traffic pattern for turbines: how wide for the downwind?

FWIW, the downwind for the KSTL 30s goes right over my backyard, and we are 5nm off the extended centerline for those runways. 737s over our place allll daaaayyy lonnnng.. (and the occasional Prime 767).
 
PaulS said:
I don't really understand your point, I suspect for most people who have spun in the pattern and died, it was their first time..... and last.

That was my primary instructor, and yes he would regularly spin train students, I'm pretty sure you have to understand spins to teach them. In fact he had a student put a plane into an incipient spin base to final, which he saved. He had seen at least one massive screw up and what precipitated it. So I absolutely trust what he says over some guy on the internet berating pilots who don't do steep turns in the pattern.

I'm not an ace pilot, I don't need thrills in the pattern, in fact I work to keep my patterns mundane. If I get to the point where I need a 60 degree turn to correct things, I just power up, go around and try again. You do you, I'll do me. There are no medals for banging around a pattern.
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The point is, it is not the angle of bank that causes a spin. In fact, most pattern spins occur from someone trying to maintain a shallow angle of bank but adding rudder to "help" the turn.

This causes the inside wing to stall, and the aircraft rolls and enters the spin. Even if you recover, you are nose low close to the ground.

If you bank more you can be coordinated and then if you stall, the nose drops, but a wings does not drop. Or, if you bank too much and use top rudder, and you stall, the aircraft rolls through wings level and you relax a bit of back pressure and fly off. And later change your pants.

The thing that is paramount is COORDINATED turns.
 
Pinecone said:
Doesn't say they spun it.

The T-38 had a Warning in the Dash 1. This aircraft can develop sink rates at traffic pattern altitude that preclude recovery or safe ejection.
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Please tell me more, for instance, was that put in the book after that crash? What that describes to me is a partial stall caused by a steep bank or too slow or a combination of the two. I agree with the importance of coordination, however, if you hardly need to tip the wings (coordinated, of course) — you hardly ever get into trouble, either.
 
Pinecone said:
The point is, it is not the angle of bank that causes a spin. In fact, most pattern spins occur from someone trying to maintain a shallow angle of bank but adding rudder to "help" the turn.

This causes the inside wing to stall, and the aircraft rolls and enters the spin. Even if you recover, you are nose low close to the ground.

If you bank more you can be coordinated and then if you stall, the nose drops, but a wings does not drop. Or, if you bank too much and use top rudder, and you stall, the aircraft rolls through wings level and you relax a bit of back pressure and fly off. And later change your pants.

The thing that is paramount is COORDINATED turns.
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Of course, AoA and subsequently airspeed are very important too. You can be perfectly coordinated in your 60 degree turn, get distracted, quickly bleed off airspeed, stall, then screw up the recovery by not resisting the urge to level the wings with the ailerons. I shudder when I read POHs that tell you to "use coordinated aileron and rudder to level the wings during a stall recovery". I was taught rudder is primary in the stall, leave the ailerons neutral. Same thing in a spin recovery, ailerons neutral.

I've done stalls where I know I was perfectly coordinated and the wing still dropped. A lot can happen, if you have a lot of experience and want to bang turns around the pattern, then by all means, have at it. But there are a lot of low time pilots, student pilots and people who want to start flying. They shouldn't be doing steep turns in the pattern. It's been a while, but I believe most training materials talk about not overbanking in turns in the pattern.
 
kaiser said:
Stall speed is about load factor. An aircraft in a 1g 60* bank turn has the same stall speed as an aircraft in a 1g 20* bank turn.
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Discussing a 1g 60° bank turn is utterly pointless. The aircraft will accelerate downward at 16fps/s (sin(60°) * 32 fps/s), only three seconds the descent rate would reach almost 3,000fpm.

kaiser said:
The difference would be the vertical component of lift, thus the 60* aircraft would be in a descent (course would also be different).
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For the second time, descending has a negligible effect on load factor. You ever hear of a graveyard spiral?
 
Pinecone said:
DUH, I did say PROPER airspeed. Proper airspeed means for the conditions of flight, which includes the bank angle.
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Thank you for clarifying your previous post, which was ambiguous as to what you meant by proper airspeed.

Pinecone said:
Oh, and that 1.4x stall speed is for a LEVEL turn.
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The math is the same for a descending turn.
 
Lindberg said:
The math is whatever you want it to be. Dumb rules are dumb. Fly the plane and do what needs to be done.
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Repetitively expressing the misconception that load factor only goes up in level turns is not just dumb but also dangerous.
 
dmspilot said:
Repetitively expressing the misconception that load factor only goes up in level turns is not just dumb but also dangerous.
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Claiming that load factor is determined by bank angle and that "excessive" bank angles are dangerous causes the misconceptions shown in this thread.
 
