Discussion: Issues with 6DOF

I think 360 pitch and roll is awesome. I would love very much to have it, but would not sacrifice full 6DOF for it. Just my opinion, Apointner I think your sim is awesome, please don't be offended! @apointner I haven't had the chance to try the LUA yet, but soon! My sim is very nearly ready to fly again!

Completing a full roll, I like the sim to stay at the set max bank angle (using the 360 check box), or my own plugin for NL2 and then have it roll back down to zero on the other side - any other movement and it feels distracting. Well for me and my setup anyway .

@apointner ,
I don’t get you fully on how you want to deal with absolute positions.

When an aircraft is in a coordinated turn, his absolute position let’s say is 30 deg. (Roll Euler angle 30).
If the pilot starts the turn very slowly and will keep a coordinated turn, the coffee on your table will stay perpendicular to the aircraft floor and you and your internal ear will perceive this turn in a same way as if you would fly in a straight line.

Are you agree ?

That’s why I don’t fully get how you want to interprete the absolute angles on your roll axis.

If you’re inside a turn, if you keep the turn coordinator “ball in the middle”, your platform roll position has to be 0.

Using Euler angles without an HPF on it will produce a false cue in my opinion.

Am I missing something?

Apointner just feels that to him the inner ear sensing the Euler angle is more important than the forces. He has different priorities is all.

Obviously we would ideally have both, full 6DOF plus 360 roll and pitch.

Trip

Well, if you want to believe it. You’re free.

Concerning the cueing, because of restrained workspace, we all have to cheat our senses.

Depending on design, we have to choose the best corresponding method.

For Stewarts, I don’t know any better method than “Classical Washout” and its derivatives.

Cheers.

Hey Siddartha

I hate to break it to you (OK,...I admit, I LOVE to break it to you!) but your sense of balance developed over 300.000 years of evolution in an environment that did not move. Being inside a vehicle (let alone a supersonic jet) was just not part of the operational design envelope of our perception.

It can be fooled especially BECAUSE your perception of motion is based on a mix of vision, ears, muscle and butt Most of those receptors are only able to detect short term changes and are almost blind to long term sensations. Or better: They are a lot more sensitive to short than to long term stimuli.

A 6DOF Stewart platform and your 360° rig both have false cues. They are simply unavoidable. It's just that these false cues are different on both platforms, and I'd find the false cues on a Stewart platform more tolerable. But in the end it's a matter of personal preference

How about this: Next time I take you on a flight, I will show you a couple of manoeuvres that will be an eyeopener for you. After that, you will never use the terms "up" or down" in aviation again. They have just no meaning in a high performance aircraft.

Dirty

Exactly. For example when you do a tight inside loop at high speed (which I think is more common than straight inverted flying?) on a 360 rig how do you handle the top of the loop? To have any chance of sensation of correct +Gs you need to be upright the whole time and never inverted, even with a g-seat or harness tensioner.

In any case simulation is best when using pressure to simulate g forces and "minimal" motion to simulate orientations. Also my testing thus far shows the more motion used the less effective and immersive a g-seat becomes. So with a g-seat anyway less is more.

I thought we always lived on a very fast moving spaceship named "earth" lol.

I can confirm that my vestibular sense is nowhere near that sensitive or accurate! Then again, I could never even walk very well. =P

For example, if I floor the accelerator in a racing sim and my motion sim maxes me out at 30 degrees of pitch for the acceleration, with proper motion compensation I have no idea that I'm actually tilted up 30 degrees. That gets totally overwhelmed by the visual input saying I'm still level and the brain interpreting gravity pushing me back into my seat as an acceleration.

We do!

Michael can explain better - ...but I already know that you got it!

Still, you made my point:

I tried @apointner's rig and even though I follow a different path, I still see "a point" (pun intended!) in building it. It is quite a thrill-ride.

Hey @BlazinH since I intend to build a G-Seat next I would very much like to hear as much detail as you could provide on this topic. How many degrees of rotation, and how much travel did you find best in conjunction with the G-Seat?

Well, like I said, I can understand that for you, it's important to have the 360º. So you can make sustained inverted flight and so on...
Your main target seems to be dog fight and aerobatics.

I will not exchange my 6dof Stewart for a 3dof only rotation rig.
I prefer to use filters to make everything fit my rig than to not even be able to use a filter.
And also because my preference is racing sims, although I also want it for air planes.

Maybe 360º rotation might be better for aerobatics and dog fights, but in all the rest, I don't think so.
The maybe is really a maybe, because for me your advantage is only in sustained climbs, lateral or inverted flights.

One thing that I'm sure, is that on my DIY list, is a g system to complement the effects.
All this is a leisure. What I want is to achieve the best result possible within the limits of the hardware I have.
That's the reason for playing with filters.

You can only tell that because you know in advance that you are on your rig, and what you feel can only be a rotation The "world" and the "world as presented in hour head" are two very different things and have less to do with each other than your brain will make you believe.
There are hundreds of incidents every year where experienced pilots (who learned about this for years in their training) fall into that trap.

Read this. Every line in this article was written with blood, sweat and tears!

Or at least watch this.


...or even better: Come over for some more coffee and cake some time. It will be an "eye opener" for you (literally)!

Position information is the last thing you need on a 6DOF rig.

OMG,... lots of coffee and cake needed, I guess But ya know, I have a good appetite

I have read, and I don't agree.

You have to understand that the tilt coordination has to be properly tuned AND combine with surge AND with a proper center of rotation in order to cheat you.

You can’t achieve the accel effect only with pitch.

I think that’s the point of desagreament here

A Hexpod delivers some small cues that were carefully selected (filtered) to allow a few correct cues to be perceived and false cues to be minimised. It is not perfect, but the best compromise you can get. Some minor improvements on algorithms are being discussed in the scientific community. But at its core this is what is going on in FullFlightSims around the world.

Your rig gives a thrill ride of inputs to the occupant, that consists of huge and scary cues, that are mostly not matching what the occupant of an aircraft feels. Some exceptions: Vertical climbs (unless engines at idle), sustained inverted flight & quick aerobatic rolls (no barrel rolls) are displayed with very little false cues, but for a big chunk of the time the cues generated by such a rig would have to be seen as "thrilling but wrong". At least from a technical/professional standpoint.

I'm not putting your thing down! It is great! It is the very reason I entered into this hobby (remember in late 2017?). When I tried it last time, I stepped out of it saying just: "WOW!!!" Because it does feel amazing,... just not "correct".

That's why it's not the path I or others want to pursue.

On a sidenote:
These hexpods...

...are certified for "Zero Flighttime Training". That means you can get a license without ever even having seen the real aircraft. It is not because they provide 90% correct cues (which they don't), it is because they avoid 99% of the false cues.


Dirty

...oh, and did I mention that I'm hungry for coffee and cake?

And if you have the $ to take it to the next level

Does anyone know what thread here on the forums gives the most comprehensive guide to building a good (and affordable) G-seat with harness tensioners? I need the "G-seat for dummies" version! Exact details so I can buy what I need and follow step by step to build it. I've looked at a number of G-Seat threads but most don't have enough detail for me to be confident in trying to replicate them.