Icon A5.. another crash Jul 27

Salty said:
I don’t think either of your example is quite right. the fallacy is In concluding that they are right BECAUSE they are an authority. Even if they are right, and they are an authority, it is still a fallacy to say they are right BECAUSE they are an authority. They are right because the facts show they are right, not because they are an expert. I think you are appealing to authority if you accept your doctors advice without understanding why the advice is being given and how they came to that conclusion.
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the point I was trying to make was that I'm not alone in thinking their marketing is suspect

admittedly though if I'm flying upwind and I'm trying to make an argument, and the editor of Flying magazine is flying downwind, if we both make 180 turns does that also reverse our opinions?
 
Martin Renschler said:
Misunderstanding of what I was trying to say. I was referring to "turning downwind" rather than making a circle into the medium air. "Turning downwind" is when you turn from base to final. You are flying a pattern which is based on ground reference. Totally different physical case than making a blind circle in the air.
Here is a thought experience: Think flying upwind with the same speed as the wind. You are hovering over a point. Lets say you can instantly turn downwind. What is the relative wind speed then? Does your plane need to accelerate to stay in the air?
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No airplane can instantly rotate 180 degrees in flight and momentarily have all the airspeed on the tail rather than the nose, wind or no wind. Wind effects don't change the physics.
 
Tantalum said:
the point I was trying to make was that I'm not alone in thinking their marketing is suspect

admittedly though if I'm flying upwind and I'm trying to make an argument, and the editor of Flying magazine is flying downwind, if we both make 180 turns does that also reverse our opinions?
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Only until the velocity of your opinion catches up?
 
Martin Renschler said:
Misunderstanding of what I was trying to say. I was referring to "turning downwind" rather than making a circle into the medium air. "Turning downwind" is when you turn from base to final. You are flying a pattern which is based on ground reference. Totally different physical case than making a blind circle in the air.
Here is a thought experience: Think flying upwind with the same speed as the wind. You are hovering over a point. Lets say you can instantly turn downwind. What is the relative wind speed then? Does your plane need to accelerate to stay in the air?
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Someone up above very eloquently posted that many things in flying that seem intuitive actually are not intuitive

The airplane is traveling with the air mass.. fly a small drone around in a circle in a plane. The drone is effectively flying in a 600 mile an hour wind.. turning around will have zero impact on the drones relative airspeed

but honestly, the best proof just go fly around in tight circles on a day with any kind of winds aloft. If you have a 20 knot winds aloft you will notice that you're upwind and downwind legs will have a 40 not delta, yet you're indicated airspeed will stay the same, assuming there are no gusts and that you can fly a well-coordinated stable turn

or a better example, the entire Earth is revolving at 2000 mph relative to itself, but walking around in a circle you don't find yourself having to compensate for this, since you're all part of the same system so to speak.
 
Martin Renschler said:
In most postings of this thread, there is a big misunderstanding of plain physics!
Yes, the plane flies in air and generally / eventually everything is relative to air.
However, when it comes to acceleration of the mass of the airplane only the reference to ground matters!!!
The moment the plane turns downwind, it needs to accelerate to its new ground speed. That energy needs to come from somewhere (namely from the difference between thrust and drag). It will take a few seconds and during this time, drag and lift is reduced.
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Oh my goodness. This is all just so...

WRONG!

Please provide your physics and equations based analysis to support these assertions.


