Advanced Helicopter FDM Feedback

[quickvenge 10]

There is no vortex ring state/settling with power modeled in the game, well I only tried with auto-trim off. If you watched Dslyecxi's video, that is a correct way to test it. I noticed with pawnee it is pretty easy to get into a low rpm/high torque state. You are probably falling out of the sky because you basically don't have engine power and your rotors are no longer spinning fast enough. All the helicopters seem to suffer from this some more than others. There is an indicator for RPM, and torque on the new gauge GUI to tell you when it is happening. But in the pawnee on the instrument panel there is a actually an functioning RPM gauage. It is the below the airspeed indicator in the actual cockpit, and surprisingly it works. There is a torque one too but it doesn't work.

How are you testing retreating blade stall? I can't get that to happen either. I start at 1000 meters just to give me space to dive into level, and fly as fast as I can forward. I don't get any roll effect, I've only tried in the Pawnee. Again this is with auto-trim off.

I've only been flying the pawnee's and Mi-48. The rest of them have really weird translating tendency in the wrong direction which was driving me crazy trying to land/hover particularly in tight spaces. I was getting use to having the cyclic in the wrong direction and decided to myself it's a muscle memory I would rather not get use too.

I'm flying fine with auto-trim off, and I don't even trim. It's weird so I don't use it. I am using an X52 setup, the most important thing is to have no dead zone. There is no true center. It all depends on what your helicopter is doing as to what center truely is. So you have to cross through that deadzone with no nulling effect. I think this is the root of all the control problems folks have with auto-trim off. If folks rely on the center spring to to give you feedback it really screws you up and something you have to unlearn. But the input controls in arma still feel off to me. It's not over sensitivity. I fly with higher sensitivities in XPLANE, than Arma 3 which at this point is more sensitive than a real R22. I haven't pegged it, but unlike xplane and DCS the controls just don't feel natural and predictable.

[worldsprayer 0]

Can someone test something for me? I've attempted this about 5 times now and its resulted in a crash of the game: I take an mh9, fly at 100kph from the stratis airfield to the nearby port city, at which point I attempt a landing (obviously ie slowed a bit) at a tactical speed on the docks at stratis 28236101. So far, I've blown up e very time, but each time I blow up, the game crashes. I just tried landing on the docks again nice and slow, and if you land on them the helo vanishes and the game crashes. And then again just now I tried to start a mission where I placed a helo on the pier with me in it...and the game crashed. Then I started a mission, helo on pier with me next to it, mission started but crashed as soon as i got in the helo. I've tried now with mutiple helos.

So...can someone verify this? I'd post it now but someone on the bug tracker is annoyed at my volume of posts atm.

---------- Post added at 06:20 ---------- Previous post was at 06:19 ----------

There is no vortex ring state/settling with power modeled in the game, well I only tried with auto-trim off. If you watched Dslyecxi's video, that is a correct way to test it. I noticed with pawnee it is pretty easy to get into a low rpm/high torque state. You are probably falling out of the sky because you basically don't have engine power and your rotors are no longer spinning fast enough. All the helicopters seem to suffer from this some more than others. There is an indicator for RPM, and torque on the new gauge GUI to tell you when it is happening. But in the pawnee on the instrument panel there is a actually an functioning RPM gauage. It is the below the airspeed indicator in the actual cockpit, and surprisingly it works. There is a torque one too but it doesn't work.

How are you testing retreating blade stall? I can't get that to happen either. I start at 1000 meters just to give me space to dive into level, and fly as fast as I can forward. I don't get any roll effect, I've only tried in the Pawnee. Again this is with auto-trim off.

I've only been flying the pawnee's and Mi-48. The rest of them have really weird translating tendency in the wrong direction which was driving me crazy trying to land/hover particularly in tight spaces. I was getting use to having the cyclic in the wrong direction and decided to myself it's a muscle memory I would rather not get use too.

I'm flying fine with auto-trim off, and I don't even trim. It's weird so I don't use it. I am using an X52 setup, the most important thing is to have no dead zone. There is no true center. It all depends on what your helicopter is doing as to what center truely is. So you have to cross through that deadzone with no nulling effect. I think this is the root of all the control problems folks have with auto-trim off. If folks rely on the center spring to to give you feedback it really screws you up and something you have to unlearn. But the input controls in arma still feel off to me. It's not over sensitivity. I fly with higher sensitivities in XPLANE, than Arma 3 which at this point is more sensitive than a real R22. I haven't pegged it, but unlike xplane and DCS the controls just don't feel natural and predictable.

