Feedback for Flight Simulation - 2020

Originally published at: http://www.mudspike.com/feedback-for-flight-simulation-2020/

A Single Amp, Single-Transducer, Haptic Feedback System   “Chosen One, break to follow F-16, left downwind runway two one”… I check left, picking the ‘dainty’ little jet up visually, and reply, “Chosen One, traffic in sight”. As we pass abeam, a tiny flick of the wrist brings with it a slight shudder, transmitted directly to…

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Thanks to our member and friend @jross for his guest article about getting your butt vibrated. Do with this knowledge what you will…but we are not responsible for any permanent injury! If I know Mudspike members, they will be trying to install 10 pound “pucks” in their seat posts…

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When I try to follow the link on your post it just tells me that its password protected.

Excellent piece @jross, reads like a fun project with fun results! Well written too mate! It makes a lot of sense to have tactile feedback from the sim.
I for one am seriously looking into this stuff. Wont be long and my pit’s going to start buzzing…

Might it not be an idea to use one of those IO modules @Troll uses for his input to output to a whole bunch of transducers? That way you could, in theory, use smaller ones to get a relatively strong effect, while also allowing a finer discriminatory effect. That way you can feel the flaps move, the afterburner go, even when your G and stall effect are battling to max it out.

Of course one would have to write the lua interface for that from scratch. Not something I have the time or skill to do.

I’m not familiar with what @Troll has done.

The basic limitation is the software as it only outputs to one sound card. I asked around and it wasn’t in the plans to add another.

You can extend it, though I didn’t get into it in that article. What I did to extend mine was output in stereo to 2 transducers (ultimately one on the left and one on the right channel).

  • one transducer (the one linked in the article) is better for medium-high freq (it will do it all however)
  • one is a heavier transducer (puck) that doesn’t do as well for high freq’s; as set up I don’t really notice anything like flaps in this heavier one, but that’s ok as the other puck covers it.
  • Each is on a separate channel out from the amp: Left -> PuckA, Right->PuckB.
  • I have a higher output amp also than the one described.

Being of different characteristics like this seems to help; I get a little more ‘punch’ for the stall/G from the heavier one while keeping all the other stuff more distinct.

There’s various combo’s possible but, again, the biggest limitation is the software. But it’s still a kick in the arse. It’s the hardest thing to describe; I think some believe it would be too loud, but as I describe, if you isolate it it’s very mild (to outside observers).

It’s just one of those things that, within about 10 minutes I was like, “Wow, I dig this!”. And just can’t stand it without it (though it wouldn’t stop me).

In X-Plane it is, in someways, better; less stuff to fiddle with; I mostly just use the G, Stall & Turbulence.

Yeah, I like it so much that if the person doing the software stopped supporting it I’d dust off my compiler and write my own app. The LUA isn’t that complicated really. Wish ED would support this stuff directly as there is a slight performance hit, but not too bad. Same for XP.

Great article, @jross!

I have been wanting to delve into haptics again, after trying the Jetseat.
The Jetseat gave me mixed emotions… Some of the feedback was fantastic, and really enhanced the immersion, while some feedback broke it. The Jetseat uses eight vibrators and they had a lot of electrical whiny noise, that I could hear through a rather beefy headset. The stall buffet feedback was my biggest gripe. The vibrators seemed to work in ”bursts”. When AoA increased the vibration bursts picked up the speed, but not in intensity.

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This was rather annoying and ruined my immersion.

I would’ve liked the vibration intensity to increase with the AoA, more like

This would give me a more useful feedback of an impending stall…

How would you describe how this works in Simshaker? Is it possible to have a continously increasing vibration, like in the second picture?

The seat in my SimBox has a bottom made out of rubber. I wonder if I could strap a transducer beneath it, using elasticord…? :thinking:

Well, you can code the teensy into a soundcard, if you want. But getting the teensy to drive transducers or vibrators would need a level of coding that is way above my skill level :slight_smile:

I was lucky enough to fly the RAF Leuchars Tornado F3 simulator. It was fixed in place but had a great system for giving the pilot ‘G’ feedback. You sat on a small ‘whoopee cushion’ like air bag. No bigger than a kids party balloon. As you pulled G the balloon slowly inflated, negative G it allowed air out. This very simple system gave a great feeling of realism. If this system was made for dcs I would want it.

On my first visit we went in the sim room and had to stand behind a line marked on the floor - this kept us out of sight of the crew. The cockpit was in front and to the right of us with the graphics all around and above us. When the pilots banked suddenly (run and break) after a long spell straight and level the world appeared to tip over. Which is exactly what I and the other spectator did.
image

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It would be realistic, if uncomfortable and even dangerous, to have the air cushion in a collar you wear around your neck. From 5G on up it would progressively restrict bloodflow through the neck arteries like a good sleeper hold would.

Getting choked out is no fun, in just the same way that pulling 9G is no fun.

I looked at the JSeat but, and this was just my intuition, I didn’t think it would, well, do what I wanted. I’m sure it’s a fine product. And I wanted to see what I could do for less money; if my system broke I could fix it more conveniently.

