Boeing 727 Question

[Mr.Vortex]

Hi all,


I have been reading the B727 FCTM and it said that the B727 can't
recorver it self from the dutch roll condition at high speed & high altitude.
Is that true? What make the B727 unable to damping the dutch roll?
Small rudder surface of B727? or large swept wing angle?

Also, does any of you have ever firewalling the throttle? Is it increase the
thrust significantly more than the takeoff rating?

Thanks for all of your reply

Best regards

[MarkerInbound]

I've hear it's the sweep of the wings. I've seen it cause the sim to shutdown due to the violence. If it gets started, the 727 is dynamically unstable. Meaning it will just get worse and worse. Recovery is a standard maneuver on checkrides. However the simple solution is to just slow down. The problem goes away below about .75 mach.

Define the TO rating. I can think of 6 different engine dash number combinations. At an airport 5000 feet up with a temperature of 40c, a dash 7 engine won't give rated thrust and your takeoff numbers will reflect it. At sea level on a 5c day, a Super 72 with a 219-15-219 engine mix will have some more EPR to give you.

[Jane-DoH]

Mr. Vortex,

I have been reading the B727 FCTM and it said that the B727 can't
recorver it self from the dutch roll condition at high speed & high altitude.

You mean the pilot can't recover the plane, or it simply will get progressively worse (dynamic instability) without any pilot intervention

Is that true? What make the B727 unable to damping the dutch roll?
Small rudder surface of B727? or large swept wing angle?

I think it has to do with the combination of wing sweep-angle, and the T-tail configuration.

Also, does any of you have ever firewalling the throttle? Is it increase the thrust significantly more than the takeoff rating?

I'm not a pilot, but I can tell you that during virtually all commercial airliner takeoffs are not done at 100% power; they are done at a reduced power settings which still allow the airplane to get airborne, and climb purposefully, yet increase engine service-life (as well as reduce noise).

Fire-walling will push the engine past 100% RPM -- it is a setting only used in emergencies such as a stall, or in windshear. Being that the engine is pushed past its normal maximum operating RPM, an inspection is generally done after something like this is done.

[JammedStab]

Try using speed brakes in such a scenario. Really damps out the Dutch Roll.

[Mr.Vortex]

To Jane DoH

Yes. I mean without pilot input.

Also, another question is what is the usual descent target speed? I've
readthe previous thread in this forum and is said the speed is about
the barber pole. Is that the common for all other airline too or it is
depeneds on the airline SOP.

Thanks to all reply.

Best regards

[Jane-DoH]

JammedStab,

Try using speed brakes in such a scenario. Really damps out the Dutch Roll.

Logical enough


Mr. Vortex,

Yes. I mean without pilot input.

Understood

[18-Wheeler]

Try using speed brakes in such a scenario. Really damps out the Dutch Roll.

My father used to fly 727's and he has said a few times that the speed brakes are the fastest way to stop Dutch Roll in them. It is possible to do it with the conventional controls only (had to be demonstrated in the old TAA sim during a check) but it's difficult to do.

[Mr.Vortex]

That's interesting!!. I've never heard about using the speedbrake to stop
the dutch roll. Does anybody have an experience to share with.:)

[MarkerInbound]

We'd hold the same mach as we were cruising at and switch over to 300-310 knots. Waiting to start down at .88 or .89 increases the fuel burn. Book says to switch to 280 knots but that seemed so slow. I'd adjust for the headwinds and tailwinds, glider flying has some uses.

[trimotor]

It's been a while, but the 727 has issues between lateral (high) and longitudinal (low) stability. Don't think the T tail has much, if anything to do with it, though get too much yaw (11° is the magic number in the back of my head) and the tail will reputedly come off.

The 727-100 will depart if Dutch Roll is left unchecked (you'd have to be dead not to notice it), though the 727-200 is pretty-much neutral (longer, and more directional stability), but obvious i.e. it won't recover itself, but won't get worse.

18-Wheeler is correct: initial actions include extending the speedbrakes - very effective - lessens the lateral stability. Hand flying the recovery (the only way) is difficult, especially in the -100, as it's easy to get out of phase with the roll and make it worse. The recover is ideally a 2-person job with the other guy checking to see that you have the correct inputs - mostly an input timing issue.