I feel like everything happens too fast in arma3. Some maneuvers should just take some time to happen, not this swinging around all over the place at the drop of a pin. I don't think the game is simulating inertia, which is a fairly important element in helicopter flight.

[quickvenge 10]

It crashes on my machine too. Funny thing is I can land at GRID 027061 on the pier box next to it fine. I landed there first and had to look at your coordinates again.

Momentum and inertia do seem off. The low speed modeling I'm mostly okay with other than what I complained about already, and the only thing that really bugs me is the translating tendency being wrong. Its the forward flight stuff. Being able to turn on a dime, Loose 120 KPH in a second and only have the copter over torque and go into low RPM is just wrong. But the sad thing is it some times does this at the wrong times without to much control input from me.

Edited August 9, 2014 by quickvenge
Fixed the grid location of the pier box.

[worldsprayer 0]

It crashes on my machine too. Funny thing is I can land at GRID 027061 on the pier box next to it fine. I landed there first and had to look at your coordinates again.

Momentum and inertia do seem off. The low speed modeling I'm mostly okay with other than what I complained about already, and the only thing that really bugs me is the translating tendency being wrong. Its the forward flight stuff. Being able to turn on a dime, Loose 120 KPH in a second and only have the copter over torque and go into low RPM is just wrong. But the sad thing is it some times does this at the wrong times without to much control input from me.

I couldnt find the area of the pier that didn't crash. a manned helo touching the pier anywhere caused a crash for me. But if it happened for you too, I'll submit a ticket for it.

I do enjoy the physics at lower airspeeds. Flying inbound to the pier for example at 100kph feels very natural (minus sudden death at touch down).

The Mh9 series still has improper torque though, at a hover you barely rotate while the pedals are centered.

Edited August 9, 2014 by Worldsprayer
Changed XH9 to MH9 after further testing

[quickvenge 10]

I couldnt find the area of the pier that didn't crash. a manned helo touching the pier anywhere caused a crash for me. But if it happened for you too, I'll submit a ticket for it.

I do enjoy the physics at lower airspeeds. Flying inbound to the pier for example at 100kph feels very natural (minus sudden death at touch down).

The Xh9 series still has improper torque though, at a hover you barely rotate while the pedals are centered.

I was flying around with an AH9 most of the evening. For a dead hover, I needed my left pedal, and a little back left cyclic, which is correct. The AH9 feels about the same amount of pedal as DCS Huey hover in my setup. I use saitek pedals. The ORCA on the other hand, I wasn't using it all, but last time I flew that was Tuesday.

Weird just tested the MH9. You are right I didn't need the pedals. So I went to the AH9, I needed the pedals. Went back to the MH9 all of a sudden I needed the pedals.

Edited August 9, 2014 by quickvenge
Added MH9 test

[worldsprayer 0]

I was flying around with an AH9 most of the evening. For a dead hover, I needed my left pedal, and a little back left cyclic, which is correct. The AH9 feels about the same amount of pedal as DCS Huey hover in my setup. I use saitek pedals. The ORCA on the other hand, I wasn't using it all, but last time I flew that was Tuesday.

Weird just tested the MH9. You are right I didn't need the pedals. So I went to the AH9, I needed the pedals. Went back to the MH9 all of a sudden I needed the pedals.

Well I sit corrected and my lsat post is edited, the ah9 is much better regarding torque spin. The mh9 has a very VERY slight spin, about 1/3 the ah9 at a guess.

---------- Post added at 08:45 ---------- Previous post was at 08:30 ----------

Something else for someone to test. After flying an mh9, I hopped out and shot out the tail rotor. Tailrotor stopped spinning

I hopped back in, ATRQ icon is red, but I can still restart engine, so I restart and lift off

The helo is not spinning hardly at all, I look in 3rd person, see tail rotor is now spinning, try and succeed at some pedal turns. tail rotor is working

I land...hop out...and tail rotor instantly stops as if its broken.

Also, I hovered backwards into some buildings in AH9 and MH9...took out the tail rotor, and when it went out I never experienced torque effect from its loss.

Anyone able to duplicate?

Edited August 9, 2014 by Worldsprayer

[metralla 19]

Can someone test something for me? I've attempted this about 5 times now and its resulted in a crash of the game: I take an mh9, fly at 100kph from the stratis airfield to the nearby port city, at which point I attempt a landing (obviously ie slowed a bit) at a tactical speed on the docks at stratis 28236101. So far, I've blown up e very time, but each time I blow up, the game crashes. I just tried landing on the docks again nice and slow, and if you land on them the helo vanishes and the game crashes. And then again just now I tried to start a mission where I placed a helo on the pier with me in it...and the game crashed.

Confirmed and tested. The game crashes when entering this area....the game crashes for other reasons not alone in this.

[vicx 10]

+1 on forward flight stuff requiring some attention. Not enough altitude delta from velocity changes due to translation lift. There are other model problems but this one seems to lead to deficiencies in other sim dynamics. This one is core.

Questions for other commenters who aren't using Autotrim.

Are you manual trimming with

A. the keyboard using trimup, trimdown,trimleft?

B. a hat switch using trimup, trimdown,trimleft etc?

C. the stick and a trim button on the stick

D. some other method

I tried using trim with a hat switch and the trims were way overscaled to be usable.

[Brisse 78]

C. the stick and a trim button on the stick

I use the pinky switch on my HOTAS Cougar. Works like a charm. Forget using keyboard or hatswitch. That works for fixed wing but not rotary wing.

You know how trim works in a real helicopter, right?

[worldsprayer 0]

I also use my pinky trigger on my G940. The hat switch trimming is for fine tuning trim for long flights when you have time to do so, not tactical flyinh...not sure why they put it in there.

And I agree that delta velocity is the leading cause from crazy yaw behavior to lack of lift from forward flight to unlevel flight. The issue I suspect is they are trying to make it LOOK like physis like that exist...but they really dont. I added in the helicopters from the HAFM pack, and none of them behave with the new physics, which suggests its just some variables they're sticking here and there on the helos instead of a system wide thing that everything flys through.

[KeyCat 131]

The post one or two above yours discusses this and is how I've been flying: Go into configure-> controls-> controller -> customize. You get the option there to flatten out your sensitivity curve.

We can adjust the "S shape" but AFAIK we have no option to flatten the curve (i.e increase the lower bound and decrease the higher) on the axis to make them overall less sensitive.

Questions for other commenters who aren't using Autotrim.

Are you manual trimming with

A. the keyboard using trimup, trimdown,trimleft?

B. a hat switch using trimup, trimdown,trimleft etc?

C. the stick and a trim button on the stick

D. some other method

I tried using trim with a hat switch and the trims were way overscaled to be usable.

I mostly use a set trim button on my HOTAS but sometimes also use trimup, trimdown etc. on a hat switch.

/KC

Edited August 10, 2014 by KeyCat

[metralla 19]

Question for developers: Include in the settings of the joystick a profile for each helicopter?

I guess if the flight is different from a helicopter to another need to save profile settings for each helicopter.

[b00ce 160]

www.youtube.com/watch?v=VbuVgdyMysE

Full forward and aft cyclic causes some unrealistic behavior. Torque/RPM should not be effected by cyclic movement.

[blackpixxel 53]

Torque/RPM should not be effected by cyclic movement.

As far as I know it SHOULD be affected. It is the same with R/C helicopters. They also lose RPM while going from neutral to a nick/roll movement.

[deepfried 1]

First impressions: Its a big improvement on the old flight model, I picked it up instantly but then I've played ToH so I guess I have the advantage there. There are some problems, I've noticed that the rudder is way too effective when moving at speed, when going 200kph I don't expect full rudder to spin the chopper around.

I'm flying with auto-trim and an xbox 360 controller.

The mi-48 seems underpowered and has a habit of dropping out of the sky when you slow to a halt, so much so that this is suicide if you attempt it at low altitude - that might be realistic I don't know. Edit: after flying it a bit more I find I actually like the mi-48, it feels really heavy so you have to be really on the ball with the collective when coming to a halt - but if you are then it handles fine and is quite stable, just takes getting used to I suppose.

Mh-9 seems fine. i guess this was the easiest port as the mh-9 is basically the Light from ToH, though thankfully the ground effect is much less savage than in ToH.

Ah-9 like a heavier mh-9, torque effects are more pronounced, collective is less sensitive. Busted the tail rotor the first 2 times I tried to take off thinking it would be like the mh-9.

The Uh-80 flies like a charm, piece of cake. Can glide round the map without even touching the collective, extremely stable so only minor control inputs needed.

Hellcat, flies a lot like the mh-9 except less skittish, no problems yet.

Ah-99, I don't like attack choppers at the best of times but i can manage this ok, seems a bit sensitive on the roll but a bit sluggish on the collective - might be intentional, but I'd expect an attack chopper like this to have more power.

Edited August 10, 2014 by Deepfried

[Variable 322]

Ah-99, I don't like attack choppers at the best of times but i can manage this ok, seems a bit sensitive on the roll but a bit sluggish on the collective - might be intentional, but I'd expect an attack chopper to have more power.

Maybe it's because of that ;)

"...the Comanche's weight requirements were unachievable due to poor management, no party was aware or in control of the aircraft's final weight; there were concerns that, when outfitted with actual equipment required for operations, the Comanche's engines would be incapable of lifting the total weight of the helicopter".

[roberthammer 582]

Well yes but that was on prototype - i think arma 3 ah-99 got fixed by that time with much stronger engines

also ah-99 should be able to do this >

still wondering if the Rotorlib can do this , also Mi-48 could benefit from it too

Edited August 10, 2014 by RobertHammer

[b00ce 160]

As far as I know it SHOULD be affected. It is the same with R/C helicopters. They also lose RPM while going from neutral to a nick/roll movement.

Cyclic input alone has absolutely nothing to do with torque/Rotor RPM. Even if it did, what makes forward/aft cyclic movement so different from laterally?

The reason why torque changes is what the aircraft is doing and collective position. If you're flying at 100 kts and you pull hard aft cyclic, no collective input, your torque will drop and your RPM will increase. If you do this with the AFM in ArmA you'll fall out of the sky because you just drooped the rotors to the point where they damn near stop spinning some how. Conversely, if you nosed down at 100 kts your torque would increase and RPM would drop. This is not from cyclic position, rather how air interacts with the rotor blades in forward flight.

MANEUVERING FLIGHT AND TOTAL AERODYNAMIC FORCE

1-159. The cyclic inputs and associated rotor disc pitch changes required to accomplish successful

combat maneuvers have a substantial effect on TAF. Large aft cyclic inputs increase the inflow

through the rotor system. Since lift is perpendicular to the resultant relative wind, the TAF of each

rotor blade may move to a point aligned with or forward of the axis of rotation (much like the driving

and driven region of a blade during autorotational flight). While the engine control system reduces fuel

flow to reduced load, the rotor system may still climb to transient ranges or attempt to overspeed.

1-160. Conversely, when the cyclic is rapidly repositioned to a more forward position, the inflow through

the rotor is rapidly reduced resulting in the blade TAF moving aft of the axis of rotation and a slowing

of rotor RPM (figure 1-71). The engine control systems sense this and increase fuel flow to the

engines to maintain rotor RPM causing torque to increase. As a general rule, when traveling at

airspeeds above bucket speed, aft cyclic results in a reduction in torque and an increase in rotor RPMs.

Recovery from an aft cyclic input (pushover or high G-turn recovery) results in torque increase as the

engines compensate for the rotor system slow down. In aggressive maneuvers, this may result in an

overtorque or overspeed if appropriate collective input is not made to keep torque and rotor consistent.

1-161. This phenomenon is exacerbated by high gross weight and also affected by ambient temperature

and density alititude. Typically, cold dry air results in more rapid rotor RPM increase during aft cyclic

input and a corresponding higher torque increase with a forward cyclic input. Hot temperatures and

higher DAs result in more collective input required to arrest a climbing rotor.