Lindberg said:
Claiming that load factor is determined by bank angle and that "excessive" bank angles are dangerous causes the misconceptions shown in this thread.
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Load factor is determined by increased elevator deflection for a given speed, i.e., a steeper bank.
 
Lindberg said:
Claiming that load factor is determined by bank angle and that "excessive" bank angles are dangerous causes the misconceptions shown in this thread.
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What misconceptions?
 
dtuuri said:
Load factor is determined by increased elevator deflection for a given speed, i.e., a steeper bank.
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Stability will increase the load factor with no elevator input. Or you'll hit the ground at many thousands of fpm. Whichever occurs first.
 
Lindberg said:
That normal turns in the pattern are dangerous. That bank angle causes spins. And a new one for me, that increased elevator deflection equals a steeper bank.
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I did not say those things, plus, phrases like "normal" and "excessive" are open to interpretation. A bank angle of 60° was mentioned specifically, so I pointed out why that could be dangerous. You responded with an incorrect statement, that load factor only increases in a level turn. You want to change my argument to something else, that's not how it works.
 
dmspilot said:
I did not say those things, plus, phrases like "normal" and "excessive" are open to interpretation. A bank angle of 60° was mentioned specifically, so I pointed out why that could be dangerous. You responded with an incorrect statement, that load factor only increases in a level turn. You want to change my argument to something else, that's not how it works.
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I didn't say you said those things. I said that "[c]laiming that load factor is determined by bank angle and that "excessive" bank angles are dangerous causes the misconceptions shown in this thread."

I will elaborate on my statement and maybe you'll like it better: The claim that load factor increases with bank angle is based on unstated assumptions, the most common of which is a level turn.

Why, just this weekend I did 45-60* banks while descending in the pattern and neither stalled and spun nor slammed into the ground at 3000 fpm.
 
Lindberg said:
The claim that load factor increases with bank angle is based on unstated assumptions, the most common of which is a level turn.
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No, it isn't. Being level has nothing to do with it.

A level turn is an example, not a requirement, of the association between load factor and bank angle.
 
Mxfarm said:
@ those pattern distances how would you ever make the runway if you lost an engine? :rolleyes:o_O
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Good point. After all, after a 3 hour flight during which the engine worked perfectly, it's bound to quit in the traffic pattern with no warning.
 
dmspilot said:
Don't know what "over the fence" means, but 1.3 Vs0 is a typical approach speed, and turns are typically part of an approach.
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Common phrase referring to your airspeed as you cross the threshold. Tends to be a bit slower than Vref because you have reduced power and are starting the roundout.
 
Allow me to add another (mostly) useless data point for my own amusement:

The fine Grumman product (pictured) flies downwind leg 1NM abeam the numbers at 600' AGL around the boat (or OLF for practice).
 
dtuuri said:
Please tell me more, for instance, was that put in the book after that crash? What that describes to me is a partial stall caused by a steep bank or too slow or a combination of the two. I agree with the importance of coordination, however, if you hardly need to tip the wings (coordinated, of course) — you hardly ever get into trouble, either.
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I have no idea when they put that in, I flew the T-38 (and AT-38B) in 81/82.

Well, the same thing applies in straight and level, PROPER speed. :)
 
Lindberg said:
I didn't say you said those things. I said that "[c]laiming that load factor is determined by bank angle and that "excessive" bank angles are dangerous causes the misconceptions shown in this thread."

I will elaborate on my statement and maybe you'll like it better: The claim that load factor increases with bank angle is based on unstated assumptions, the most common of which is a level turn.

Why, just this weekend I did 45-60* banks while descending in the pattern and neither stalled and spun nor slammed into the ground at 3000 fpm.
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Yeap. And as I stated USAF has solo students doing 60 degree banked turns in the pattern without issues.
 
Pinecone said:
Yeap. And as I stated USAF has solo students doing 60 degree banked turns in the pattern without issues.
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So, what's the practical necessity of doing them other than to build skill in managing the plane. Just because you CAN do something doesn't mean you should. For instance, if the stsll speed is so high you need a 60° bank to stay within obstruction-free airspace, that's a good reason. OTOH, if you have room to spare, the accident record proves a shallower bank is less risky.
 
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dtuuri said:
Well, there WAS elevator* input before you trimmed it nose up.
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Didn't say anything about trimming, though, trim is obviously involved in the airplane's pitch stability. In a steep bank even with the elevator locked in place, load factor would still increase. The airplane will enter a dive, speed will increase, and lift will increase due to the higher speed, even if AOA is constant or slightly decreased.
 
