cw4ogden

And looks like it’s not readily available if either know what the mi-8 main rotor spins at in terms of revolutions per minute. how is RRPM set in the hip? I’d assumed it was fixed by the maintenance pilots with fuel flow and track, as it seems not adjustiable by the pilot, or am I missing a switch etc?

And @AlphaOneSix It also possible my hip flying friend isn’t on the mark and the hip just really is a bit more susceptible to it than I’m used to. For many of the reasons you both and others have cited. I can google it, but I want to, probably already should have taken a look at what the revs per minute of the hip main rotor is because if it is significantly less than the 47, which Iirc is 225 then it’s likely my source led me astray. it still perplexes me there isn’t more in the way of literature on it, but I can’t in good conscience say it’s wrong, and I’ve fleshed it out fairly well now, but I just can’t tell if it’s right or I’ve learned to live with it.

Good to know. @Viktor_UHPK I'm curious which manual is that you're referencing? I know, at this point how to work around the VRS. My question is how accurate is it? It's much harder to get into now that I've learned the module, but I still think there is something off with how it's working. I get that following a shallow approach to land will keep you out of it, but in reality, you need to be fairly steep for it to be a problem. It's unfortunate VRS diagrams are notoriously non-aircraft specifc, but the way I read the diagrams, and the way we always flew IRL, unless you were coming in in excess of 30 degree approach angle, VRS was not part of the equation. As I mentioned earlier, we even had a rule of thumb for flying: if your intended landing area is at or above your feet / pedals area, you were safe from the portion of the aerodynamic envelope prone to VRS. You didn't have to consider rate of descent at all. You just can't get into it on approach, in anything but a very steep approach (barring a large tailwind or high altitude operations near max G.W.).

Excuse the formatting (copy paste) From MI-8 flight operations manual - seems the throttles are meant to be set all the way up for anything above about 3000' https://www.scribd.com/document/322000057/Flight-Operation-Manual-for-the-Mi-8-Helicopter 2.8.3. Take-off-landing operations and maneuvers at low speeds near the ground at airfields and sites, located at altitudes higher than 1000 m, are made with at least 93% revolutions of the main rotor for the purpose of ensuring reserves of pedal control in these modes. Also from Mi-17 manual: Reduction of the gas generator rotor speed below 85 to 88 % at an airspeed close to zero even at the main rotor speed within the acceptable limits, causes transition of vertical descent at a speed up to 20 m/s (vortex ring condition).

I know it's a long shot getting any re-look. I'm trying get to the bottom of whether or not it's even a problem, which by community standards, is an un-setttled question.

I did some testing and am leaning towards a theory: The VRS issue I have may be the autorotative brake state not being implemented, or implemented correctly. Also called windmill brake state. Test number one I repeated a few times, but want to try more iterations was as follows: 1000' AGL near zero forward airspeed, rate of descent around 400 m's on the VSI. Results: modeled well. Feels right for an out of ground effect, high OGE, "I got distracted" type of VRS. Pitch / roll controllability remains good, if not a little too good in a developed Ring state. What I was unable to do, and leading back to the first point, was break a developed ring state by dumping collective and entering the windmill brake state. methodology: High OGE hover, induce VRS, confirm by adding collective, verify increased vertical descent rate - corrective action, bottom collective pitch and break the vortex via upflow through the rotors - does not seem to work as it should. Test number two: Tactical approach to LZ style landing / traditional dust landing style approach. (Fast approach, with an aggressive decel - understanding we are talking cargo helicopter standards) This style approach should also be riding the autorotative brake state, and yet, what it feels like is I still have to avoid VRS criteria during transition through ETL, even though my rotor is mostly unloaded, due to the upflow resulting from the decelerative attitude. You can't simultaneously have a vortex ring building while the rotor is being driven, or is unloaded by autorotative upflow. You can get into a VRS type state by botching the approach and arriving too high, but flown to the ground in the manner of what would be a dust landing, but flown properly, the airflow never comes up through the rotor disk. Additionally and possibly related, dumping the collective to the floor in cruise flight, again in the autorotative brake state regime, the aircraft falls out of the sky. It shouldn't. It feels like upflow and autorotative brake state is not working, or not strong enough. If I dump the collective with, say 100 knots forward airspeed, I should be able to remain in level flight for quite a while, in a decelerative attitude, exchanging speed for level flight. The hip just seems to drop like a rock regardless of how much rotor disk you tilt into the wind.

