SimHQ is fortunate to have Aerospace Engineer and Guest Writer Erik Pierce, write a week-long series on some of the technical aspects of DCS: Black Shark.

The Series Introduction and Erik's bio is here:
http://simhq.com/_air13/air_426a.html

DCS: Black Shark and Coaxial Rotor Aerodynamics is here:
http://simhq.com/_air13/air_427a.html

Tuesday - Trimming the Black Shark is here:
http://simhq.com/_air13/air_428a.html

Thursday - Autopilot, Part 1
http://simhq.com/_air13/air_429a.html

Friday - Autopilot, Part 2

Excellent intro and article. I am looking forward to the follow-ups.

Beautiful article. Very much looking forward to the rest. Thanks for writing it.

Good overview. I knew the Ka-50's net torque was caused by differential blade angles on the rotors but I never thought of it in terms of shuffling the lift (and related blade torque) around. Also the left bank tendency is not something I had thought much about.

You mention maneuvers in the vertical plane and how to avoid rotor collision but this leaves out the all important horizontal plane. It's a big deal to have it memorized that left/right turns are less/more dangerous while at the limits of the flight envelope. I would go so far as to even plan my mission route and formation tactics to favor the turn direction that lessens the chance of rotor collision.

I like the Ghostbusters reference.... that made it pretty damn clear that I don't want to cross the beams....er blades

Great stuff. Reinforced what I had suspected all along from engineering intuition.... Now, how do I use this to get the simming people I know to play the game? It seems that people either love or hate the Shark. It's this technology that makes me love it but all my simming buddies hate it for those same reasons. Sigh!

Oh, the "Black Shark For Dummies" was my article, Leo, and the one you want to show them if they're not into switchology or want to go deep into the sim.

Then if they want to do things properly and want to know what's actually going on (and why) they read these articles. These are the "real deal" of what's going on.

The super cool thing about the sim is that we fly together in the same server with the high difficulty settings and work well as a team.

He transfers lift from a horizontal plane into a vertical by pulling back on the cyclic while simultaneously changing the pitch of the blades by use of the pedals to offset the difference in torque and transitional lift until airspeed is sufficiently low, at which point he rapidly changes the dynamic of relative pitch until the the helicopter has turned about, facing the ground. At that point he returns the rotors to a more natural state, pulling back on the cyclic to regain horizontal lift with the helicopter facing the other way.

I do "the thing with the thing."



The truth is that both approaches are complimentary, and we've spent some time on Teamspeak talking through how to do stuff and why it happens, making the sim much more enjoyable for both of us. Lots of "oh, I get it!" back and forth. Plus Chief to ring in with switchology in the areas where both of us are a bit fuzzy.

Great article, thanks for your work.
I had just finished wading through chapter 4 of the BS manual in an effort to try and get to grips with some of the fundamentals, and why things are the way they are.... your article was a breath of fresh air and added another dimension to what I have to learn. It was also a good and easy read.. made perfect sense.

Keep up the good work.

Great article, Erik, thanks! Two things I noticed though:

- 2nd paragraph, 1st sentence: end should be "upper rotor generates more torque than the LOWER rotor."

- 2nd paragraph, 2nd sentence: "torque acts opposite to the direction [OF ROTATION] of the rotor blades."

wow, never knew thats what happened. Now I know and can avoid this....thanks!

Thanks to all for the kind words. I really want to share what I've been learning about this fantastic simulator and really struggle to put what (I think) I know in a format is neither condencending or uninformative. So far (based on the kind comments!) I seem to have acheived that hallowed middle ground! We'll see how well I do on the other articles!

Frederf,
I don't fly my routes fast enough to make horizontal maneuvers a concern and I also didn't experiment specifically to see if rotor collision risk is greater for a turn in one direction or the other - I treat any maneuver near Max IAS as risky! - but kudos to you for incorporating this into your flight planning. That's a mark of a very smart pilot!

GregP,
You only found 2? You're not looking hard enough! Seriously, though, thanks for the editorial comments and feedback. I do truly appreciate it. My editors/reviewers did a great job of catching most of my errors, but those two happened to get by all of us.

And yet he STILL flies circles around me!

Part 3 has been published.

Trimming the Black Shark is here:
http://simhq.com/_air13/air_428a.html

I think trimming is the one thing that turns most first timers off to this simulation. It took me an hour after I installed the game to wrap my head around the process but after the light went on it was second nature. I think too many want to "kick the tyres and light the fires" but that just isn't a workable approach to Black Shark. I've spent hours just hovering perfectly still while watching a friend gyrate madly through the sky trying to do the same. I can't get him to crack the DVD case open any more. Sad.

