cw4ogden

This makes theoretical sense. VRS is about UP-flow through the rotor. Heavier aircraft, in general, and heavily loaded aircraft will push more air downward to stay aloft, than their lighter, or lightly loaded counterparts. Heavily loaded aircraft, in theory would be somewhat less likely to encounter it. But also have a much smaller available power margin to power your way out of the early phases. Great work by the way. I don't think my track files found the "smoking gun". But sounds like a good place to start, for sure. Tagging @NineLine (because this may be a new finding and for your track files).

Could you post your track files and any findings here as well? Understand you can't post the source, graphically, it would be something like this? Are there different charts for different configutations, or operating conditions, or just one chart?

I was not aware. Thanks for the information. What is the source document?

Soviet doctrine is going to be written for the Afghanistan theatre. It’s likely never been updated, or at least changed significantly in those updates to address a problem that isn’t killing that many. Wouldn’t be sad if we had 6000 foot hip performance at sea level regarding VRS because somebody misunderstood what the manual meant? What if the entire problem is the fact that it was modeled on the one clause, maybe the only in the MI8 manual that’s written as a rule of thumb for operating at 6000 feet or so? that could explain why it’s always felt like we’re operating at high altitude even near sea level, speaking solely to VRS not performamce. 40 kph is going to be associated with ETL and maybe a small cushion or even rounded up possibly for ease of memory. I don’t know what to make of 6 to 13 degrees approach angles, to associate with anything. I don’t know. It seems an odd range? Am I fine at twenty? it could mean normally, light weight etc angles up to 13 degrees are safe, but decreasing to six as you take on aggravating factors like weight or altitude.

Yes, those numbers seem reasonable the same way 300 feet per minute seems reasonable, as an avoid criteria range, though. Not that it is saying that’s where the phenomenon will start. that has fudge factor built in for any number of things as well. regarding approach angles, we keep talking about it like we can just choose your airspeed, rate of descent and your angle, independent of each other, when you can’t. there’s an airspeed (groundspeed technically) for every approach angle and associated rate of descent. Just clarifying not leveling criticism. I can’t see the video on my phone, but I will watch it and let you know. 6 m/s down is fast. That’s what? 1200 ft / min? I’d have guess 800 -1000 tops feet per minute for an unloaded mi-8. What is forward airspeed, is my question I don’t care about the rate of dissent so much is how fast is he going forward?

And here’s the kicker, what if the mission asked me to fly that profile? What do you tell the boss, No can-do sir, that’s too steep an approach angle? No, you would dig out some charts and figure out exactly how close to that demon you can fly. But you can’t, do that in DCS or real life, because the charts don’t exist, because the whole thing is a phony, at least with regards to the steep but well within a tactical approach style landings. So what does a real life pilot do? You keep your approach angle below 30°, and you avoid going straight down at all costs. But when you do have to go straight down you just do it slowly, using a ruler of them with no more than 300 ft./min., yes I know the gauge is measured in meters per second. I’m sure the Russians have their own with thumb, In the US Army 300 ft./min. is designed to keep you absolutely 100% above the vortex ring envelope. it works in any DA any gross weight combination. It lead to confusion early on in this thread, so, for everyone wondering where the hell 300 ft./min. came from, either with respect to this thread, respect to hearing it used in relation to vortex ring state, that 300 ft./min. comes from the horizontal line, if you drew one up across and intersecting tangent to the top of VRS. You physically cannot be in vortex ring state, in vertical descent at that rate of descent or slower. It works because it’s failsafe. It’s origin is to avoid the need for charts. Or possibly to combat the lack of specific charts. Not because it’s the rate of descent at which VRS is going to start occurring. It’s the rate it can’t occur, basically. And for straight down it’s plenty. It’s slow, but that’s just how you have to do it. You can define straight down as anything beyond that thirty, because it’s going to feel like it. But generally talking vertical descents here. Can you exceed 300 feet per minute? Sure. But at that point, you are now your own test pilot, and you better be prepared to be your own lawyer, because you are in no man’s land my friend. Joe Schuckatelli, pilot extraordinaire, can tell you it is safe at 600 ft./min., But There’s not a chart he can show you to prove it. And it won’t be true for all conditions. That’s where the 300 minute rule of thumb comes from, and explains why there is an entire lack of charts in general regards VRS, They are unnecessary for 99.99% of all flight profiles. ... #1. don’t exceed a 30° approach angle. A standard glide slope is 3 degrees for reference. 30 is your shoes / pedals area. Don’t come in 30 times too steep. #2 If you can’t follow rule one, you must go down slowly. You can Probably go faster than 300 feet Per minute, but why be your own test pilot? Stay in the known safe region, because you don’t know where the drop off is, because no one does. #3 If you Must land with a tailwind, apply both rules #1 and #2. That is everything you need to know about vortex ring state to be a helicopter pilot. if you can say you have diligently followed all three, rules and have never gotten into VRS I salute you! You can get into the vortex rings like state during rapid decelerations as well, but that’s a whole other discussion. It’s essentially coming backwards from the bottom of the chart in a windmill brake state, up through the bottom of the graph, it’s usually transitory and usually results in the ass end falling out. Right before your rotor wash blows past you. That phenomenon has caused countless hard landings, (crashes were no one dies) but that hazard is nowhere near as well flushed out as VRS is. *** for the technically inclined, yes I know a hard landing has a specific meaning, I’m referring to the many Class A mishaps that were labeled “hard landings”, so as not to be alarmist about the accident rate in media coverage.