@AlphaOneSixI’d welcome a better qualified expert if you know one. I don’t write off the possibility it’s correct, but you really could Certify the DCS hip model for flight in real life without serious control measures that would be reflected in real world literature and real world history / real world training procedure etc. I can’t find. I’m having a hard time putting my finger on what’s off or feels off, other than to say it feels far too susceptible to it. Maybe it’s a simism, but I’ve flown dozens of helo sims and had aircraft in crazy flight profiles that ride the edge of the flight envelope for good reason and I’ve never had a problem with VRS the way here, it can render you a smoking hole in seconds. Nor do I know of anyone who has. I welcome evidence to the contrary. My intent isn’t to die holding a hill, but also to not have people see helicopter flying as an inherently unsafe. I don’t think the mi-8, if it flew like it did here could be certified. Yes it’s Russian, and they are different than us but we’d see a string of these fatalities if it was accurate.

@Fri13 I want to run a couple tests once DCS finishes updating. I'm going to try to find the actual source of what feels wrong and see if I can provide an example of it. I take your points, and I'd reiterate I'm not saying it's off by a lot. It needs a tweak. Not an entire rework. The coding is good for VRS, I like how they modeled it. I just question it's accuracy based the fact everyone has to learn how to fly the DCS mi-8. Everyone qualifies their statement with, I had trouble with VRS at first, but I learned to live deal with it. The actual reality is the vast majority of people never experience VRS. Not intentionally, nor inadvertently. VRS accidents are rare. They happen, but they are rare. And DCS doesn't feel wrong, necessarily. Just wrong for the conditions, lightly loaded aircraft operating near sea level, it's far too aggressive. The current flight model is what I would expect to feel operating at high altitude near max gross weight. Conditions where you are on the edge of the phenomenon. Not sea level, not lightly loaded and not doing a simple approach to landing.

Sure, but that only takes a swing at me the observer. It doesn't account for the multitude of other anecdotal evidence. You can not minimize the importance the pilot plays in simulation development, or you do it at least at your peril. And here we are. With a glaring flaw in the flight model, and you want me to chock it up to my memory is fuzzy. Maybe so. But all other evidence brought forth indicates my observation is correct. No specific MI-8 charts for VRS No long list of lessons written in the blood by dead mi-8 crews No credible people arguing "hey, actually it is that bad." No hint of it being vested in reality from a guy who flew a similiar aircraft and took it on himself to say, that's not enough, ask a real real expert. Who confirmed VRS doesn't plague the Mi-8 community the way it plagues the DCS community. It should be manifestly impossbile to get into VRS with any approach angle less than about 30 degrees, which is a very steep approach. Yet we have a forum with post after post of "why do I die when I try to do a simple landing"? Say you like it, say it's part of the DCS experience, just don't say it's representative of reality because it isn't for the many many reasons I've cited.

Hey thanks for the post. I'm in need or moral support. Additionally, there would absolutely be VRS pilot charts specific to weigh configurations and density altitudes that anyone arguing against should be able to find quite easily. All this back and forth aside. The VRS modelling is close. It's not too far off. But where it is off, it is off in a big way if I can encounter it under normal flight maneuvers. Dynamic rollover, settling with insufficient power, Loss of tail rotor effectiveness (not implemented I believe), ground resonance, retreating blade stall, blade compressibility, and vortex ring state: None of these are unknown quantities. We pour over charts before every takeoff, mostly nowadays by computer which is sad a bit in and of itself, because you really lose the context of the numbers you generate. There is no conceivable way, in my self proclaimed expert opinion, they can have VRS right as it currently is modeled. Now invariably someone will counter with the charts exist. And they do. At the test-pilot and engineering level. And the fact they are not generated for the pilot in any Mi-8 specific form yet discovered by the forum army, we can assume, and have confirmation from my source, it doesn't fly significantly different than any other helicopter with regards to VRS. And I'm saying as a a guy with extensive time in a similar bird, extensive time in simulation community both professional and as a hobbiest, training the exact flight condition to instructor pilot candidates, because you don't get the demonstration as part of any curriculum I just wouldn't sign you off to be an Instructor without having felt it personally. Because this is my bailiwick and a pet peeve of mine personally within that bailiwick I can say without hesitation, something is very off with VRS. I want to check approach angles and run some more tests, but it is wrong, close, but wrong enough to be considered a serious bug in my opinion. There's no way in hell I'd certify this flight model as is, and it's only because of the valiant, yet unfinished attempt at modeling a complex aerodynamic phenomenon that is VRS. VRS is by and large not part of any pilot's thought process, except for when operating under very specific flight parameters. It is deadly, it is not common.