ANGULAR MOMENTUM AND TOTAL AERODYNAMIC FORCE COMBINED EFFECTS

1-162. Angular momentum and TAF combine during cyclic pitch changes. During aft cyclic or Gloading,

the rotor increases and torque goes down. During G-load recovery, torque increases as the

engine control systems work to maintain a rotor RPM attempting to decrease. Aviators must be able to

apply appropriate and timely collective inputs to maintain consistent torque and keep rotor RPM

within limits.

DIG-IN

1-163. While making large aft cyclic movements, the pilot must be aware of the helicopter’s tendency to

rapidly and unpredictably build G-forces. As the cyclic is moved aft, the rotor disk responds by tilting

aft, which tilts the thrust vector aft and ultimately causes the aircraft to pitch nose-up. This rapid pitchup

also increases the length of the aircraft thrust vector, which will in turn increase the pitch-up rate.

The rapid onset of the pitch-up motion due to the tilting and then lengthening of the thrust vector is

considered destabilizing and countered by the helicopter’s horizontal tail or stabilizer, which will try to

drive the nose back down. For large pitch-up rates, the tendency of the main rotor to continue

pitching-up will overpower the horizontal tail/stabilizer and the aircraft will dig-in and slow down

rapidly. Dig-in is usually accompanied by airframe vibration and sometimes controls feedback.

1-164. Aft cyclic movements give predictable increases in G-load up to the dig-in point; however, the

dig-in occurs at different G-levels for each model of helicopter. The point at which dig-in occurs

depends on a number of factors, but most important is the size of the horizontal tail/stabilizer and

amount of rotor offset. For most helicopters, this point is between 1.5 and 2.0 Gs. Pilots should be

prepared for dig-in during aggressive aft cyclic inputs, especially during break turns.

GUIDELINES

1-165. Below are good practices to follow during maneuvering flight:

• Never move the cyclic faster than trim, torque, and rotor can be maintained. When entering a

maneuver and the trim, rotor, or torque reacts quicker than anticipated, pilot limitations have

been exceeded. If continued, an aircraft limitation will be exceeded. Perform the maneuver with

less intensity until all aspects of the machine can be controlled.

• Anticipate changes in aircraft performance due to loading or environmental condition. The

normal collective increase to check rotor speed at sea level standard (SLS) may not be sufficient

at 4,000 feet pressure altitude (PA) and 95 degrees F (4K95).

• Anticipate the following characteristics during aggressive maneuvering flight and adjust or lead

with collective as necessary to maintain trim and torque:

• Left turns, torque increases. (Pedal input)

• Right turns, torque decreases. (Pedal input)

• Application of aft cyclic, torque decreases and rotor climbs.

• Application of forward cyclic (especially when immediately following aft cyclic

application), torque increases and rotor speed decreases.

• Always leave a way out.

• Know where the winds are.

• Most engine malfunctions occur during power changes.

• If combat maneuvers have not been performed in a while, start slowly to develop proficiency.

• Crew coordination is critical. Everyone needs to be fully aware of what is going on and each

crewmember has a specific duty.

• In steep turns the nose will drop. In most cases, energy (airspeed) must be traded to maintain

altitude as the required excess engine power may not be available (to maintain airspeed in a

2g/60 degree turn rotor thrust/engine power has to increase by 100 percent). Failure to anticipate

this at low altitude endangers the crew and passengers. The rate of pitch change is proportional

to gross weight and density altitude.

• Many maneuvering flight over-torques occur as the aircraft unloads Gs. This is due to

insufficient collective reduction following the increase to maintain consistent torque and rotor as

G-loading increased (dive recovery or recovery from high G-turn to the right).

[CaptainObvious 95]

@b00ce, you are a helo pilot in real life or is my memory failing on me?

[b00ce 160]

@b00ce, you are a helo pilot in real life or is my memory failing on me?

A Blackhawk crewchief/mechanic that wants to be a pilot and does a lot of reading.

[CaptainObvious 95]

A Blackhawk crewchief/mechanic that wants to be a pilot and does a lot of reading.

Ah, still, it's nice to have input from guys who are dealing with the real things.

I'm afraid to give any feedback of this FM as I have no clue how these things really fly. ;)

[hoizen 18]

Ah, still, it's nice to have input from guys who are dealing with the real things.

I'm afraid to give any feedback of this FM as I have no clue how these things really fly. ;)

I believe everyone's input is valid. After all, we all play this game for fun (it's not a full blown flight sim meant for training). If you don't find something too fun let the devs hear your input.