Sent from my iPhone using Tapatalk Pro
 
Martin Renschler said:
What I am referring to is inertia (V=M*A). If you fly a square pattern and crab on your cross wind you have no velocity in the direction of the wind. If you then turn downwind, you need to accelerate the plane in the direction of the wind. Until your plane has reached wind speed plus relative speed in that direction, you have less lift.
This is why ground speed matters in this case.
I do agree that if you blindly fly a circle without reference to any ground pattern, the wind has already accelerated you in the direction of the wind. However that is a different case than flying a pattern.
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You are mixing frames of reference. If you insist on using the ground as your frame of reference, you have to include the velocity of the air mass (in which the plane is embedded) in your calculations. It should be relatively simple to convince yourself that the total momentum change of an aircraft making a 180 degree turn is 2mv (+mv - (-mv)), regardless of wind direction. The energy required to make that momentum change comes from banking the wings to divert some lift to the lateral axis, and is the same effort regardless of wind direction. You don't have to increase your airspeed to turn "downwind". Your groundspeed will increase when turning downwind, and you can thank the moving air mass for that. (There's that darn frame of reference thing again.) The airspeed will not change during that steady level turn to downwind unless there is shear or gusts. My undergrad chem students struggle with frames of reference, too. When they get it, it is liberating.
 
Well he joined today for the sole purpose of arguing the aviation equivalent of flat earth issues. Draw your own conclusions.
 
Tantalum said:
Someone up above very eloquently posted that many things in flying that seem intuitive actually are not intuitive

The airplane is traveling with the air mass.. fly a small drone around in a circle in a plane. The drone is effectively flying in a 600 mile an hour wind.. turning around will have zero impact on the drones relative airspeed

but honestly, the best proof just go fly around in tight circles on a day with any kind of winds aloft. If you have a 20 knot winds aloft you will notice that you're upwind and downwind legs will have a 40 not delta, yet you're indicated airspeed will stay the same, assuming there are no gusts and that you can fly a well-coordinated stable turn

or a better example, the entire Earth is revolving at 2000 mph relative to itself, but walking around in a circle you don't find yourself having to compensate for this, since you're all part of the same system so to speak.
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If you fly the pattern, you are not "traveling with the air mass" you are flying a straight line with ground reference. You are actually holding against the traveling air masses.
 
Martin Renschler said:
If you fly the pattern, you are not "traveling with the air mass" you are flying a straight line with ground reference. You are actually holding against the traveling air masses.
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Seriously dude? You are very much incorrect.

The pattern is obviously a reference to ground maneuver but that is completely irrelevant to the fact that you are very much traveling with the air mass. You’re spewing so much false information it’s going to confuse our members who are still trying to learn and benefit from such a discussion.
 
So when it comes to the downwind turn and falling out of the sky, does it matter if you have a Bernoulli wing versus a Newton wing?

:happydance:
 
@Martin Renschler I noticed you are a new poster here.. so.. if you are not trolling us then Welcome to PoA! You are certainly getting a baptism by fire here. Don't take anything here personally

However.. I must warn you that these opinions on flying patterns and headwind/crosswind/tailwind are dangerously incorrect

A ferryboat crossing a river from one shore to the other does not experience a change in its speed over the water (only ground) should it need to turn around halfway to one of the shores. The only change in water relative speed it will experience is the same change it would experience crossing a pond and turning back resulting from the drag of its rudder and turning. Mind you, even that pond crossing is technically also "flowing" along with the Earth, the universe, etc. The ferryboat turning downstream (from cross stream) doesn't suddenly need to reaccelerate in the water, the passengers are not going to feel a jolt and the skipper will not see the speed change, it has no idea the ground is the reference, it is simply traveling through the water.. only crabbing relative to the ground, which is completely agnostic to the boat. However, if you are driving a car across a road flooded by a river, then yes, turning your car around will see differences in water speed, but that's because it's anchored to the ground and traveling in the "system" of the ground. Put the car on a treadmill and drive over it the speed relative to the treadmill will be the same, regardless if you are crossing the treadmill left or right or going in circles

Anyway, we've given you plenty of examples here. If you want to keep pushing this point then I have a few shovels I can lend you
 
Salty said:
Be careful not to do it in high winds or you’ll fall right out of the sky.
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The way I see it is that there is a difference between people claiming the effect doesn't exist by laws of physics (which I oppose) or the effect doesn't matter in practice when all is good (which I also experience as a pilot but I am not flying my base to final turn stalled in high winds and trying to climb, too, as the A5 did). Fortunately, planes have a lot of area in the wind, therefore acceleration to the speed of the wind is pretty fast when you give up the crab coming out of base plus you are usually descending during the turn to final which helps you get ahead of the wind again.
 
