Low altitude steep descending turns...

At some point, someone suggested you do your research and work with your instructor at safe altitudes. Maybe multiple individuals said this. That's good advice.

Read up on load factor / degree of bank. Something like this.
60 degree bank = load factor 2 = 40% increase in stall speed
45 degree = load factor 1.4 = 20% increase

Error on the conservative side..

Also: http://www.airlinepilotforums.com/t...n-descnding-turn-load-factor-stall-speed.html - Read joepilot's response. Post #4

If you ask me, and especially in these trainers, we shouldn't mess with pattern salvaging. However, one of the best bits of advice I got from an instructor, if you're going to overshoot final and you want to keep the approach going, don't tighten up the turn... Keep a normal bank angle in, but hold the turn for a bit longer. Aim for the threshold, or slightly to the left side of the runway (left pattern). Make a kind of tear drop entry onto final. Nothing exaggerated, just enough to intercept a good lineup.
 
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FastEddieB said:
Not sure that's right.

If I initiate a turn using only aileron and a tad of rudder, without pulling back on the stick, the plane will descend and I don't believe AOA will increase.

It's the holding altitude with the elevator that increases the AOA, not the turn itself.

I think. Though anything involving aerodynamics can get complicated very quickly, and when math comes in I'm pretty well cooked.

In any case I remember doing wingovers at well over 60º bank and very low speeds in a Citabria without stalling. I think that's only because no attempt was made to hold altitude.
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I tend to agree with you. Rolling into any bank sans backpressure or trim will result in a descent. Some of the horizontal lift is used to keep the airplane from falling like a rock(steeper equals more FPM on the descent), and some is vectored in a direction to make the airplane change heading, but the total lift(and AOA) is the same.

If I'm wrong, and I could be, I'd like to read why.
 
dtuuri said:
Aha! You aren't good 'nuff to do it, are ya! Why else are you so defensive? Always turning final too late aren't ya! Don't be like this, OP. Just keep asking yourself, "Am I too high or too low?" Then make an adjustment. Then repeat right away. That's how it's done. Constant reappraisal, make a "guess" and make an adjustment. If you guess wrong, you'll know it in five seconds, then do the opposite.



dtuuri.
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Defensive? Not here. 30 degrees works fine for me. Want 20? I don't care.

Switching from your inaccurate statement to personal attacks, eh? That won't help make your inaccurate statement more accurate.

I'll let the Warbird guys and the F-18 kids arriving at the airport know that they're all bad pilots because they used more than 30 degrees of bank and let them know dturri said so. They'll be quite amused, I'm sure. Have to pass this grand wisdom on, you know.

But look! A bonus! Oh joy. Someone finally explains "constant adjustment" to me! Holy crap! No one has EVER mentioned THAT before! Manna from heaven! My god man, no instructor ever said that and demonstrated it before ex-DPE dturri came along and mentioned it on an Internet forum! Amazing!

ROFLMAO. YGBFKM.
 
I think I tend to use a bit more than 30° in the pattern, fairly routinely. I'd have to check my videos, but I don't think 35° to 45° is that unusual for me.

I think limiting pattern turns to x° has a few downsides...

1) When approaching that limit and still needing a tighter turn, when up against a hard limit a pilot may have a tendency to hurry the turn with rudder - and skidding is in my opinion a bigger danger than a tad more bank at that point.

2) Turns pretty much keep you blind in one direction or the other during the duration of the turn. Less than 3° per second can keep that wing up and blocking a pilot's view for a loooong time.

3) Shallow banks can also result in pretty wide patterns, often beyond gliding range of the runway. That entails its own small risk.

I'm NOT advocating "bank and yank" or cowboy heroics in the pattern. Just that there's a happy compromise somewhere between too steep and too shallow.
 
denverpilot said:
Switching from your inaccurate statement to personal attacks, eh? That won't help make your inaccurate statement more accurate.
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Help, Help, Nate's being repressed!

Oppressed-monty-python-and-the-holy-grail-.jpg
 
FastEddieB said:
If I initiate a turn using only aileron and a tad of rudder, without pulling back on the stick, the plane will descend and I don't believe AOA will increase.

