BS Auto Pilot description and operation

It has commonly been noted that in the normal autopilot mode with the three normal autopilot channels on, the autopilot will fight you if you move the controls. This is not true. It is true that absent any control inputs from the pilot, the autopilot will attempt to hold the aircraft's heading and attitude. However, if the pilot moves the cyclic or the pedals, the autopilot is aware of that and makes no move to interfere, although it continues to provide control input for the purpose of dampening (stability augmentation is the term typically used in the West).

While I do not disagree with you, I feel "dampening" IS "hindering".

Just try to turn off heading hold and step into the pedal - The Ka-50 is MUCH more agile that way.

I only turn on heading hold for hovering, "Route mode" and "turn to target" (and YES I'm aware that in RL you do NOT turn it off).

Pitch- and bank hold are nice to have engaged all the time, tho.

Just my opinion.

The HSI switch if in the Manual mode allows you to set the desired HDG bug. In AUTO the heading and course pointers are driven by the NAV system.

Manual pg 2-18 item 13

Just try to turn off heading hold and step into the pedal - The Ka-50 is MUCH more agile that way.

I just spent 20 minutes doing just this, and I found that there is no difference in agility. Yaw rates are the same, and authority is the same.

I think there is a small differens between having HDG HOLD on or off whilst yawing.

It is true that Yaw rate is the same, but what I think happens, is that once You lessens the amount of pedal input, and it falls within the 20% of AP authority, the AP takes over and tries to stabilise Your heading at the heading present when the amount of pedal input fell into those 20%.

I feel that I need to feed in a small amount of additional pedal travel inorder make the AP stabilise heading where I like it to. Whitout HDG HOLD any amount of pedal works. With HDG HOLD the pedals need to be bought outside the 20% before the AP recognises it as a heading change. If inside 20% the helicopter will still turn, but once the pedals are zeroed it will try to regain the initial heading.

Normally I fly with all 4 buttons on, cause that gives the smoothest flight, but once I need maximum agility , but still dampened controls, I switch off HDG HOLD and ALTITUDE HOLD.

Wothan

If inside 20% the helicopter will still turn, but once the pedals are zeroed it will try to regain the initial heading.

You can turn 180 degrees, but if you don't trim, the AP will still bring you back to the original heading.

In order for me to replicate "fighting the autopilot", I had to use extremely minute pedal inputs. I found that pushing the pedal more forcefully (but by no means jamming on it), it turned just fine with absolutely no pause around the "20%" mark. If you want to make a very minute heading change (less than about 5 degrees), then barely touch the pedals will work fine, although at a certain point the AP will stop you. If you tap the trimmer at that point, you'll stay at the new heading. If you want to make larger heading changes, get on the pedals just a little harder and you won't see any delay at all. If you were truly fighting the autopilot, you would see a slight pause around 5 degrees of change, or right about there. I didn't see it, personally.

No - I´m not experiencing "fighting" the AP.

I can turn fine with HDG HOLD on using the pedals, also using small pedal inputs.

What I meant is that when You approach You desired heading with HDG HOLD on, once You start to lessen You pedal input at some point You will get inside 20%, and at that point the AP wil recognise that as Your new heading. You can still control yaw with the pedals, but try to zero them and the AP will try to yaw the helicopter to that heading.

Hard to explain - but it feels like kind of "rubberbanding" once pedal movement comes within those 20%.

Blipping the Trim button will keep the exact heading once You have stabilised Your desired heading with the pedals, but that was not part of my explanation of how I feel the differens between using HDG HOLD or not.

I think that both the AP and the trim works correct as it is now.

The good thing is that every "Pilot" has the option to choose what ever Autopilot / Stabilisation mode (s)he prefer.

I use the trim during the various phases of flight - Right after take off, when established in forward flight at the speed and altitude I want, and again when going into a hover.

I always fly with the Pitch and Roll stabilisers on. I rarely use the flight director mode. Altitude hold is used during long cruise sections, as well as when in auto hover.

I use the HDG hold during cruise and in auto hover, but usually turns it off together with the altitude hold when strafing targets, as I feel that I have more precise control off my flightpath, and thus easier can correct my aimpoint that way.

Wothan

If I fly with ALT HOLD on (just the light) and don't use the collective brake it should impact me right? Reason being after leaving autohover the light remains on.

WHen you turn off auto-hover you should also turn off the altitude hold channel, unless you expect to remain at the same altitude.