The aircraft has significant MEL restrictions relating deispatch with inop yaw dampers.

[By George]

Obviously slowing down using any means helps but the best way to recover is as the 'down' wing starts to rise apply full into down wing aileron and back to neutral. Wait for the wing to go 'down' again and repeat the action. After about four cycles the rolling motion begins to dampen out and normal roll control becomes effective. If you're good you can work both wings but it requires very good co-ordination. During my initial Command training we had to be familiar with Dutch Roll recovery but only in the Sim. If my memory serves me correctly in the early days they lost a 707 trying it in the aircraft. Quite a strange aerodynamic event the first time you see it. Good to know the limits of the envelope we don't seem to 'explore' this enough these days.

[411A]

If my memory serves me correctly in the early days they lost a 707 trying it in the aircraft. Quite a strange aerodynamic event the first time you see it
Yup....and the early 707's were much the same, divergent dutch roll was a definite possibility, if not handled correctly. Later models with series yaw dampers were much more stable.

[aterpster]

trimotor:

The aircraft has significant MEL restrictions relating deispatch with inop yaw dampers.

It's been a long time, but my recollection is that at least one had to be operative. And, it was two operative unless at a non-maintenance station. The altitude restrictions were significant, just as they were if one became inop enroute.

The -100 was far worse than the -200, thus more restrictive if memory serves me.

[Jane-DoH]

Marker Inbound,

We'd hold the same mach as we were cruising at and switch over to 300-310 knots.

You typically would be cruising around M=0.84-0.85 right?


trimotor,

It's been a while, but the 727 has issues between lateral (high) and longitudinal (low) stability.

I never heard anything about the plane having poor longitudinal stability, I guess you learn something new every day.

Don't think the T tail has much, if anything to do with it, though get too much yaw (11° is the magic number in the back of my head) and the tail will reputedly come off.

11-degrees of sideslip?

The 727-100 will depart if Dutch Roll is left unchecked (you'd have to be dead not to notice it)

Of course, the plane rolls and yaws back and forth all over the place.

the 727-200 is pretty-much neutral (longer, and more directional stability)

I thought a shorter plane had more directional stability (at least that's why I was always under the impression that the 747-SP had a bigger tail) than a long plane

The aircraft has significant MEL restrictions relating deispatch with inop yaw dampers.

Was it's dutch roll characteristics worse than the 707?


By George,

Obviously slowing down using any means helps but the best way to recover is as the 'down' wing starts to rise apply full into down wing aileron and back to neutral.

I assume if you were getting dutch-roll, the yaw-dampers would be dead, would you use small rudder inputs with the ailerons, or just the ailerons alone?


411A,

Yup....and the early 707's were much the same, divergent dutch roll was a definite possibility, if not handled correctly.

I assume the 707 had worse dutch-roll characteristics than the 727 because of it having a higher wing-sweep?

[MarkerInbound]

No, we'd normally be at long range cruise around .80. It make a big difference fuel wise between .80 and .85.

Braniff lost a 707 on a delivery flight with Check Airman, Feds and Boeing pilots on it. We had a 727 Check Airman who was old Braniff and you knew every time he was giving the check you'd see Dutch Roll as the flight control malfunction. I have seen so many pilots get out of sync playing whack-a-mole on the rising wing. You don't want to add any rudder inputs.

MEL for both the -100 and -200 just says to comply with the AFM restrictions. Can't remember the -100 but the -200 is a max 270 kts at 30,000 and a sliding scale to 310 at 26,000 and then it jumps to 350 at 25,000 and below.

[CaptainSandL]

As Dutch Roll in the 707 and 727 were tricky to handle without a yaw damper, the 737 prototypes were originally fitted with two YDs due to anticipated MEL restrictions. Once they flew it, it was proven to be a pussycat and the second YD was removed. There is also no MEL restriction if the YD is inop.

In my experience in both 737 Classics and NGs if you induce a Dutch Roll at cruise alt & Mach it will decay to zero in about 6-8 oscillations with the YD off, or just 1.5 with the YD on - both figures are without any pilot input.

S&L

[By George]

'Jane-Doh', Your question has been answered by 'MarkerInbound' I was taught to use aileron only and yes for the exercise the Yaw dampers were off.