[gatordev 219]

There is no vortex ring state/settling with power modeled in the game, well I only tried with auto-trim off. If you watched Dslyecxi's video, that is a correct way to test it.

Got to watch Dslyecxi's video yesterday and overall, I think he's on point (as usual). However, how he is testing for VRS is not correct (in either sim). People confuse Settling with Power and VRS as the same thing, and it is not. Settling with power can be due to power required exceeding power available, which then causes Nr to droop. VRS is different in that Nr is at 100% the entire time and you lose control authority. In the video, his test to enter VRS is by lowering the collective all the way down and entering an autorotation (as demonstrated by Nr climbing). Entering an auto is the VERY WAY to get OUT of VRS, not to enter it. The 4 states of rotor flow (in order) are Normal, VRS, Autorotation and then Windmill braking. While different aircraft will have some varying procedures, the general idea is the same. Here's one from A1-H60RA-NFM-000 (MH-60R NATOPS):

To recover from this condition:

1. Decrease collective pitch.

2. Increase forward airspeed.

3. Enter autorotation if altitude permits. A considerable loss of altitude may occur before the condition

is recognized and recovery is completed. During approach for landing, conditions causing vortex ring

state should be avoided.

From his video, at the bottom when he tries to recover (again, in DCS), you can see the RPM CAUTION Light, which indicates he's trying to yank more power than the engines can give him. This is text book Power Required exceeding Power Available (and completely normal in a helicopter). Again, VRS keeps the rotors at 100%, so what is demonstrated is not the same thing as VRS (regardless of what DCS calls it).

Does that mean his point about VRS being in there isn't valid? Of course not, but just clarifying that it doesn't actually happen as depicted. And I say that as someone who has been in Pr > Pa situations more than I'd care to admit.

I use the pinky switch on my HOTAS Cougar. Works like a charm. Forget using keyboard or hatswitch. That works for fixed wing but not rotary wing.

You know how trim works in a real helicopter, right?

Modern helicopters have two trim functions. One is the force trim, where you just mash a button, but often there is also a hat switch that adjusts trim just like in fixed-wing. While it may not be practical within the game engine, it would be a nice-to-have.

[quickvenge 10]

I just watched Dsylexci's video again. Watched/watched it. Not just listen/watch. You are correct he basically descended so fast, and attempt to power his way of it and ran out of engine power. That is not the correct way to test VRS. He made a big deal out of it I thought he knew what he was doing, and I was mainly listening to his video not watching. You can easily exceed exceed engine power and hit low RPM in ARMA 3 now. Sad thing is it can happen to you off of a 200KMH dive if you pull up/bank too much.

VRS does happen in DCS, also in XPLANE. In DCS the way to test is just a steep glide path approach and hold try to hold a high descent rate say 1000FPM, what will happen is you are holding that descent rate and out of the blue a sudden increase in descent. I never really noticed control authority loss other than in the collective, but that is probably hard to model or I can't tell given my joystick. Either way if you don't react fast enough that increase is normally fatal if you are too low to the ground. For me it normally happened, if I was to impatient and landed with a tail wind, and did it to steep and to fast. So in reality it is easy to avoid. Maintain a low descent rate, and land into the wind is what I was always told.

So in arma 3, I basically tried to do the same thing. Descend into my down wash, with a high rate and hold it. See if I get an unexplained sudden increase in descent rate, I never got that. So I'm pretty sure VRS is not modeled.

Now after reading, and trying to figure out the different between settling with power, vs VRS. I'm confused. What I described above is another form form of settling with power, but caused by VRS? Basically I have power and it is getting eaten by my downwash? So is that settling with power or VRS?

Edited August 11, 2014 by quickvenge
Added confusion on settling with power vs VRS note.

[papy.rabbit.08 0]

Just played it since this morning, it's a really nice feature, even if the playing appears to be less stable, you can be flying with the blackfoot and suddenly it totally lose control and you crash, for I don't know what reason, execessive speed or wind, I don't know...

Another thing, is that a T-100 can destroy a blackfoot flying in 2-3 bullets. It makes you lose control and crashing everytime, absolutely impossible to keep the control when getting hit by the T-100 machingun...