Before you fire off a single round of ordinance, learn to hover. Learn it WELL. Ingress at full speed to some random map point. Stop at that point and hold that point... HANDS OFF. Learn how to do it quickly and smoothly. Once you master the stable weapons platform, it's a turkey shoot. As long as the turkeys aren't shooting back, of course. Once you learn the weapons while holding still, employment of is much easier at combat speed.

This is a study sim. Perhaps the most study intense sim ever. The article author has done his studying, shared his advice, thoughts and experiences. Put in a little bit of "training time" as he has and the fun will follow.

Thanks for the article! Very nice read!

Hi,

Great stuff !

Erik "EinsteinEP" Pierce should have been hired to make training tracks for Eagle
Dynamics.

This is essential stuff that we need to know. to fly that sim.

Thank you Erik

A big hurrah for LawnDartLeo's statement. Well done sir. Great article yet again from EinsteinEP.

Thanks for the article, but I'm a bit confused about the use of the trim button in the sim now with the latest patch. Previously, I would press and hold the trim button during any manoeuvre and then release it when I reached the heading/state I wanted. I have been doing that in the sim now with the latest patch and have had two occasions when after trimming, the controls do not respond. Turning off the AP channels and turning them back on helps.

But from reading the article, it seems I should only be pressing the trim button once, after I have used the controls to establish the flying state I want. is that right?

thanks

smith

There are two camps of folks out there: the press-and-hold-Trimmer and the tap-Trimmer camps. Each approach works, but pressing and holding the Trimmer button during an attitude change (e.g., bank to the left) is a good practice to get into if you plan on using the autopilot and maintaining smooth transitions (more about that in an upcoming article!).

The fact that your controls "lock" with patch 1.0.1 is probably unrelated to the autopilot, however. After the pilot releases the Trimmer button, the new Trimmer logic implemented in 1.0.1 waits for BOTH the cyclic AND rudder inputs to be centered before the helicopter will respond to those inputs. For example, if a pilot releases the Trimmer button, centers the cyclic, but leaves the rudder a bit off center, the sim ignores BOTH until BOTH controls are centered, the helicopter is a smoking crater, or the cows come home*. This Trimmer lock is why many pilots have opted to revert back to the "old" Trimmer (which you can select in the options menu). Big kudos to the ED folks for leaving that option up to the user!

If you don't think this is what caused your issue, and you can repeat it, save the .trk file and post it up at the ED forums at www.digitalcombatsimulator.com. They got some pretty smart guys over there who can diagnose it for you.

[*I haven't fully tested this condition yet.]

Thanks EinsteinEP. i use a Cyborg 3D (non-force) with a twist rudder and that may be it.

Great series of articles.
I am looking forward to the rest of them.


Wheels

Good summary of the trim system. I really like the way it works in BS; you are correct that it requires practice. Trim experience, however, can vary quite a bit on different controllers. On my Saitek HOTAS the 1.01 style trim works very well as long as you remember to center both the cyclic and rudder. On other sticks, results vary.

On my Logitech G940 FFB stick operating in non-FFB mode, letting go of the cyclic and rudder only works about 70% of the time without sticking. This is due to the stick's lack of precise centering in non-FFB mode--which is much worse than the spring-loaded Saitek. Although you mention in the article that this is often due to operator error, it can also be due to hardware. I addressed this issue on the G940 by introducing some deadzone on both the cyclic and rudder pedals, and this has pretty much solved the problem. I'm not crazy about having to use deadzone, but it works quite well.

FFB trim is supposed to be the most realistic way of trimming, but from what I hear, the old MS FFB stick is the only one that works really well. I have an old MS FFB Pro, but unfortunately, its a Gameport stick and doesn't work on W7. Unfortunately, the G940 is not yet really suited to use with BS in FFB mode since there is too much play in the stick, and too much cyclic "bump" when engaging the trim. Also, rudder trim happens instantly in FFB mode, so you literally have no time to center the rudders before having your yaw adversely affected--especially, if the pedals are shifted by any significant amount prior to the trim. IMHO, when operating in FFB mode, ED really needs to provide the ability to turn off rudder trim or at least hold rudder position independent of the cyclic until the user manually recenters the pedals. In any case, there are definitely things that ED can do to better support the G940, but until they do, I find that the older 1.01 manual trim method works best.

Part 4 has been published.

Autopilot - Part 1 is here:
http://simhq.com/_air13/air_429a.html

Very nice! Any chance for a slight expansion on the Flight Director Override?

