Is adverse yaw well modeled in P3D?

[snglecoil 1,828]

12 hours ago, Delta558 said:

Adverse aileron yaw is caused in the main by deflection of the ailerons (no surprises there!) and the effect that has on the shape of the wing / airflow over said wing. If you are in a balanced turn of any angle, once you have centred the stick you are just flying through the air so will also pretty much centre the rudder because the removal of the aileron deflection removes the requirement for rudder. There are still aerodynamic reasons for the use of rudder whilst in a banked turn, but the actual adverse aileron yaw is removed the instant the stick is returned to centre in a lateral sense.

^^^ This is absolutely correct. Any airfoil producing lift also produces induced drag as a result. As you initiate a roll to the right, your ailerons are configured to add lift (and corresponding drag) to the left wing, while decreasing lift and drag on the right wing. The differential in drag creates causes the nose to yaw to the outside of the turn...left in this case. As Delta558, points out. once the desired bank angle has been reached, the ailerons are neutralized and the primary cause of adverse yaw has been removed. Once established, a level turn requires only very slight adjustments to the rudder to maintain coordination. 

Now, how well this is modeled in the A2A 172, I don't know. I'll have to go back and try it out myself!

 

[Chock 17,769]

9 hours ago, portanav said:

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.

Yup, that's true, I'm not comparing or confusing the two, I merely used a demonstration of slip to point out that the vast majority of flight sim add-ons do not demonstrate the ability to simulate quite a few manuevers as convincingsimulations of their real-world counterparts, among these, stalls, spins and slips. The point being that if you find one which does some of this stuff correctly, there's a good chance it's flight model will be somewhat more detailed or accurate and therefore it is more likely to include things such as an accurate portrayal of adverse yaw.

[mpw8679 428]

7 hours ago, Bobsk8 said:

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. 

Its also amazing the number of pilots that should have no business piloting an aircraft in real life.  No disrespect to u or your piloting skills just saying.  It does not take real world experience to understand the basic controls of an aircraft and how to apply them.  This should be understood before even taking control of a real airplane.

[Simicro 247]

DJJose, Bobsk8: sorry I wrote something that did not exactly reflect my thinking. Maybe because I am not a native english speakers I did not understand everything and there were things that were confusing or unclear to me on the 1st page.

" So why is it that I apply NO rudder in the A2A and the ball is centered? " I don't know. I did not say that A2A is bad. It was just a neutral question.

I admit I have only 20 hours in a real plane vs 200 hours CFI, etc.

It is amazing how, with condescendance, you see bad intentions where there is not.

OK thanks all, I'm OFF.

 

[jcomm 5,890]

Actually default prop aircraft in FSX used to over-model adverse yaw.

Some of the default aircraft in P3D have that problem too. The A36 is probably less affected, but IRL they're pretty much feet-on-floor... and also the original aircraft ( Carenado ? ) might have had it's FDM more fine tuned.

Unfortunately I never found A2A's approach to the modelling of turns that good, starting with the fact that they couldn't really overcome the inherent limitations, for instance, of a proper turn coordinator offering plausible standard turn rates... but that's another story.

It's been a long time since I last used the A2A Cessnas and Comanche though … Things might have changed for better...

Simicro, ELITE, which you also own, is near perfect in simulating the proper amount of adverse yaw typical of each of the aircraft models it includes in it's hangar. I actually miss the Tobagos in version v9 XTS... Those were very interesting to control in turns, but not only, because apart from the pronounced adverse yaw they were also very prone to prop effects... 

 

Edited October 30, 2018 by jcomm

[cowpatz 243]

The affect of adverse yaw can vary with airspeed. To demonstrate adverse yaw to students (C152, C172) I would have them reduce the IAS to a safe margin above the stall and then move the aileron relatively quickly from one way to the other. The student would then observe the nose move left or right, opposite to the direction of the applied aileron.

