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360 Degree Flight Simulator

Discussion in 'Commercial Simulators and Peripherie' started by FLY-Moscow, Aug 25, 2016.

  1. joe extraknow

    joe extraknow Member Gold Contributor

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    @apointner

    it seems require high ceiling in order to pitch 360 degree.

    What if I try to make limited pitch angle say +/- 60 degree in total 120 degree. The whole frame is still rolling in 360 degree but inner seat hung on an axis can be pitching +/- 60 degree, like this:


    The seat back/under is connected to an actuator to push/pull for pitching. Do you think this is feasible and sound safe?
    Last edited: Dec 23, 2019
  2. apointner

    apointner Siddhartha

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    Yes that could be a good compromise. To be honest more then 70° Pitch is really uncommon, except you like to simulate pure Aerobatics. Beside the the ceiling height many, many problems occure with real 360° Pitch. Like Euler angle Bankflip at PitchUp 90°, Safety, rotary cable feedthrough, ...
    Much more important i think is Belttension, Seatpaddles anyway.
  3. joe extraknow

    joe extraknow Member Gold Contributor

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    Thank you for your reply. I like to do feasibility study before considering to build one. It has always been my dream to fly a jet on motion simulator. I can imagine how good feel would be on your rig! Like:





    There is a safety concern before even I can start to think of such project. Hope you can shed a light on this concern. I know you don't have to answer my questions on the public forum. It is understandable.

    1) I see your belt tension is from front by cabling with motor. What is a scheme you implemented to safely use: 100% enure it would not: a) choke you to death; and b) lose so you fall while rolling 180 degree up side down?

    2) How did you implement the rolling motion is 100% deterministic? There is no surprise or "randomness" behavior. Otherwise it will kill me though. It cannot be locked up, and has to be slow reset to center, etc.

    3) To whom live US may answer this one. I cannot build this at my garage or back yard. Otherwise I cannot move it to my basement. It has to be build and constructed inside the house at basement. If I hire some one to do the welding inside house, is this legal in US?

    Thanks again
  4. apointner

    apointner Siddhartha

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    Uhhh, dream on about the Typhoon-ride. Something like that can not be simulated, nor described. But 99% of all simbuilders would´t enoy such a ride anyway :eek:
    I would say my SimPit is may able to fake the real stress in a Robin DR :D
    About safety: Max. torque from DC motor is 500N, so no problem for me or the Harnes. Also i installed a meachical stop to cover my jewels :-D
    While flying inverted and pushing neg Gs, the Belt is quite loose, so my Butt don´t touch the seat (scrreeem!). However i can´t slip out or under the 5 Point Harness.
    Your second Point is critical: There are always runaway in the development stage, so better take care of a sitter :-D
    Now i run the SimPit for about 500h alone in the garage...i´ve installed emg switches, wireless emg. brakes, rollbar/basket and most important emg. alarm to catch my wife. I didn´t need any of these things yet, but you know. Ah and one missing thing...what if i´m blacked out and the simpit keeps spinning!? Ok i could recover this with a some lines of code, but again...you know.
    About 3...it´s not legal to weld inside a house? Something goas really wrong here, men!
    Ah and for the Air Bladders...@SeatTime can you compare Air-Pads with moving Plates and with Belttension? What are then Pros and Cons? The Frex AirG actuators seem to be to slow.
    • Like Like x 1
  5. SeatTime

    SeatTime Well-Known Member

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    Yes I tried air bladders and they work, but compared to my other systems the sensation is weak and they were not as reactive as plates/harnesses connected directly to a motor.
    • Like Like x 1
  6. joe extraknow

    joe extraknow Member Gold Contributor

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    Thanks for the reply. It seems that 360-rolling is not for me!

    I may consider 3DoF instead of 6DoF, with relatively large range of roll and pitch (say +/- 45 degree). I rule out the Sway and Yaw dofs based on my recent findings...

    I did some online search, and found a paper publish recently on experimental tests with a large group of very experienced pilots on a 6DoF commercial twin jet engines simulator plane:
    https://reports.nlr.nl/xmlui/bitstream/handle/10921/1430/TP-2016-629.pdf?sequence=1

    On the Motion Perception (MP) rating, the results show that without sway and yaw the MP is actually better around 1.5 (natural) --- not too weak and two strong:

    Sway-Yaw-effect.jpg

    (Update: sorry, PM=2 is natural, with sway in this case is actually better, because of sided wind).

    On Motion Fidelity (MF) Rating, the results show that without sway and yaw the MF is slightly lower than with sway and yaw:
    Sway-Yaw-effect.-2.jpg
    This is not important to me since I would not use real equipment with realistic FFB as they do. Also, I am not a pilot so I really have no experience and could not tell too much about Fidelity anyhow.

