Turn initiation:Aileron or Rudder?

[Planechaser]

Flying the water run this morning got me thinking about this.

 

I was taught, by Jack Funnel for those who know him, to initiate a bank for a turn with the aileron. If he told my why not to use the rudder it never stuck; I just knew that you never did. Initiate with aileron and then balance with rudder, then lift it around.

 

Now this was fine until a mustering pilot taught me the other day to initiate with the rudder..... No adverse yaw of the nose before the turn, no nose up before the turn; slip it in, balance it up and then pull it around, practically with no aileron at all( which to read Stick and Rudder is the cardinal sin of a turn, leading to the end of the world as we know it!! His pet hate, I get the feeling.)

 

Strick and rudder holds that intiating with the rudder drops the nose and leads the unwary into a spiral dive. End of story. Don't do it. Ever!

 

The mustering pilot thought that at low level, many more pilots are killed through aileron stall leading to wing stall, than spiral dive.

 

At 500ft or less you are very aware of the ground and a nose down attitude, so to bank with your nose slightly down, building up speed is better than to bank flat or nose slightly up, especially if you are flying close to the stall point anyway.

 

You have less chance of stalling your wing if you don't stall the aileron. You have trouble stalling the aileron if you don't use the aileron!!

 

This made sense to me, and although I probably fly 6 of one and half a dozen of the other at the moment, I am acutly aware of that slight stall of the aileron to initiate a turn.

 

Airspeed building up in a tight turn is managable, airspeed washing off in a tight turn..........

 

I am inerested in others thoughts on this.

 

 

[pudestcon]

Well it may be that different techniques are used to suit the purpose i.e. ag operations at slow speed, high wing loading and high angles of bank. But for recreational purposes I'll stick with aileron 1st followed closely by as much rudder as is needed so no adverse yaw comes into play. I would suggest if there is a danger of aileron stall you are flying too close to the edge!

 

Pud

 

 

[eightyknots]

Flying the water run this morning got me thinking about this.I was taught, by Jack Funnel for those who know him, to initiate a bank for a turn with the aileron. If he told my why not to use the rudder it never stuck; I just knew that you never did. Initiate with aileron and then balance with rudder, then lift it around.

Now this was fine until a mustering pilot taught me the other day to initiate with the rudder..... No adverse yaw of the nose before the turn, no nose up before the turn; slip it in, balance it up and then pull it around, practically with no aileron at all( which to read Stick and Rudder is the cardinal sin of a turn, leading to the end of the world as we know it!! His pet hate, I get the feeling.)

 

Strick and rudder holds that intiating with the rudder drops the nose and leads the unwary into a spiral dive. End of story. Don't do it. Ever!

 

The mustering pilot thought that at low level, many more pilots are killed through aileron stall leading to wing stall, than spiral dive.

 

At 500ft or less you are very aware of the ground and a nose down attitude, so to bank with your nose slightly down, building up speed is better than to bank flat or nose slightly up, especially if you are flying close to the stall point anyway.

 

You have less chance of stalling your wing if you don't stall the aileron. You have trouble stalling the aileron if you don't use the aileron!!

 

This made sense to me, and although I probably fly 6 of one and half a dozen of the other at the moment, I am acutly aware of that slight stall of the aileron to initiate a turn.

 

Airspeed building up in a tight turn is managable, airspeed washing off in a tight turn..........

 

I am inerested in others thoughts on this.

From what I remember, the author of Stick and Rudder wanted to see the end of rudders altogether. He was almost wishing them away when he predicted in the 1940s, when the book was written, that before long there would no longer be rudder pedals fitted to aeroplanes. Instead, his forecast was that the rudder would be automatically operated via a linkage from the aileron. Yes, he definitely favoured aileron initiated turns.

 

 

 

[Spin]

My feeling is that; as with so much else aviation related, the answer isn't either or but both, - as you become more experienced and familiar with a given aircraft, you feed in whatever controls are necessary to achieve your aims, anticipating the secondary effects you will either use or have to overcome. The answer is closer to one extreme or other depending on the aircraft too, I recall that Tiger Moths are described as requiring the rudder to lead the way into a turn and the Drifter is a bit that way too.

 

 

[Guest ozzie]

I have found that it has a lot to do with the design of the aircraft. The more diheadral and washout seems to require more initial rudder to start the turn. The Thruster and it's earlier cousins were all rudder aircraft.

 

 

[farri]

I am inerested in others thoughts on this.

Though all aircraft obey the same laws of physics, not all aircraft perform equally!... What may work well in one aircraft may end in disaster in another!