[Jane-DoH]

By George,

'Jane-Doh', Your question has been answered by 'MarkerInbound' I was taught to use aileron only and yes for the exercise the Yaw dampers were off.

Understood

[JammedStab]

Obviously slowing down using any means helps but the best way to recover is as the 'down' wing starts to rise apply full into down wing aileron and back to neutral. Wait for the wing to go 'down' again and repeat the action. After about four cycles the rolling motion begins to dampen out and normal roll control becomes effective.

The sharp aileron input seemed to be the basic recovery manouver as taught to me but speedbrakes seem to be much more effective.

With the sharp aileron input, as said above, you did it into the rising wing. So choose a wing and then each time it is rising, apply aileron input quickly and then back to neutral. You could screw it up though. If you look at the ADI and after having chosen a particular wing to apply aileron against, you do it 180° out of sync because you mistook the rising horizon on the ADI as the rising wing. Oops.

We practised it in the sim but did it in the real aircraft on a post maintenance check. Yaw Damper off and then a small kick in one direction of the rudder starts the cycle. Real plane seemed to handle like the sim.

Here is the kind of strange part. Initially the wings tended to dip more or less equally on either side of wings level(call it the neutral point). But, after some aileron recovery inputs you can end up with a new neutral point such as, for example, 15° right bank being the new neutral point and equal wing dips from that point. Happened in the sim and on the airplane.

[Old Fella]

Never operated the B727 and do not know if it is less susceptible to Dutch rolling than the B707, but would think there is more to it than a 3 degree difference in wing sweep. (B707 35 degrees - B727 32 degrees). I remember induced Dutch Roll and recovery certainly grabbed our attention. FL150 over Bass Strait when converting to B707 and being trained by Qantas. Interesting exercise to say the least. Why did we do it in the aircraft and not the Sim? Because the Qantas Sim was dismantled and sent to Aer Lingus as soon as we completed the Sim training phase of conversion.

[trimotor]

Jane Doh: the 727 wasn't poor in terms of directional stability - just that the latreral stability was very strong. (courtesy, probably, of the amount of wing sweep).

The longer -200 had effectively more rudder 'volume', as the extra fuselage length behind the CG provides additional moment arm for the fin. Surmising (never flown the machine), but this is probably the reason for the 747SP's additional fin/rudder area - the aircarft is shorter, so has less moment arm, though the same wing/engine (basically).

[Mr.Vortex]

Is it possible to have an adverse yaw induced a dutch roll during the approach
phase with 30 to 40 flap degree?. [PS. YD off]

Since, I used to fly Flight simulator [I know it isn't real, but it helps me to learn]
on B727 by hand on final. I believe I have a strong adverse yaw during making the alignment to the runway by hand [I turned YD off to see the airplane handling quality] and hence dutch roll which add a difficulty during landing.

What about the real aircraft? Does any one have any experience or idea about
dutch roll during the approach or landing phase?

Best Regards

[By George]

The 727 on approach was conventional in all respects. I see Mr 'Vortex' you are only 17, there is nothing wrong with that and it's good to see young people interested. In a modern jet, rudder is used only for x-wind landings, either to kick it straight during the flare or use cross-control wing down whatever your preference during the approach.

[By George]

Before I get shot down, rudder is obsviously used for take-off, directional control and x-winds etc. you should never see 'Dutch-Roll' characteristics in normal flight. For what it's worth the 727 is the nicest handling of all the Boeings I have flown.

[stilton]

Right about that, although I do like the B767 I think the B727 is the best handling narrowbody ever made.



A real Pilots Aircraft, she flew like a dream :ok:

[MarkerInbound]

At first I was going to say if you're not doing .83 in the pattern it shouldn't be a problem. However, thinking about it, you've got a lot more lift and drag with flaps 30 (you're not going to see flaps 40 due to noise restrictions.) Plus you lose some yaw damping due to the nose being pitched up and blanking part of the vertical fin. So I don't know.

[con-pilot]

I took my type rating check ride in the aircraft, a -100. One of the tests was to recover from an induced Dutch roll. This was a long time ago so I cannot remember the airspeed and altitude where this section of the check ride took place. I think we were at FL 240 and at 300 Kts IAS, I think.

The FAA check airman was in the jump seat behind me and another FAA pilot was in the right seat. The pilot in the right seat turned off both yaw dampers and then induced the Dutch Roll, then just before he gave me control of the aircraft the check airman instructed me not to use the spoilers, but to use the flight controls.

Using the full aileron into the roll stopped the Dutch Roll, the yaw dampers were turned back on and the check ride continued.

I was more nervous about the full dirty stall than the Dutch Roll bit.

As some have said earlier, the 727 was a very nice flying aircraft and when light we used some really short runways, shortest I personally flew into and out of was 4,800 feet. Passenger load was only 15 people and we two hours of fuel on board on takeoff. I was actually more worried about sinking into the ramp/taxiway/runway. Oh, we could use flaps 40, which I did on that runway.

So, also as some one else already posted, to let a Dutch Roll develop into a serious condition, you'd have to be dead already.

And yes, if one or both yaw dampers were out, there were some very restrictive conditions one had to abide by. If I remember correctly, if you lost both in flight, the magic numbers were below FL 240 and 250 Kts IAS. But it has been a while since I flew the 72.

[Jane-DoH]

Old Fella,

If I recall, the 707's 35-degree sweep-angle figure was based at the 1/4-chord mark (I think it was around 37.5 at the leading-edge); the 727's 31.5 degree sweep-angle was based at the leading-edge as far as I know, with the sweep at the quarter-chord being 28.5.


trimotor,

Jane Doh: the 727 wasn't poor in terms of directional stability - just that the latreral stability was very strong. (courtesy, probably, of the amount of wing sweep).

Okay, I understand

[Vc10Tail]

Does the 727 wing dihedral additional to sweep have a combinatorial causal effect? Reduced aerodynamic damping at high altitude might also be influential I reckon.

What could cause a Dutch Roll apart from YD failure..Turbulence?

"Handling the Big Jets, D.P.Davis" has an exhaustive and best technical explaination of how to deal with Dutch Roll.It also explains series dampers and Roll dampers.

Does 727 suffer from significant Mach Tuck.Is there a Mach Trim indicator on the 727?

[Spooky 2]

It's been a long time but as I recall the roll rate on the 727 almost doubled with spoilers deployed and one-half deployment was where it was most noticeable. Not sure why deploying the spoilers would be the appropriate recovery maneuver?

[Old Boeing Driver]

Every training session on the 707 and the 727 had a dutch toll drill somewhere along the line.

The trick was to aggressively move the control wheel to the stops towards the wing that was coming up, then back to neutral (level) position.

As soon as the other wing started up, you did the same thing. It usually took 2 or 3 "slaps" as we called them to get the dutch roll stopped.

As I recall, they were called "slaps" because when you moved the control wheel hard one way or the other, it caused one of the spoilers on that side to "slap" up to assist the aileron"

Did many of them this way, and it worked.

[MarkerInbound]

The yaw damper is installed to prevent Dutch roll. So even in turbulence there should be no Dutch roll. There is no Mach trim in the 727. With a Mach limit of .90 I don't know what the critical Mach number is. And Mach tuck isn't much of a problem until you get close to critical Mach.

Been through many of the drills OBD mentions. I've seen them get out of hand if the pilot got out of sync with the ailerons. Like the old method of stall recovery (not losing altitude) it shows you can fly the plane. In the real world if you have a yaw damper failure you are going to have to slow down and go down so close the thrust levers, pull the boards and request a descent.

[Rick777]

As someone typed in the 707, 727, 747, and 75/767. I just have a couple of comments. I only ever did Dutch roll in the sim in the 727 and found it a difficult recovery. The 707s I flew had yaw dampers, but in the sim recovery seemed much easier. I also flew the KC135 for many years. It didn't have a yaw damper, but did have a rudder axis for the autopilot. Take offs and landings were of course autopilot off and it was always funny to watch new guys Dutch roll their way down final. We also had to be able to air refuel autopilot off.
As far as longer or shorter planes being more stable I vote for longer. The 747-100/200s that I flew were very stable. The SP was very much less so.
My favorite narrow body plane is the 757. Going out of Denver on a hot day in a fully loaded 727 was a little much for my old heart. No problem in a 757 though. Also never had to go full power in the flare to avoid planting it.

