AoA is defined as the angle the chord line of your wing makes with the relative wind. Pitch is the angle the longitudinal axis of your airplane makes with the ground, right?

Oh, sorry, I just looked back and saw that you're talking about this in the context of the takeoff roll only, and I guess that would make them the same. But, for future reference, it's best to qualify statements like that every time you make them - not everyone may go back and read previous posts.

It still doesn't make them the same as they are not the same.

To illustrate Jesse's point. Imagine you are on takeoff roll on a 5 degree downhill slope in a headwind.

Your pitch angle starts, and remains until you pull back, level to the ground, which is down 5 degrees.

Your angle of attack starts at a negative, as the wind is hitting the wing from above, but as you gain speed, your angle of attack moves towards 0 and then into the positive, as your airspeed increases.

You are, in that case, effectively in a dive on the ground.

Pitch angle is your angle relative to the plane perpendicular to the force of gravity.

AoA is your angle relative to the wind.

Better, IMO, never to equate the two.
 
To illustrate Jesse's point. Imagine you are on takeoff roll on a 5 degree downhill slope in a headwind.

Your pitch angle starts, and remains until you pull back, level to the ground, which is down 5 degrees.

Your angle of attack starts at a negative, as the wind is hitting the wing from above, but as you gain speed, your angle of attack moves towards 0 and then into the positive, as your airspeed increases.

You are, in that case, effectively in a dive on the ground.

Pitch angle is your angle relative to the plane perpendicular to the force of gravity.

AoA is your angle relative to the wind.

Better, IMO, never to equate the two.

And if you pull up too too early your pitch will increase, your drag will increase, and your AoA will decrease. You'll either balance the equation out thrust = drag , lift = weight, and blast tail low all the way down the runway until you crash into a tree. Or you'll stall, plop down onto the runway, and hopefully come to your senses.

I don't think people realize how easy it is to generate enough drag on takeoff that you end up with a positive pitch (tail low) and enough drag to severely lengthen your takeoff or prevent it all entirely.
 
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I don't think people realize how easy it is to generate enough drag on takeoff that you end up with a positive pitch (tail low) and enough drag to severely lengthen your takeoff or prevent it all entirely.
Need a demonstration of this? Try a takeoff with full flaps. Don't ask how I know...... :rolleyes:

-Skip
 
Actually, I meant AoA -- "Deck angle" and "Pitch Attitude" are other ways of saying Angle of Attack (unless the wings pivot).
:rolleyes:

And you're right -- AoA does change slightly (less AoA) at higher DA/ Pressure Altitude while TAS needs to increase to achieve the same amount of lift for the same amount of weight as Standard Conditions.

Please, please, please, Dan, be careful what you say as a CFI. People can Google search "Angle of Attack" and run into your post. Then they will get a totally wrong impression of the terms deck angle, pitch attitude, and AOA. They are NOT the same except under certain circumstances (which you did not mention).
 
They are NOT the same except under certain circumstances (which you did not mention).
If something is only the same during a certain circumstance that means that they are not the same. I simply don't see how a CFI (him) can say that they are.

They simply *are not* the same thing or even similar to each other. The most important thing to understand about AoA is that it is completely unrelated to your pitch.
 
And if you pull up too too early your pitch will increase, your drag will increase, and your AoA will decrease. You'll either balance the equation out thrust = drag , lift = weight, and blast tail low all the way down the runway until you crash into a tree. Or you'll stall, plop down onto the runway, and hopefully come to your senses.

I don't think people realize how easy it is to generate enough drag on takeoff that you end up with a positive pitch (tail low) and enough drag to severely lengthen your takeoff or prevent it all entirely.

Here is the aha moment I was talking about. More weight, hotter, made the plane mush during rotation. Just a tad more speed, and I was not mushing(if you do not want to call it reverse-command, fine) along the runway, but was climbing smartly. Just as expected when it was cool, with a light load.

BTW, there seems to be a chiding note here that I do not know what AOA is. Trust me, after rotarywing flight school, I get it. High AOA = high drag.
 
I'm sorry, I guess I didn't follow my own advice. I was not trying to say that AOA IS Pitch, but that the actual physical AOA (# of deg) is the same as the actual physical pitch angle (again, # of deg) when on a takeoff roll, prior to lifting off. Chuck, I understand what you're trying to get at with your example, but I have to beg to differ with it. If you're on a downslope takeoff roll into a headwind, all the wind in front of you is going to deflect upslope and run parallel to the ground, thus not allowing you to have a negative AOA. Now, if you're at altitude and you start a descent, then you can have a negative AOA, but it doesn't seem logically possible if you're on the ground.

