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1 hour ago, jcomm said:

Nice to browse thorugh it, down to 1989 :-)

http://austinmeyer.com/blog/

Interesting to read what he's been telling in his public talks about the improvements for XP11

http://austinmeyer.com/2017/01/05/x-plane-11-flight-model-improvements/

Great, Thank you Jcomm

In Austins newest blog entry, he tells a story about hitting a wake turbulence of a MD 80 in real life. Thank god he survived....

Tom

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Interesting read about the wake turbulence... and very nice and handy way of depicting it using Xavion.

Thanks for the heads up.

cheers

-E

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Austin is not the first hit by a wake :) I like to see depiction of it in my Foreflight as well, but I wonder if he considers known wind condition which can make quite a difference where wake turbulence will shift 

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Austin mentions Beta 2 and also Beta 4 regarding the new / updated / more detailled modelling of propwash / slipstream effects... So along the XP11 run, I believe

 

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27 minutes ago, jcomm said:

Austin mentions Beta 2 and also Beta 4 regarding the new / updated / more detailled modelling of propwash / slipstream effects... So along the XP11 run, I believe

And I believe you should look at the dates.

Austin was writing about the X-Plane 11 Beta Versions. We had 15 Beta versions. So I don´t really see any new informations in these statements, but they were new in january.

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13 hours ago, Longranger said:

And I believe you should look at the dates.

Austin was writing about the X-Plane 11 Beta Versions. We had 15 Beta versions. So I don´t really see any new informations in these statements, but they were new in january.

Indeed Karsten, my bad :-/

For a moment I thought the .02 after the 11 was indicative of beta 2 ... Duh!

So, they're all implemented long time ago... I wouldn't say so... Well....

 

 

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1 hour ago, jcomm said:

For a moment I thought the .02 after the 11 was indicative of beta 2 ... Duh!

So, they're all implemented long time ago... I wouldn't say so... Well....

Most of the changes Austin talks about in his blog post are planned for 11.10.

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26 minutes ago, Pascal_LSGC said:

Most of the changes Austin talks about in his blog post are planned for 11.10.

Ah ! Thx Pascal. So when he mentions beta 4 regarding the "new" calculations for propwash effects, probably this didn't actually make it's way into 11 beta 4, and was somehow postponed to 11.10...

Let's hope this is the case... although I confess that I was convinced it had been modelled since XP10...

 

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You're welcome !

I'm not sure wether the enhanced spiraling slipstream has already been implemented. However, in the Flightsimcon presentation he talked about better account of negative wind, which should help taxiing and simulate special aerobatic cases. And the new PT6 engine is for 11.10 as well.

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27 minutes ago, Pascal_LSGC said:

 

I'm not sure wether the enhanced spiraling slipstream has already been implemented.

Well, in a way they were all implemented in the Beta, but there is a difference between implemented and works as desired. Some of these elements were never implemented in X-Plane before. A large part of the later Beta versions were ratrher erratic behaviour changes in the flight model. Austin had to get something together that somehow works, but I think we all agree it is far from perfect, it is more controlable.

So I would expect that he willtry to refine all these changes in 11.10 (if he has the time between the new ATC and his Airbus). But I would be carefull not to get his old Blog elements into the equation. Those were his hopes, but it doesn´t always work as hoped.

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One thing is for sure, and it was the Major change in X-Plane sin Austin introduced torque effects in XP9 - yes.... XP didn't take them into consideration before that, when MSFS, even if not in the most perfect way, was doing it for ages!

The one thing that really changed was the implementation of Murmur's finding about the double computing of prop torque in the FDM!  That REALLY made a change, but is NEVER mentioned by the LR team ...

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19 hours ago, sd_flyer said:

Austin is not the first hit by a wake :) I like to see depiction of it in my Foreflight as well, but I wonder if he considers known wind condition which can make quite a difference where wake turbulence will shift 

he mentioned in the text that he uses the latest wind data from the nearest ads-b weather report and factors it in aswell

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Ok,

just received confirmation this will be up for X-Plane 11.10.  Let's wait then !  Looks very promising to me.

