AOPA Rod Machado article

  • Thread starter Thread starter Roger, Roger
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z987k said:
Well there is more mass, but the two bowling balls should be same shape and volume, so the drag would be the same on both objects. The heavier one would have a higher terminal velocity, but both would accelerate at the same rate.
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My calculations say differently. The acceleration of the balls depends on the vector sum of the weight and the drag force. At any given time, the lighter ball has a smaller net force acting on it. The weight force is proportionate to its mass, but the drag force is not, and acts disproportionately on the lighter mass.

I think that a thought experiment can show that this is true. Both balls must experience a decreasing acceleration over time, if they are ever to arrive at a zero acceleration. If the acceleration decayed at the same rate, they both stop at the same terminal velocity. Clearly the the lighter ball must experience a more rapidly decreasing acceleration.
 
jrh said:
...we, as an industry, had terrible accident rates. Accident rates have steadily declined over time to all time lows in recent years. It's hard to pinpoint exactly what causes what, because there are so many different types of accidents and changes in training that have occurred over the years. But...
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Good read, thanks JRH.


Personally I think its a change in culture. If you talk to guys who started flying in the 60s and 70s, things were different. Really different. Things were friggin' wild. In some respects, things were completely out of control. The father of one of my friends first job, at 400TT was flying a DC3 filled with fish off of the beach in Sitka. The stories he tells are insane. Training is better now. Not because it teaches us how to fly better (honestly, modern training probably doesn't) its because it teaches how to make better decisions. That's why we are safer, because modern instructors instill a sense of caution that, if my buddys' fathers' stories are to be believed may not have existed in quite the same form back in the day.
 
About the constant airspeed, constant 60* bank, constant vertical speed, <2G descending turn-
With a nose down pitch attitude of 30*, the vertical component of drag starts to become important, does it not? Could that possibly explain some of why one might not feel 2Gs? Also, what about the fact that there is essentially no engine thrust (we're assuming idle power here, so the prop is windmilling and for all intents and purposes a drag producing device). I could be way off base, as I'm having a really hard time picturing the free body diagram of such a situation in my head. And I'm too lazy to put it on paper at the moment.
 
MikeD said:
I think we should wash people out of civilian flight training who aren't hacking it to standard, instead of keeping them on as professional students simply because they keep merrily paying the bill with a plethora of $$$; as some places I've seen do.
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+1
 
TwoTwoLeft said:
That and with enough thrust!
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:thup: "The sum of all upward forces not just lift ..."

Training is better now. Not because it teaches us how to fly better (honestly, modern training probably doesn't) its because it teaches how to make better decisions.
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Well, it should be doing that. I would argue it isn't (we have the same accidents over and over and over again and very few of them are functions of raw flying skill or lack of, I believe). A superior pilot relies on superior judgment to avoid using superior skill...and since we've clearly failed to impart superior judgment on many pilots, they then must rely upon skills they don't have.

So what would you do if you inadvertently got in a spin or a massive wing drop?
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I'd recover.
 
tgrayson said:
With a 10 degree angle of descent, the load factor should be about 1.97. I calculate the descent angle at 90 KIAS at 1500 fpm to be just over 9 degrees.
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Ah, you've run the numbers already. Thank you.
 
Roger said:
About the constant airspeed, constant 60* bank, constant vertical speed, <2G descending turn-
With a nose down pitch attitude of 30*, the vertical component of drag starts to become important, does it not? Could that possibly explain some of why one might not feel 2Gs? Also, what about the fact that there is essentially no engine thrust (we're assuming idle power here, so the prop is windmilling and for all intents and purposes a drag producing device). I could be way off base, as I'm having a really hard time picturing the free body diagram of such a situation in my head. And I'm too lazy to put it on paper at the moment.
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tgrayson said:
With a 10 degree angle of descent, the load factor should be about 1.97. I calculate the descent angle at 90 KIAS at 1500 fpm to be just over 9 degrees.
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Wouldn't the feeling of less g's in the butt meter in a descending turn come from the fact that there would be a small forward weight component? It would only feel that way since the pilot may be leaning forward slightly from being nose down and his weight going forward slightly?
 
tgrayson said:
With a 10 degree angle of descent, the load factor should be about 1.97. I calculate the descent angle at 90 KIAS at 1500 fpm to be just over 9 degrees.
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And the problem with this post is most people are never going to bother to do th math. They just don't care enough about the math. What they do care about is the fact that they are flying in the airplane are are trying to keep it from comming apart. I'm not saying your math holds no place in aviation, but when am I going to bust out my clculator in flight and do this? When am I going to even bother with it on the ground. There are simplified ways of doing what your doing, and most people (unless you are going be desgining an airplane) just don't care about running numbers like that. That doesn't make them dangerous or incompetent, or even better pilots, because if it did, airplanes would be falling out of the sky like rain on south Florida summer afternoon. It's nice that you know all these math figures, but quite frankly, not many of us care. Sorry to be so blunt, but I'm just stating the obvious.
 
tgrayson said:
I've found that a proper, thorough understanding of the academic always, always, always translates to understanding the practical application in almost every area of human endeavor. The real problem is that people often don't have a adequate academic understanding, hence they can't apply it.
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Not everyone is a college math major, or whatever you majored in. So the majority of you posts are over everyones head. Sorry man, you'll have to dumb it down for most of us.
 