The charts are notoriously vague and notoriously non specific to airframe, so I’d take those numbers with a grain of salt. I’d guess they interpolated data for whatever helo they teach based on the “1.0” mark you see in most generic VRS diagrams on the speed axis and set it to ETL transition speed, and converted units for rate of descent. In other words, they tailoring the drawing so the edge of the envelope for VRS is the ETL transition speed of whatever aircraft appropriate to the instruction they give. Giving their pilots some yardstick to measure where the phenomenon occurs. And that’s based on the assumption no one is training newbie pilots in a mi-8. They’re probably dealing with the Robinson or a jet Ranger. Which would indicate the hip probably has a little wider VRS envelope than that diagram. and I just re-state, the fact that we look at hand drawn diagrams instead of engineering charts with multiple asterisks and a three hour block of instruction on how to use them, the fact we are trying to quantify the units for Pete’s sake with respect to VRS should tell us something.

This was one of the first things brought up, early on in the thread. The VSI being in meters per second. It is also anecdotal evidence, but the mere fact there are not aircraft specific charts for each aircraft is evidence as well. As is the fact the charts have units of measure that not even defined, much less propagated with actual airspeeds and rates of descent tells us VRS is not the hazard DCS mi-8 would lead you to believe it is. If VRS was as dangerous in real life as in DCS hip, there would be aircraft specific charts. There would be charts specific to gross weight and specific to altitude and temperature. Here is an example: We fly close to the edge of the performance envelope for retreating blade stall, anytime we fly at high speeds, retreating blade stall; not a deadly killer like VRS. Yet, chart after chart is available to predict at what airspeed I will encounter retreating blade stall. And if it's cold, I'm more worried about blade compressibility, (a stupid name for rotor going supersonic) I have to compute that number. Neither will be my death, but I'm required to compute them, nonetheless. I can't takeoff without computing that number, 15 pages of charts in the -10 and it's not going to kill me. Yet I don't even have a single chart for VRS in my manual. I compute no VRS numbers on performance planning worksheet, and if you ask someone for your VRS performance planning numbers they are going to look at you like you have a dick growing out of your forehead. And all of that is because, as I pointed out up in the thread, VRS is deadly, yes, but it is not common. You really kind of have to be an jackass, or unaware of the phenomenon, or unaware you are landing with 10+ knots tailwind to get into it. I would take as evidence any such chart, but they just don't exist at the pilot level. Test pilot data, for sure, but not for the pilot, not for the Mi-8, not for any helicopter I know of, because VRS is so easily avoidable. We derive all sorts of mostly unnecessary trivial numbers prior to a flight, and it's one in a hundred flights you need one of those numbers outside your basics IGE OGE hover power / Go No Go torque, and not a single one of them relates in any capacity to VRS.

Don't take me wrong. This thread is going on two months, now. I appreciate the back and forth, but it can be aggravating because I have heard all the counter-arguments by this point. I'd welcome new evidence. A VRS chart specific to the MI-8 or similar. But the discussions tend to devolve into "you don't know how to fly it", while I give out free rotary wind aerodynamics classes that fall on deaf ears. And it sounds like they are doing a re-look. So mission accomplished, even if they find everything is hunky-dory, as is. The issue will be put to bed. What frustrates me, in debating it, is I have a circumstantial case that's pretty solid. I also have the background to be speaking from experience. And still that wasn't enough so I phoned a friend who's in the Mi-8 community to see if the hip had any type of restrictions aimed towards VRS, or flight characteristics that would be markedly different than the bird he and I both flew. He gave some wiggle room, but the answer was a pretty definitive, "the Mi-8 is not a VRS deathtrap"> That's all I can do. ED wants to give me an MI-8 and a safety pilot, I'll investigate. But barring that, it doesn't match what I experienced, and I've trained the maneuver. There's no evidence it's an abnormal hazard within the hip community on the internet, and my hip pocket source also confirms the Mi-8 handles essentially like any other helo he has flown. This should have been relooked just on the circumstantial case alone, and the controversy surrounding it. It really should have been re-looked when pilot after pilot chimed in and said this feels wrong. It's gonna get a re-look so I'm fairly happy, even if I end up being full of hot air. I have no dog in this fight other than flight model accuracy.