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6 hours ago, Pascal_LSGC said:

I'm not sure wether the enhanced spiraling slipstream has already been implemented. However, in the Flightsimcon presentation he talked about better account of negative wind, which should help taxiing and simulate special aerobatic cases. And the new PT6 engine is for 11.10 as well.

Wait, I thought he was through messing with the PT-6, and the new changes were already in the first 11.0 release? 

If there are any major changes still coming, then it will throw off the work many aircraft designers have already done to adapt their turboprop planes and helicopters to the new XP11 turboprop. That engine model needs to be locked down ASAP, if it isn't already.

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1 hour ago, Paraffin said:

Wait, I thought he was through messing with the PT-6, and the new changes were already in the first 11.0 release? 

If there are any major changes still coming, then it will throw off the work many aircraft designers have already done to adapt their turboprop planes and helicopters to the new XP11 turboprop. That engine model needs to be locked down ASAP, if it isn't already.

No, there is still work in the Pt-6 modelling approach, and in the spiralling slipstream modelling, but specially the latter will, supposedly, just make prop aircraft flight dynamics model more realistically  the effects of propwash / spiralling slipstream, so, they can only get better...

The same applies to ground physics, which are now clearly flawed and have a chance of, at least, getting better...

This is not as the ancient "Torque Bug" which some developers circumvented using their tricks, through Art Stab or plugins...

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19 minutes ago, jcomm said:

No, there is still work in the Pt-6 modelling approach, and in the spiralling slipstream modelling, but specially the latter will, supposedly, just make prop aircraft flight dynamics model more realistically  the effects of propwash / spiralling slipstream, so, they can only get better...

The same applies to ground physics, which are now clearly flawed and have a chance of, at least, getting better...

This is not as the ancient "Torque Bug" which some developers circumvented using their tricks, through Art Stab or plugins...

Well, it still conflicts with what Ben wrote during the last few betas before 11.0, saying they needed to lock down the new engine and flight modeling, so developers could get started on their updated v11 planes. Many have already done that, like the X-Trident Bell 412 and Dreamfoil Bell 407, both using turboshaft engines. Carenado is in the process of updating their fleet to v11, starting with the turboprops, because those are the ones most affected by the changes in XP11.

So now Austin is going to change things again?

I'm hoping that whatever he's still working on is so minor, that it won't send everybody back to the workbench again.

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I think the changes due for 11.10 are only propwash / slipstream and ground physics related. It appears to me Austin has finished the Pt-6 / jet / turbofan engines updates ( ? )

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2 hours ago, jcomm said:

The same applies to ground physics, which are now clearly flawed and have a chance of, at least, getting better...

I'm still not sure if the flaw is in the ground physics itself, or in the exaggerated weathervaning + flawed propeller slipstream.

I suspect that the ground physics might be ok, and the only culprits are the other two (both of which are almost certainly not accurate).

 

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1 hour ago, Murmur said:

I'm still not sure if the flaw is in the ground physics itself, or in the exaggerated weathervaning + flawed propeller slipstream.

I suspect that the ground physics might be ok, and the only culprits are the other two (both of which are almost certainly not accurate).

 

Probably all of the above !

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50 minutes ago, Murmur said:

I hope he's still working on it, because the current prop slipstream doesn't seem to be accurately modeled.

I think whats missing is the P-Factor in the equation. I don't think P-factor is modeled. When flying at a high angle of attack and low airspeed the ball in the inclinometer doesn't move.   

Maybe you could shoot Austin a email Murmur !?

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P-factor is indeed active at any AoA, provided you're not aligned with the relative wind. 

Yo-Yo ( ED / DCS ) tried to achieve the best possible modelling of it's effects starting with the P51d, where inflight, in a sideslip situation you would clearly feel the pitching up or down moments ( in that case they manifest themselves in pitch instead of in yaw... ) depending on if the sideslip was left or right.

And, on a different matter,  also think Murmur's "thesis" about the origin of the poor ground behaviour of aircraft under x-wind is probably due to an overdone / overcalculated weathervane effect. Maybe it's also being calculated twice :-)

And yes, if the propwash update was in since beta4 of 11.0, than I also hope Austin continues to work on that... The "Visual Flight Model" mode should also allow us to glimpse some of the effects.

 

 

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