The control question to end all control questions (real Gazelle control deflection)

[Dvst]

Bonjour fellow flying antilopes.

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

 

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". :joystick:

 

 

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?

Edited September 2, 2016 by Dvst

[Shadow_1stVFW]

Very well written. I hadn't thought about curving the axis like this until now. Thanks for the idea.

 

Sent from my SAMSUNG-SM-T707A using Tapatalk

[0xDEADBEEF]

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.

 

But at the same time you give up max deflection, which you can only overcome by using the trim function, which I personally don't on helicopters. I prefer modding my springs to give little to no friction, as trim in a non-ffb stick is just unrealistic and gives away the possibility to actually feel the attitude of the helicopter via the actual stick deflection off center. If you want realism, get an extension to match the throw you are looking for. Especially in helicopters I would not use any kind of curves because of the way they work and are piloted.

[Drakoz]

This is a great analysis and suggestion. I bet a lot of people forget, or don't know they can adjust the curves in DCS using the "mixer" sliders on the Tune panel. It is a very powerful feature.

 

I would also suggest, though, that the human brain is a lot better at compensating for an S curved axis control than some might think. In RC flying, for example, many pilots add Expo (as we call it - basically the S curve or curvature in DCS) to our controls for the same reason people do it in DCS. But it's even more important with an RC radio control because we are flying (sometimes purposely twitchy) aircraft with our thumbs - and it's hard to move a joystick with your thumb. :) Yet, people compensate very well with practice. So much so that many RC pilots will add significant Expo (a large S curve) which gives very fine control around stick center, but with a flick of the thumb, they immediately get a radical control input - what I call a kick.

 

With practice, regardless of how non-linear or linear the control stick is, you will get used to it. And if you practice using S curves that are constantly different (which happens if you fly different aircraft, or different settings for different purposes), you will also get good at immediately recognizing where the S curve knees are and compensating for it, even if someone sneaks in and changes the curves on you without you knowing it. Not immediately, but within a few minutes an experienced pilot will compensate.

 

 

 

I often explain the concept as kicking the stick. Balance a broom (bristles up) on the palm of your hand. Now move the broom back and forth slowly. Easy enough. This is like the more flat part of the S curve. You balance the broom by moving your hand slowly and the top of the broom follows closely. This is all fine control.

 

Now quickly, throw your hand 2 feet to your left, then 2 feet to your right, then back to center, all the while not losing control of the balance of the broom. That is like exceeding the knee of the S curve. The part I call kicking the stick. Here, you are focused on a radical hand movement, but the broom can't immediately follow your hand. So you make an input on the broom that would cause it to fall if you then didn't immediately compensate back the other way to catch the fall. For example, when you move your hand back to center, you have to slightly go past center to stop the momentum of the broom from falling over, and then you can center your hand.

 

The two motions of the broom require completely different strategies in how you compensate for losing balance. And, flying a helicopter sometimes requires the same thing - especially one like the Gazelle. To get the Gazelle to respond quickly and radically (say a left aileron roll), you must kick the Gazelle stick hard left, a split second later, the Gazelle will respond quickly and radically. But now you must quickly kick the stick back the other way to catch the response and stop the Gazelle from turning to far.

 

If you had to kick the stick (balance the broom) with a soft (flat line) curve, you end up having to move your hand too far to get the "kick". It takes too much movement of your hand to kick the stick. But with Expo (an S curve), you can move your hand a relatively small amount - just past the knee of the curve, and you get the equivalent of kicking the stick, but with a very fine (small) movement of your hand. And sometimes kicking the stick works best if you don't have to move much. The force control of an F16C flight stick is a perfect example of this, where flight control is practically a muscle twitch of the hand instead of a movement of the arm.

 

Of course, all this applies equally to a flat curve (like on a real helicopter cyclic), but much of my point (and Dvst's point) is that our short joysticks don't quite work like the real thing. The throw is wrong. The proper way to solve that is to extend the stick so you can put a flat curve on your DCS control inputs that matches the real thing. But in lieu of that, adding Expo (S curve) to our short sticks is in fact the proper way to deal with it. I say that because reducing the max throw (reducing saturation) is the worst thing to do. It preserves a flat response curve and makes the short stick feel more like the real thing, but it actually removes the amplitude of your max throw, preventing you from performing a proper kick when needed.

 

 

Some of you will disagree. And of course you would be right as we are all different in how we feel about our controls. It's a more complex topic than I have explained here. It's all about the human/machine feedback loop, muscle memory, and our ability to _subconsciously_ compensate for different controls.

