60North

Real FDR data playback of flight ET302 with X-plane. First 2 minutes for now. Based on the real FDR data released in the preliminary report. (So not me flying by hand, this is real data playback)

How an aircraft stalls will vary from type to type and the input from the pilots and weather. Not many have tried this with an airliner, but if you check out the AF447 accident report (A330) and how it went down you will see that it "glided" (wings level) all the way down from cruise in the stall. So I guess again XP has it right if we use that example I can also tell you this is also what happens in the big professional 737 sims I tried M

Murmur is correct. It is also called yaw induced roll. Below a certain airspeed (crossover) on airliners, the rudder will overpower the ailerons. The reason is that at low airspeed maneuvering you need more rudder authority. Like on decrab in crosswind and keeping the aircraft on the centerline on a slippery runway, one engine out scenario, (Vmcg etc). However you do NOT want this at high speeds as it is very dangerous (as you experienced), so to prevent an accidental hard rudder input at high airspeed, airliners use what is called "rudder phaseout". The higher the airspeed, the less rudder deflection you will get if you stamp on the pedal. At low airspeeds, the max rudder deflection on an airliner is around 30 degrees, at cruise it is only a few degrees. But basically the aircraft manufacturer can set the crossover speed to what is necessary and safe. Have a look at this real accident replay by NTSB, USAir 427, the rudder on the 737 went by itself to full deflection, the pilots countered with full aileron+rollspoilers but didn't have a chance... We model this pretty close on our 733, within 2 kts if I recall correct. https://www.youtube.com/watch?v=7CIAXOq9pwI M

More likely the airbus FBW (artificial stability) kicking in

Sure do Robert. Let us know if there is something we can do to help alleviate/speed things up for you porting one of your projects over.

As a long time XP developer, personally I think it was a wise decision by PMDG to hold off any XP11 updates until atleast XP v 11.10. XP 11 has (as usual) been a moving target flight model wise (and other stuff). This is tradition in a new XP run which normally does not stabilize until v xx.1 or xx.2 Especially on the prop/engine side of things (DC6) things have been a work in progress for the past year. Any effort made by PMDG since XP11.0 release would mostly have been a waist of time with a very high risk of work being broken. To me it shows that PMDG sets quality and stability first, and I'm sure they had enough on their plates and better time spent on P3D in this period. Also not to mention this is their first XP project, and an early 11 release could have given them a support nightmare and bad reputation. We now after 11.1 expect things to stabilize (by experience), and XP developers now can get back in the game without a big risk of their work being broken by LR. So we now have a few years of sunshine and peace ahead, and I'm sure PMDG will be a part of it one way or the other - atleast I hope so :) M

Right, on a single engine prop, the left and right side wing will have slightly different aoa depending on if the prop in front of it is moving up or down, so different lift. Also correct, a low wing aircraft will have less dihedral effect than a high wing https://www.dropbox.com/s/o9arneiwo13uvy4/dihedral.jpg

Sounds like you are using an old IXEG version, if so update to v1.2

Jcomm, we have worked with austin on this, documented and reviewed the whole ground effect on all aspects. Pitching moments, lift and drag should all be well inside the ballpark now. This is extremely complicated stuff and affects different types of aircraft differently depending on geometry, configuration etc. So what you experience will vary as in real.

The updated groundeffect made it into b5

If you are experiencing obvious weird behavior - especially in a beta - the first thing you should do is delete the XP prefs files and try again.

We are working with austin on the ground effect pitching moment, at this point it is uncertain if the new model will make it into 11.10

Thats off course up to you, but speaking of the FMS, as you know, the FMS is much more than the FMC, it also consists and depends on several other systems like the AP, and A/T to mention a couple. They all need to interact correct, modes, sensitivity, behavior to be right. Further, and most important maybe, for the whole FMS to be anywhere realistic the flight model needs to be right to get the correct vertical profile ( lift, drag, engine performance etc etc)! So you are on very thin ice already judging how good the FMS is on any sim aircraft unless you have deep knowledge in all these areas which means you need to be an engineer - and - an in type pilot to have anywhere near an objective view of the FMS. (You off course might be, I don't know but it's not common). Sure, but it's in no way objective (which was what I reacted to in your post) it is an opinion ;) M

What IS very misleading is judging an aircraft by just by parts of one system as you do. All aircraft have their strengths and weaknesses. What is important to each user also varies a lot - the list is endless - but to most users it is the overall impression that counts. Should you try to give an "objective" view, you would have investigate in huge detail each system, flight model, 3D, textures, sounds etc etc and then try to sum it up, but it still would be biased since I'm pretty sure you do not have the competence (formal education) needed in all these areas.

Correct, FSX has got it very wrong according to the documentation I've seen. They have mixed up several of the effects, confusing span with chord etc. XP10 is very close, XP11 appears to have some issues, but thats most likely an unintentional bug that will get fixed. Might not even be ground effect related.