Then again, I'm just a 75-hr pilot, I could be wrong (it's happened once before and I'll never forget it!).

Jesse et al, I apologize for the confusion in terms.
 
I dunno, maybe its just me, but I think the title of this thread should be changed...every time I see it, I totally think I'm reading something else....

FWIW, it always draws my attention, and I perk right up.
 
I dunno, maybe its just me, but I think the title of this thread should be changed...every time I see it, I totally think I'm reading something else....

FWIW, it always draws my attention, and I perk right up.
Don't go blind, Nick! B)
 
I'm sorry, I guess I didn't follow my own advice. I was not trying to say that AOA IS Pitch, but that the actual physical AOA (# of deg) is the same as the actual physical pitch angle (again, # of deg) when on a takeoff roll, prior to lifting off.
As you know the AoA is the angle between the relative wind and the wing cord. As you rotate the angle of attack will increase along with your pitch. They will not remain the same number as the relative wind will change. Pitch is relation to the horizon. Relative wind is relation to the airflow. The airflow will not be fixed to the horizon.

If you jerk on the yoke hard the angle of attack is likely to jump fairly high. If you climb out at a 10 degree pitch the angle of attack will not maintain 10 degrees and will decrease as the direction of the airplane through the air shifts up.

If you have enough thrust you could rotate to a 60 degree climb and away you go. You're AoA is not likely to be 60 degrees. The relative wind would be coming from an angle higher than the horizon (think direction of flight) Right around 15 degrees AoA or so you'll hit critical angle of attack and the lift will rapidly decrease.

One could attempt to try and say AoA is equal to pitch during rotation--but this is a pretty worthless thing to think about. I'm not sure what one gains by thinking that as it doesn't remain true for more than an instant. Just because a number may equal another number at a moment in time does not mean they have anything to do with each other.

Then again, I'm just a 75-hr pilot, I could be wrong (it's happened once before and I'll never forget it!).
Hours mean nothing. How much you want to know--means everything. There are plenty of multi-thousand hour idiots.
 
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If something is only the same during a certain circumstance that means that they are not the same. I simply don't see how a CFI (him) can say that they are.

They simply *are not* the same thing or even similar to each other. The most important thing to understand about AoA is that it is completely unrelated to your pitch.

You've got a good point there Jesse!
 
To illustrate Jesse's point. Imagine you are on takeoff roll on a 5 degree downhill slope in a headwind.

Your pitch angle starts, and remains until you pull back, level to the ground, which is down 5 degrees.

Your angle of attack starts at a negative, as the wind is hitting the wing from above, but as you gain speed, your angle of attack moves towards 0 and then into the positive, as your airspeed increases.

You are, in that case, effectively in a dive on the ground.

Pitch angle is your angle relative to the plane perpendicular to the force of gravity.

AoA is your angle relative to the wind.

Better, IMO, never to equate the two.

Exactly right -- AoA is in relation to the relative wind -- BUT..

(keep in mind what started this whole thread -- the discussion of the pitch attitude of the airplane on takeoff)...

But...

When you rotate to 10 degrees nose up attitude (as indicated on the AI) on this downhill run the way you have on a level run -- what will happen?

Right -- you will climb out at Vy (In a 35 Bonanza, for example).

Soo....

Getting back to the original -- very narrow -- discussion....

For a given airplane, there will be a certain pitch up attitude that will give Vx in standard conditions (In the case of high DA/PA, there may be somewhat less pitch up, but still very close (within 3 degrees)).

The only thing that needs to change is airspeed, depending on weight and altitude. The Indicated a/s will certainly need to go up as weight goes up.

But the pitch up can remain the same.

I'm trying to be as clear as I can here -- I am talking about the flight regime from level takeoff roll through rotation through Vx.

After that AoA has additional nuances as we add in differential AoA due to banks, etc.

BUT -- let;s ignore that for a moment.

If you call it "nose pitch up attitude," "Deck Angle," -- what have you, it will be essentially the same, with slight deviation downward (less) with increased pressure/density altitude, while speed for a given angle will need to increase proportional to weight.