It's the holding altitude with the elevator that increases the AOA, not the turn itself.


In any case I remember doing wingovers at well over 60º bank and very low speeds in a Citabria without stalling. I think that's only because no attempt was made to hold altitude.
Click to expand...

You may not be good at math but your reading comprehension is impeccable. I asked a question and some people assume I'm dangerous and add **** I wasn't asking about. In reality I've watched a lot of videos of high banks done at very low altitude and I was simply wondering if those pilots were getting closer to a stall condition or not.

I have my answer. Thank you.
 
dtuuri said:
Yes, yes! That's the secret! Are you listening, OP?

dtuuri
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Are you? Please pay particular attention to:
When around 75 kts how close are you getting to a stall condition at 30 degrees, at 45 degrees, at 60 degrees? Here I could have added descending but unfortunately I assumed people knew that by my proximity to the runway. By descending I mean NOT holding altitude.

Am I correct that the slower you are going and the steeper you turn the higher the stall speed (plane stalls more easily) ?

Someone tell the difference in stall speed in the above scenarios when descending vs. holding altitude.

:rolleyes:
 
Yep non of the wrangling about G forces or how wind is loading the wing matters if you stall spin into the ground. Keep the high angle turns up high or low in the simulator. Have your instructor teach you a power off 180 up high you should be able to do one with 500 feet loss. If you do some sim work, you will find why turning back to the airport after an engine loss is a bad idea. The amount of ground that is needed in the windscreen to do a proper steep turn is quite scary and why most people do a flat turn that leads to the stall spin because of decayed airspeed.
 
2Airtime2 said:
Are you? Please pay particular attention to:
When around 75 kts how close are you getting to a stall condition at 30 degrees, at 45 degrees, at 60 degrees? Here I could have added descending but unfortunately I assumed people knew that by my proximity to the runway. By descending I mean NOT holding altitude.

Am I correct that the slower you are going and the steeper you turn the higher the stall speed (plane stalls more easily) ?

Someone tell the difference in stall speed in the above scenarios when descending vs. holding altitude.

:rolleyes:
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I'm sure it can be calculated mathematically, but not by using the generic word "descending" since it depends on the load factor. Find someone with a angle of attack indicator and try a demonstration.
 
2Airtime2 said:
I have my answer. Thank you.
Click to expand...

I doubt you have a correct answer. You seem to be looking for a free lunch, ie, steep turn with no consequences. If you want to turn--you need angle of attack, period. The more turn you need the more angle of attack you need--and the closer to the stall you are. Banking without adding back pressure results in a greater turning radius because airspeed increases. Yes, it will turn, but not as much as you need, so you'll need to bank even more to compensate for the excess speed. There's the right answer, is that the same as the one you had?

dtuuri
 
2Airtime2 said:
Are you? Please pay particular attention to:
When around 75 kts how close are you getting to a stall condition at 30 degrees, at 45 degrees, at 60 degrees? Here I could have added descending but unfortunately I assumed people knew that by my proximity to the runway. By descending I mean NOT holding altitude.
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You are flying a C-172. In the POH are charts that give you the stalling speeds for these bank angles. Others have explained it to my satisfaction, so I didn't feel the need to guild the lily.

2Airtime2 said:
Am I correct that the slower you are going and the steeper you turn the higher the stall speed (plane stalls more easily) ?
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Absolutely. Someone who is buying a plane (Cherokee 180C), I would think, knows this from the very first or second lesson.

2Airtime2 said:
Someone tell the difference in stall speed in the above scenarios when descending vs. holding altitude.
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There is none in uniform flight.

dtuuri
 
An experiment might be enlightening.

If someone here has a plane with an AOA indicator, trim up for level flight, then either nudge the yoke to the left (let's say), or have the autopilot initiate a turn, without applying any back pressure and without altitude hold on.

The plane will, of course begin a descending turn. All that needs to be done is to monitor the AOA indicator for any change.

My guess is that it won't change, but I remain "convince-able".