 

Turns can be done in several numbers of ways!... The technique used to achieve the desired result, depends on several factors!...The ability and skill of the pilot, The type of aircraft being flown, The atmospheric conditions it`s being flown in and The intended maneuver to be performed!

 

Due to the nature of the operation, mustering requires an advanced level of skill and shouldn`t be placed in the same catogary as recreational flying!...It would be foolish and dangerous for the every day recreational pilot to do what mustering pilots do!!!

 

Frank.

 

Ps, I have a bag full of tools, for doing my turns!!!!

 

 

[pudestcon]

Ps, I have a bag full of tools, for doing my turns!!!!

Such as an open ender, ring spanner, tension wrench, and don't forget the adjustable set spanner!!

 

Oops nearly forgot - add to that my favourite, the "Johnson Spanner"

 

Pud

 

 

[Guest rocketdriver]

Hi Planechaser .. I'm with Pud on this .... I believe that you use the primary controls for their primary effect .... Apologies if this is old hat, as I suspect that it is for you and many others, but some of our lower time members might find this useful?

 

Control Primary effect Secondary effect

 

Rudder Yaw Roll

 

Aileron Roll Yaw

 

Elevator Pitch None

 

The rudder controls which way the nose points (yaw), not the direction of flight. Angle of bank controls the rate of turn. (Ask your instructor to demonstrate this if unsure).

 

1. Hold the wings level with aileron and apply rudder. The nose swings off to one side and then the a/c continues on in much the same direction as before. Note that if, instead of holding the wings level, you hold the stick central, the wing dihedral will cause the aircraft to adopt a bank angle in the same direction as the yaw (the secondary effect of the rudder), and then it will commence to turn due to the bank angle ........

 

2. Hold the rudder central and apply a little bank with the ailerons, holding the angle at no more than 15 or 20 degrees. The nose may or may not (dependant on design features) initially swing off in a direction opposite to the turn. Then you will notice that the nose drops a little due to sideslip exerting pressure on the fin which creates a yaw into the direction of the turn (the secondary effect of the ailerons) before everything settles down to a gentle turn.

 

In some aircraft (and soaring sailplanes are notorious for this) applying the ailerons alone causes the nose to make a major deviation in the wrong direction ..... adverse yaw .....due to the excessive drag of the down going aileron and the fact that gliders (and ag planes?) are often flying very close to their stall speed. It was often said that you needed to "lead with the rudder". In fact, you added pounds of rudder in same direction as the stick (the direction of the turn or roll out manoevre) simultaneously with every ounce of aileron applied (well, thats what it felt like!), and then, as you centralised the stick or even held off the bank little bit, the rudder came off too .... .

 

The idea of course is to keep the ball (or yaw string for a glider) central whilst turning ...... Primary controls for primary effect ...... works every time in my book!

 

 

[Guest Maj Millard]

I'm for aileron first, closly followed by rudder as required.

 

Let it be remembered that many fatal fixed-wing aircraft accidents whilst mustering, are in aircraft that were never really designed for what they are put through IE: low speed, flapped turns in hot gusty conditions, with insufficient height for recovery from sudden wing drops. (Cessna 150-172 types) Add to that an exhausted tired pilot who has been at it since sun-up with many hours in the saddle, and you have an excellent recipe for disaster.

 

There are some aircraft types that like a bit of rudder first, but they are more the exception than the rule.

 

One memorable example for me was my very first takeoff in the Lazair, with it's beautifull 36 Ft span tapered wing. There was a lot to deal with, First twin-engine flight, first inverted V tail aircraft, with the control stick hanging vertical from overhead !...plus two 185cc 2-stroke engines providing only a total of 18 Hp, so everything needed to keep running..thank you very much !!.

 

The aircraft levitated after a rediculously short run, and I commenced a steady climb- out with both engines singing well.

 

At about 400ft I threw in some left aileron to turn crosswind,...and it turned promptly to the right !!....what the !!....I stomped on some left rudder and around she went beautifully as the lazair can. Even though the aircraft has well balanced differential ailerons, the long wings induced a lot of adverse yaw, and the rudder was needed to counteract it...................................Maj...

 

 

[Planechaser]

Hi Planechaser .. I'm with Pud on this .... I believe that you use the primary controls for their primary effect .... Apologies if this is old hat, as I suspect that it is for you and many others, but some of our lower time members might find this useful?Control Primary effect Secondary effect

 

Rudder Yaw Roll

 

Aileron Roll Yaw

 

Elevator Pitch None

 

The rudder controls which way the nose points (yaw), not the direction of flight. Angle of bank controls the rate of turn. (Ask your instructor to demonstrate this if unsure).