The conclusion of the series, Part 5 has been published.

Autopilot - Part 2 is here:
http://simhq.com/_air13/air_430a.html

Thanks to Erik for a terrific series!

Rotor collision tendency is actually made worse by turns in one direction and made better by turns in the other. I'm pretty sure that for the same rotor load there are times when turning makes the rotor collision not happen when it would in straight and level flight. It may be overzealous to make your flight plan to prefer the safer turn direction but it is non-trivial to train rapid combat maneuvers to prefer a given direction. Dodging an incoming missile is usually not a gentle maneuver and picking one way to turn can mean the difference between a narrow escape and clapping the blades together in a flurry of doom.

The "“ДИР УПР" button (Flight Director) is a pretty curious beast that I don't fully understand myself. I know that it is with a very large grain of salt that we use the same term "flight director" (roughly translated from Russian) for both the function in the Ka-50 and the function of the same name in a civilian airliner like a Boeing 737 for example. The B737's flight director and most others in the western aviation world is simply a visual guide of what to do with the aircraft to get it to go where you want it to go. The Ka-50 has some HUD visual aids for navigation and airmanship when in FD mode, but the similarity ends there. Unlike the flight director in a B737, the Ka-50's FD mode gets its mitts into the control loop and has a pretty good say into what the control surfaces do or don't do.

With FD off your Heading, Bank, Pitch buttons actually activate two different functions: both the filter-stabilization and the ability to hold a value. With FD on the filter/stab function still works but the hold function is overridden (similar to having Trimmer button depressed) for the purposes of the FD.

So FD is flying with stabs on, holds off, and the autopilot generates visual HUD cues instead of control inputs.

What I'm trying to look up is if the Autopilot's 20% authority is ever disabled by pilot control input. You think the autopilot wants to go left and the pilot wants to go right then -20% and +100% means the result of their fight would be +80% input to the right. However I have a suspicion that if the autopilot detects that the pilot really wants 100% input, it gives up its 20% so it doesn't limit the pilot from going to 100% when he needs to.

Great job on these!

Btw, I'm the resident shaman in our squadron that routinely shakes a bag of chicken bones at the autopilots he mentioned, purging them from my cockpit!

However, many is the time that I arrive a bit worn to an objective area from flying everything by hand while Einstein is fresh as a daisy and refreshed from look-ma-no-hands-I'm-drinking-coffee autopilot use.

Just a fantastic bunch of articles. Have learned a thing or two which I'm going to utilize in my own flying. Many thanks for the education!

I would love to see more of this type of writing on DCS Black Shark. It would be fantastic to see similar articles on traffic patterns around airport landings, FARP traffic patterns (What does the crossed T mean?) and of course weapons employment with this beast.

Wonderful articles...

Believe it or not, there's really not much else to expand on! Like Frederf pointed out, from a controls perspective, flying with Flight Director on means that pilot inputs are augmented for stability and that's all! No other autopilot control feeback goes to the rotors at all in any mode. Although one could say that Flight Direct "basically turns the autopilot off", the modes still function as described, the autopilot keeps track of desired conditions and deviations, it just shows the appropriate corrective actions in the HUD and HSI rather than actually affect the control inputs.

One way to keep this in mind to remember that with the autopilot Flight Director on, the pilot has to do all the work while the autopilot "directs".

You can download the high-quality Black Shark manual free from www.digitalcombatsimulator.com (look under Files) which has a section that details these steering cues, which is why I chose to omit it from my article (pages and pages of pics and descriptions!).

If have specific questions, you can always PM me or check out the forums at www.digitalcombatsimulator.com.

Absolutely fantastic series of articles here, Erik. It amazes me that so many have written so much on the Black Shark's controls and I always manage to find a few new ideas to try with every article I read.



This EXACTLY sums up why FD so confused me at first - I too was thinking of that projected ideal flight path.




These two statements are by far the most perfect and succinct explanations I've come across of what the heck the FD is ... thanks guys!

Great articles, thanks a lot Erik! Finally I understood why some peope were going on about "pressing the trim button every time they move the controls". At least I think I understood Just to be sure:
- Keeping the trim button pressed has the same effect then having FD enabled
- Therefore, if I don't have the trim button pressed while moving the controls (assuming FD is not enabled of course) I basically fight the autopilot inputs.

Correct?

Short answer: yes.

Long answer: I wouldn't go as far to say that pressing the Trimmer button has the same effect as the Flight Director mode - they are certainly two different functions! - but your point, I believe, is that autopilot control feedback is disabled in both cases, which is absolutely true.