Most modern aircraft do have differential ailerons that reduce the affect of adverse yaw. However it seems optimised for a certain speed range. Adverse yaw is due to the drag of the down going aileron being greater than the up going one. To compensate the up going aileron will go up further than the down going goes down. The affect is only evident when aileron is applied as in entering or exiting a turn, not when it is in the turn as the ailerons will be basically central.

To the original poster, to see how well a model's FDE is I would suggest trying the above demonstration method and see what happens. Don't look at the ball, look at the nose against some point on the horizon.

 

 

[turnandbank 243]

21 hours ago, Bobsk8 said:

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

True, but only while in the turn. You will need to use a little rudder when entering and leaving the turn to maintain coordinated flight. This comes from practice and the "seat-of-the-pants" feel when flying an actual aircraft but is more difficult to get right in a desktop sim. You don't get the real world feedback.

[Delta558 50]

2 hours ago, cowpatz said:

 Don't look at the ball, look at the nose against some point on the horizon.

 

 

A very good point - I believe that the Turn/Slip instrument in the sim is set to work on amount of rudder applied proportional to bank angle. Basically, MS stuffed up the use of rudder in the early sims and we are still left with the same instrument as the subject has not been highlighted enough and that poorly reacting instrument has just become accepted.

[FDEdev 955]

5 hours ago, cowpatz said:

The affect of adverse yaw can vary with airspeed. Most modern aircraft do have differential ailerons that reduce the affect of adverse yaw.

To see how well a model's FDE is I would suggest trying the above demonstration method and see what happens. Don't look at the ball, look at the nose against some point on the horizon.

Concerning adverse yaw and speed/AoA. The C177 (with differential ailerons) adverse yaw at 70kts is double the value than at 105kts. (and the roll rate significantly decreases in this speed range as well) 

You can't generalize adverse yaw and judge the FDE if you don't know how much adverse yaw (and at what speed) the airplane concerned actually develops.

E.g. the C177 and C195 both suffer from significant adverse yaw while there's e.g. virtually no adverse yaw in the A36.

 

Edited October 31, 2018 by FDEdev

[FDEdev 955]

19 hours ago, Bobsk8 said:

Nice to see a CFI tell it like it is. 

CFI isn't a guarantee for knowledge and/or ability. E.g. take a look at the various statistics about the high percentage of CFIs involved in stall/spin accidents.

The FAA once conducted a test with CFIs  to perform power on stalls in a C152 and a surprisingly high number of CFIs had their feet on the floor during this test! (they were surprised when their 152 snapped into a spin).

In another survey more than 30% of CFIs stated that they spin aircraft certified in the normal category!! 

Edited October 31, 2018 by FDEdev

[CFIJose 5,485]

14 hours ago, mpw8679 said:

Its also amazing the number of pilots that should have no business piloting an aircraft in real life. 

and you have proof? Is it in the hundreds or thousands? Non-sense!

[CFIJose 5,485]

3 hours ago, FDEdev said:

CFI isn't a guarantee for knowledge and/or ability. E.g. take a look at the various statistics about the high percentage of CFIs involved in stall/spin accidents.

I'm intrigued and want to be enlighten by your sagacity. Please share the statistics.

Also post your credentials as a CFI and proof of membership to the FAASTeam if any.

Thanks.

[FDEdev 955]

35 minutes ago, DJJose said:

1. Please share the statistics.

2. Also post your credentials as a CFI and proof of membership to the FAASTeam if any.

1.  So you don't have to search for all of them individually https://www.amazon.com/Light-Airplane-Pilots-Guide-Awareness/dp/1879425432

2. I never had the need to become a CFI.

 

[CFIJose 5,485]

13 minutes ago, FDEdev said:

1.  So you don't have to search for all of them individually https://www.amazon.com/Light-Airplane-Pilots-Guide-Awareness/dp/1879425432

2. I never had the need to become a CFI.

 

So instead, you decided to become an FDE developer?

[FDEdev 955]

1 minute ago, DJJose said:

So instead, you decided to become an FDE developer?

Huh?