Great thread - thanks guys!

In normal use, Pitch and Bank Hold are actually Attitude Hold. They are not just dampening or artificially stabilizing. The only time you get just pitch, bank, and yaw dampening is when in Flight Director when those three buttons are on. In my opinion, there should be separate Pitch, Bank, and Yaw dampening switches, apart from these Hold buttons that should really only be to engage the AH functions. Yaw trim really should also be separate. Unfortunately, in both cases I guess Kamov didn't do that.

I'm not sure you mentioned this, but it's also important to point out that the selected Heading Hold setting is always running (limited to 20% authority, of course) when Head Hold is On, Route is Off, and you are not in Flight Director. The only time you can actually see its setting in the heading tape in the HUD (the diamond) and the physical HSI ball (both markers), though, is when the DH/DT is in the middle position. It is reset by either turning Head Hold off/on again or retrimming, though your retrimming obviously will trim the yaw adversely, as well, unless you're careful.

I have done some more testing...

Your methodology is good. But if the AP is providing up to a 20% authority, an input then would only provide 80% of the force you apply. So even though you are giving input you are still fighting that 20% authority.

Even though your inputs are making a correction it does feel as if you are fighting the AP. If you weren't, then flying with FD on would make no difference.

IMO it is just a phenomenon that is present because of the lack of FFB. If we had FFB, or if we had the real flight controls, I dont think it would at all be an issue.

But there is something that is definitely going on otherwise there would not be so many threads and topics regarding how the whole AP thing is working and how to use it.

If the pilot moves the controls and causes a change in the aircraft's heading or attitude, the signals mentioned above are still sent to the autopilot. However, in addition, a signal is sent that corresponds to the movement of the controls, effectively cancelling out the signals from the attitude indicator and gyros. This results in the aircraft's heading or attitude changing, although changes caused by instability or turbulence are still being corrected.

But if the AP is providing up to a 20% authority, an input then would only provide 80% of the force you apply. So even though you are giving input you are still fighting that 20% authority.

This is key - the AP receives two separate sets of signals: one set from the pilot's controls and one set from the stability instrumentation. This allows the AP the "gauge" that the deviations it is receiving from the instrumentation are due to the pilot's input. Really, it doesn't "gauge" anything, but the two signals merely cancel each other out, leaving the AP with nothing to correct.

Example: I input left cyclic. The AP begins to receive two signals - one from the controls, telling it that the cyclic has moved to the left and by how much and one from the instrumentation, telling it that the aircraft is banking to the left and deviating from the previously trimmed position. The AP wants to bank the helicopter to the right to bring it back to trim, but because the controls signal is proving it with left cyclic input, the result is no input from the AP onto the helicopter.

Example: I input left cyclic. The AP begins to receive two signals - one from the controls, telling it that the cyclic has moved to the left and by how much and one from the instrumentation, telling it that the aircraft is banking to the left and deviating from the previously trimmed position. The AP wants to bank the helicopter to the right to bring it back to trim, but because the controls signal is proving it with left cyclic input, the result is no input from the AP onto the helicopter.

So, when we move the controls, we lose all stabilization augmentation, aren't we? Then, the helicopter will have the same behaviour when we move the controls with and without the SAS on. Am I correct?

Regards!!

EvilBivol/AlphaOneSix

(I'm using a phone so pardon sp/format/etc)

This sounds asinine but regarding this subject I think we must dismiss for the moment what the REAL Kamov does and consider only what this sim does. And what the sim does does not exactly match what you have described in my experience. Let's fly one maneuver as an illustration:

To me the most usefull maneuver is a simple aggressive turn-on-target while in forward flight at 200+ KPH. Try doing this with STAB buttons on and STAB buttons off. With the HDG STAB button on your turn will be sloppy, with pauses and accellerations in rate-of-turn that are frankly unatural. Turns are an area where helicopters tend to require less work than small fixed wing aircraft to perform. Most helicopters require almost no peddal input for coordination. Watch the ball during your BLUE BUTTON ON turn. Try and keep it centered. Watch the horizon and note the lack of consistancy and precision in Rate-Of-Turn. Now, turn the HDG STAB off and do the turn again. You'll get a much easier, much (sorry) prettier turn. This isn't the way it should be, but it is in this game. Autopilots are designed to help the pilot, not hinder his ability to fight effectively.