I haven't found that an academic understanding correlates to being able to practically apply the information at all. I suggest those of you who think that that is the case speak with someone who works in fabrication. The engineer brings plans down that are at times untenable to the practical reality, then several guys with a combined experience literally in excess of a century but often times without anything more than a highschool education figure out how to make it work. Some of the best pilots I know don't have a thorough grasp on the aerodynamics of wings and bodies yet are so skillful at the art of flying its amazing.

Consider the professional marksman, the man may not have a grasp on the fundamental physics behind the flight of the bullet, or really know anything about physics, or kinematics but he has a 1" group at 500 yards. Contrast that with the physics professor with years of training and experience teaching and carrying out experiments on the physical world. The physicist might not even be able to hit the target. Knowledge doesn't hurt your skill level, but knowledge of why something works without operational experience leaves you bereft of a true understanding of how it works.
 
jrh said:
I didn't mean to say chit chatting with everyone is a requirement to be a successful instructor.

I meant that instructors need to be personable and build a relationship with their clients beyond a "just the facts, ma'am" approach.

If two people are going to spend that much time in a confined space (cockpit) together, they *must* get along on a personal level. They don't have to be best buddies and go out to the bar together at night, but I've found it helps to converse about things aside from strictly flying.

If the client feels a personal connection to their instructor, they are less likely to quit.
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I agree. My Instrument instructor and I get along quite well and it makes the process that much easier. The worst CFI I ever had was somebody who didn't even want to teach. Look, I completely understand wanting to go on to bigger, better things, but that does not give a CFI the right to have a pissy attitude towards teaching and seeing it as a dead end. When I get my CFI's, I hope to make the best of it and learn alot about myself that I never knew before. If I can't make that work, then off to banner towing or the DZ to build time. I do not want to be "that guy" who has no business teaching. Student pilots are paying an arm and a leg to learn to fly these days, the least a CFI can do is have a good attitude, you don't have to be Neil Armstrong to be a good instructor.
 
ppragman said:
I haven't found that an academic understanding correlates to being able to practically apply the information at all. I suggest those of you who think that that is the case speak with someone who works in fabrication. The engineer brings plans down that are at times untenable to the practical reality, then several guys with a combined experience literally in excess of a century but often times without anything more than a highschool education figure out how to make it work. Some of the best pilots I know don't have a thorough grasp on the aerodynamics of wings and bodies yet are so skillful at the art of flying its amazing.

Consider the professional marksman, the man may not have a grasp on the fundamental physics behind the flight of the bullet, or really know anything about physics, or kinematics but he has a 1" group at 500 yards. Contrast that with the physics professor with years of training and experience teaching and carrying out experiments on the physical world. The physicist might not even be able to hit the target. Knowledge doesn't hurt your skill level, but knowledge of why something works without operational experience leaves you bereft of a true understanding of how it works.
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:clap:
 
Whenever I have a CFI applicant come to me for a spin endorsement I'll have them show up with a prepared lesson to teach me stall and spin awareness. As soon as equations go up on the board I put my head down and pretend to go to sleep.... If they still keep writing... ZZZZZzzzzzzz. The student is not there for a math lesson, they want to learn how to control themselves and control the airplane. Aerodynamics can be explained without math, and it NEEDS to be.

The perfect example is the basic definition of a stall:

A wing will stall when the critical angle of attack is exceeded
(Student understands what it takes to stall a wing, but has no idea what that means or how they can physically do it)

Alternate Definition of a Stall:

A wing will stall when the lift is no longer sufficient to counter the LOAD imposed on it.

Key word being load... Wing LOADing, LOAD factor, aircraft payLOAD. All these lead to the big picture.
(Correlate that with control inputs, now student sees HOW they can exceed critical AOA, and stall at any airspeed)

Next step, go fly and abuse that elevator...
 
tgrayson said:
With a 10 degree angle of descent, the load factor should be about 1.97. I calculate the descent angle at 90 KIAS at 1500 fpm to be just over 9 degrees.
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What would the numbers look like at somewhere close to redline, idle thrust, and a pegged (or greater) VSI?
 
Matt13C said:
Wouldn't the feeling of less g's in the butt meter in a descending turn come from the fact that there would be a small forward weight component?
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Yes. The bolded portion of the following equation tgray posted is calculating the weight being supported by drag.

G force in a descending turn = cos(descent angle) / cos(bank angle)


mshunter said:
Not everyone is a college math major, or whatever you majored in. So the majority of you posts are over everyones head. Sorry man, you'll have to dumb it down for most of us.
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If this:

tgrayson said:
With a 10 degree angle of descent, the load factor should be about 1.97. I calculate the descent angle at 90 KIAS at 1500 fpm to be just over 9 degrees.
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is over your head then I suggest stopping by your local middle school. I'm certain 90 percent of them could set you straight. I know 8th grade algebra class covers what we discussed in this thread, less the use of the trigonometry term cosine.

Keep in mind that the limiting factor is rarely ones ability comprehend. I'm certain, in this and many other cases, that this includes yourself.

ppragman said:
I haven't found that an academic understanding correlates to being able to practically apply the information at all.
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I doubt you'll find a single psychologist that agrees with you. Learning begins with memorizing what the item is, working to understand it and finally applying it. Doesn't this sound familiar?

I would argue that if the student couldn't apply it, he/she obviously didn't have an adequate understanding of it.

ppragman said:
Some of the best pilots I know don't have a thorough grasp on the aerodynamics of wings and bodies yet are so skillful at the art of flying its amazing.
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You're absolutely right, some people can just do it. However, the mere fact savants exist does not support any argument for abandoning academics.
 
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