X-Plane V10 Plugin 2.0.2.0

Real life situation in 737-800

iPhone positioned on the floor.



Thanks

@yobuddy

Imagine you are siting on a chair. You are exercising a pressure (weght) on it, if I tilt this chair 30deg to the side you will feel that you are falling to the side.

I can insure you that the pressure on your butt (weight) will be half in this scenario.

Is this not the most natural fenomenon that when you bank, the local heave (your chair) is modified ???

Please, forgive me guys if I smile, but you are exactly making my point even if not intentionally

If you hold the phone in one orientation (1st half of the video) then you will have accelerations of say...
x = 0.00 m/s^2
y = 0.00 m/s^2
z = 9.81 m/s^2

If you then tilt it into another orientation, or move it around (2nd half) you might get accelerations of say...
x = 0.00 m/s^2
y = 9.81 m/s^2
z = 0.00 m/s^2

...or anything in between, depending on the angle of tilt.

So, if I wanted to play devils advocate here I might say that "this rouge gravity component messes up my nicely planned motion measurement activity and should therefore be cancelled out mathematically"

.... but instead I would like you guys to see the underlying hidden truth (for lack of a better expression) that in the first half of the video @hexpod was actually pushing against the phone from below while it was laying flat in his hand. If you then tilt it up vertically, you are actually pushing against it from the back (from the phones perspective). In both cases, as well as in any other case there ACTUALLY is a force acting on the vehicle (phone) and a pilot/driver/bacterium inside the phone would feel being thrown over to one or the other side.

If you go through a banked corner, you will have centrifugal force (like in any other corner), only this time because of the bank angle a component of that force sin(bankangle) will act along the vehicle vertical axis. Are you sure that this couldn't have been a perfectly plausible scenario?

Maybe it even was a case of a sim that uses accelerations without the gravity component or any other physically incorrect mathematical construct. @pmvcda told me about such a driving sim. If that was the case, then yes of course that is what we will have to work with and make the best of it. But X-Plane does provide proper accelerations (aka containing the gravity component) and I can tell you that in X-Plane whenever there IS an acceleration value being shown, there actually IS a force acting on the vehicle.

Dirty

That's hilarious!!!! Great!!! I can imagine you sitting in the plane with the two phones And it is nicely time-matched between the video and the data. Thanks!

In X-Plane? Are you sure? Because that would be a bug the size of Texas I can't confirm right now, because I will be windsurfing in Egypt for the next three weeks, but if you want to find out, here's what you need to do:

1. Take a glider aircraft and position it way up in the air (10.000ft)
2. Show the "motion platform stats" data tab and find the longitudinal acceleration (should be "Accel-Z").
3. Push the nose down to gain speed. I mean A LOT of speed!!! ...and then some more...!
4. Pull the nose up into the vertical quite aggressively without breaking the wings off.
5. Hold a pitch of 90° as good as you can.
6. Observe the longitudinal acceleration.

As there is nothing pushing the aircraft, and very little pulling on it (only a little drag) the longitudinal acceleration should initially show a minimal deceleration (aerodynamic drag) but as the airspeed bleeds off it should be pretty close to zero. Certainly not close to 1G.

Could you try this out?

Maybe here is the point of wrong assumption.

At the starting point the +1G is not there anymore because it’s washed out. (No additional emulation) - the platform is centered.

Than, we are not adding it twice, (emulating again) it is subtracting this 1G once a tilt occurs.

Again, of course we are talking here about the scenario where the Euler angles are NOT in use or where they are strongly washed out.

Best.

Gravity 0 in xplane exists as well as in real life in some circumstances. lol

I am glad that some developers like @pmvcda , instead of willing to cancel the gravity component want to add it to the titles where it is not present.

To all developers, @yobuddy @value1 , to all simmers: please guys, after more than 10 years of simtools existence, maybe it’s time to give another try and reconsider your cueing approaches.

Please give a try, don’t tilt your platform with Euler, just try to tilt it with velocities and the gravity component whenever you have a chance to access this kind of telemetry.

With new tools like washout, smoothing etc, simtools
finally gives us the possibility to push our hobby on another level of realism.

I am on the last beta and still see a small bug in surge and sway while playing back the reply.

I’ll try to write to Austin asking for a double check

First of all, thank you very much for taking part in this discussion. I think the communication is the real force of this community.

Yes, entering in the edge knife flight will transfer 1G from heave to sway. This steady sway is washed out on the sway dof and the tilt coordination (sway on roll) which is NOT washed out will take over, tilt the platform and keep it tilted.

The platform will sink for a short while and bank, transfering the pressure from my butt to the side of my body.

What appears to you false (unnatural) in this scenario ?

Of course we cannot tilt the platform up to 90 deg but still, banking 25 deg. through the gravity component which went to sway (actually roll in our coordination channel) is better than nothing.

I am not giving up. I will keep searching where you think the false cueing occurs.

Thank you for being concerned by the discussion.

Best

It can be, there is a better approach for this scenario (than the one I described above).

For the moment I am not aware a better one exists but If you ( @yobuddy of someone else) propose an alternative I will be more than happy to try it out.

I doubt linear accelerations (without gravity) + Euler angles could satisfy us more than accels with G and velocities.

We all want to get a cool motion out of our 6-dof rigs with a minimum amount of false cueing.

Cheers

Spot on!

Washout needs to be on Accel_Vert, Accel_Lon and Accel_Lat. The tilt-coordinartion is not washed-out. Indeed, only a part of the sidle load can be cued, but that's what we will have to live with.

Well explained!

I think I do understand but I disagree

I did the barrel rolls tests you are asking for.

I am ready to change my mind if someone comes with logical arguments and will propose a better solution.

I dont have time to fine tune it but I think the main idea of accel+G / angular veloc. is there.

test made using SimTools filters with hexpod plugin.

@value1 , @Dirty , @yobuddy , @Thanos , @pmvcda , please guys, list what appears to you wrong, false in this approach.

thank you

Yes that’s right.

Austin just prepared a test build for us adding needed telemetry in replay.

@Psionic001 , I PM you the link for download if you want to test it.

Cool. I’ll download and give it a try.
Thanks.

Hey @yobuddy

I promise, if I ever make it back into PDX we will be going for a beer. Equipped with a pencil and a huuuuge stack of paper

I think there are two key points of misconception (correct me if I'm wrong)

1. You think that if you don't cancel out gravity in the exported data, you will be applying it twice.
2. You think that gravity is a force.

Please embrace (just for a minute or two) the idea, that gravity is NOT a force, but instead just a side-effect of the curvature of 4D spacetime. We, in this very moment, are all racing through the fourth dimension (time) at the incredible speed of 1 second per second (kinda). But since the ground beneath you will not allow you to go "straight" through spacetime, you are feeling the centrifugal acceleration of that curvature. It's an illusion, because you are so used to perceiving the world from the perspective of an accelerated frame of reference. Kinda like Coriolis force is only an apparent force that only exists in the rotating frame of reference from which you measure it.

As simple as possible:
Whenever there are accelerations exported out of X-Plane (motion platform stats), there actually IS a force present causing that acceleration. Ignoring that force means ignoring something that the occupant feels. That "floating" 1G has a cause. Find it! Understand it! Use it! Cue it to the user! It's your friend, not your enemy.

Dirty

That looks plausible to me.