The control question to end all control questions (real Mi-8 control deflection)

[Dvst]

This is a shameless crosspost from the Gazelle forums because the same question applies to the Mi-8 :)

 

Bonjour fellow flying antilopes.

Feel free to skip the giant preamble and go straight to the question.

 

We all know that many of the control problems in simming come down to the differences in deflection between our home joysticks and their real life counterparts we are trying to approximate.

Now, since the DCS helicopters ( and especially this beauty ) really do require us to properly train our muscle memory, those problems become harder to just ignore or work around for me.

Of course the easiest sollution would be to match the deflection or travel of the real controls by extending the stick ( easily done with a Warthog ).

 

A similar approximation is the popular decrease of Y-Saturation to at least match whatever control deflection we can get out of our sticks.

If ( for example ) I guestimate the stock Warthog's deflection to be about 17-18 cm (meassured point to point using the hypothetical centerline of the lever ) and a fellow forumite was kind enough to meassure real control deflection for the Huey; we arrive at the conclusion that my trusty desk stick covers about 49% of the Huey's cyclic range.

So with Y-Saturation set to 49 the two controls turn out to be reasonably matched.

 

The obvious problem of course is losing half the Huey's cyclic.

The answer must lay in some kind of curve.

But what curve?

S and J type curves present a massive problem: although they dampen or sharpen up the controls to an arbitrary point of individual comfort, they can only be used to match the *real* controls at exactly one point of the entire axis.

To stick with the Huey cyclic example: a curve setting of about 20 will result in the halfway point of the deflection being roughly matched to the real one.

The problem being that the stick will now be too mushy and insensitive below that point and too increasingly sensitive above.

Whats far worse though is the ( pardon me ) curving nature of the curve, which distorts all proportional sense of movement we can feel and train for naturally.

Our hand-eye coordination simple is not geared towards easily decoding none-linear proportions ( I suspect this is why many virtual pilots prefer completely linear control inputs - it is in a way easier to rehearse the delicate manipulation of a shortened linear axis than it is to memorize a disproportional curve ).

What sounds complicated in the abstract is actually rather easy to feel. Give the Huey a quick whirl with 49% saturation and repeat whatever you did with a 20% curve.

 

Luckily a curve does not need to be as gradual as s-curves are.

A simple compromise that really works for me (as a person who prefers linear inputs) is what I daringly call a 3-point curve (aka 2 straight lines ).

The idea is to break the axis up into 2 stretches: one stretch matching the real life deflections exactly and one stretch that is more sensitive but still localy linear all the way to 100%.

The result is two hapticaly linear stretches of control.

How large the 1 to 1 "matched section" of the curve needs to be is somewhat a matter of taste, I decided to pick the first 20-25% since that covers all things hovering for the Huey.

Easy to gauge by setting Y-Saturation to match the real control and then watching the control indicator box during hover.

Here is what it looks like (note the first 25%):

Give it a try - especialy if you can't really get to be friends with normal curves or if you tend to think "something is mushy here".

 

 

Now finally the reason I'm posting this wall 'o text: This method of mapping "desk-to-real" can only work as intended by actually *knowing* the travel or deflection of the real life controls.

To achieve something similar for our polygon Gazelle one would need the figures concerning the real Gazelle *gasp*. . . and I can't find them.

My instincts tell me that the Gazelle's cyclic has a very similar pitch deflection throw to the desk Warthog ( maybe shorter even ) and I'm almost certain that the roll deflection is actually a *substantial* bit shorter than the Warthog's X-axis.

 

I would really love to know for sure.

Can anyone help with the real life data?

 

So can anyone help with the Mi-8?

What are the real life cyclic and pedal deflections?

Edited September 2, 2016 by Dvst

[msalama]

Hmmm... tried something akin to what you've done, found the rest of the setting after the "knee" just too sensitive for my taste. Granted, haven't flown the Gazelle at all yet, because I want the development to settle down 100%(ish) first, but as it comes to the Mi-8, I still prefer a curves setting because it's more gradual still. Anyway, I know what you mean, and some other craft may actually benefit greatly from using settings like the one you described...

[Rogue Trooper]

For choppers, this is probably the most critical discussion us chopper simmers could have. Choppers are far more critical than jets when it comes to controllers.

 

For me there are a number of questions...

1) What ensures that those lucky dudes who own a correct throw cyclic will get the most out of the module they purchased. Is the sim perfect for them?

I do not own a superb chopper cyclic stick, but this is where we must start our conversation, we must have a reference point from which the rest of us can work from (give or take a few cm of throw).

We must have sim to life accuracy and this important information should be published at release!

Our own weaknesses should never come into this conversation.

 

2) Then, what do us not so lucky guys with our standard sticks need to do so that we can accurately replicate the controllers of the module. For sure this is difficult without (1).

 

I have a hawg with a 10 cm extension, mounted betwixt legs. Total pitch throw measuring from the top of the Hawg is 24 cm, around 12 cm from centre to either extreme.

 

In both the Current 1.5 S and 2.0 A I use no curves or saturation in either the Gazelle or MI-8, but a fella has to wonder what control I am losing due to the loss of throw in either module. however the critical questions still remains unanswered, what is the real life throw of an Mi-8, huey or Gazelle cyclic?