The more ED reps defend the autopilot system as simulated or, in some cases, admonish players for unrealistic technique, the more convinced I become the there are flaws in how this system is modeled in Black Shark. I just can't imagine that a REAL test pilot would sign off on a system that makes precise, aggressive fighting MORE difficult.

Regards,

Smokin' Hole

Watch the ball during your BLUE BUTTON ON turn. Try and keep it centered. Watch the horizon and note the lack of consistancy and precision in Rate-Of-Turn. Now, turn the HDG STAB off and do the turn again. You'll get a much easier, much (sorry) prettier turn. This isn't the way it should be, but it is in this game.

I tried this over and over and over and with a MAJOR glaring exception, I found that I was able to make beautiful turns (as tight as possible without losing sltitude or power limiting the engines) just fine with both HDG HOLD on as well as off. But there is a MAJOR exception which is probably what everyone is running into...

My "desired heading" was set to 45 degrees, and I noticed that while doing about 20-30 360 turns, I would get a big jump in the controls at 45 and 225 degrees (180 out from 45).

My method was as follows:

I took off and gained some altitude (around 200 meters) and some airspeed (about 220km/h). With the HDG HOLD OFF, I entered into a nice, sexy 60 degree bank to the left, centered the trim ball, pressed and released the trim button, and let go of the cyclic. The aircraft stayed in a nice, tight turn with a 60 degree angle of bank. I let it go arund maybe 10 times, only making adjustments to the collective (I was not using ALT HOLD, but I probably should have been). No problems after about 10 circles, si I turned on the HDG HOLD. No change whatsoever UNTIL the aircraft's heading got to the "desired heading" (the diamond on the heading scale). At that point, the aircraft had a jump in yaw to the right (which, since I had 60 degrees of left bank, made the aircraft pitch up in relation to the horizion). After playing with the collective to arrest my climb, the aircraft continued around all nice and pretty. When I got to 225 degrees (180 degrees out from my "desired heading" of 45 degrees), the aircraft jump in yaw to the left, resulting in pitching down in relation to the horizon, followed by adjustmnets once again of the collective. I continued for another 10 or so circles, and it happened again every time right about 45 and 225 degrees.

I don't know if this is supposed to happen in the real aircraft or not, but I will bring it up on the tester forum and see where it goes.

Mates, this kind of support, investigation and development of DCS modules is AMAZING.

Working all together we are constructing the best simulator saga for decades. I am proud to be part of this. Very proud.

I just tested this, and your statement is incorrect. I tap "D" and it only descends while the button is pressed, as soon as I let go, it stops descending. Also, the overhead light switches from "AUTO HOVER" to "AUTO DESCENT", but only while the button is pressed. As soon as I let go of the button, the light switches back to "AUTO HOVER".

 

The switch IS spring loaded and it IS acting like it.

 

Finally, what is wrong with pressing "R" once to turn on Route mode and "R" again to turn it off? Would you like a completely seperate command for every single cockpit switch for off and on? LSHIFT+LCTRL+E for Battery #1 on, and maybe LSHIFT+LCTRL+LALT+E for Battery #1 off?

First I should note that I am using a Saitek X-45 HOTAS and am attempting to use the Aux. 3-position switch to control the autopilot route - descent switch.

I have a "quick D press and release macro" bound to a position of the Aux switch. Because I assumed it was a simple 3-way toggle switch, I set this to a macro instead of a plain key because of this misunderstanding. Also macro is actually misbehaving such that it is only doing the press command and not the release one. These two errors compounded have given me odd results that made me think it was not momentary.

Also the manual states (6-22)

Upon reaching the desired altitude, set the DESCENT push-button back to neutral and

thus cease the descent.

On the other direction, ROUTE, the spring is not spring loaded but rather a toggle making this an interesting switch. What is annoying is that because my physical joystick switch is not spring loaded I either have to press the switch on-neutral-on-neutral to turn ROUTE mode on-off or program a complicated advanced command.

While I understand that every switch doesn't need a key bind by default, it should at least have a sim command associated with its state. It is no crime to have 500 key binds and only 100 of them bound by default. Someone making a real cockpit will thank you by giving each switch state a separate command.

And if DCS:BS does not have every switch state have an associated sim command, it should at least for all the on-HOTAS commands! People are trying to bind these functions to their HOTASs and having to whip up a zany macro to accomplish what would be simple if the devs gave a few extra key commands is rather frustrating!