[Vc10Tail]

Was the 727 roll rate assisted by spoiler's as high as the 747? Any idea of magnitude? 10 degrees per sec? Was there a restriction to this maneuvre or could be applied at will? No slats or flaps I suppose!
Must have been a handy maneuver for traffic avoidance or Intial turn off the airways on emergency descent.I wonder what kind of g loading you impose during the high roll rate and if you encroach the load limits? Was it a recommended Boeing maneuver at all or more of test pilot and wanna be test jockeys? :)

It's been a long time but as I recall the roll rate on the 727 almost doubled with spoilers deployed and one-half deployment was where it was most noticeable. Not sure why deploying the spoilers would be the appropriate recovery maneuver?

[JammedStab]

Was the 727 roll rate assisted by spoiler's as high as the 747? Any idea of magnitude? 10 degrees per sec? Was there a restriction to this maneuvre or could be applied at will? No slats or flaps I suppose!


Personally, I found that the 727 with flaps extended had a much greater roll response rate on final compared to the 747.

On a turbulent approach in the 727, it was more like quick jabs of aileron to level the wings as all four ailerons and spoiler were operating. Perhaps the same was true of the 747 in terms of which controls were being operated with aileron input but I found it noticeably less roll responsive. There were several aircraft in between though so it is all based on memory.

[MarkerInbound]

Personally, I found that the 727 with flaps extended had a much greater roll response rate on final compared to the 747.

Went straight from the 727 to 744. I think it's mainly the difference in size and mass.

Must have been a handy maneuver for traffic avoidance or Intial turn off the airways on emergency descent. I wonder what kind of g loading you impose during the high roll rate and if you encroach the load limits? Was it a recommended Boeing maneuver at all or more of test pilot and wanna be test jockeys?

Can't use speed brakes with flaps extended on a 727. It's not really a handy maneuver at all. You think you have to turn. Then you realize you want to turn faster than normal. So you pull the boards. Now you're slowing down so you have to add thrust and pull the nose up if you're hand flying. Ok, now you can start turning. Versus just turning the plane. Why would there be any G load issues during a roll? The G load is a function of bank angle if you're holding a constant altitude and not roll rate.

[Rick777]

The 747 rolled ok once it got started, but there was nothing quick about it. Quick inputs of aileron like on a 727 do nothing at all.

[Vc10Tail]

Am not sure if there is or isnt a relationship between roll rate and g loading that's why am asking.I imagined higher roll rates impose more loads than low roll rates..better I review "Handling the Big Jets" again am sure I will get a precise Test Pilot answer.
As mentioned earlier other than spoileron "slaps" to bite off the otherwise divergent Dutch roll application of speed brakes was at how many units up?

Went straight from the 727 to 744. I think it's mainly the difference in size and mass.



Can't use speed brakes with flaps extended on a 727. It's not really a handy maneuver at all. You think you have to turn. Then you realize you want to turn faster than normal. So you pull the boards. Now you're slowing down so you have to add thrust and pull the nose up if you're hand flying. Ok, now you can start turning. Versus just turning the plane. Why would there be any G load issues during a roll? The G load is a function of bank angle if you're holding a constant altitude and not roll rate.

How does this bird behave on a x-wind final approach with both YDs off/unserviceable?

What the lowest hright Boeing limits the use of speed brakes if arriving hot on speed?

[Vc10Tail]

Part 1: Static Lateral Stability

The lateral motions in an aeroplane are of two types,assuming that the aeroplane posseses 'static stability' about the directional, or yaw axis ans has roll or 'dihedral stability'. Directional Stability addresses the tendency of the aeroplane to point into the oncoming airstream and is provided by the vertical fin.It is often referred to as "Dihedral Stability", since a wing dihedral angle provides the necessary restoring rolling moment.Dihedral (when wing tips higher than wing root..opposite to anhedral) effects on the rolling moment of a yawed wing.

Part 2 : Dynamic Lateral Stability (To be continued...)
Am not sure if there is or isnt a relationship between roll rate and g loading that's why am asking.I imagined higher roll rates impose more loads than low roll rates..better I review "Handling the Big Jets" again am sure I will get a precise Test Pilot answer.
As mentioned earlier other than spoileron "slaps" to bite off the otherwise divergent Dutch roll application of speed brakes was at how many units up?

[Vc10Tail]

(Continued...)