This can be seen as you burn fuel on a long XC -- you find yourself taking off some of the nose up trim to maintain the same airspeed and altitude. The additional weight requires either faster airflow or a greater Angle of Attack to displace more air to lift more weight.

I should not have equated AoA with deck angle earlier and I can see how this would be confusing, so my apologies.
 
Well, it's not just about me "teaching them."

I did W&B and checked DA before taking off many times. Haven't you?

Yep... But not every time. I know that in the 182 I can take my 350lb friend in the copilot seat and not be out of the front of the envelope even with nothing in the back seat or baggage compartment. I know that my MGW is 2950 and MLW is 2800 and empty is 1737 and useable fuel is 78 gal/468 lb. 2205 empty plus full fuel, 745 payload as long as I burn at least 2.25 hours of fuel before landing. DA generally isn't even a consideration, the 182 gets off the ground pretty quick and the shortest runway at my home drome is 5800 feet long.

But, there's lots of people (I'd even bet the majority) who use the "if it fits, it'll fly" mentality and never even think about W&B or DA. Look at the "dummy screens" that Cirrus added to the Avidyne boot-up sequence and you'll see that they agree.

Again, the thread and discussion has wandered a bit, but I can't agree here. I think every pilot needs to understand all the cues available to him/her. If all she's got is the ASI, and is betting everything on that one cue, there will eventually be a problem.

I agree, it would be nice if all pilots were that way - But that ain't gonna happen, sadly. Not everyone has the passion for aviation that you or I do. To some it's a status symbol, some just want to go fast. And the ONE thing that will always work, if they're within W&B, is indicated airspeed. (Technically CAS, but IAS is generally very close to CAS at Vy.) There will NOT "eventually be a problem" using IAS. There WILL eventually be a problem with using pitch attitude. That's what I'm getting at.

As someone said earlier here, the pilot should be able to takeoff with the panel covered.

Yeah, it's when the wheel starts to shimmy. LOL

(In a zero-zero takeoff, guess which instrument is replacing the ground to verify pitch?)

Control: Attitude indicator.
Performance: Airspeed indicator.

Please don't misunderstand -- AoA is rather vague to most pilots and the ASI becomes their AoA indicator. BUT (a emphatic but), we aren't flying airspeed -- we are flying a wing -- and we need to know -- intuitively and otherwise -- what that wing is doing.

I would suggest that knowing the true meaning of angle of attack is going to be a far more important concept for new pilots to be taught than to try to teach them all the cues you're mentioning - Those, they will learn on their own and they're different for every airplane.
 
As an aside...

I appreciate all the feedback/comments.

This is another reasons why forums are useful -- we can discuss, proffer arguments, see how we need to adjust how we think/explain, and thereby become better aviators.

It's all good.
:)

Amen! I'm glad we can have a civil discussion, even though I'm just a punk PP-ASEL and you're a godlike CFI. ;)
 
And the ONE thing that will always work, if they're within W&B, is indicated airspeed. (Technically CAS, but IAS is generally very close to CAS at Vy.) There will NOT "eventually be a problem" using IAS. There WILL eventually be a problem with using pitch attitude. That's what I'm getting at.
Sort of--but not really--the liftoff speed and approach speed and stall speed all vary with weight. I can fly a 172 at 45 knots on final as long as I don't plan on climbing and am solo.

If the W&B remains constant as will the indicated airspeed for the above configurations even with differing temperatures and elevations.
 
Yep... But not every time. I know that in the 182 I can take my 350lb friend in the copilot seat and not be out of the front of the envelope even with nothing in the back seat or baggage compartment. I know that my MGW is 2950 and MLW is 2800 and empty is 1737 and useable fuel is 78 gal/468 lb. 2205 empty plus full fuel, 745 payload as long as I burn at least 2.25 hours of fuel before landing. DA generally isn't even a consideration, the 182 gets off the ground pretty quick and the shortest runway at my home drome is 5800 feet long.

But, there's lots of people (I'd even bet the majority) who use the "if it fits, it'll fly" mentality and never even think about W&B or DA. Look at the "dummy screens" that Cirrus added to the Avidyne boot-up sequence and you'll see that they agree.

Well, remember what momma said -- "Just because everyone's doing it doesn't make it right."