I'll also claim expertise on flying without haptic feedback and evaluating accuracy of flight modeling because I have done that, professionally. There are plenty of good arguments like why tempt fate potentially breaking a great module, but haptic feedback is a lousy one, as is saying pilot's are unreliable reporters of accuracy. There's truth to that argument, but not to the degree expressed in this discussion. And not for something so flagrantly obvious to any pilot with an ounce of time; it's why this topic is the dead horse we are beating. Dead horse arguments only happen when one side is intractable in their belief the horse is even a horse.

I’d counter your first argument with training. When a line pilot arrives at the instructor pilot course (us army) they can fly like champs. But you ask them to demonstrate a VMC takeoff pattern and approach, like they are the instructor telling me the “student” what to do, they fall apart. Until you are trained to do it, you can’t fly and give instruction on a task at the same time. As a matter of personal insight learned as an instructor training new instructor pilots, what you’d call situational awareness, is nothing more than division of attention and prioritization of tasks. No one can do two things at a time with the one fabulous caveat - if you can do one, or the other, or better yet both without thinking about it. The way you drive without thinking about it. A new instructor pilot cannot talk and fly at the same time usually. both go to varying degrees of shit depending on personal aptitude and preparation, ie how long did you rehearse you’re “MOI” or method of instruction. Prescripted sentences like “to begin the VMC takeoff, apply smooth collective input while simultaneously achieving a positive rate of climb and and accelerative attitude” while they are demonstrating the maneuver. With time, they can speak, but their flying looks like crap until they can either fly or talk without thinking about it. that’s all situation awareness is, diverting your attention amongst many things and keeping track of which will kill you first. Any task you can do without thinking is gravy on the potatoes. Nor everyone can do this job. A significant portion bordering on half are born straight out of training to be lifelong co-pilots. Not everyone makes pilot in command, fewer still become instructors, and fewer still the instructor for the instructor pilots. The sentiment I’m getting is it’s like flying is some sort of cowboy shit, and pilots are stupid stick wigglers, and that’s just not the case. I don’t claim to be an expert lightly and for much beyond the scope of what’s being discussed here. But for VRS in a medium lift cargo helicopter, I am an expert.

A more naive version of me might have thought I’d be welcomed as someone with authority finally throwing the bullshit flag on a known issue, and prepared to make a case on your behalf, with evidence both tangible and circumstantial to make your sim more accurate. silly me.

@HiobIn no world does it make sense to pit your extensive YouTube viewing history against my credentials and call it a draw because you just won’t come around to reason. And asserting pilots are a poor resource for determining a simulation’s authenticity is one of the stupidest things on its face I’ve ever seen asserted. Who then do you put the task to? if you’d devoted 1/3 of your energies wasting my time to looking into my assertions and observations you’d have likely learned something. but here we are, you steadfast in your life experience endowed sense of authority and my absolute inability to crack your severe case of Dunning Kruger syndrome. I’m out. I don’t need the aggravation arguing with you brings me.

I didn’t throw out a thesis, I made an observation based on many many factors all of which you, as you say reject summarily, without offer anything substantive to the conversation. You can not get into VRS in the conditions you can in DCS, that is my observation. It’s manifestly impossible in probably any helicopter because the aerodynamics don’t work the way the DCS hip teaches you that you have to fly. Congratulations, and welcome the world of bad habit transfer if you ever get the chance to be an Mi-8 pilot. You have lots of hypothesis and theories on why my observation is wrong. I merely have an observation. I have hypothesis for why the observation might be happening, but you're not acknowledging my observation as even valid much less getting to my hypotheses.

