Is adverse yaw well modeled in P3D?

[CFIJose 5,485]

17 minutes ago, Raging Bull said:

 

Well, having flown some real aircraft around the skies never using or ‘needing’ rudder, it’s wasn’t necessary. (C152 i recall and a Piper warrior on occasions). 

Perhaps it wasn’t totally ‘coordinated’ in the turn, but barely (or not) noticeable anyway. I never looked to be honest at the turn and slip indicator. Most light aircraft turns are not that sharp so never really need it.  

I’m guessing if multiple intructors never taught me to use it wasn’t necessary. 

Just because you did not use it, did not notice it, or were not taught by multiple instructors, it doesn't mean it's not necessary.

The rudder is there for a reason and it's to correct for adverse yaw.

[Raging Bull 23]

9 minutes ago, DJJose said:

Just because you did not use it, did not notice it, or were not taught by multiple instructors, it doesn't mean it's not necessary.

The rudder is there for a reason and it's to correct for adverse yaw.

If there IS a lot (or any) adverse yaw. Not always a lot in some airplanes. 

I managed to land it, so that’s the main thing. 🙂

[Bobsk8 12,543]

3 hours ago, tttocs said:

The OP referenced a 30 degree turn.

Scott

I have 100's of hours in a 172, and a 30 degree level turn requires almost no if any rudder. 

[Chock 17,769]

As some others have pointed out, a lot depends on the actual aeroplane you fly in the sim, and by that I mean two things, first, the type and how its wings are configured, and second, who the simulation of it has been made by, because all sim aeroplanes are certainly not equal in terms of their quality.

Adverse yaw happens for a lot of reasons as you probably know, the most obvious ones being: the initial increase in lift as you input aileron increases the induced drag; the decreasing angle of attack of the upgoing wing and the opposite effect on the downgoing wing shifts the centre of lift of each wing, and more profile drag with the increased camber of upgoing wing the reverse of this on the other wing.

All of these things are often amplified by a longer wingspan, since the effect will induce more leverage when it is further out on a long wing; this is why it is very often a noticeable feature of gliders, since they tend to have rather long wings. There are of course other things which affect whether a wing will be susceptible to adverse yaw, and indeed things which can be done to mitigate it too in terms of design, so don't be too surprised to find it isn't necessarily a noticeable effect on an aircraft where you might reasonably expect it to be present.

Leslie George Frise, designer of things such as the Bristol Beaufighter and the Jet Provost, designed the Frise Aileron in the 1930s, which projects out from the wing a bit when deflected up specifically to increase the drag of the downgoing wing in order to reduce adverse yaw (see many mid-1930s onwards aeroplanes). Before that showed up, many aeroplanes had balance horns incorporated into the design of their ailerons in an attempt to achieve the same thing (see many WW1 biplanes), as well as to reduce control forces at speed. If you see these on an aeroplane, you know that an attempt has been made to do something about adverse yaw. On modern airliners, jet fighters, and more sophisticated GA aeroplanes, you might also see them deploy spoilers on the downgoing wing in a roll, to increase its drag a little.

Most glider pilots know that you really do have to give the majority of gliders a really serious bootful of rudder to initiate a turn, for two reasons really; one is that adverse yaw tendency and the other is that there is no propwash acting on the tailplane to make the rudder more effective. In gliding, this is especially the case when you feel a wing tip up as you touch the edge of a thermal and so immediately want to turn into that thermal. It's not uncommon to bank gliders over at very steep angles in order to stay in a thermal, so counteracting adverse yaw quickly is something glider pilots get used to, but it is something they have to watch out for when they get into something like a Cessna and modify their habit accordingly, so it is worth bearing in mind that speed and rudder input/technique will have a bearing on whether you experience adverse yaw. Be careful though; whilst it is fine to be shoving your boot down to the floor in a glider which is floating along at 40 knots, if you do that up near its Vne, you risk over-stressing the tail, and that's true for any other aeroplane too, so watch those V speeds with that rudder!

So how do you know if adverse yaw has been replicated, or even if it would be present at all on the real version of your sim aeroplane? Well, there is a test you can do to find out if your sim aeroplane is something sophisticated, or perhaps not, in terms of how it has been flight modeled, and that is to try a sideslip in it. You will certainly find that the ones which can do a convincing sideslip will generally be the ones with a more sophisticated flight model in all areas, whereas the ones which continue to maintain altitude even when you get them virtually sideways, are not really behaving as a real aeroplane would and are unlikely to be portraying other flight behaviour as well as they could do. If you want to see that in action, here is a little video which ably demonstrates what I mean...