I agree, it would be nice if all pilots were that way - But that ain't gonna happen, sadly. Not everyone has the passion for aviation that you or I do. To some it's a status symbol, some just want to go fast. And the ONE thing that will always work, if they're within W&B, is indicated airspeed. (Technically CAS, but IAS is generally very close to CAS at Vy.) There will NOT "eventually be a problem" using IAS. There WILL eventually be a problem with using pitch attitude. That's what I'm getting at.
I think there could be a problem eventually if they think airspeed is all that matters. We see it all the time at airports across the country and see it in the accident records -- pilots landing long and fast since the fly with "a little extra speed" to "stay safe."

And unless I haven't said it enough -- I am NOT recommending only using pitch attitude.

Rather, it is an additional cue that is relatively constant. You should be able to compare what you normally see and the other indications (including airpseed) and quickly determine the outcome of the takeoff.

Even hearing and smell can provide cues to pilots who regularly fly the same a/c. Burning oil smell? Engine sounds different? Those are cues that shouldn't be ignored unless you have another data point that confirms or denies what you're hearing/smelling.

Control: Attitude indicator.
Performance: Airspeed indicator.
And what are you controlling with the AI?

I would suggest that knowing the true meaning of angle of attack is going to be a far more important concept for new pilots to be taught than to try to teach them all the cues you're mentioning - Those, they will learn on their own and they're different for every airplane.
I disagree. AoA is a relatively abstract concept that is best taught on the ground, with practical application taught in the air. How do we teach application? Through the demonstration and observation of cues -- airspeed, pitch, bank, stall indicators, buffeting, reduced slipstream sound -- and so on.
 
Amen! I'm glad we can have a civil discussion, even though I'm just a punk PP-ASEL and you're a godlike CFI. ;)

If I ever come across that way my sincerest apologies! We are ALL learning -- if a pilot doesn't come back from a trip around the patch with some new insight that pilot had better stop flying.

And the best thing about aviation (for me) is that it so so rich that it can never be mastered -- there are always new things to learn.
 
If that were the case, it wouldn't matter what was taught first.

Sure it would - Teach the right thing first, and the rest will be easy. Teach the wrong thing first, and it's hard to get the right thing pounded into their head. Believe me - When I get a student from Roadmaster, it takes weeks to get rid of the crap they were taught. (I generally get them for 4 weeks unless they REALLY need more.) A student from Fox Valley Tech is better on the first day than the Roadmaster student is after 3+ weeks, because they were taught the right way from the beginning. A student that hasn't gone to a school, I have to keep for 6 weeks 'cuz the lawyers said so, but they're ready to go after 3 and I've gotten compliments from examiners on them.

But yes, the law of primacy applies to all learning. If something you are being taught contradicts something you "know" (even if what you're being taught is right) you will naturally be skeptical and it will take longer for that lesson to stick. (Ron? Anyone? Someone back me up here... Or tell me I'm full of crap. ;))
 
Actually, I meant AoA -- "Deck angle" and "Pitch Attitude" are other ways of saying Angle of Attack (unless the wings pivot).
:rolleyes:

That is ONLY correct when you are either on the ground, or in level flight in perfectly smooth air.

Wait, I'm under the impression that pitch does not necessarily = AoA. AoA is defined as the angle the chord line of your wing makes with the relative wind. Pitch is the angle the longitudinal axis of your airplane makes with the ground, right?

You got it PJ. That is why an airplane, which will always stall at the same angle of attack, can stall at any speed, any bank angle, any pitch, any attitude.
 
Sorry Dan, but AoA has a very specific meaning and one that's considerably different than pitch attitude (or the identical deck angle") and it's important to understand the difference. The standard definition of AoA is the angle between the relative wind and the chord line of the airfoil. Pitch attitude or deck angle is the angle between some fixed longitudinal line (typically the line that's level in cruise flight) and the horizon. To illustrate the difference consider an airplane attempting a loop with an entry speed slightly below Va and an agressive pullup that comes close to stalling the wing all the way through to a vertical line. At the start of the pullup the relative wind is pretty much from straight ahead so the increase in AoA (pretty small to begin with) will match the increase in deck angle and will be in the vicinity of 16 degrees. As the loop progresses, assuming the pilot keeps the airspeed just above stall (this is NOT the way to fly a loop!) the AoA will be constant as the airspeed bleeds off and the pilot has to reduce the g loading to keep from stalling. Meanwhile the pitch attitude continues to increase eventually reaching 90 degrees.