The @Hiobwhat exactly have you brought to the discussion other then summary rejection of my points, many you obviously didn’t read? what’s your role here other than quoting your extensive YouTube viewing history? Haptic feedback is copout argument for not fixing a bug. to address your newest points. I have no depth of vision wearing nvg I have no peripheral wearing nvgs. pilots learn to adapt to their circumstances. And guess what else we spend a lot of time doing as actual pilots: flying simulators. And your assertion there is no correlation between sims and real life skills is hogwash you read somewhere. It’s not factual. The very reason flight simulation exists is that correlation. In my case, the qualifications I speak to as relevant are IN addition to the actual pilot stuff, is lead test and development and certification of an actual heavy lift cargo simulator. Located in Daleville, Alabama run by a company called L3. Stop being a naysayer and get on board fixing the thing you’re a fan of.

@Hiobwhat exactly have you brought to the discussion other then summary rejection of my points, many you obviously didn’t read? what’s your role here other than quoting your extensive YouTube viewing history?

@scoobieThanks for the vote of confidence and getting what I’m trying to say. The debate seems to be focused on if it’s even broken, somehow, and that boggles my mind because it’s never gonna get fixed if people can’t agree it’s messed up. I don’t really care if it ever gets fixed because helos in dcs are secondary to me, and the hip beautiful as she is is just too close to my old job to be a whole lot of fun, versus the harrier which brings me a lot of joy to fly. A window into a different world I’d you will. You’re just a troll at this point. and kind of an unpleasant one to interact with.

When an experienced pilot hops in your sim, and their very first impression is: "What the heck was that?" And it's so foreign feeling you have to google it, just to see what they are trying to simulate. And when you do, you say, "Oh, that's supposed to be VRS?' Literally with less than 10 minutes of play time. Your sim isn't right. The difference being I have been flying it a year mostly in silence, because I didn't feel my personal experience base was enough. No MI-8 time at all. So how can I say it's broken, now? Hey Ed, does the hip fly significantly different than the bird we both flew with regards to VRS? No? ok thanks.

All the more reason to call them out, so they don't just transfer the black eye to the brand new module.

My only goal is to make your sim better. I have no motivation besides it being more accurate. Motivations a developer may have are many. It's old code, it's a mostly "finished" module they don't want to revisit. I wouldn't be here making a case to relook VRS if it was well implemented. I'm not sure what kind of evidence you would find convincing, but bias, opinion etc. doesn't account for how completely broken VRS is. Period. It's not like it's a close call, like somehow maybe I'm mis-remembering how flying works. That's what makes this problem so egregious, the sheer obviousness of how flipping broken it is. It also has the unintended side effect of giving the impression helicopter flying is more dangerous than it is. No one in their right mind would EVER get in an mi-8 if it was as dangerous as DCSs version is. It would have never made it out of flight testing certification. The R-22 is a perfect example of a flying death-trap Pilots DO have to work around. And guess what? I can find tons of information on R-22 mast bumping, how to avoid it, charts data etc. It's got it's own section of special regulations just to fly. None of that exists for the pilot for the hip regarding VRS. Why? Because it's not a flying death trap. VRS modeling is so bad, no agency would ever certify the DCS MI-8 as safe for civil or military use. You can question my credibility, I get that. I'm just a random internet random person. But I am in a position to know it's broken. And when that wasn't enough, I solicited the input of my hip pocket MI-8 instructor, I called a favor in to ask to help make your sim better. But guess what? It really sucks to come on here and try and help. I get why no one tries to bring any real life experience to DCS in the form of improvement because, it seems the DEVs always know better than a player base saturated with former pilots to some. Nothing like a player base trying to bite the hand that feeds them. You guys are saying maybe it's this or maybe its that. No, it's not. The answer is staring you straight in the face, you just don't like it. Nor does ED's subject model expert. VRS modeling for the MI-8 is a joke. It's worse than a joke. It's a black eye on an otherwise very good module they refuse to address. Personally, I think they put so much effort into coding it, maybe they felt the need to exaggerate it on purpose, so players would "experience" their work. There is no debate to be had here honestly. You want to believe it's some kind of subjective experience thing, and that could be a plausible explanation, If it weren't so obviously unrealistic. I've been there and done that, to include working on the certification of various simulators. I'll also let you in on a secret: subject matter experts trying to get a job with a software company may pad their resumes. They may not be the guru's they claim to be to get the job. What I find disturbing is how quickly you can throw out what I'm saying. Do you treat your doctor the same way? I'll say it again, as far as DCS goes and user subject matter experts within the community that have the specific experience and the knowledge base to be considered an "expert" regarding Vortex Ring State, you are talking to him. You just don't believe him. I'm happy to keep my input to myself if this is the kind of reception I'm going to get. To borrow on what you said: "I can‘t emphasize it enough - I do know."