Martin Renschler said:
You are actually holding against the traveling air masses
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That is simply wrong. When you fly north to south are you "holding yourself" against the 2,000 mph rotational velocity of the Earth? See my ferry example above.. if that doesn't help illustrate then nothing will. I wish you the best of luck.
 
Martin, the simplest analogy I can make for you is to make a 30 degree banked turn for 360 degrees in a circle at altitude.

No matter what the wind is doing, the plane will always carve out the same circle in the air.

Now, if I make a 30 degree banked turn in the pattern from downwind to base, with wind, no physics will change, except I will turn something a bit more or less than 90 degrees to put my ground track where it needs to be.

I’m still doing 30 degree banked turns, and the plane isn’t doing any funky accelerations.

Think about it for awhile, or go fly with someone and have them show you.

Trust us, you aren’t the first to misunderstand this, and won’t be the last.
 
Martin Renschler said:
Misunderstanding of what I was trying to say. I was referring to "turning downwind" rather than making a circle into the medium air. "Turning downwind" is when you turn from base to final. You are flying a pattern which is based on ground reference. Totally different physical case than making a blind circle in the air.
Here is a thought experience: Think flying upwind with the same speed as the wind. You are hovering over a point. Lets say you can instantly turn downwind. What is the relative wind speed then? Does your plane need to accelerate to stay in the air?
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Good God. No possible way this is not a troll. It's too early in the day to be that drunk.

Sorry, that was unkind. If this is NOT a complete troll, I owe @Martin Renschler a beer. Pretty sure my supply is safe, though.
 
I have to stop reading this. I thought these basic relativistic elements are learned by the time someone is what, 10 years old? This is painful and I've determined *must* be a troll

Martin Renschler said:
Does your plane need to accelerate to stay in the air?
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No. A commercial airliner flying from London to Boston turning back to London doesn't suddenly need to reaccelerate to stay in the air. You do realize that planes have no knowledge of the ground... right?

How come someone be this misinformed?
 
Tantalum said:
@Martin Renschler I noticed you are a new poster here.. so.. if you are not trolling us then Welcome to PoA! You are certainly getting a baptism by fire here. Don't take anything here personally

However.. I must warn you that these opinions on flying patterns and headwind/crosswind/tailwind are dangerously incorrect

A ferryboat crossing a river from one shore to the other does not experience a change in its speed over the water (only ground) should it need to turn around halfway to one of the shores. The only change in water relative speed it will experience is the same change it would experience crossing a pond and turning back resulting from the drag of its rudder and turning. Mind you, even that pond crossing is technically also "flowing" along with the Earth, the universe, etc. The ferryboat turning downstream (from cross stream) doesn't suddenly need to reaccelerate in the water, the passengers are not going to feel a jolt and the skipper will not see the speed change, it has no idea the ground is the reference, it is simply traveling through the water.. only crabbing relative to the ground, which is completely agnostic to the boat. However, if you are driving a car across a road flooded by a river, then yes, turning your car around will see differences in water speed, but that's because it's anchored to the ground and traveling in the "system" of the ground. Put the car on a treadmill and drive over it the speed relative to the treadmill will be the same, regardless if you are crossing the treadmill left or right or going in circles

Anyway, we've given you plenty of examples here. If you want to keep pushing this point then I have a few shovels I can lend you
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If you cross a river crabbing so you cross the river in a right angle and then you decide to give up crabbing and go downstream, for sure everyone in the boat will feel the acceleration from 0 mph downstream to the rivers speed plus the boat's speed.
To give again the example where my logic doesn't apply is when you are not crabbing. If you simple head across the river aiming away from shore you will be going a lot sideways (with the speed of the river). If you turn downstream from such a pattern, you won't feel the acceleration downstream as you were already going at it.
However flying a pattern with ground reference you will be crabbing and holding against the wind.
 