Actually, I meant AoA -- "Deck angle" and "Pitch Attitude" are other ways of saying Angle of Attack (unless the wings pivot).
:rolleyes:
 
But yes, the law of primacy applies to all learning. If something you are being taught contradicts something you "know" (even if what you're being taught is right) you will naturally be skeptical and it will take longer for that lesson to stick. (Ron? Anyone? Someone back me up here... Or tell me I'm full of crap. ;))

Hang on -- the law of primacy applies to all learning -- of course.

Context, context, context....(read the thread)

The law of primacy states that that which is learned first is learned best. Thus the terrier-like grip people have on all their bad juju.

This is why the Army is so big on Basic training, why sports coaches drill "the fundamentals," and why illiteracy is rampant (figure that one out).

Anyway, I'm tired and wanna go read the 2008 FAR/AIM....:rolleyes:
 
Oh, sorry, I just looked back and saw that you're talking about this in the context of the takeoff roll only, and I guess that would make them the same. But, for future reference, it's best to qualify statements like that every time you make them - not everyone may go back and read previous posts.

That's what I was getting at in the first place - "Well, I saw where a CFI said AoA = pitch so that must be right!" is what needs to be avoided!
 
Please, please, please, Dan, be careful what you say as a CFI. People can Google search "Angle of Attack" and run into your post. Then they will get a totally wrong impression of the terms deck angle, pitch attitude, and AOA. They are NOT the same except under certain circumstances (which you did not mention).

Again, that's why I've been pestering ya, Dan. :yes: I wonder how many OWT's started this way... With a simple misunderstanding of a person of authority.
 
BTW, there seems to be a chiding note here that I do not know what AOA is.

Not at all, Doc... We're chiding Dan for not watching carefully what he says as a CFI and qualifying statements that aren't true under all conditions.

Hopefully someone is still actually reading the thread and thinking about (and learning about) AoA and such in the process. It's certainly got me thinking. :)
 
I'm sorry, I guess I didn't follow my own advice. I was not trying to say that AOA IS Pitch, but that the actual physical AOA (# of deg) is the same as the actual physical pitch angle (again, # of deg) when on a takeoff roll, prior to lifting off.

Exactly... But as soon as you lift off, if you keep the same pitch attitude, your AoA is lowered.

In fact, this brings to mind a simple formula that could be taught: When upright and not banking, Angle of Attack plus Angle of Travel = Angle of Pitch plus angle of incidence. Since angle of incidence does not change, for the rest of this post we'll just assume it's zero for simplicity.

If we were to be able to make a flight from takeoff to landing without making any turns, and using level runways, here's what would be happening:

1) During the takeoff roll, if the runway is level, AoT=0, so AoA=pitch.

2) Upon rotation to climb pitch, AoA increases. AoT=0 until liftoff so AoA=pitch until liftoff. Increased AoA means increased lift, and lift>weight momentarily, which accelerates the airplane upward.

3) Holding climb pitch just after liftoff, as the airplane accelerates upward at climb attitude, AoT increases due to lift being greater than weight but pitch attitude remains the same, resulting in a lowering angle of attack. When the angle of travel (still at the same pitch attitude) has increased enough to result in the angle of attack lowering to the point where lift = weight once again, we will be in a steady-state climb.

4) During steady-state climb, AoT+AoA=Pitch, and all three will be positive. Lift will also equal weight.

5) At the top of the climb, we lower pitch, which lowers the angle of attack, which results in lowering lift, so lift < weight which results in negative vertical acceleration, which lowers climb rate, which results in the positive angle of travel being reduced.

6) When climb rate and angle of travel are down to zero, we hold our pitch steady, the angle of travel will once again be zero, and angle of attack (this is important!) will be the SAME as it was during the steady-state climb at the same indicated airspeed (actually, it will be negligibly lower due to the slightly lower weight of the aircraft due to fuel burned, but not enough for us to notice!)

7) As we accelerate from climb speed to cruise speed, the increasing indicated airspeed means that we don't need such a high angle of attack to maintain the same lift. We slowly lower pitch attitude (and trim nose-down for the higher speed) as we accelerate. AoT=0, so AoA equals pitch again, and lift = weight while we're in a steady state vertically.