Armed with this new information I will be making a better X-45 profile though. Now with working!

I have found that with HDG and Roll hold on there is always some influence on the controls. In the Sim this feels like a slight hesitation or reluctance to get into the turn.... the "rubberbanding" effect described earlier is a good way to explain it. To me it seems that as long as the Blue buttons are ON you have a certain breakout force to overcome to get the Helo turning.

It would seem in forward flight the KA50 Roll stability is pretty good neutral to perhaps a very slightly positive. Pitch stability is pretty average. Longitudinal stability is similar to roll but I reckon straight out neutral. Working with this I did some testing to come up with the best combination to get the best overall manoeuvrability .... for following a road/river or aggressive heading changes etc. Pitch stability is vital as it determines speed control. So I believe the best combination for aggressive flying in the SIM is:

1. Pitch Hold ON

2. Roll Hold OFF

3. ALT Hold OFF

4. HDG Hold OFF (but HOTASABLE ON/OFF)

5. DH/DT switch in neutral position

6. FDs OFF

With this set up Pitch and trim as usual to maintain speed. In the roll axis just fly it like an aeroplane. With ROLL Hold off you will need to actively control bank angle. Slight pressure is required to maintain a specific bank angle. Use rudder as required to keep the skid ball in the middle. Anytime you want HDG Hold Just HOTAS it on as long as the DT/DH switch is in the vertical/centre position HDG Hold will synch to your current heading and the HDG diamond will synch to your track. As soon as you want to start manoeuvring again HOTAS Hdg Hold off and do your thing. This setup allows crisp turn entry and rapid reversals with no breakaway force to be overcome. You still need smooth inputs or PIOs will ensue.

As you start decelerating to Hover you need all the Stability Augmentation you can get so get all 4 Blue buttons on.

Great post Ivank. I think the following statement is not correct:

The Auto Hover system does not actively fly the helicopter to the Hover reference point. The Auto Hover system simply attempts to stabilise the Helicopter at a point in space.

In fact, the autopilot will fly you back to the hover reference point, at least very close to it. You can try it best on an airfield at a couple of meters height in front of some hangar. Activate hover, steer the aicraft away from the hover point and then let go of the controls. There is some magic rubber band pulling you back to your original position :).

The HSI switch if in the Manual mode allows you to set the desired HDG bug. In AUTO the heading and course pointers are driven by the NAV system.

 

Manual pg 2-18 item 13

Thanks IvanK. For resume, we can only set the bug manualy in Man mode? No action with A/P or other?

yes I am pretty sure it only affects the HSI display.

AggiAggi. Roger will go and test as you suggest. I know the manual says it will do exactly as you describe but so far I cant get Auto Hover to take me to the Hover initiation point.

Edit.

Agree after testing it certainly does provided the Hover is initiated at almost 0 speed or the ref point is updated at close to zero speed. I have amended the text.

I have found that with HDG and Roll hold on there is always some influence on the controls. In the Sim this feels like a slight hesitation or reluctance to get into the turn.... the "rubberbanding" effect described earlier is a good way to explain it. To me it seems that as long as the Blue buttons are ON you have a certain breakout force to overcome to get the Helo turning.

 

It would seem in forward flight the KA50 Roll stability is pretty good neutral to perhaps a very slightly positive. Pitch stability is pretty average. Longitudinal stability is similar to roll but I reckon straight out neutral. Working with this I did some testing to come up with the best combination to get the best overall manoeuvrability .... for following a road/river or aggressive heading changes etc. Pitch stability is vital as it determines speed control. So I believe the best combination for aggressive flying in the SIM is:

 

 

1. Pitch Hold ON

2. Roll Hold OFF

3. ALT Hold OFF

4. HDG Hold OFF (but HOTASABLE ON/OFF)

5. DH/DT switch in neutral position

6. FDs OFF

 

With this set up Pitch and trim as usual to maintain speed. In the roll axis just fly it like an aeroplane. With ROLL Hold off you will need to actively control bank angle. Slight pressure is required to maintain a specific bank angle. Use rudder as required to keep the skid ball in the middle. Anytime you want HDG Hold Just HOTAS it on as long as the DT/DH switch is in the vertical/centre position HDG Hold will synch to your current heading and the HDG diamond will synch to your track. As soon as you want to start manoeuvring again HOTAS Hdg Hold off and do your thing. This setup allows crisp turn entry and rapid reversals with no breakaway force to be overcome. You still need smooth inputs or PIOs will ensue.

