Bank Angle in the Pattern

flyingcheesehead said:
I was hoping I wouldn't be the first to say that.

Folks, a 45-degree banked turn at a steady rate of descent has the SAME load factor as a 45-degree banked level turn. If you're banking at 45 degrees and your load factor is less than 1.414, you're *accelerating* downwards, which is not something that can be sustained for a very long period of time.
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I read this whole thread waiting for someone to say this. There is no such thing as a banked 1g turn. Whoever made the comment about people finding obscure exceptions to score pedantry points was right. The only time a 45* banked turn would yield less than a 1.414 load factor would be while accelerating downward, which only happens for a few seconds while transitioning from constant altitude to constant descent rate.
 
jasc15 said:
I read this whole thread waiting for someone to say this. There is no such thing as a banked 1g turn. Whoever made the comment about people finding obscure exceptions to score pedantry points was right. The only time a 45* banked turn would yield less than a 1.414 load factor would be while accelerating downward, which only happens for a few seconds while transitioning from constant altitude to constant descent rate.
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The only time a 45 degree banked turn would yield a 1.414 load factor is when the pilot pulls to exactly a 1.414 load factor. Most pilot are not that good.

It's not an obscure exception. It's the way aircraft work.

Banked turns at about 1 G are no harder (or nonexistant) than a banked turn at 1.4 G or .4 G or...
 
comanchepilot said:
Plus, I've slam dunked into airports [even VFR] by ATC - slowing down to gear speed and then tossing some flaps - and then simply pulling some G's [say 2.5 or so] is a GREAT way to get rid of energy - I've been 155kias on downwind or some angle to the airport - at idle - slowed to gear speed, dumped the flaps to white line still at pattern altitude and simply cranked a coordinated turn remaining at altitude til about 65mph then unloading the wings in the turn - you end up about 1.3Vso 100 AGL when your stomach catches up . . .

G's are great way to get rid of excess energy . . .
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That's how I enter patterns in my Long EZ. speed 150k roll into the downwind at about 80 deg with power off, dropping gear at same time, roll into the base, speed down to approach. piece of cake.
 
trcsmith said:
That's how I enter patterns in my Long EZ. speed 150k roll into the downwind at about 80 deg with power off, dropping gear at same time, roll into the base, speed down to approach. piece of cake.
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Oh Goodie..... Another experimental guy....:wink2::wink2:

Welcome to POA...:yesnod:
 
trcsmith said:
That's how I enter patterns in my Long EZ. speed 150k roll into the downwind at about 80 deg with power off, dropping gear at same time, roll into the base, speed down to approach. piece of cake.
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Oh the dreaded overhead break!

I saw an air force lear do a nice overhead break once at ILM with about 60 degrees bank
 
trcsmith said:
That's how I enter patterns in my Long EZ. speed 150k roll into the downwind at about 80 deg with power off, dropping gear at same time, roll into the base, speed down to approach. piece of cake.
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I avoid the overhead these days. Too many people reporting it as aerobatic or unnecessay. I will enter the 45 in the Glasair at 150-160 indicated then do a 45 degree bank to the downwind. On downwind at the 45 position another 45 degree turn at 120 indicated to get be below Vfe. Flaps on base then a 30 degree bank to final at 90 indicated and then shooting for 80 kts on final.
 
In the course of another conversation a friend of mine who is an airshow pilot in a Giles 202 also flies a bonanza A36 for business travel etc. he just told me :
. I am sometimes up to 90*, even in my bonanza, although not with passengers :) Referring to a slipping turn in the pattern - downwind, base, final

So, I think this discussion, while interesting and educational is moot... Answer: depends on the pilot and their abilities
 
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denverpilot said:
Ding ding ding. They're just not teaching anything more than 30 degrees these days.
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Nate, you'd better quit with the grandpa act or I'm gonna start calling you old. ;)

45-degree steep turns are still on the Private Pilot PTS, so they are teaching *everyone* "more than 30 degrees these days."
 
Capt. Geoffrey Thorpe said:
The only time a 45 degree banked turn would yield a 1.414 load factor is when the pilot pulls to exactly a 1.414 load factor. Most pilot are not that good.

It's not an obscure exception. It's the way aircraft work.

Banked turns at about 1 G are no harder (or nonexistant) than a banked turn at 1.4 G or .4 G or...
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Private Pilots who pass their checkride are that good. You're not going to get a steep turn within 100 feet of altitude at 45 degrees unless they pull very close to 1.414 load factor - And their average load factor throughout the turn is going to be even closer.

The point is, regardless of who does it, that a 45-degree turn by any pilot is going to be at a load factor much closer to 1.414 than to 1.

In fact, it's much more difficult to make a 45-degree banked turn at a load factor of 1, and you wouldn't be able to hold it for very long. As I said, a 1g 45º banked turn will result in a vertical acceleration of 9.43ft/s^2, or a 566 fpm increase in your vertical speed for every second you hold it. What will quickly happen is that the angle of attack of your wing will increase (and the inner wing moreso than the outer one), but the angle of attack of the tail will decrease. Absent any change in input from the pilot, the airplane will nose down and decrease its bank angle. If the pilot were to only hold the 45º bank angle, the airplane would accelerate and then pitch up to maintain its trimmed airspeed, which would result in a load factor greater than 1. In reality, the pilot would most likely allow the nose to stay up and even help it along a little - It's what we were all trained to do, and it should be a completely subconscious reaction to any pilot with even 100 hours in their logbook.

So, the idea that a "1g" turn in the pattern is going to allow a high bank angle turn to final without increasing stall speed is a myth: We'll only get the turn rate of a 30-degree coordinated vertically steady-state turn, it's not possible to sustain that state for more than a second or two and even then it'll add a lot of airspeed that we don't want on final.

Now, I do know how to unload the wing in a turn - What I'm saying is that you're most likely unloading it to maybe a 1.3 or greater load factor in that turn. While the coordinated "fully loaded" 45º turn results in a 19% increase in stall speed, the 1.3 load factor results in a 14% increase in stall speed. At the speeds we're talking about, that's only a couple of knots' difference.

So why not stick with a nice 30-degree banked coordinated turn instead of all this foolishness? There is nothing wrong with overshooting the centerline and returning to it, it simply means you need to start the turn earlier next time.

I shudder to think that a student pilot would read this thread and try some of this stuff on their next solo flight. Some of what's being suggested here could easily be fatal.
 
flyingcheesehead said:
Private Pilots who pass their checkride are that good. You're not going to get a steep turn within 100 feet of altitude at 45 degrees unless they pull very close to 1.414 load factor - And their average load factor throughout the turn is going to be even closer.
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Within 0.1% of the necessary pull on the yoke? No way.

The point is, regardless of who does it, that a 45-degree turn by any pilot is going to be at a load factor much closer to 1.414 than to 1.
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Typically it would be probably somewhat closer to 1.4 than 1, but only because the pilot is pulling on the yoke.

In fact, it's much more difficult to make a 45-degree banked turn at a load factor of 1, and you wouldn't be able to hold it for very long. As I said, a 1g 45º banked turn will result in a vertical acceleration of 9.43ft/s^2, or a 566 fpm increase in your vertical speed for every second you hold it.
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Let the nose drop, the speed comes up. How fast depends on how far you let it drop. Trying to hold exactly 1.000 would be no harder than trying to hold exactly 1.414. No one can do either.

So why not stick with a nice 30-degree banked coordinated turn instead of all this foolishness?
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Think about what is supposed to be the typical cause of the stall spin accident on the turn to final - using rudder / elevator instead of increasing bank because they are told over and over that it is increasing bank that increases the stall speed. That's why not. That's why it is important to understand that it is the PULL that kills you. Keeping the bank to 30 degrees does not keep you safe. In fact, if you don't let the nose drop a little in your 30 degree bank your speed will decay and you will stall even if you don't load up much. I bet if you watched closely, your nose drops as you turn when the power is off.

And, what is the thing that pilots try to do if things look short? Pull. Ever heard the phrase "trying to stretch the glide"?

Pull kills. Bank doesn't.

There is nothing wrong with overshooting the centerline and returning to it, it simply means you need to start the turn earlier next time.
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Couldn't agree more.

I shudder to think that a student pilot would read this thread and try some of this stuff on their next solo flight. Some of what's being suggested here could easily be fatal.
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I shudder to think about how many pilots don't seem to understand that it's the pulling that increases the load factor - not the bank angle. And, even if you don't increase the load factor significantly, trying to keep the nose up will cause your speed to decay. The end result is the same.

Pull kills. Bank doesn't. Why do "we" teach to not bank? What's wrong with actually teaching people how an airplane really works?
 
Jeanie said:
In the course of another conversation a friend of mine who is an airshow pilot in a Giles 202 also flies a bonanza A36 for business travel etc. he just told me :
. I am sometimes up to 90*, even in my bonanza, although not with passengers :)

So, I think this discussion, while interesting and educational is moot... Answer: depends on the pilot and their abilities
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At least once on every flight in the last 10 years I will stand my experimental on its wing at 90 degrees. Usually the guys /gals flying with me are pilots or adrenaline junkies and they love it... if it is a new person or someone who is squimish, they get a smooth, low bank turn ride... With that said I always (try )to limit my banks while in the airport traffic area to 60 degrees or less.;):)
 
Capt. Geoffrey Thorpe said:
Within 0.1% of the necessary pull on the yoke? No way.
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Nobody said within 0.1%. I would say that on a successfully completed steep turn, the pull is within 10% at all times, but the average is within 1% or the turn would be outside tolerance. So, if it's 10% less than necessary, they'll have to correct with more than necessary to even it out, or they'll be outside the altitude tolerance.

Typically it would be probably somewhat closer to 1.4 than 1, but only because the pilot is pulling on the yoke.
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Right. But if the pilot doesn't pull on the yoke at all, the airplane itself is going to tend to both level out and increase the load factor on its own. A 1G 45º banked turn is not possible to sustain for very long, and it's not a good solution to the problem we're talking about here.

Let the nose drop, the speed comes up. How fast depends on how far you let it drop. Trying to hold exactly 1.000 would be no harder than trying to hold exactly 1.414. No one can do either.
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We're not talking precision here - Between holding 1.000 ± 10% or 1.414 ± 10%, it will be much easier to get the latter, and the latter is possible to sustain indefinitely in a 45º bank, while attempting to sustain the former for more than a few seconds will result in a crash.

Think about what is supposed to be the typical cause of the stall spin accident on the turn to final - using rudder / elevator instead of increasing bank because they are told over and over that it is increasing bank that increases the stall speed. That's why not. That's why it is important to understand that it is the PULL that kills you.
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I don't disagree with that at all. The problem is, that a 1G 45º bank is NOT the solution! The solution is to discuss the real issue, which is the skidding base-to-final turn and why the BEST solution *is* to keep the bank to a reasonable (IMO, 30º) limit AND not to skid AND not to pull too hard!

Keeping the bank to 30 degrees does not keep you safe. In fact, if you don't let the nose drop a little in your 30 degree bank your speed will decay and you will stall even if you don't load up much. I bet if you watched closely, your nose drops as you turn when the power is off.
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As it should - If you pull too much, your speed will decay more, if you don't pull enough, your vertical speed will be too great.

And, while 30 degrees doesn't keep you safe, attempting a 45º 1g turn is LESS safe than a properly executed, coordinated (even if you overshoot) 30-degree turn.

Pull kills. Bank doesn't.
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So, let's tell the students WHY pull kills, and WHY a skid kills, rather than suggesting that a steeper, unloaded bank and its associated downward acceleration is the right answer, because it's not.

I shudder to think about how many pilots don't seem to understand that it's the pulling that increases the load factor - not the bank angle. And, even if you don't increase the load factor significantly, trying to keep the nose up will cause your speed to decay. The end result is the same.
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Yup.

Pull kills. Bank doesn't. Why do "we" teach to not bank? What's wrong with actually teaching people how an airplane really works?
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I think it's rooted in two things:

1) There are a lot of instructors out there who either don't understand how an airplane really works themselves, or don't care enough to teach it to their students.

2) There are a lot of good instructors out there who don't want to overwhelm their students with too much information too early on. It's easier for a student to remember "don't exceed 30 degrees of bank in the pattern" than it is for them to remember all the other stuff that goes into making an airplane fly, since they're likely somewhat overwhelmed with just the physical aspects of flying.

However, instructors that haven't yet covered the "why" behind the 30-degree "rule" absolutely MUST emphasize that it's OK to overshoot the centerline, and that they MUST stay coordinated.
 
no matter how quickly I turn the little knob on the STEC control head, the airplane won't bank as steeply as some here are proposing. I must be doing something wrong.
 
JHW said:
no matter how quickly I turn the little knob on the STEC control head, the airplane won't bank as steeply as some here are proposing. I must be doing something wrong.
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Yeah..... The STEC should be OFF while you are in the pattern...:yes:..

If ya can't hand fly it while in the pattern, you should leave the plane in the hangar..:nono:
 
Push the back-course knob.

JHW said:
no matter how quickly I turn the little knob on the STEC control head, the airplane won't bank as steeply as some here are proposing. I must be doing something wrong.
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Capt. Geoffrey Thorpe said:
Pull kills. Bank doesn't.
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But if you bank without more pull, you accelerate downwards at an ever-increasing descent rate.

The fact remains that in a steady descent rate, straight ahead, you are at 1G. In the turn, same steady descent rate, the load factor increases. The steeper the bank, the higher the load factor and the higher the stall speed. Banking at 45° when at 1.3Vso while turning base-to-final is as dumb, IMHO, as skidding that turn at 30°. If one is well above the 1.3 at 45° it's not so bad, but now the turn radius increases and we still have the overshooting problem unless we start planning better, including making allowances for the wind, which might be behind us on base, or on the nose.

A good landing starts way back when we turn downwind and start thinking ahead.

I think that many here who use 45° are at 1.5 or 1.6 or 1.7Vso when they do it. Shoot, I see many pilots on short final at those speeds, and they either float forever or land really flat.

Dan
 
I'm not following this "1 g 45 deg turn" logic. In order to turn you must be changing direction which requires an acceleration. Without the acceleration force you wouldn't change direction. So how do you turn and maintain 1 g?
 
Silvaire said:
I'm not following this "1 g 45 deg turn" logic. In order to turn you must be changing direction which requires an acceleration. Without the acceleration force you wouldn't change direction. So how do you turn and maintain 1 g?
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Wings generate the force. If you bank, some of that force works to accelerate you through the turn. If you are only around 1G, you will not have enough force to maintain altitude (since some is making you turn) and you will start to accelerate downwards. But you will still turn.
 
Well that's the part I don't get. When you say "accelerating" downwards do you mean like a skydiver in free fall, where your vertical speed is constantly increasing? Because if you are descending at a constant 500 fpm in a straight descent there is no acceleration, you are at 1 g.

It seems to me that in order to negate the acceleration caused by the turning motion you'd have to have an equal force opposite to that vector and since the turning force would be continuous so would the rate of vertical speed increase have to be as well. I know you can do this but, in the pattern?

Also, why would you do it? Wouldn't it be better to just fly a normal turn at 1.5 g at a speed that will carry you through without stalling? For one thing, any increase in vertical speed is going to have to be arrested at some point and that will require more than 1 g anyhow.
 
Everskyward said:
... I know that we are not supposed to exceed 30 degrees with passengers whether in the pattern or not but there's no issue with doing steep turns empty.
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Huh?

How do you take a practical test, then? The examiner is a passenger. So is an instructor for any training beyond the private pilot certificate.

There is nothing wrong with exceeding 30 deg bank with passengers, as long as they are comfy with it. In fact, it's a nice way to get a photo of something on the ground (do watch your airspeed and stay away from the stall).
 
Silvaire said:
Well that's the part I don't get. When you say "accelerating" downwards do you mean like a skydiver in free fall, where your vertical speed is constantly increasing? Because if you are descending at a constant 500 fpm in a straight descent there is no acceleration, you are at 1 g.
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Accelerating.
 
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flyingcheesehead said:
45-degree steep turns are still on the Private Pilot PTS, so they are teaching *everyone* "more than 30 degrees these days."
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45deg isn't steep.
On my checkride in 1982 and flying with a friend DPE until the mid 90's, steep turns was 60deg. It was routine run of the mill stuff even by student pilots with no CFI onboard. It was nothing special.
45deg was declared steep turns sometime in the 90's IIRC. I know this simply because in the late 90's I gave a CFI total heart failure when he said do a steep turn and I kept rolling way past 45. (Him and I didn't get along very well. I was just doing what I was taught. He thought airliner stuff was on the edge flying. ...70kts in a STOL 172 as slow flight..sheesh. Coward! That was practically cruise speed in that plane and I know damned well it will fly very stable in the low 40's with the ASI needle bouncing off the zero stop due to airflow problems over the pitot tube)

Now 45 is considered steep however it's pattern stuff. It won't be long before 30deg is considered steep. Mr Coward wanted a maximum of 15deg bank anywhere in the pattern and that was over a decade ago...He's probably teaching 10deg steep turns by now.

If you want flat skidding turns, take up driving cars. Airplanes have ailerons for a reason. Deal with it or find another hobby.
 
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fgcason said:
45deg isn't steep.
On my checkride in 1982 and flying with a friend DPE until the mid 90's, steep turns was 60deg. It was routine run of the mill stuff even by student pilots with no CFI onboard. It was nothing special.
45deg was declared steep turns sometime in the 90's IIRC. I know this simply because in the late 90's I gave a CFI total heart failure when he said do a steep turn and I kept rolling way past 45. (Him and I didn't get along very well. I was just doing what I was taught. He thought airliner stuff was on the edge flying. ...70kts in a STOL 172 as slow flight..sheesh. Coward! That was practically cruise speed in that plane and I know damned well it will fly very stable in the low 40's with the ASI needle bouncing off the zero stop due to airflow problems over the pitot tube)

Now 45 is considered steep however it's pattern stuff. It won't be long before 30deg is considered steep. Mr Coward wanted a maximum of 15deg bank anywhere in the pattern and that was over a decade ago...He's probably teaching 10deg steep turns by now.

If you want flat skidding turns, take up driving cars. Airplanes have ailerons for a reason. Deal with it or find another hobby.
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During my training my first instructor had me at the max allowed for the plane of 60 degrees. All the instructors after he left just wanted me to be more than 45 degrees. I don't know if it is a comfort level with the airplane, their own personal comfort, or just the thought that someone else is flying?

I was taught 30 degrees in the pattern. If I exceeded it a little I never caught any flack for it.
 
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wabower said:
Like you did?
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$$$$$$$ is the only reason I'm not flying right now. Overpriced POS restricted use rentals and no funds to buy a plane...yet. Unlike the car bank angle turn flying stuff, it has absolutely nothing to do with flying the airplane properly. Heck, the roll angle on my motorcycle often exceeds what some people are afraid of in an airplane.
 
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flyingcheesehead said:
Nate, you'd better quit with the grandpa act or I'm gonna start calling you old. ;)

45-degree steep turns are still on the Private Pilot PTS, so they are teaching *everyone* "more than 30 degrees these days."
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Find an instructor teaching them in the pattern at a ratings mill. I wasn't talking about out in the practice area. :)
 
denverpilot said:
Find an instructor teaching them in the pattern at a ratings mill. I wasn't talking about out in the practice area. :)
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I don't think turns over 30 degrees in the pattern should be taught, at a ratings mill or otherwise.

What needs to be taught is *coordinated* turns, and that it's OK to go past the runway centerline.

I've already covered why teaching a 45-degree unloaded turn in the pattern is a bad idea, due to the downward acceleration. IMO, teaching a 45-degree loaded turn is also a bad idea, since we're at 1.2-1.3 Vs0 and a 45-degree loaded turn is going to make the stall at 1.19Vs0.

30 degrees, coordinated, go past the centerline if you need to. The radius of a 30-degree coordinated, loaded turn at 75 knots is 863 feet and the stall speed will be raised only to 1.07Vs0. It provides us with a turn that is plenty tight while also maintaining a good safety margin above the stall.

Folks, I know there are plenty of bad instructors out there who will parrot the "30 degrees in the pattern" rule and not understand it or teach the most important related thing (staying coordinated). That does not mean that it's not a good idea. It does mean we need to emphasize coordination. The "solutions" to this "problem" that are being talked about in this thread are, frankly, nothing short of ridiculous.
 
Capt. Geoffrey Thorpe said:
Accelerating.
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Gotcha, however, having successfully executed this 1 g, 45 degree banked turn aren't you now going to have to pull more than 1 g to stop the vertical acceleration? Other than to bleed off excess altitude, what's the point?
 
Silvaire said:
Gotcha, however, having successfully executed this 1 g, 45 degree banked turn aren't you now going to have to pull more than 1 g to stop the vertical acceleration? Other than to bleed off excess altitude, what's the point?
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Don't forget flying is supposed to be fun. :)
 
It is and I've been having fun for over 40 years now but some of this stuff we do naturally every day I guess I never really deeply pondered the actual physics behind it. It's interesting though.
 
Silvaire said:
It is and I've been having fun for over 40 years now but some of this stuff we do naturally every day I guess I never really deeply pondered the actual physics behind it. It's interesting though.
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Speaking of the physics of turns - the optimum bank angle is about 45 degrees when attempting a turn back to the runway after engine out or glider tow rope break. At least according to the author of these two papers:

http://jeremy.zawodny.com/flying/turnback.pdf

http://www.nar-associates.com/technical-flying/impossible/nonoptimalcost_screen.pdf
 
Not a lot of people are running perfectly good airplanes at flying speed into the ground because they banked too much. People are falling out of the pattern into the ground because they spun.

One can complete the turn faster then the constant state 30 degree bank if they trade their altitude for airspeed which then allows them to increase their load factor and bank while gaining the buffer that is needed to not stall.
 
flyingcheesehead said:
I don't think turns over 30 degrees in the pattern should be taught, at a ratings mill or otherwise.

What needs to be taught is *coordinated* turns, and that it's OK to go past the runway centerline.
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Okay we'll see how well that goes over when there's a parallel runway.

Teach students to SPEED UP if they have to increase bank angle. How to speed up? Get the nose DOWN. And DESCEND faster.

Yes, you have to learn how to judge if you have enough altitude remaining to do it.

It has zero to do with bank angle. It's about energy and whether or not you have enough of it, or have altitude to trade for it.
 
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