There are two types of possible lateral dynamic motion.The first is called the "Spiral Mode". If a spirally unstable airplane,through the action of a gust or othe disturbance,gets a small initial roll angle, a gentle side slip in the same direction of roll is produced if rolled tp the right...slideslip to the right hand side. If the dihedal stability is low,the directional stability keeps turning the airplane qhile the continuing bank angle maintains the side slip and yaw angle.As this process develops,the spiral gets tighter and steeper until finallt, if motion is unchecked, a steep, high-speed, spiral dive results! The motion develops so gradually,however, that it us usually corrected unconsciously by the handling pilot,who may not be aware that the spiral instability exists.A combination of high directional stability and low dihedral,or roll stability leads ti a spirally unstable aeroplane.

The second lateral motion is an oscillatory combined roll and yaw motion rederred to as the "Dutch Roll" ( coined to mimick drunken Dutch sailors landing on their next port of call afyer a long spell on rough seas I suspect). The Dutch Roll may be described as a yaw and roll to the right, followed by a recovery toward the equilibrium condition, then an overshootibg of this condition and a taw and roll to the left, thenafter back past the equilibrium attitude, and so on. The oscillatory period is usyally of the order of 3 to 5 seconds.Damping is increases by large directional stability and small dihedral and decreased by small dirwctional stability and large dihedral. Although usually stable in a normal airplane,the motion may be so slightly damped that the effect is very unpleasant and undesirable!

Swept wing aircraft have large digedral stability even when they have no dihedral angle.This is because, the effect if an angle of yaw is to increase the swewp back angle of onw wing panel and decrease it for the other side of the aeroplane. The change in sweep alters the effective dynamic pressure normal to the quarter-chord line of the wing panel, increasing the lift on one side of the wing,lowering it on the opposite side, and producing a restoring rolling moment. Nevertheless, many swept wing aeroplanes have a considerable dihedral angle, not for aerodynamic reasons bit to give adequate ground clearance for the wing tips and especially wing -mounted engine nacelles during take off and landing.These aircraft may then have too much dihedral effect for satisfactory Dutch Roll damping.The technical name for Dutch Roll is Oscilatory lateral stability. The problem is solved by installing a yaw damper YD.The Yaw Damper is in effect a special purpose autopilot that damps out any yawing oscillation by apying rudder corrections instantaneosly.Some swept wing aircraft demonstrate an unstable Dutch Roll mode.If the Dutch Roll is very lightly damped or unstable,the YD becomes a safety requirement rather than a pilot and passenger design convenience.Dual YDs are required and a failed YD is cause for limiting flight to lower altitude and lower Mach numbers.At high sltitude there is reduced aerodynamic damping due to high altitude low air density.At the lower altitudes Dutch Roll stability is improved.

Part 3 ...to be continued. "Turning performance".

[Vc10Tail]

Flight paths of aeroplanes are controlled primarily varying the magnitude and direction of tge lift vector and by varying the thrust or power contributed by the engines.The magnitude of the lift vector is a direct function of the angle of attack (alpha) or the lift co-efficient C^L.Alpha is controlled by pitching moment contributed by the horizontal tail, to achieve the desired C^L.Tail load is varied by changing elevator angle.
In a steady level flight Lift L= W Weight.When pitching up Lift will be greater at highet alphas and will exceed the weight.The ratio of the L/W is the LF Load Factor.Since weight is force due to gravity when L=W lift =1 g.If lift is 3 times the weight it means the aeroplane is subject to 3 g's.
A stable aeroplane adjusts its speed and flight path angle quite rapidly and subsequently settles down at the speed for which lift equals weight and at the flight path angle FPA for which forces are in climb or descent equilibrium as the case might be.The essence of the equilibrium is that the speed is determine by the L=W condition (i.e by C^L), and the FPA is determined by the thrust.Therefore speed is determined by the position of the elevators and the flight path angle by the throttle.