Watch as I sideslip the A2A Piper Commanche in from a too high approach, and then see how the Carenado Beech Bonanza does with the same attempt to sideslip in from the same position. No prizes for guessing why A2A add-on cost more than Carenado ones after watching this comparison. The A2A aeroplane replicates a genuine sideslip, the Carenado one doesn't do so at all. This is the sort of thing you are paying for with a more expensive add-on:

 

[FDEdev 955]

If you want to experience adverse yaw you should try the Alabeo DA42 or the Carenado DA62. With the long span wings there's, like on gliders, quite a bit of rudder required when starting/stopping a turn.

In the various YouTube reviews you will see that even RW pilots/IPs tend to totally ignore the required rudder input and let these two planes awfully slip through the turns.   

[FDEdev 955]

2 hours ago, Chock said:

Watch as I sideslip the A2A Piper Commanche in from a too high approach, and then see how the Carenado Beech Bonanza does with the same attempt to sideslip in from the same position. No prizes for guessing why A2A add-on cost more than Carenado ones after watching this comparison. The A2A aeroplane replicates a genuine sideslip, the Carenado one doesn't do so at all. This is the sort of thing you are paying for with a more expensive add-on:

Oh well, Chocks usual unqualified Carenado FDE bashing.  Why are you comparing a Beechcraft Bonanza with a Piper Commanche? Do you know that the slip the same way IRL?

If you are unable to slip the default A36 and/or you don't notice a difference in the ROD, it's definitely not the airplanes fault. 

Btw, it was funny to watch how you tried to force the A36 to side slip the way you wanted, instead of doing it the way to airplane would require it. But in both cases you never achieved a stable slip, it was simply an uncontrolled wallowing through the sky (followed by a really bad off center 'arrival' in the Commanche).

 

 

 

Edited October 30, 2018 by FDEdev

[FDEdev 955]

6 hours ago, DavidP said:

I think you'll find in types such as the 172 that most of the rudder is to do with engine torque. Demonstrating adverse yaw in these types, while not difficult, meant aggressively rolling the aircraft left and right and eventually you could see some sort of effect. The amount of rudder input needed on these types is often overstated by simmers.

Good point. Adverse yaw depends a lot on the speed of the aileron application and how much aileron you apply.  If you are slowly, autopilot like, rolling into a 20° banked turn with only a slight aileron deflection you will only notice (if any) very little adverse yaw.

If you rapidly slam the yoke to it's limit on the other hand you will definitely notice the adverse yaw, even in a 172.  

[portanav 12]

7 hours ago, DavidP said:

I think you'll find in types such as the 172 that most of the rudder is to do with engine torque. Demonstrating adverse yaw in these types, while not difficult, meant aggressively rolling the aircraft left and right and eventually you could see some sort of effect. The amount of rudder input needed on these types is often overstated by simmers.

 

Tail draggers, of course, are different beasts.

Torque only affects an aircraft during takeoff, as it applies more weight (thus drag) to the left main (on american made aircraft). Torque has no effect on an aircraft in flight; the only effect coming from the engine input in flight comes indirectly from the propeller's slipstream, producing a yaw to the left and this is normally overcome (neutralized) by the fixed trim tab found on the rudder (of all Cessna and Piper aircraft) and factory set (for cruise speed). So in a turn (of more the 30 degrees bank) where more power is needed to maintain cruise speed, the slipstream effect will be added to the adverse yaw. Even if their was no adverse yaw (due to differential ailerons) you will still have to apply some rudder in the turn one way or the other. A turn to the left will now cause slipping into the turn because of too much yaw as the slipstream effect plays it's part once again, requiring rudder input in the opposite direction of the turn, though negligible at times (theory wise that is).

So in short, rudder is always needed during a turn once power beyond the cruise setting is required to maintain the cruise speed.

Even on more advanced aircraft like the B737, some rudder input (very little by the yaw damper) is used in the turn at times.

Edited October 30, 2018 by portanav

[Chock 17,769]

1 hour ago, FDEdev said:

Oh well, Chocks usual unqualified Carenado FDE bashing.  Why are you comparing a Beechcraft Bonanza with a Piper Commanche? Do you know that the slip the same way IRL?

If you are unable to slip the default A36 and/or you don't notice a difference in the ROD, it's definitely not the airplanes fault. 

Btw, it was funny to watch how you tried to force the A36 to side slip the way you wanted, instead of doing it the way to airplane would require it.