Too many "Stick and Rudder" aficionados.
 
FastEddieB said:
Seriously, go back and read some of the posts.

There are a few here who are seriously mistaken about how a steady wind affects an airplane in flight. Martin Renschler’s* recent (#245 above) being just one of the more blatantly in error.

Gusts and shear, which do affect an airplane in flight, are a different matter entirely and just confuse things.


*Martin’s post is his first, and so far only post. So we may be getting trolled.
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Missed that one.
 
Martin Renschler said:
If you cross a river crabbing so you cross the river in a right angle and then you decide to give up crabbing and go downstream, for sure everyone in the boat will feel the acceleration from 0 mph downstream to the rivers speed plus the boat's speed.
To give again the example where my logic doesn't apply is when you are not crabbing. If you simple head across the river aiming away from shore you will be going a lot sideways (with the speed of the river). If you turn downstream from such a pattern, you won't feel the acceleration downstream as you were already going at it.
However flying a pattern with ground reference you will be crabbing and holding against the wind.
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Okay, I give up. Just trust us that that is wrong. The boat does not stop to 0 and have to pick up speed again. Tacking and sailing through the Woods Hole with a swift current I can guarantee for you that the boat has no idea what the ground is doing, it's simply travels through the water. Same thing with the airplane, it simply travels through the air. We were not the accelerating and reaccelerating after each tack, in fact we had it down so well we only lost about one knot of boat speed in the better executed tacks. That loss in boat speed was due to the tack itself and not from changing directions in the current
 
Martin Renschler said:
If you cross a river crabbing so you cross the river in a right angle and then you decide to give up crabbing and go downstream, for sure everyone in the boat will feel the acceleration from 0 mph downstream to the rivers speed plus the boat's speed.
To give again the example where my logic doesn't apply is when you are not crabbing. If you simple head across the river aiming away from shore you will be going a lot sideways (with the speed of the river). If you turn downstream from such a pattern, you won't feel the acceleration downstream as you were already going at it.
However flying a pattern with ground reference you will be crabbing and holding against the wind.
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Martin,

The boat doesn’t know where the shore is, and will make the same turn rate with respect to the water no matter what the current is doing.

For your own future credibility on the forum, take a posting break and go fly with a CFI or someone who can demonstrate the actual physics.

You will slap yourself when your internal frame of reference finally “gets it.”

Trust me, you really did not discover some new science that has been otherwise unknown for 100 years of flight.
 
MooneyDriver78 said:
I hope so, although I believe the human race is getting dumber.
A later post he changes Newtons formula to V=M*A.
Maybe this new physics is designed to be used with new math?


Tom
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Thanks for pointing this out. Typo of neighboring keys. It's F=M*A. I like any discussion that is to the point not just saying "trust me, I am right".
 
Martin Renschler said:
Thanks for pointing this out. Typo of neighboring keys. It's F=M*A. I like any discussion that is to the point not just saying "trust me, I am right".
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Time to stop. Not one member agrees with you and your credibility to the forum is zero. Sorry but you need further education on this subject.
 
Food for thought for the argument here:

Answer not a fool according to his folly, lest thou also be like unto him. Answer a fool according to his folly, lest he be wise in his own conceit.
 
Martin Renschler said:
The way I see it is that there is a difference between people claiming the effect doesn't exist by laws of physics (which I oppose) or the effect doesn't matter in practice when all is good (which I also experience as a pilot but I am not flying my base to final turn stalled in high winds and trying to climb, too, as the A5 did). Fortunately, planes have a lot of area in the wind, therefore acceleration to the speed of the wind is pretty fast when you give up the crab coming out of base plus you are usually descending during the turn to final which helps you get ahead of the wind again.
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Unfortunately, what you believe or do not believe does not change the facts.
 
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