The Direction of the lift vector is perpendicular to the wing plane. The wing Angle if Bank ( theta) is controlled by aileron controls via their assymmetric deflection.The resultant Rolling Moment banks the aeroplane and tilts the lift vector to one side. The horizontal component of the Lift vector (L sin× theta) accelerates the plane laterally and curves the flight path. Its vertical component (L cos x theta) balances the weight-if sufficient in magnitude.In a turn if radius R, the lateral force,L sinx theta ( theta=bank angle), must balance the centrifugal force in the aero plane ( equal and opposite outward of the turn).For a level turn the weight must be equal to the vertical component if lift. For a 45 degree bank the Lift is 41% greater thsn the weight and the aeroplane is subjected to 1.41 g's.Therefore in a turn the stalling speed is increased and is one if the reasons fir maintaining a speed margin of 20% to 30$ above the level flight stall speed for takeiff and landing.This margin us required fir maneuvering that may become necessary to avoid an obstacle along the flight"s tragectory.
The turning performance of an aeroplane in level flight can be related to the rate of turning or "Roll rate".The radius of turn is reduced and the rate of turn is increased by INCREASING the LF.The design maneuvre LF is 2.5 for transport aircraft ,upto 3.8 for small G.A. aircraft, and upto 7 to 8 for combat aircraft! The minimum turn radius for a given speed is obtained eith a high CL max, high q ( dynamic pressure) and LOW wing loading.With a fixed speed q decreases with high altitude.So an aeroplane with a high C^L max and low wing loading ( which is a case for Boeing 727 wing ).When looking at the Maneuver V-n diagram, the "corner" velocity,i.e. fastest rate of turn is at the intersection of the C^L max curve and maximum velocity structural limits.

High speed aircraft often have wings that are sufficiently flexible so that aileron effectiveness is seriously reduced due to wing twist under load.The aileron lift at the rear if the outer panel may twist the wing to a lower angle of attack,which counteracts much of the aileron lift.In extreme cases ,the net effect may be even reversed ("aileron reversal") so that a positive aileron angle might actually reduce the outer panel wing lift.In such design (B727 in case),the outboard ailerons are utilized only during low speed regime, and high speed roll control us obtained by small inboard ailerons fir gentle maneuvres and by spoilers for HIGH RATES OF ROLL.

[MarkerInbound]

How does this bird behave on a x-wind final approach with both YDs off/unserviceable?

What the lowest hright Boeing limits the use of speed brakes if arriving hot on speed?

Never had a yaw damper failure in 13 years. Since Dutch roll is a high altitude high speed issue I wouldn't expect it to be an issue on approach. And Boeing has no limitation on minimum altitude for speed brake use. The only limitation is you can not have the boards up and flaps extended in flight.

In such design (B727 in case),the outboard ailerons are utilized only during low speed regime, and high speed roll control us obtained by small inboard ailerons fir gentle maneuvres and by spoilers for HIGH RATES OF ROLL.

The outboard flaps are unlocked as the flaps extend. Boeing figured if you are extending flaps you aren't going fast. There is a spoiler mixer in one of the wheelwells. As you turn the yoke past some point (I want to say 10 degrees but am not sure) it starts bringing up the down wing spoilers to increase the roll rate. It's not just a 727 thing, 737s and 747s all have spoiler mixers.

[Vc10Tail]

Yes observed the spoiler mixers on the other Boeing wings Marker Inbound.

That write up above was to relate to your query on relevance of load factor on Roll rates.

Never had a yaw damper failure in 13 years. Since Dutch roll is a high altitude high speed issue I wouldn't expect it to be an issue on approach. And Boeing has no limitation on minimum altitude for speed brake use. The only limitation is you can not have the boards up and flaps extended in flight.



The outboard flaps are unlocked as the flaps extend. Boeing figured if you are extending flaps you aren't going fast. There is a spoiler mixer in one of the wheelwells. As you turn the yoke past some point (I want to say 10 degrees but am not sure) it starts bringing up the down wing spoilers to increase the roll rate. It's not just a 727 thing, 737s and 747s all have spoiler mixers.

[MarkerInbound]

I'm not an engineer.

The turning performance of an aeroplane in level flight can be related to the rate of turning or "Roll rate".The radius of turn is reduced and the rate of turn is increased by INCREASING the LF

I normally think of turning as heading change or yaw and not roll. You can roll an airplane with no heading change and perform rolls with zero G load during the roll. Granted you won't finish at the same altitude you started at in most airplanes. Which is why I said there shouldn't be any increased G load during a faster roll. There is going to be some spanwise stress during a roll. The wingtip is being left behind during the roll with the outboard ailerons locked. The rolling force is created close to the fuselage which will put stress on the wing attach points. How much more is created during a faster roll I have no idea.