 

1. Hold the wings level with aileron and apply rudder. The nose swings off to one side and then the a/c continues on in much the same direction as before. Note that if, instead of holding the wings level, you hold the stick central, the wing dihedral will cause the aircraft to adopt a bank angle in the same direction as the yaw (the secondary effect of the rudder), and then it will commence to turn due to the bank angle ........

 

2. Hold the rudder central and apply a little bank with the ailerons, holding the angle at no more than 15 or 20 degrees. The nose may or may not (dependant on design features) initially swing off in a direction opposite to the turn. Then you will notice that the nose drops a little due to sideslip exerting pressure on the fin which creates a yaw into the direction of the turn (the secondary effect of the ailerons) before everything settles down to a gentle turn.

 

In some aircraft (and soaring sailplanes are notorious for this) applying the ailerons alone causes the nose to make a major deviation in the wrong direction ..... adverse yaw .....due to the excessive drag of the down going aileron and the fact that gliders (and ag planes?) are often flying very close to their stall speed. It was often said that you needed to "lead with the rudder". In fact, you added pounds of rudder in same direction as the stick (the direction of the turn or roll out manoevre) simultaneously with every ounce of aileron applied (well, thats what it felt like!), and then, as you centralised the stick or even held off the bank little bit, the rudder came off too .... .

 

The idea of course is to keep the ball (or yaw string for a glider) central whilst turning ...... Primary controls for primary effect ...... works every time in my book!

Don't know about only for low hour guys, RD. Old hat is what keeps us alive!! I am always up for a lesson.

Something about old pilots and bold pilots....?

 

The harder you are pushing it the more this applies in my opinion.

 

 

[eightyknots]

One memorable example for me was my very first takeoff in the Lazair, with it's beautifull 36 Ft span tapered wing. There was a lot to deal with, First twin-engine flight, first inverted V tail aircraft, with the control stick hanging vertical from overhead !...plus two 185cc 2-stroke engines providing only a total of 18 Hp, so everything needed to keep running..thank you very much !!.

The aircraft levitated after a rediculously short run, and I commenced a steady climb- out with both engines singing well.

 

At about 400ft I threw in some left aileron to turn crosswind,...and it turned promptly to the right !!....what the !!....I stomped on some left rudder and around she went beautifully as the lazair can. Even though the aircraft has well balanced differential ailerons, the long wings induced a lot of adverse yaw, and the rudder was needed to counteract it...................................Maj...

That Lazair sounds like one interesting aircraft to fly, Maj:ecstatic:

 

 

[foxy]

ok...my take on it all.......you can clearly see from the primary and secondary effects that rudder and aileron go hand in hand...Spin has it spot on. Aileron and rudder should be used co-ordinated with each other....once the turn is initiated with both, the aircraft is established in the turn, and you'll find the controls (control column and rudder) will be in the neutral position. If you are conducting a 'level' turn, the nose of the aircraft shouldn't change pitch at all. The nose is in its level attitude, horizon in that sweet spot in the windscreen.....even in a turn, you keep it there.....you are only baking the wings, and balancing the turn...the horizon should just be tilted in the windscreen.

 

all aircraft are different, yes, but rudder and aileron should still be co-ordinated.....use them together and they counter their own secondary's.

 

 

[Kenchhidu]

In my grand knowledgable experience(0.8 hrs on two TIF's) I was told to lead with the rudder. The CFI I'm about to start training with went as far as showing me a 'hands off' turn, as a demonstration, where he rolled the wings with rudders secondary effect, conducted a balanced turn, then rolled out with rudder. I know this isn't the way to turn but showed the power and importance of the rudder. Also, isn't the secondary effect of the elevator to change the airspeed? Or is that not classed as 'secondary effect'

 

 

[Kenchhidu]

What's scary about teaching effects of controls???.......................

 

 

[Tomo]

In high drag slow ultralights you often need a lot of rudder with aileron input. I usually apply them at the same time to stop yaw, a good way to practice it and get to know is to roll the aircraft on it's nose back and forth. And see just how much rudder you need!

 

Aircraft like the Cessna you could almost get away with no rudder altogether! (no not really) but compared to high drag ultralights. The Frise ailerons help with that.

 

I'm a do what you need to person, as no size fits all when it comes to different aircraft I've found. Typically aileron with rudder following, or at the same time. The only time you should use rudder to roll is if you are stalled in my opinion!