 

If you read the comments in relation to that clip, you would notice I am not suggesting a Commanche and a Bonanza handle exactly the same, they just happened to be two single-engined GA aeroplanes of approximately the same three-axis control configuration I had installed in my sim which served the purpose of demonstrating that a better flight model is likely to better simulate an aspect of flight. In this case a slip, and as such, indicate that attention to detail has been paid in creating said flight model.

And for your information, I also considered using an Alabeo Tomahawk to make the comparison, and that too, is not the same as a Commanche, but it would have sufficed just as well for the point of the video, which was not to compare aeroplanes but to compare one maneuver in two aeroplanes and how their capability to perform it convincingly has or has not been simulated by their flight modeling.

If you are seriously suggesting that comments about Carenado's very well known lack of attention to detail in many respects, are in any way limited to me alone pointing them out, then you really are not paying much attention. Many other people have also commented on this. Regularly. So feel free to direct your frequent attacks at them too on occasion, instead of constantly having a go at me (and yes, I have noticed that you do this).

All aircraft, from a Tiger Moth to a Boeing 747, use the same control inputs to perform a slip, i.e. opposite aileron and rudder, not necessarily to the same degree it is true, but this is something which will occur when you feed those inputs in and it is of necessity when performing a slip, a requirement to feel around a bit for the best deflection, but it most definitely will be there. The fact that the Carenado aeroplane literally does not do a slip, instead requiring you to stick it in a dive and hope the flaps and gear will hold the speed down should be apparent from the video comparison. It's got nothing to do with not finding the correct inputs to make it simulate a slip properly, it just doesn't simulate one in even a remotely convincing manner.

Now it's certainly not the only add on aeroplane to be guilty of that by any stretch of the imagination, but it does, in this instance, serve to demonstrate how very much better the flight modeling of an A2A aeroplane is in that regard, and this is the point I was making to the O/P, that in searching for an aeroplane for the simulator which has the nuances there along with the basic controls, that is where the admittedly pricier stuff from A2A starts to justify costing a bit more.

Edited October 30, 2018 by Chock

[portanav 12]

Please note, there is a difference between slipping and skidding. Skidding like with a car is outside of the turn, slipping is (skidding) into the turn or towards the center of the turn. The term "side-slipping" is experienced only during descent in an uncoordinated turn or deliberately by the pilot on approach (using cross-controls) to increase the aircraft's rate of descent. The latter used commonly in flapless aircraft.

[Simicro 247]

Hi all,

Many thanks for your overwhelming participation. I fly the A2A C172 and always have autorudder OFF.
 

Quote

 

tttocs: I have a few hundred hours grinding through the sky in a variety of 172s.  If you're suggesting that the ball will stay centered in a 30 degree banked turn without rudder input, I guess we'll have to agree to disagree.

Bobsk8: I have 100's of hours in a 172, and a 30 degree level turn requires almost no if any rudder.

DavidP: Don't forget that 172's etc have differential ailerons that offset any adverse yaw. Most modern aircraft aren't affected significantly compared to older types such as Austers etc.

DJJose: I find that in the A2A 172 is well modeled. Not only will you need right ruder (right turn) to maintain coordinated.

 

 

So it is not clear (yet) to me if the real C172 (maybe there are many models) needs rudder or not in a 30 degree banked turn.

I think it does. So why is it that I apply NO rudder in the A2A and the ball is centered?

 

Quote

FDEdev: If you want to experience adverse yaw you should try the Alabeo DA42 or the Carenado DA62.

 

Thanks for the suggestion, I did not think about that. I would rather wait for the DA62 by Vertex.

 

[skelsey 765]

As others have alluded, something which needs to be considered when it comes to books like 'Stick and Rudder' is that it was written in 1944 when aeroplanes were made of sticks and fabric. As a result, whilst the basic physics are unchanged, aircraft design has moved on quite a bit since Langewiesche's day and as a result some of the handling 'qualities' (or otherwise!) and techniques applicable to aircraft that Langewiesche was familiar with are not always relevant to more modern aircraft.

Adverse aileron yaw in particular is one of these areas, with the development of things like differential Frise ailerons which are very effective at minimising the adverse yaw experienced when deflecting the ailerons.

The C172 is a very stable aeroplane with mostly benign handling qualities. As others have discussed, the vast majority of adverse yaw is experienced when the ailerons are deflected to roll in to (and out of) the turn, and this is where co-ordinated use of rudder is necessary to maintain balance. The amount of rudder required is highly dependent on the amount of deflection and the speed with which the aileron is applied (so a fast, large deflection will result in a much greater out of balance condition than a small, smooth one).