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dtuuri said:
So, what's the practical necessity of doing them other than to build skill in managing the plane. Just because you CAN do something doesn't mean you should. For instance, if the stsll speed is so high you need a 60° bank to stay within obstruction-free airspace, that's a good reason. OTOH, if you have room to spare, the accident record proves a shallower bank is less risky.
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Well, we did the traffic pattern at 300 KIAS. :D

Jets don't require much rudder, so very unlikely to spin.
 
dmspilot said:
Didn't say anything about trimming, though, trim is obviously involved in the airplane's pitch stability. In a steep bank even with the elevator locked in place, load factor would still increase. The airplane will enter a dive, speed will increase, and lift will increase due to the higher speed, even if AOA is constant or slightly decreased.
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In simple terms, load factor is a result of the curving flight path. The thing that makes it curve is the horizontal tail surface. In wings level flight they hold the nose up (cut 'em off and straight down you'll go). If you tilt the wings, you change that "up" to "around". If you don't increase elevator — you'll increase speed and turn radius and lose altitude. Which would then require more bank than necessary and make you too fast to land. So, you need to add more elevator so that doesn't happen. No need to bring in "stability" nor sines and cosines, it's just simple logic.
 
Pinecone said:
Well, we did the traffic pattern at 300 KIAS. :D

Jets don't require much rudder, so very unlikely to spin.
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Yaw dampers help too, I'd imagine. So, I'm still thinking about See's crash. What category would it have been circling in? Or, what's the T-38s stalling speed in the circling configuration? Slayton said See was too timid and didn't fly "aggressively" enough. :rolleyes: Whatever that means about a circling approach. In my experience, both high speed and high bank should be avoided on a circling approach. I'd call that sort of flying "too aggressive".
 
dtuuri said:
If you don't increase elevator — you'll increase speed and turn radius and lose altitude. Which would then require more bank than necessary and make you too fast to land. So, you need to add more elevator so that doesn't happen. No need to bring in "stability" nor sines and cosines, it's just simple logic.
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You missed my point. Load factor will increase in either case.
 
dmspilot said:
No, it isn't. Being level has nothing to do with it.

A level turn is an example, not a requirement, of the association between load factor and bank angle.
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It happens to be the only example the FAA uses in the AFH. And it's the, usually unstated, perhaps unknown, assumption by most pilots making unqualified claims that stall speed increases with bank angle.

"With an approach speed of 1.3 Vs0, and a 60 degree bank resulting in stall speed that is 1.41 times higher than normal, you would be incorrect."

Here you may have been assuming a constant descent rate rather than level flight, regardless, as an unqualified statement, this is inaccurate.
 
Lindberg said:
It happens to be the only example the FAA uses in the AFH. And it's the, usually unstated, perhaps unknown, assumption by most pilots making unqualified claims that stall speed increases with bank angle.
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The FAA is wrong about a lot of things.

Screen Shot 2022-10-03 at 4.14.16 PM.png

Lindberg said:
"With an approach speed of 1.3 Vs0, and a 60 degree bank resulting in stall speed that is 1.41 times higher than normal, you would be incorrect."

Here you may have been assuming a constant descent rate rather than level flight, regardless, as an unqualified statement, this is inaccurate.
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Well I didn't say "coordinated turn" either so why aren't you complaining about that? My statement was accurate for the point being made. You're not going to be able to bank 60° without increasing the stall speed for more than a second or two. That "qualification" is insignificant.
 
It's amazing... I can easily do 90-degree bank turns below s&l stall speed with nary a peep from the stall horn or other complaint from the airplane. No, not in the pattern. I think they are called wingovers. Wings stall because they are asked to provide more lift than they can provide. That's controlled by the elevator.
 
Lindberg said:
If you're 5 miles away on downwind as some are suggesting, then no, I don't think you're in the pattern.
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It's a normal pattern for that airplane. It's on the high-end, though. Most other jets will be able to fly slower in the pattern and fly a bit tighter pattern.
 
dmspilot said:
For the second time, descending has a negligible effect on load factor. You ever hear of a graveyard spiral?
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Graveyard spirals are not stalls, nor are they caused by or related to, load factor. Improper recovery from a spiral can result in increasing load factor and stalling - if you pull the elevator before leveling the wings.

A (nose low) descent lowers the angle of attack. Stalls occur at the critical angle of attack. Not pulling on the elevator and allowing the nose to lower, most certainly lowers angle of attack, which moves you further from stalling.
 
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Salty said:
Graveyard spirals are not stalls, nor are they caused by or related to, load factor.
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I didn't say that a graveyard spiral was a stall, nor did I say that it was caused by load factor. You're on the wrong track.

Salty said:
can result in increasing load factor and stalling
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And they can result in much worse things happening than stalling.

Salty said:
A (nose low) descent lowers the angle of attack.
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That is an incorrect statement.

Salty said:
Not pulling on the elevator and allowing the nose to lower, most certainly lowers angle of attack, which moves you further from stalling.
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The temporary and transitory decrease in angle of attack, during the transition from level to a descent, is not germane to the discussion on stall speed vs. bank angle and bank angle vs. load factor. It's negligible and shouldn't be part of a defense for 60 degree banks in a traffic pattern.
 
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iu
 
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