 

 

[foxy]

correct cfi......the nose does pitch in a turn...the whole point is that its the pilots job to stop it from pitching out of the level attitude!! and also hence using rudder and aileron together stopping the yaw in opposite direction..;)

 

 

[Guest Maj Millard]

Eightyknots, yes the Lazair was one of those flying machines that you can never forget, I was lucky enought to get about 35 hrs in the one I flew.Ozzie still has one tucked away, lucky barstxxx..............................................Maj...

 

 

[Bryon]

I was taught this:

 

Imagine two sticks.One end of each stick attached to the control column, the other end of each stick attached to the corresponding rudder pedal

 

As you moved the control column to the left, the left rudder moved forward, as you moved the control column to the right, the right rudder pedal moved forward

 

Automatic coordinated turns

 

That is how to do it.....

 

One does not follow the other, they both move together

 

It is like marriage, practice makes perfect

 

 

[Planechaser]

Then the mustering blokes tell you that the next level up is not the level turn, which we all practiced to the point of tears.("you dropped 10 ft. You rose 5ft. Keep it level!!") but the decending turn, which is the safty net for low AND slow. Like the man says, low is fine, and slow is fine, but low and slow is another animal entirely.

 

I was very proud of my level turns, and he just looks over at me with a look like" If it's a bit dicey mate, try that in the wrong setting and you're dead!"

 

Like farri said, mustering is a different level of skill altogether, requiring a slightly different bag of tools!!

 

 

[Spin]

Nicely put Byron, co-ordinated control inputs are the key i.m.o. This is the power vs attitude debate for approaches revisited, with people tending to revert to whatever was drummed into them (literally sometimes) by their original instructors. I'm afraid I get a bit narked when lesson 6 "Effects of controls" patter gets trotted out as the final word on the subject with the suggestion that any deviation is akin to heresy and will render us unfit for the company of "real" pilots. Quite funny in light of the fact that the "lead with rudder in Tiger Moths" conversation was with a grizzled RAF veteran, who had flown everything from Tigers to Lancasters and gone on to amass an astonishing number of hours on Viscounts and similar. Instructing on Tigers, RAF and civilian accounted for a fair chunk of his log book hours incidentally.

 

 

[Guest rocketdriver]

Hi Foxy

 

If you are turning with the same speed as you were when you were flying s & l, than you MUST increase the Angle of attack. Why? Because part of the lift that was countreacting weight and so keeping the a/c level is now employed in turning the aircraft .... so the total lift has to increase in order to hold the aircraft in level flight AND turn in the desired direction ..... The effect is slight at angles of bank below about 15 degrees and progressively more noticeable as bank angle increases until at 60 degrees bank, you need twice as much lift force than that for straight and level .... a 2G turn ......

 

Cheers

 

RD

 

 

[Guest ozzie]

That Lazair sounds like one interesting aircraft to fly, Maj:ecstatic:

Met a guy who is CAD drawing the Lazair and is talking with Dale about bringing it back into production.

Would not hold your breath tho. Sounds like it may be a while.

 

I have yet to find an aircraft that is as enjoyable as the Lazair to fly. I consider myself very privileged to have been involved with it.

 

There were a lot of dissapointed people at Airventure when they found out the Lazair had been out of production for 20 odd years. it seems the design will never be out dated.

 

Ozzie

 

 

[Tomo]

Aileron and rudder should be used co-ordinated with each other....once the turn is initiated with both, the aircraft is established in the turn, and you'll find the controls (control column and rudder) will be in the neutral position.

I think where the confusion is, is about the controls in the neutral position... elevator may or may not be in the neutral position in a turn, normally not for a level turn as you need to increase AoA.

 

 

[Tomo]

However in steep turns close to the stall with high power output engines you may need a little bit of rudder to counteract the rotating propeller thrust effect. (Not something ultralighters need worry about)

Indeed, something I was going to mention but didn't want to muddy the waters! Anyway now you've got me started...

 

Full power and steep turn in a pusher engine aircraft you need to use rudder one way or the other to stay balanced. I know in a Drifter at full steam and right hand steep turn you'll need top rudder or you'll be pointing at the ground.

 

 

[foxy]

guys...i am aware that angle of attack is increased to maintain lift in a turn...if you read my last post, i did actually state that...and also said that the whole point was that its the pilots job to keep it level in a level turn....hence the pilot's job is to increase the A of A to do that.....the post was about rudder and aileron being used co-ordinated....thats the point that is trying to be conveyed......rudder and aileron used together.....not one followed by the other...