Anyone game?
 
FastEddieB said:
I think I tend to use a bit more than 30° in the pattern, fairly routinely. I'd have to check my videos, but I don't think 35° to 45° is that unusual for me.

I think limiting pattern turns to x° has a few downsides...

1) When approaching that limit and still needing a tighter turn, when up against a hard limit a pilot may have a tendency to hurry the turn with rudder - and skidding is in my opinion a bigger danger than a tad more bank at that point.

2) Turns pretty much keep you blind in one direction or the other during the duration of the turn. Less than 3° per second can keep that wing up and blocking a pilot's view for a loooong time.

3) Shallow banks can also result in pretty wide patterns, often beyond gliding range of the runway. That entails its own small risk.

I'm NOT advocating "bank and yank" or cowboy heroics in the pattern. Just that there's a happy compromise somewhere between too steep and too shallow.
Click to expand...

I was taught 30° max bank in the pattern. Even with just 20-25°, on a 1/2 mile wide pattern, I can still get wings level for a while on base. If I turn final late because I'm dawdling, distracted or misjudge the tailwind, I just hold the same bank angle a little longer and fly back towards the numbers.

Overbanking and misuse of the ruder is what turns planes into flaming lawn darts. Keep the same bank, keep the same rudder, just hold the turn long enough to point back at the numbers. If you're too wide to do this easily, just go around and turn final a little earlier the next time.

One thing I found after buying the Mooney, it's a lot easier to judge the base to final turn when I can see the runway and not just the bottom of the wing . . .
 
Everskyward said:
I'm sure it can be calculated mathematically, but not by using the generic word "descending" since it depends on the load factor. Find someone with a angle of attack indicator and try a demonstration.
Click to expand...

Even better, with an instructor, trimmed as slow as you can at altitude, find out how much bank it takes to stall, if you let it descend. You can calculate it for level, coordinated flight. You'll have a very different answer. Maybe even try it in slow flight, though you won't be able to trim it; just hold constant airspeed.

I think you'll find 30 deg bank is plenty of margin for all the cases except level turns in slow flight.
 
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Everskyward said:
Did you google "uniform motion" and post that just so you could come up with an answer to my question?
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Yes, since you didn't know what it meant. I thought it was kind of cute, didn't you?

dtuuri
 
Hank S said:
Overbanking and misuse of the rudder is what turns planes into flaming lawn darts.
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I'll go with "misuse of the rudder", but not the "overbanking".

Pull too many g's in a coordinated 45° banked turn to final and stall, and the nose should break directly away from you. Easy to recover, assuming a pilot is comfortable with stall recovery. Roll the wings level, full power and climb back out as you've always done with practice stalls.

Pull too many g's in a skidded 30° banked turn, and that stall may be the last thing you ever see as the plane rolls near inverted and points to the ground.

I'll stand by the caveats expressed in my prior post.
 
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dtuuri said:
Yes, since you didn't know what it meant. I thought it was kind of cute, didn't you?

dtuuri
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Cute is in the eye of the beholder, but you were also evading the question.
 
Everskyward said:
Cute is in the eye of the beholder, but you were also evading the question.
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How so? I know what "uniform" means when it comes to physics. I was trying to enlighten you with a nice little video.

dtuuri
 
dtuuri said:
How so? I know what "uniform" means when it comes to physics. I was trying to enlighten you with a nice little video.

dtuuri
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Define it with respect to the question posed by the OP in this thread.
 
MAKG1 said:
Even better, with an instructor, trimmed as slow as you can at altitude, find out how much bank it takes to stall, if you let it descend. You can calculate it for level, coordinated flight. You'll have a very different answer. Maybe even try it in slow flight, though you won't be able to trim it; just hold constant airspeed.
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A "very different answer"? If you do, it's because of all the confounding factors your scenario indroduces. You really should have studied Stick and Rudder. You'd then know that propeller blast on the tail skews the results. William Kershners chapter on flight mechanics is also a good read. Then you'd know that the wings need to make less lift in a climb and more lift in a descent (AoA) than level flight, which also messes up your experiment. Report back on frequency after you've read 'em. :)

dtuuri
 
dtuuri said:
A "very different answer"? If you do, it's because of all the confounding factors your scenario indroduces. You really should have studied Stick and Rudder. You'd then know that propeller blast on the tail skews the results. William Kershners chapter on flight mechanics is also a good read. Then you'd know that the wings need to make less lift in a climb and more lift in a descent (AoA) than level flight, which also messes up your experiment. Report back on frequency after you've read 'em. :)

dtuuri
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Umm, I did read Stick and Rudder, and who said anything about prop blast?

In a descent, you can do all of this power off.

Heck, virtually the entire thread is identical in a glider.
 
Everskyward said:
Define it with respect to the question posed by the OP in this thread.
Click to expand...

:rolleyes:



2Airtime2 said:
Please pay particular attention to:
When around 75 kts how close are you getting to a stall condition at 30 degrees, at 45 degrees, at 60 degrees? Here I could have added descending but unfortunately I assumed people knew that by my proximity to the runway. By descending I mean NOT holding altitude.
...
Someone tell the difference in stall speed in the above scenarios when descending vs. holding altitude.
Click to expand...
First, some facts. The load factors in a bank are the same whether descending, climbing or level flight as long as the plane is not being accelerated in any way, ie, it is not changing due to an imbalance. That is, the forces are in "equilibrium" or the plane is in "uniform" flight. For the plane to sustain a uniform condidtion, the lift must be stable and for that, the AoA must be as well. A steep spiral will pull as many 'g's as a level banked turn and stall at the same speed with the caveat that there is a different effectiveness from the horizontal tail/elevator combination due to the added energization caused by the prop blast. That is why some planes refuse to stall from a steep bank with power at idle, but stall quite nicely in a climb. The former case runs out of elevator authority before the wing can reach a critical angle of attack.

A plane maintaining 75 kias is in uniform flight at the different bank angles you mention, so the stalling speeds are found in the POH. If the pilot "unloads" the wing to avoid a stall, the turn is unloaded as well and the radius of turn widened.

dtuuri
 
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dtuuri said:
The load factors in a bank are the same whether descending, climbing or level flight as long as the plane is not being accelerated in any way, ie, it is not changing due to an imbalance.
Click to expand...

So, you say a descending aircraft requires more AoA in a decent in one post, and that it's exactly the same in the next. Which is it?
 
MAKG1 said:
Umm, I did read Stick and Rudder, and who said anything about prop blast?

In a descent, you can do all of this power off.

Heck, virtually the entire thread is identical in a glider.
Click to expand...

:confused: I thought your experiment was to show I'm wrong. You agree with me? I must be getting paranoid since Nate sic'd the National Guard on me.

dtuuri
 
MAKG1 said:
So, you say a descending aircraft requires more AoA in a decent in one post, and that it's exactly the same in the next. Which is it?
Click to expand...
Good catch there. Of course, the flight mechanics reference is a result of the tail down force being less in a climb due to the engine and prop component of thrust acting against gravity, unburdening the work required from the wing. As you say, this thread could apply to gliders as well. Maybe I should have left that bit of trivia out of the discussion. It really is a small tidbit of no practical advantage to know, but good for proving that a plane doesn't really climb due to "excess lift".

dtuuri
 
2Airtime2 said:
I used the wind as an example. I made that up. The basis for my question is to learn what the plane is capable of doing safely (if ever need be). ?
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Every plane has an operating envelope and it may differ quite significantly. A J-3 Cub and a Cirrus are not the same. Similarly, pilot capabilities vary considerably. Someithing that Bob Hoover accomplishes safely would end up being a disaster for someone with lesser skills to attempt. A newbie pilot should concentrate on learning to keep himself and his aircraft well inside the operating envelope and not be thinking that the entire envelope is his for the taking to salvage a poor pattern. Going around should be your solution, not operating at the edges of the performance envelope to salvage an approach.


2Airtime2 said:
I'd like to be the better pilot. Wouldn't I need to know what the plane is and is not capable of so I know what not to do?
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You have to learn to be a safe pilot before you're ready to expand your capabilities towards the full envelope of the aircraft you fly. A safe pilot doesn't get into a situation that requires superior piloting skills to extricate himself from. This doesn't mean you can't go up with an instructor and explore what the aircraft can do, but the majority of your efforts should be directed at keeping the aircraft well inside it's operating envelope as you train for your intial certificate. After you get your certificate there will be plenty of time for you to seek out some aerobatic instruction if you desire to become familiar with exactly how much an aircraft can do and how to recover when you've gone beyond its control limit. Many pilots are content to be safe, conservative flyers who never need to operate the aircraft at its margins. If they find themselves out of position, they go around and try it again, correcting whatever it was that caused the approach to be bad. It's called good ADM. Many of the accident reports I've read have been of pilots who've tried to salvage a poor approach by asking the aircraft to do something beyond their skill level or the aircraft's capability. I salute your desire to become a better pilot but you have to learn the basics first and not expect that a safe pilot is one that can use every trick in the book on an approach to avoid going around.
 
fiveoboy01 said:
I am not sure that's correct. The load factor isn't the same when descending.
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You guys are missing the point. In A steady climb or a steady descent, the load factor is 1G. Add a bank and it rises. You're saying that a turn initiated with rudder only will bank the airplane and the nose will drop and the load factor will fall, and it does as long as that descent continues to accelerate. A curving descent path with respect of the surface of the earth will do that but you have to keep the nose dropping farther and farther to keep the load factor under 1G; that's how NASA does the weightless thing in big airplanes when training astronauts, but they can only get a few seconds of that before thay have to pull out of it. If they just did a steady descent path--a straight line--they get no G drop, and the same is true in a descending turn, a fact that confuses some people and leads them to think that they're safe pulling harder or banking steeper in the descending turn, and it can kill them.
 
That explanation makes sense. I'm definitely no physicist, I was just thinking in terms of where gravity and the horizontal component of lift come into play and the directions that they pull in a level turn versus a descending turn. In a level turn they should be equal but in a descending turn I would think that they would not be, or at least be vectored in a different direction....
 
fiveoboy01 said:
That explanation makes sense. I'm definitely no physicist, I was just thinking in terms of where gravity and the horizontal component of lift come into play and the directions that they pull in a level turn versus a descending turn. In a level turn they should be equal but in a descending turn I would think that they would not be, or at least be vectored in a different direction....
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Have you ever been stumped by the question often posed to aspiring CFI candidates, "If lift equals weight and thrust equals drag, why doesn't the airplane stand still?" Or split apart, I suppose.

When you simply bank, no matter how you get there, the prop is pulling in the direction it's pointed and gravity is pulling from the side. It's a slip. Pretty soon the slip is going to weathervane in the direction of the pull of gravity and then the prop will pull that way, which is downward as well as to the side. Rinse, repeat. With gravity and prop thrust working together in this new alliance, airspeed will rise. When you stop this falling, i.e., the plane reaches a steady state, the turn radius will be higher at increased speed and the load factor and angle of attack for all intents, will be the same as in level flight.

dtuuri
 
dtuuri said:
Have you ever been stumped by the question often posed to aspiring CFI candidates, "If lift equals weight and thrust equals drag, why doesn't the airplane stand still?" Or split apart, I suppose....

dtuuri
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Newton figured out the laws of motion a while back.
 
Witmo said:
Newton figured out the laws of motion a while back.
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Drag is the answer - there isn't any, if the airplane isn't moving through the air. Newton called it - no acceleration, steady state, doesn't mean an object isn't moving in space.

Besides, the "Lift" thingy is predicated on movement through the air, isn't it?
 
You guys just need some good flying weather, we spend way too much time on the web.
 
dtuuri said:
First, some facts. The load factors in a bank are the same whether descending, climbing or level flight as long as the plane is not being accelerated in any way, ie, it is not changing due to an imbalance. That is, the forces are in "equilibrium" or the plane is in "uniform" flight.
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But the OP asked about flight in the pattern which is anything but "uniform".
 
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