On this we agree. It's a great sim. Best civilian helo sim I've flown by miles and miles. But that is all the more reason to make sure VRS isn't the one poorly modeled aspect of the best helo sim. I wasn't intending to quote you. Early on, up in the thread, the discussion turned to the VSI and I was told to "stare" at it essentially.

Except it really isn't regarding the VSI. That was the point. No one looks at a VSI for normal maneuvers. That is just how DCS pilot's have learned to modify their behavior to adapt to what in real life, is a relatively benign aerodynamic hazard. I don't want to sound flippant, but what you are saying, in a nutshell, is I need more hardware to learn how to fly properly. And that's just a dumber version of the argument that: I just need to learn how to fly it. I can fly it, it's not a matter of me being unable to adapt, or needing more hardware. It's that real life is not being replicated here, and I've stated why. If you have a counter-argument why the Mi-8 should fall out of the sky where other helos do not, I'm receptive to a productive dialog and evidence supporting the model being correct, it's just that thus far, I haven't seen any, and I've seen plenty of evidence to the contrary. In short, I don't know why someone would post arguing against the possibility your sim could be made more true to real life. I'm not asking them to remove VRS, just revisit it. See if it might need a tweak. No amount of "to to fly it this way." is gonna sink in with me, because you're missing my point. I shouldn't have to stare at my VSI. It's a DCSism caused by improper modeling of VRS. It's an adaptation necessary to fly the computer, and your saying I should change my expectations, or learn to fly computer helicopters. No! For the love of God do you people not want those with real world experience to come forward? Or should I take the advice of many given, and just let you have your broken sim because it isn't worth it fighting with the ED fanboys? I don't give two craps about it honestly. But much like a piece of trash laying on the ground, I 'm not that guy that knowingly walks on by and says "not my trash". This isn't my trash. But I'll pick it up, if no one else will. If I'd had a piece in the development we wouldn't be having this discussion, no way I'd let the bug in to begin with. And if it isn't a bug, no way I'd let my community flounder asking for clarity without providing it. Two options are possible: It's right, and the reams of information surrounding mi-8 flight standardization procedures, and techniques and charts to avoid VRS is just absent from the internet. Or, It's wrong.

I've watched them. I posted about them up there somewhere but my take from the videos is this: Both accidents I reviewed the helicopter was near stationary at a high hover and induced too high a sink rate. That's fine, the game should model that, and it does, well. Both pilot's only corrective actions appears to be pulling more collective. Meaning both pilot's crashed not knowing why the hell they even crashed. That's not uncommon. Failure to identify the emergency procedure is linked to a lot of accidents. But it indicates, at a minimum, they were poorly trained on vortex ring state. Or they were extremely un-proficient in recovery technique. That tells us something. Specifically, it tells us VRS is a relatively unknown phenomenon in real life in the Mi-8, just like every other helicopter. Two accidents for an aircraft with a service record and fielding level that is unmatched globally. VRS is an aerodynamic phenomenon common to all helicopters. It doesn't differ drastically with the weight, the number of rotor blades, or various factors. If anything, the larger the helicopter, the larger the induced flow required to stay aloft, and thus the harder it will be to get into VRS. VRS is about upflow through the rotors. It about when you are operating in a column of vertical air. Due to being stationary and descending or descending with forward speed and a tailwind. What is modelled incorrectly, in my opinion is the ability to encounter VRS on approaches to land. You just can't. Not in any helicopter. You can't get into VRS while you are outrunning your own down wash because it is that downwash being pushed back up into the rotor system that is responsible for the phenomenon. When you try to demonstrate VRS to a student, it is NOT easy. You have to hunt for that one special spot where you are travelling along with your own downwake. Then you have to stay in it, then you have to push the down stick too far down. A VRS accident's parralel in a fixed wing, is a power on stall and spin accident. Unless you just didn't learnt to fly, or you did, but you just got really careless, it's never ever ever going to be a problem. If I have to go straight down, or almost straight down. Yes, eyes get riveted to the vertical speed guage. And for good reason. I'm not downplaying VRS, but some perspective, people. VSI is not even part of your scan, ever for a normal or even tactical approach. It would be a deadly distraction, number one. I'd smack you on your helmet the moment you took your eyes off the objective. VSI is included in no real life pilot's scan on a VMC approach. Yet, to fly this bird, all I hear is I'm doing it wrong and all I need to do is focus on the VSI. No, you shouldn't have to come up with non-real world procedures to accommodate flight simulator quirks.

@Pilot IkeYes, I alluded to something similar up in the post. It kind of feels like it was exaggerated, either knowingly or not, to ensure the code had the opportunity to be appreciated. DCS is probably the first to take even take a swing at modeling VRS, and kudos for the vision, let's just see it through to correctly implemented, hopefully.