8) Transition to descent: Let's say we're going to descend at cruise speed, leaving trim unchanged and lowering power. Lowering power means that there will be more drag than thrust. That will slow the airplane down, and since we're trimmed for cruise airspeed, the nose will lower to compensate. When the nose lowers, AoA will be reduced, again resulting in weight being greater than lift, resulting in downward acceleration. Since we started with our vertical speed and AoT at zero, the downward acceleration will result in a descent. If we hold descent attitude, the AoT will lower until once again the AoA is back to the same value it was at in cruise. So, since we have the same indicated airspeed as we had at the end of cruise, once the AoT is lowered to where the AoA is the same as it was in cruise, we'll have a steady-state descent.

9) In the steady-state descent, lift=weight. AoT will be negative, pitch will be somewhere around zero, AoA will still have the same positive value as it did in cruise if we are still at cruise airspeed.

10) Let's just say we transition to our landing speed in the descent. As we slow down, we'll need a higher AoA to develop the same amount of lift. To keep the descent rate the same, we'll need the same amount of lift and we'll need to increase both pitch attitude and AoA as we slow down. Then, we'll maintain that pitch attitude and AoA to keep the same rate of descent.

11) We're on final, getting ready to flare. We pull back to increase pitch and AoA, which increases lift, so lift>weight again which results in an upward acceleration, reducing our descent rate. We also pull power. We'll then be in a very slight steady-state descent, slowing down and needing to increase pitch and AoA to maintain the steady state. If we do it right, our mains will touch the ground at or before we reach the stalling AoA. At that point, AoT=0 again (level runway), AoA=pitch (again, assuming 0 angle of incidence) and if we hold the same AoA we had just after touchdown, the weight will slowly transfer to the landing gear as we lose lift due to the slower airspeed as we roll out.

(That was fun. Am I a geek? :rofl:)

Chuck, I understand what you're trying to get at with your example, but I have to beg to differ with it. If you're on a downslope takeoff roll into a headwind, all the wind in front of you is going to deflect upslope and run parallel to the ground, thus not allowing you to have a negative AOA. Now, if you're at altitude and you start a descent, then you can have a negative AOA, but it doesn't seem logically possible if you're on the ground.

Right again, PJ.

Then again, I'm just a 75-hr pilot, I could be wrong (it's happened once before and I'll never forget it!).

:rofl: We wouldn't LET you forget it! :D
 
Sort of--but not really--the liftoff speed and approach speed and stall speed all vary with weight. I can fly a 172 at 45 knots on final as long as I don't plan on climbing and am solo.

If the W&B remains constant as will the indicated airspeed for the above configurations even with differing temperatures and elevations.

Right - But if you fly book numbers (which are for gross weight), you won't kill yourself on a high-DA takeoff.
 
To illustrate Jesse's point. Imagine you are on takeoff roll on a 5 degree downhill slope in a headwind.

Your pitch angle starts, and remains until you pull back, level to the ground, which is down 5 degrees.

Your angle of attack starts at a negative, as the wind is hitting the wing from above, but as you gain speed, your angle of attack moves towards 0 and then into the positive, as your airspeed increases.
Nope... *Pitch attitude* starts at -5 degrees. Angle of attack starts at 0 and stays at 0 until you pull back on the yoke.

PJ's got it:

t0rnad0 said:
Chuck, I understand what you're trying to get at with your example, but I have to beg to differ with it. If you're on a downslope takeoff roll into a headwind, all the wind in front of you is going to deflect upslope and run parallel to the ground, thus not allowing you to have a negative AOA. Now, if you're at altitude and you start a descent, then you can have a negative AOA, but it doesn't seem logically possible if you're on the ground.
 
If I ever come across that way my sincerest apologies! We are ALL learning -- if a pilot doesn't come back from a trip around the patch with some new insight that pilot had better stop flying.

And the best thing about aviation (for me) is that it so so rich that it can never be mastered -- there are always new things to learn.

Amen!

I didn't think YOU came across that way, but that sort of thing has happened here before and those discussions generally become unproductive. I'm glad this one hasn't done that! :yes:
 
While the "natural tendency" is to attempt a climb with less airspeed than should be used when taking off from a high DA runway, using the MGW "book numbers" can also lead to serious problems if you are light and the runway length is marginal, a surprisingly common situation.

Right - But if you fly book numbers (which are for gross weight), you won't kill yourself on a high-DA takeoff.
 
Well, remember what momma said -- "Just because everyone's doing it doesn't make it right."