 

But, it really just boils down to what you get used to - practice. Practice will allow you to overcome any flat or S curve you are given, and in fact, with more practice, you'll get to the point that someone can throw any type of curve at you, and within a few minutes, you will compensate for any amount of non-linearity and be flying with that curve. It may not seem possible - I'm sure many of you have spent hours getting frustrated at making your stick control the helicopter as you want no matter what S curve or Saturation values you use. But keep practicing and you will eventually see what I mean. Worry less about if the control is perfect, and worry more about learning to fly with the control you have.

 

I'll say, however, if your goal is to make DCS as close to reality as possible, than Dvst's analysis is very significant. Real helicopter cyclics are very sensitive, and do not have an S curve. Matching that sensitivity with no Curvature in DCS probably requires lengthening your stick to match the real thing, and applying what Dvst said about saturation, etc.

 

Regards,

Michael

[Hawkeye60]

I've read this thread with great interest and because of the points made here, have adjusted my warthog axis to

 

100% saturation X and Y

 

12-15% curve X and Y

 

This has made a huge difference in the fine control around stick center

 

and made hovering and transitioning to hover much easier!

 

I do have a 25cm home made extension on the warthog.

 

This leads to a question,

 

Anyone flying the Gazelle have a helicopter cyclic, or a long extension on the stick?

 

What difference did it make in the control? Did you need to adjust the axis?

 

I ask because I see there are extensions and kits available to turn the warthog into a helicopter cyclic.

 

All for about $110.00 plus shipping.

 

Before I spend and do the modifications, I need more info!

 

Any insight appreciated.

[Drakoz]

I can't comment on having an extension, except to say that having one will allow you to use less curve and still get the same result or feel regarding fine control. Plus, you can get that feel, using less curve than with a shorter stick. Hence what Dvst was talking about. Finding the right settings and extension to mimic the actual aircraft stick. Ideally, the stick length should be such that you have 0 curve and 100% saturation and it matches the sensitivity of the real aircraft. But that varies from one aircraft to the next.

 

On the other hand, taking my comments into account about learning to fly and learning to deal with what you have, even if you don't have an extension..... Start learning to fly with a large amount of curve so you have good fine control at the middle of the stick while you are learning. When you get comfortable that you can hover with those settings, then start to remove the curve (flatten out the curve) and then practice until you get comfortable again. Eventually you will get to the point that you can fly and hover comfortably with no curve at all.

 

I gave the example of learning to fly an RC helicopter. When I started, I had the rates on my RC controller so low (fine - like adding a lot of curve, or dropping saturation to 70%). The helicopter was easy to fly, but not very responsive. As I got better, I kept making my controls more and more sensitive (saturation back up to 100%, and removing the curve). Now when I fly using the settings I started with, I can't stand it. There's no response because the control is too flat (takes too much input to get a reaction). On my RC helicopter, I fly with 100% saturation, and only a minor curve (because a 3D acrobatic helicopter has the controls so sensitive that you typically need some curve for fine control, but full saturation because the flick of a thumb needs to send the helicopter into an insane loop or roll - and that's what we want for RC).

 

So saying it again, in DCS use Curve (and maybe Saturation) to learn. But your goal should be to eventually have Saturation set to default (100%), and no curve. If you can fly DCS with these settings competently with a stock joystick, then you can fly a real helicopter.

 

The only statement against that is PC joysticks have springs and center detents. Take a Warthog for example, If you are hovering a helicopter with a Warthog and you are constantly crossing over the center detent, it can get annoying as it affects your fine control. You have to constantly vary your hand force to overcome the detent to not over compensate. Real helicopters don't have this issue (no centering detent). You can reduce the detent by doing the spring mod. Helps a lot. For me, I fly with a MS Force Feedback 2 with the FFB spring force set very low. There is no center detent to contend with using that stick.

 

In fact, I can fly with 3 fingers on the stick. That allows me to relax and have better fine control. And in fact, I learned that from my first flight in a real Robinson R44 - the instructor told me to rest my hand on my leg, relax my hand. and use 3 fingers (2 fingers and my thumb) on the stick. Made a _huge_ difference.

 

Now I fly with my entire hand on the stick, but that's because as I practiced, I was able to fly with my full hand on the stick and still remain relaxed and in control. No arm pump from squeezing the stick too much or feeling like I have to hold my muscles too much. This is all just part of the learning experience, be it a real helicopter or DCS. You need to learn to relax and maintain fine flight control, and as you do, you'll see that a more sensitive stick is in fact better. But starting out, go ahead and turn down the sensitivity (add Curve or drop Saturation) as it makes it easier to learn when you are a novice. We don't get to do that in the real helicopters.

 

Regards,

Michael