 

As you start decelerating to Hover you need all the Stability Augmentation you can get so get all 4 Blue buttons on.

I'd recommend when people are going into a hover to sometimes turn altitude hold off until they can help stabilize the hover, especially over uneven terrain. Otherwise the two will be fighting over who gets all that conservative cross-axis 20% authority.

That hesitation or rubberbanding is the 20% authority of the FCS attempting to assert the Attitude Hold function (or wings leveling, in civilian aircraft...though "level" is relative to where it's been set). It does not magically switch off, as some have suggested, when you apply input. My newest GlovePIE solution for Blackshark is evidence of this. The different settings in the script between the Standard Dynamic Trim and Flight Director Dynamic Trim are incontrovertible evidence of this. You can't argue with the numbers.

You can certainly fly with Attitude Hold/Wings-Leveling on, with manual trim, automatic Trim Update, or neither. It's especially useful when landing. And while my Standard Dynamic Trim mode is the best method when often going in and out of hover or altitude hold, using the Flight Director (preferably with my Flight Director Dynamic Trim mode) will by far give you the most behaved and least conflicted flying experience short of using forcefeedback; the reason being you can keep all the hold channels on, but Attitude Hold is off. Instead, you get only rate-dampening...including on Head Hold. Each will attempt to get you down to zero movement in that axis when there is no input, within the 20% authority limit per axis.

The reason without the GlovePIE script running that you have to "hold" bank or pitch even in FD is because, 1) most helicopters have some pitch up to level in forward flight above a certain very steep down angle, 2) the Ka-50 here has an instability in pitch at ground trim causing a very strong pitch up past level, and 3) the Ka-50 here also as a slight rolling tendency to the right. That last one, the rolling to the right with Attitude Hold off (what you get in FD mode) is enough to keep you from needing to apply bank continuously to the right in a turn. If you manually trim a left bank that otherwise won’t hole in FD mode, though, you've trimmed out the right bank ability. So even in FD with the three channels on OR with all the channels turned off, you still have to trim in the bank, as well as the pitch. And of course this causes issues with accidentally trimming the yaw.

The optimum way is NOT to turn off the three channels, but rather running that script. Keep them all on. When NOT in Flight Director, you can choose between Manual Trim or Standard Dynamic Trim with liberal use of resetting the heading diamond (off/on Head Hold or trim) or Auto Turn to Target...especially when hovering. If you don't need any of the automated autopilot modes except the simple channel dampening, then switch your helo to Flight Director and double-click the pinkie (or whatever button you change in the script) to Flight Director Dynamic Trim. Now you get just a touch of auto-trimming in the bank, and slightly less auto-trimming in the pitch from the Standard mode. It's not totally Care-Free Maneuvering, so to speak, but it is truly a joy to fly. Strafing, climbing, and yawing around to head back down as you approach zero-speed at the top has never been so natural.

Not to mention Nap of the Earth and recovering from near-crashes are a snap, too. Butterfly-inducing stuff, without the Gs.

I don't know if this is supposed to happen in the real aircraft or not, but I will bring it up on the tester forum and see where it goes.

AUTO TURN ON TO TARGET

This mode can only be used in the Hover and is considered a tactical mode that operates in the lateral axis only). The Auto Turn on to target mode is simply a method to align Target Line of sight with the Helos for and aft axis. When a target is designated the AFCS sytems takes the angular deviation of the SHKVAL head from the aircrafts centreline and simply yaws the KA50 to drive this angular deviation to ZERO. Pilot technique is to designate the target then press the Auto Turn to target switch. As long as this mode is active the AFCS will attempt to keep the SHKVAL Line of sight to zero in the yawing plane. (Yet to be confirmed .. For the Auto turn on target function to be operative the HDG HOLD mode select switch must be on).

Just a little correction on the AUTO TURN ON TARGET. This mode can also be used in the ROUTE mode not just the HOVER. You can turn it on while on route to a waypoint and the aircraft will turn and point itself in the direction of the skhval. It will no longer chase the Waypoint. This way you can maintain forward flight in autopilot and steer the aircraft with the skhval when a target is seen so that you can engage a target in autopilot. Very useful.

Good post though:thumbup:

Great support,,, but WOW my head is spinning just like my chopper :doh: