X-Plane 11 Propeller Modeling / X-Plane Developer Blog

[Macpah 46]

New blog post by Austin:

 

http://developer.x-plane.com/2017/01/x-plane-11-propeller-modeling/#more-7343

 

Excerpt:

 

So, in X-Plane, we of course break the prop down into tiny little pieces and add up the effects from all of them to get a weighted average of the spiraling-slipstream speed for the entire prop, and scale that rotational speed from zero right at the axis of the prop hub to maximum out at the prop tip, and bang, we got a spiral slipstream with math that I believe proves that we are making a very good approximation. (And, doing the math in this new way results in propeller spiral slipstream that runs about 45% higher than the previous model… a positive indication since the spiral slip-stream was previously under-represented!)

So, now we have better propeller spiraling slip-stream, with the needed rudder effects, and it feels GREAT to fly.

 

___

 

 

I'm now really looking forward to beta 4.

[be77solo 125]

Curious, when he changes stuff like this, does it affect existing aircraft or only new aircraft?

 

Wondering what (if anything) changes like this do to my existing 3rd party fleet of awesome Simcoder REP planes.

[Jimmy RFR 406]

Quite an interesting read. Might take them a bit to get that one dialed in correctly, I'm thinking. 

 

However, it's great to know that they're constantly working on refining the flight model.

Curious, when he changes stuff like this, does it affect existing aircraft or only new aircraft?

Wondering what (if anything) changes like this do to my existing 3rd party fleet of awesome Simcoder REP planes.

 

I'm thinking that there's been quite a bit added under the hood in XP11 - I'm speculating that the changes in the electrical systems alone likely mean that the REP programs are going to need (or could benefit from) some adjustment and rework for XP11.

 

Any changes to the internal flight model are also liable to throw off the REP stuff as well.

 

End of the day though, since the REP devs are trying to get everything as close to real life as possible, these under-the-hood changes should make their lives easier in the long run.

[Paraffin 2,197]

Curious, when he changes stuff like this, does it affect existing aircraft or only new aircraft?

 

Wondering what (if anything) changes like this do to my existing 3rd party fleet of awesome Simcoder REP planes.

 

With changes to the basic flight model like this, the answer has usually been that it doesn't affect current models, but you get the changes by loading the model into Planemaker and saving out a new version. I suspect that's the case here.

 

For a model with plugin-enhanced flight model changes like the REP series, I'd wait to see what the developer says about it. 

[strider1 575]

Best news ever ! This has been one of my biggest gripe with XPX. Do I finally get to use the rudder to counter act the the left turning tendencies when in the air !?

[Macpah 46]

Best news ever ! This has been one of my biggest gripe with XPX. Do I finally get to use the rudder to counter act the the left turning tendencies when in the air !?

 

I second that, can't wait for the next beta...

[strider1 575]

Curious, when he changes stuff like this, does it affect existing aircraft or only new aircraft?

Wondering what (if anything) changes like this do to my existing 3rd party fleet of awesome Simcoder REP planes.

I think that's why Laminar was encouraging developers not release any native XPX-11ADDONS till 11 goes final.

[sd_flyer 6,034]

So now I can get into my own prop wash during  360 steep turn?

[whoispankaj 51]

Does it mean that the left vanning tendency is going to get more worse during crosswind takeoff? Sorry I don't understand the aerospace stuff..

[strider1 575]

Does it mean that the left vanning tendency is going to get more worse during crosswind takeoff? Sorry I don't understand the aerospace stuff..

If the cross wind is from the left then probably. If it's from the right then left turning tendency should counter act the weather vanning a bit. Austin has been hard at work on the flight model lately so I'm sure the weather vanning will get some attention ! Google 'left turning tendencies'.

[sd_flyer 6,034]

If the cross wind is from the left then probably. If it's from the right then left turning tendency should counter act the weather vanning a bit. Austin has been hard at work on the flight model lately so I'm sure the weather vanning will get some attention ! Google 'left turning tendencies'.

 

 

Left turning tendencies can be due clockwise rotating propeller without any weathervaning

[strider1 575]

Left turning tendencies can be due clockwise rotating propeller without any weathervaning

Huh ? I am pilot, I familiar with the left turning tendencies ! The spiraling slipstream might exasperate the weathervaning bug is all I am saying.

[sd_flyer 6,034]

Huh ? I am pilot, I familiar with the left turning tendencies ! The spiraling slipstream might exasperate the weathervaning bug is all I am saying.

 

Sorry I misread you sentence 

[wiler 394]

sorry but i used to fly REAL cessnas and the left pull isnt as exptreme as the model in xp11. there is some but not nearly as much as what is modelled in this program, turn it down!!

[strider1 575]

sorry but i used to fly REAL cessnas and the left pull isnt as exptreme as the model in xp11. there is some but not nearly as much as what is modelled in this program, turn it down!!

 

What left pull ? Are you talking about the engine torque? That makes the plane roll to the left in the longitudinal axis. The spiraling slip stream model has been broken forever. Are you sure you use to fly Cessnas ? The left turning tendencies should make the plane yaw to the left, as in real life. That doesn't happen with current model. When was the last time you flew a real Cessna ? Left turning tendencies is the basics we lean about in ground school.

 

Maybe you need to take a look at your joystick calibration!