I think this needs to be published.

 

The Mi-8 is very similar to the gazelle, whilst total throw of the stick is debatable, the total movement of MI-8 stick from empty hover (Joystick cheat diamond trimmed back and right, Diamond below horizontal line and top of diamond just below the horizontal reference line) to a forward speed of 200 Km per hour is only about the one and one quarter length of the diamond... tiny

Both these machines have very small operating areas for the stick during normal use but allow for full stick throw in extreme conditions.

 

so generally speaking the centre area is critical, if you can expand this area with a curve whilst not reducing total throw then this is the way I would go.

Edited September 2, 2016 by Rogue Trooper

[msalama]

This is what one of the BST devs says about it. Not a direct answer to the questions raised here, but helpful still IMHO as it gives an inkling of how the developers themselves view this. Although even their opinions vary it seems ;)

 

https://forums.eagle.ru/showpost.php?p=1869001&postcount=2

https://forums.eagle.ru/showpost.php?p=1744409&postcount=4

[_Randolph93]

This is what one of the BST devs says about it. Not a direct answer to the questions raised here, but helpful still IMHO as it gives an inkling of how the developers themselves view this. Although even their opinions vary it seems ;)

 

https://forums.eagle.ru/showpost.php?p=1869001&postcount=2

https://forums.eagle.ru/showpost.php?p=1744409&postcount=4

 

As mentioned in these posts, after experiments with the right curve I think using linear input is best solution.Sure with added curve I had somewhat better aim(as Mi-8 has unguided weapons)

but with linear input there is less trimming annoyance and I feel as I have better control of the chopper overall.

[msalama]

Might work for you, but a common short-throw JS still doesn't mimic the real thing in any way. You'll either need an extension, or to set up curves, in order to make it behave at all like a real chopper cyclic. True, you'll need to trim a lot if you use curves, but I've found that less of a problem than using a coarse short-throw stick at default. But as always, YMMV...

[BitMaster]

A WH elongation is highly desirable I guess. If I could mount my stick the proper way I would buy one right away.

 

Having flown R/C for like 20 years, scratch build my balso bombers etc.., I have fiddled with S curves ( progression or degression ) and Dual Rate switches throughout that time on Radios far superior in programming and mixing than DCS and DX allows in our case.

 

The outcome, aka wisdom, of this endless hours spend programming airplanes and helis is this: You should not fix digital what you messed up mechanically or could easily fix mechanically instead ( our WH elongation )...for many reasons.

 

The longer stick gives more travel resolution, linear and always reproducable.

 

 

I do not use any more Degression-S-curves to smoothen the 0-point. I fly linear, everywhere and always, much more simple and always reproducable.

[Fishbreath]

I've never had any trouble flying any of the helos with a purely linear CH Fighterstick, personally. If I were inclined to change the curves, I'd probably go with simply reducing saturation to match the length of my controls—unlike in airplanes, in my experience you never really need full controls deflection in a helo, since trimming changes the centerpoint anyway.

[gospadin]

I do not use any more Degression-S-curves to smoothen the 0-point. I fly linear, everywhere and always, much more simple and always reproducable.

 

I too have moved to linear. If needed I'll reduce saturation.

[msalama]

If linear works for you, fine. It has never worked for me with short-throw controllers, so I'll keep on using curves regardless. I'm just finding everything much more precise that way...

[rrohde]

Heck, even on my 20cm extended VKB Mamba I still use curves because the stick's resolution is way too fine around the center - so linear isn't always the go-to option with extended controllers.

[Frusheen]

I'm using a full length cyclic from Komodo Simulations. All linear the mi-8 has perfect response.

[DieHard]

I setup my CH Fighterstick, Pro Throttle and Pro Pedals as Chuck suggests in his guide, (page 7).

https://drive.google.com/file/d/0B-uSpZROuEd3NVJwVjhQZG0xZ2M/view

 

 

Watch this video:

===========

 

 

I knew a guy a few towns over, he lived out in the country. He was a VietNam vet from the mid-1960's. In his front yard, he bought a gutted out Huey via military surplus and placed it there for all to see---he just could not get the 'Nam out of his head; and did not want to!

 

You realists should buy a Mi-8 cockpit via military surplus and build a realistic sim-pit. I am fine with my puny joystick, LOL!

 

Interesting discussion. That's the joy of a broad spectrum audience (customers) bringing their own views and experiences to the subject.

Edited November 24, 2016 by DieHard

[DieHard]

As mentioned in these posts, after experiments with the right curve I think using linear input is best solution.Sure with added curve I had somewhat better aim(as Mi-8 has unguided weapons)

but with linear input there is less trimming annoyance and I feel as I have better control of the chopper overall.

 

That is how I learned to fly the DCS WWII German aircraft.

 

After awhile I will probably reset my controllers to zero linear also. I bet the Mi-8 autopilot will perform better.

 

My current setup via Chuck's Guide, I can sim-fly the Mi-8 freehand not using the autopilot at all with pretty good results including landing it, even on a shallow slope as to setting up JTAC units in MP servers.