I’m still sort of experimenting. At this point it seems the optimal system would be 2 transducers, one for higher-freq effects (general purpose), and one with more mass for G & stall. I sort of have it and, based on how you describe the JSeat, it is better for those 2.

I have one transducer on an arm (the only component left over from the BK2 that didn’t fail) and one attached below my chair as illustrated in the article. It’s hard to tell exactly but it feels like the one on an arm is where I feel the stall ‘slapping’ when the stall is deep. And I just think it’s more convincing in VR.

When I’m really ‘haulin’ on the stick, for both G and Stall, it is definitely more intense; If I have the amp gains or setting levels too high, well, it lets you know.

The best analogy I have, and it depends on where you live/drive, is the ‘rumble strips’ on the side of the roads here in the USA (when you drift off to the side of the road): No, it’s not that intense (but you could design a system that was!) but it is similar. And the intensity is based on how fast you are going when you run over them.

Seems it’s all about; power output, transducer mass, and effect frequency. As I alluded to in the article, when set too high, the G and Stall feedback tells you, “Stop that!”, which in my mind is analogous to the real world. My butt-meter would graph just like your second illustration.

But it’s just a sensation; if you play without a headset then nobody around you will know (the sound from the sim will be much louder). May spend some time today trying to record this and upload a video to YT. May have to use my phone…

That isolation seems important; without it, as I’ve set it up (bottom of my chair) the ‘energy’ goes into the floor more (I have hardwood flooring FWIW).

LOL - Yeah I’ve had a similar thought; I could imagine the emergency room report :slight_smile:

“sat on the air cushion”

Here’s the trick to it all: getting it all ‘balanced’, or tuned such that you don’t ‘clamp’ the effect sensation. Or (not illustrated) you don’t get the full range:

It seems a matter of matching up the components as I mentioned above. It’s a formula consisting of the software (settings level for a given effect and use of limiting compressor), the WAV file, amplifier power, and transducer design. The system I describe in the article works, but perhaps not optimally. But it does work pretty well as is.

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I have tried a Viggen simulator that had G balloons in the seat and harness tightener that pulled the shoulderstraps in. The effect was subtle, but very convincing!

Please do!

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Video is uploading now. It’s just under 8 minutes but my dog internet connection is going to take about an hour+ 2 hours! to upload it. I’ll post back when it’s in place.

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To the real life pilots here, what does a stall feel like? A rumble? A rattle? Like a boat on a choppy sea?

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Depends on the aircraft and how it’s flown.
A Cessna 172 in a straight an level stall, where you idle the engine and maintain altitude until it stalls is no big deal. It starts to rumble a little and then the very annoying stall warning horn starts howling and then the nose pitches down. If flown with a sodeslip it may drop a wing, slightly.

More high performance aircraft, with a higher wing loading (smaller wings) will have more abrupt stall characteristics.

But generally you will feel a rumble from turbulent air hitting the stabilizer, as AoA increases. Closer to the stall the rumble increases as the air ontop of the wings get more and more turbulent.

Flying a high wingload aircraft, pulling it through a turn and pressing an accelerated stall, is a different experience and resulting stall is more violent.

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Depends on the stall and the aircraft.

A text book stall demonstrated perfectly to a new student pilot in a training aircraft -

First Demo.

IP "OK Bloggs I will now demonstrate a fully developed stall…note the higher pitch angle, low and decreasing airspeed, reduced control effectiveness and light buffet. You can now possibly feel an increase in the buffet. The nose and wing might drop but haven’t. The aircraft is now stalled and will sit here happily until I carry out the standard stall recovery as we discussed in the briefing. "
SP “But nothing happened”
IP " Look at the VSI and note the high rate of descent, also look at the ASI and note the low fluctuating airspeed. You can see from the altimeter that we are sinking rapidly. I will now recover, note the loss of height as I do so "

Second Demo
IP "I will now demonstrate a fully developed stall. Note the higher than expected pitch angle, the low and decreasing airspeed, reduced control effectiveness and light buffet all indicating the approaching stall. You can now feel full buffet and note the airspeed as the wing and nose drop vigorously showing we have stalled.You must also note the aircraft’s tendency to yaw which will develop into auto-rotation and a spin.
SP “Aagh…Uurgh”
IP “l now carryout the standard stall recovery. Do you have any questions?”

A rapid entry, banked attitude, power, rough pilot handling, being outside the cg limits and yaw make the stall more technically interesting.

A gentle entry with no power, slip ball perfectly in the middle and smooth handling of controls the student will probably not notice the aircraft has stalled.

On the other hand with the nose pitched down and a banked attitude of 120 degrees or more and a rotation like a sycamore seed.you are now spinning. They always notice this.

NB many aircraft are fitted with a stall warning system where a buzzer or light will activate about 5kts pre stall. In larger aircraft a stick pusher or stick shaker may operate.

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I would describe the rumble as buffet. It is more vibration rather than noise caused by turbulent air braking away from the aerofoil and rolling over the elevator causing a small oscillation in the stick/yoke.

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The definitive teaching manual in UK.

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