Once the required bank angle is reached and the turn is established, the ailerons are neutralised and the rudder pressure required is very much reduced (the amount required will depend on design factors affecting the directional stability of the aircraft -- most aircraft left to their own devices will tend to 'slip' in to the turn (toward the 'down' wing), but this sideslip will cause airflow to strike the 'down' side of the fuselage and fin, and if the fin is well-designed and the bank angle appropriate this will naturally provide a yaw in to the turn which may well be sufficient to negate the need for much if any rudder at this point - further, in a level or climbing turn a small amount of opposite aileron may be required to 'hold off' bank and this opposite deflection will further aid the yaw in to the turn).

When rolling out of the turn the ailerons are obviously deflected in the opposite direction and again this is where co-ordinated rudder pressure will generally be required to balance the roll-out. Again, the amount of rudder required will depend upon the speed and magnitude of the aileron deflection.

The modern three-axis microlights I've flown most recently IRL require only the very tiniest amount of rudder pressure when rolling in or out of medium turns and you could quite easily get away with keeping your feet on the floor if you are gentle and not a perfectionist!

What happens to the ball when you roll in or out of the turn, particularly if you use large/rapid aileron deflections?

As others have also mentioned, another major use of the rudder is to balance the yawing tendency due to slipstream when changing power settings -- in general a power increase will require co-ordinated right rudder pressure whereas a power reduction will require co-ordinated left rudder pressure.

[FDEdev 955]

1 hour ago, Chock said:

If you are seriously suggesting that comments about Carenado's very well known lack of attention to detail in many respects, are in any way limited to me alone pointing them out, then you really are not paying much attention. Many other people have also commented on this. Regularly. So feel free to direct your frequent attacks at them too on occasion, instead of constantly having a go at me (and yes, I have noticed that you do this).

Now it's certainly not the only add on aeroplane to be guilty of that by any stretch of the imagination, but it does, in this instance, serve to demonstrate how very much better the flight modeling of an A2A aeroplane is in that regard, and this is the point I was making to the O/P, that in searching for an aeroplane for the simulator which has the nuances there along with the basic controls, that is where the admittedly pricier stuff from A2A starts to justify costing a bit more.

You apparently didn't read (or understand) what I wrote. It's exclusively about their FDEs, nothing else. There's a simple reason why it is you how gets most of my replies if it's about aerodynamics/FDEs. You are admittedly a master of copy & paste but with a serious lack of understanding about basic aerodynamics and FDEs.

Most of the time, like in this (and many other) threads, you have simply wrong expectations and you are drawing wrong conclusions due to your lack of knowledge and/or experience.

Judging an FDE simply by how much they react to an aileron and opposite rudder input makes little sense, especially if you haven't flown any of the airplanes mentioned IRL.

The A36 does react to cross controlled input like any other airplane. The question of how much it should react can only be answered by doing tests with the real airplane and/or Pireps.

Their very old C185 (with the ultimate FDE) slips exactly like the real one, with the identical required rudder and aileron input, simply because four RW C185 pilot provided the necessary info.

If you want to experience a very high quality GA FDE you should try the Alabeo C177B. This FDE has been designed by using a very detailed NASA test, where they fitted a 177B with AoA, side slip vanes and a weathervaning pitot-static tube. This resulted in a much more precise and detailed test flight report than usually possible.  

Stating that Carenado/Alabeo airplanes generally have bad or 'cheap' FDEs is plain and simple not true.

 

[CFIJose 5,485]

2 hours ago, Simicro said:

Hi all,

So it is not clear (yet) to me if the real C172 (maybe there are many models) needs rudder or not in a 30 degree banked turn.

I think it does. So why is it that I apply NO rudder in the A2A and the ball is centered?

 

Ask Scott at the A2A forums. He would certainly know.

As someone with more than 200 hours as a CFI in 172s (both fuel injected & carb) I find  the A2A version of the 172 to be as good as it gets for practicing the four fundamentals of flight & private pilot maneuvers. I've said this before and it is worth mentioning again, using the sim will never be like flying IRL.

Pat yourself on the back for at least making a conscious effort to fly coordinated in your flight simulator.

[Bobsk8 12,543]

2 hours ago, DJJose said:

Ask Scott at the A2A forums. He would certainly know.

As someone with more than 200 hours as a CFI in 172s (both fuel injected & carb) I find  the A2A version of the 172 to be as good as it gets for practicing the four fundamentals of flight & private pilot maneuvers. I've said this before and it is worth mentioning again, using the sim will never be like flying IRL.

Pat yourself on the back for at least making a conscious effort to fly coordinated in your flight simulator.

It's amazing the number of people that have no real experience in piloting an aircraft in real life, willing to tell us how one should really be controlled. Nice to see a CFI tell it like it is.