Here is the source link I used. http://cybercom.net/~copters/aero/settling.html I believe the units are arbitrary, you can substitute any unit of your choice and as long as you do the conversion to the other line of the graph you are ok. VRS diagrams are notoriously non-specific to model of helicopter. That's also a direct result of, as I described, it's just not the hazard it is in the MI-8 module. There aren't a lot of charts on it. My main assertion here is we have people complaining routinely, they can't figure out how to do a normal landing because of VRS. And that is a three degree (using a glideslope) to five or six degree approach. VRS should be isolated to steep approach angles, vertical descents or operating with significant tailwind limits. I like the fact they implemented it, and it reacts the way I would expect a fully developed VRS to react, just way too fast, with too little warning, and happens in flight profiles I would never expect to encounter it. In DCS it feels like it's not safe to take a large helo straight down, and there is some truth to that. You absolutely don't want to mess with VRS. My demonstrations were at at least 1000 feet AGL if not higher. It will kill you, and you will die before you have time to scream in the flight regime it occurs. But not the way it does in DCS. Not during routine approaches to landing at an airfield. I'd be happy to hear what you find, and I can give it some tests myself. But I'm not TACVIEW smart, and that's the tool needed to see the parameters versus say the instruments.

Nor do I mean to sound combative. Please take my apologies if it sounded so. I'm just making a case to revisit this. Yes, I know it's a dead horse, been beaten on many threads here. But ultimately, what you've got is a forum full of people who either agree it's broken, or learned to live with it and therefore feel it's a trial by fire then next generation should have to endure. If you are saying you feel it is correctly implemented, that's a different point. I took it more to mean we should kind of learn to live with it, and I think that's too low a bar for the best helo module in DCS. I'm making a subjective case to some extent, but trying to bring objectivity to it where possible. The fact is no one in real life ever says "whew, took me a while, but now I finally learned how to stay out of VRS!" But this board is littered with similar posts. I'll use another analogy from driving, VRS is akin to not running into the guardrails on the side of the road. Normally it's not a problem, as you know where they are and there is ample clearance; but in the hip module you drive three inches from the guardrails. If you look at a standard vortex ring state diagram you'll see anything less than about 30 degrees approach angle and you just can't get into it. That's not replicated here. Maybe that's the hiccup. A thirty degree approach angle is a point in space down by your feet somewhere. It's a very steep descent. Any flight profile with a circle of action above that 30 degree approach angle should never enter VRS. And I don't necessarily disagree the flight model has the parameters wrong, with the exception state above, as much as the early warning signs, as you alluded to and the rapidness with which it becomes unrecoverable. It's too quick for a lightly loaded aircraft at low density altitude, in my opinion. But I also don't know why people wouldn't welcome a relook.

Experienced pilots rarely get into VRS. There is no indication the Mi-8 is much different than any other helicopter with regards to VRS. Yet to fly the Mi-8 in DCS you need to be hyper-vigilant with regards to Vertical speed. And that's just not how it is in real life. You're saying I just don't know how to fly the sim. I'm saying the sim doesn't fly right.

The Mi-8 has the best flight module in the game for helicopters. It actually feels like flying a helicopter. It's a great work. It's a masterpiece in flight simulation. But it is off the mark for VRS. I base that off 2500 hours or so of heavy lift helicopter flying experience. I'm not bashing the module. I love the module. But the VRS modeling is not realistic is what I am saying. I'm not speculating as much as offering my real world experience and backing it up with someone who is actively in the mi-8 community. It's far too prone to VRS in DCS verus real life. I used to demonstrate vortex ring state to students. I have a pretty good understanding of the phenomenon and know first-hand what it feels like and DCS feels wrong. Very very wrong with regards to VRS.