Not saying it's right - I'm just saying it happens, and it happens way more often than it should. :(

I think there could be a problem eventually if they think airspeed is all that matters. We see it all the time at airports across the country and see it in the accident records -- pilots landing long and fast since the fly with "a little extra speed" to "stay safe."

On takeoff, if they think airspeed is all that matters, they'll be alive.

On landing, if they think airspeed is all that matters, they'll be alive *IF* they don't buy into the "more speed = more safety" myth. If they fly right on the book numbers for both, they'll be alive. They'll float more on landings when they're light... But they'll be alive.

Even hearing and smell can provide cues to pilots who regularly fly the same a/c. Burning oil smell? Engine sounds different? Those are cues that shouldn't be ignored unless you have another data point that confirms or denies what you're hearing/smelling.

Yep - Same thing with trucks. :yes: I now have over 200 hours in N271G and she talks to me. :)

And what are you controlling with the AI?

Pitch and bank. If you're upright, increasing pitch will increase AoA but the same pitch doesn't necessarily mean the same AoA unless calibrated airspeed and bank angle are the same.

Where people get dead on high-DA takeoffs is holding the same pitch attitude, whether it's using the AI or looking outside (which might be worse if there's higher terrain in front of you as it may create the illusion of a lower pitch angle). In high DA, pitch must be lower to achieve the same CAS and AoA.

I disagree. AoA is a relatively abstract concept that is best taught on the ground, with practical application taught in the air.

Oh, I most certainly agree with that. I just said it's very very important to make sure it's taught correctly, not where to teach it. The only benefit anything in the air would really have is if you put a "pitch string" on the side window of a twin. I'm not sure how well it would work in a single due to propwash.
 
While the "natural tendency" is to attempt a climb with less airspeed than should be used when taking off from a high DA runway, using the MGW "book numbers" can also lead to serious problems if you are light and the runway length is marginal, a surprisingly common situation.

In Aerodynamics for Naval Aviators we are told we can interpolate, but never extrapolate.

Thus we should be able to figure out that Va is slower when we are lighter. The same is true for Vso.
 
Not saying it's right - I'm just saying it happens, and it happens way more often than it should. :(

On takeoff, if they think airspeed is all that matters, they'll be alive.

On landing, if they think airspeed is all that matters, they'll be alive *IF* they don't buy into the "more speed = more safety" myth. If they fly right on the book numbers for both, they'll be alive. They'll float more on landings when they're light... But they'll be alive.

Let's pick on one of this group of pilots -- we'll call him "Mister T."

Let's imagine Mr T knows "airspeed keeps me flying" and one gusty morning hears the stall horn beep at him on short final -- Mr T exclaims, "Stalls are bad!"

He adds power ("since power makes me go faster" -- remember, Mr T lives in a one cue world).

Now he's higher than expected, so he pushes the nose over, the airspeed builds and he doesn't hear the horn again. He lands 1/3 down the 5668' runway at County Airport and it's a three point greaser. "I'm a good pilot," thinks Mr T.

Mr T may fly to Saturday breakfast and back for the next 30 years and never have a problem.

Mr T may fly XC to the Fly-in once each May and never have a problem.

But if Mr T should encounter some situation out of the ordinary -- let's say a blown cylinder -- and he's gotta put it down into the K-Mart parking lot -- Mr T won't likely make it.

Why? He's only known "airspeed keeps me flying," -- and stalling over the Dollar Store would be Bad -- so he maintains his normal 10 knots faster than book (as a buffer) and lands 30% longer than required and plows into the idling Kenworth at the far side of the lot.

Sorry, but while I understand your point, we should not and cannot toss up our hands and say, "You know what -- forget the other stuff -- just keep that needle on that spot on that little dial over there and you'll be good to go."

While there are pilots flying with this one cue level of understanding, there are also gun owners who can't strip down, re-assemble, and function check their firearm, deer hunters that can't shoot worth a d***, homeowners who don't understand where the water comes from -- and so on.

You keep stripping out my qualifier that I've added to nearly every post so far but I'll add it once again -- Pitch attitude on takeoff is another very important cue that a pilot should use to determine if a takeoff is progressing as expected, and the Attitude Indicator can be used to verify that pitch attitude (in the Bonanzas, 10 degrees nose up gives Vy with full power).

Using a single cue -- airspeed, bank angle, ball position, power setting, FPM -- will eventually be revealed as a weakness with perhaps fatal consequences.
 
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