    The paper had a very interesting conclusion. Not sure what those results mean to a fighter jet simulator. As fighter at higher speed of pulling or banking on a turn, I will think the sway and yaw would be less affect or important while pilot is supposed to experience higher g-force.
    Appling such high g on sway motion makes no sense to me. Just like a car, with large lateral-g on cornering, but car is hardly swaying though. On my racing rig, I turned my traction loss actuator motion way down to ensure my rig does not sway/swing at high speed cornering.
    Last edited: Dec 27, 2019
  7. apointner

    apointner Siddhartha

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    Look interesting! You have to note that this is only a decrap maneuver that was performed in a normal Level D flight simulator. The maneuver was always controlled and executed within the flight envelope.
    Result: The roll axis is more disturbing and translational forces help the pilot.
    But, uh...
    imagine what happens when this happens:

    This manoeuvre without roll axle would hardly cause any stress - the pilot would act as he has trained.
    But with roll axis he would probably pee in his pants! And may he would even overreact...and we are only talking about 45° bank.
    I tried this maneuver myself in your A-320 Level D Sim (max. roll angle 22°)...forget it, has nothing to do with reality.
    In summary: is even 45° roll angle enough? I'm not sure, if you want real flying fun you won't get around 6dof + roll/pitch with ~70° angle, imho.
    Last edited: Dec 27, 2019
  8. joe extraknow

    joe extraknow Member Gold Contributor

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    Not sure if any one could make a 6dof rig with ~70 degree roll/pitch. I would guess it is hard to do so and probably very expensive.

    Even though if have such platform being built, my concern would be on the SimTool SW itself, which does NOT use mathematic model of 6dof to calculate the translational movements (heave, sway, and surge). It simply let user apply arbitrary fix weights on 6 actuators. Most of people just uniformly assigned to all 6 actuators. Thus, it cannot produce translational motion correctly. Flight sim based on a rigid body as roll/pitch/yaw, the coordinates are fixed on center of body as rolling/pitching/yawing hence the translational motions are referenced to the center body (airplane/pilot), not to the ground.

    For an example, as shown below, with 45 degree banking for a turn:
    plane-turn.jpg

    Say, if the plane needs heave up for 2 inch, the SimTool just cannot accurately feed the data to the rig doing so. It will lift rig up for 2 inches that will actually contribute to both heave and sway motion from plane/pilot point of view. Similarly, if the plane needs to sway 2 inch, it will move rig right/left for 2 inches that will also actually contribute to both heave and sway motion from plane/pilot point of view. This is because SimTool does not calculate each actuator actual movement in order to make correct translational movements from plane/pilot reference.

    I guess I may think of just making 2DoF (roll/pitch) with max up to ~60 degree (that is feasible), then add air bladder under seat for heave and a sway rail mounted under seat for seat sway motion. Does this sound good?
    Last edited: Dec 27, 2019
  9. SeatTime

    SeatTime Well-Known Member

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    There is a 6DOF math/filter plug-in for simtools, or just use the FlyPT mover stand alone app with or without simtools.

    IMO Air bladder is no good for heave - as it is just like siting on a air filled ball ... bounce, bounce, bounce :). Flight Sim? See the actual flight data discussed in other threads, Roll/Sway, Pitch/Surge really only used for initial on-set 98 % of the time in aircraft and you don't need or want allot. Eg if you roll a rig 60Degrees the secondary (unwanted) movements back to center are likely to be very noticeable even with washout. IMO Heave and heave body pressure is the most important and prominent DOF.
    • Agree Agree x 1
  10. BlazinH

    BlazinH Well-Known Member

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    The main issue using air bladders for heaving imo is that they're not as efficient as directly driving panels with motors. Either way its going to take a lot of power but to get the same speed and stroke out of both it will take more power driving bladders due to resistance of air movement. This is especially true when racing if you want to feel road texture due to high frequency outputs. You can use larger supply lines to move air faster but that induces more and more of a spongy feel as their size increases due to compression of a larger volume of air.

    Other than for heaving though air bladders are a great alternative, especially if you don't wish to cannibalize a seat. And if air bladders feel weak then its possibly from under-engineering and moving on to something else to quickly.
  11. apointner

    apointner Siddhartha

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    Yes, that is really a problem. But simulating quick or constant roll rates with Plates is
    very complex, isn´t? You need pressure on the Side of the Torso/Arms and even more on the Head (because quick rolls causing this head bouncing). Even with Air bladders it seems impossible to me :think
    Ok with 360° Roll axis this problem is gone, anyway *g
  12. joe extraknow

    joe extraknow Member Gold Contributor

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    @apointner
    What is the motion SW you are using if not SimTool?

    @SeatTime
    Do “math plugin” and PlyPT SW support 3DoF too? As air bladder would not be considered for heaving the seat, the 3DoF maybe the way to go. I can add sway and surge rails mounted under the seat, not for whole seat motion but for seat bottom only.

    @SeatTime and @BlazinH
    Thanks for the info. I will Guess this conclusion (on air bladder) applies for seat back for surge push, right? I am thinking about, on my racing rig, to add air bladder on the back of seat with a plate on front of the bladder. I guess this is a bad idea now ?
  13. SeatTime

    SeatTime Well-Known Member

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    You can certainly use bladders for other DOFs, they just were not what I went with.