Linked the full video, but this slide is saying essentially what I am saying. Also where the thirty degree rule of thumb comes from. Approach angle is the key variable, not any particular rate of decent. Unlike the generic VRS diagram, this one shows units, and the airspeed range we are talking about is less than 10 knots or so. Below a thirty or so degree approach angle, it is physically impossible to be descending in your own downwash, you go forward 2 units for every unit you go down. So, as the gentleman points out, you are vulnerable in a very small window. Too fast rate of descent, but shallow angle is no problem, because by definition that angle means your going horizontally faster than vertically. Too steep, also no problem, as long as you descend fast enough, you will hit the windmill brake state - no vortices. Essentially on a crazy steep approach you are safe from VRS, that is, until you try to arrest your descent. At which point you will enter VRS but coming up from windmill brake area on the bottom of the graph. To encounter VRS, the aircraft has to be near stationary with respect to the column of air it's flying in. That can actually be 20 to 30 knots GROUNDSPEED with a 10 to 20 knot tailwind, but your indicated airspeed is still going to be in that sub 10 knot INDICATED airspeed region, i.e you are not moving with respect to your own column of air. Capitalization is for emphasis on those two words / concepts. Yes, you can get into VRS with a decent amount of ground speed caused by downwind landing conditions, but the corollary to that, is because of that tail wind, you still have no significant airspeed. VRS is a near stationary column of air phenomenon. Or in this example, one where you were descending near vertically, due to that descent being into a moving column of air. It should not be occurring at 30 KIAS and a 30 degree approach angle and no wind, which is what I tried to demonstrate in the track files.

I had a hard time getting a track file that was a good example. I don't know if that means I've learned the quirks of the flight model, or if what I am trying to shed light on is subtle. The two I provided aren't smoking guns, per se. But they illustrate, to me, especially if you look at an external view from the side, that the incipient phase is starting somewhere above 30 knots or so. If you watch, try to visualize "where is the downwash?" The thing illustrated by the track file is the phenomenon is occurring, or at least beginning to occur in phases of flight where the downwash would be well behind the aircraft. That's what I meant by use the external view. Does the flight profile look like it would be regurgitating air? Or would it be getting fresh bites on every pass? At the point in the track file where the aircraft starts to drop like a rock, the bird is solidly in the VRS danger range. The approach angle goes from below that critical 30 or so degree angle to 40 or 50 degrees. But VRS seems to be what's sucking the bird into that 40 degree approach angle range. And I think that is where the problem lies. So, I guess I'm saying what feels wrong isn't so much the modeling of the phenomenon, but where it starts to kick in. To me it feels like it's kicking in too early. I marked up a VRS diagram to illustrate my hypothesis. It's obviously not meant to be spot on accurate, but show graphically what I think is going on. The blue line stretching to encompass about where we see VRS starting to occur, currently in DCS. And in the track file you can see the bird is exhibiting full blown VRS, i.e. the red circle at about a 40 degree angle. As shown on the graph, even at a 40 degree angle, you are still only in the light turbulence and thrust variation area of the graph. Versus DCS mi-8 at around 30 degrees you are flirting with disaster and essentially dead by 40 degrees. For VRS to happen, you have to be re-ingesting your own downwash, which requires vertical or near vertical descent. That is the key piece missing. You can't be in VRS if you are not in the same chunk of air you were a half a second ago. You need to be going almost straight down. You have to be descending into your own column of air, and that just doesn't happen with any significant forward airspeed, or sideward or rearward for that matter. Additionally, related to the graph, it feels like the red area of the graph is much bigger in DCS and the yellow area much smaller than depicted. Meaning the difference between incipient VRS and full blown VRS is razor thin. That also explains why things go from hunky-dory to FUBAR so quickly in our model. There is very little yellow area in DCS in my estimation. Thanks to you and the team as well.

That’s also an excellent point. The hip certainly isn’t the latest hot module, but it’s fan base is large. But the hind is going to be the biggest helo release, to date I would assume. And therefore an excellent time to throw one stone at two birds. I appreciate the feedback. And I’m not dying on the hill of it being incorrect, so much as warranting a relook. The community is divided hotly divided, that should be enough to investigate. And as you mention, because the Hind may be similarly modeled.

Good eye. I looked for wind cue on the approach but didn't see any. That's probably why they want a track file instead of video so they can see the exact parameters.

Thanks for the vote of support. I mainly just wanted it relooked. My case is almost entirely circumstantial. It may very well be realistic that the Mi-8 rides a lot closer to the VRS flight envelope than my frame of reference, but there's not much evidence that's the case, and a fair amount it indicating it behaves much the same as any similar helo. So, hopefully this means mission achieved. I took it on knowing it was already a severely beaten horse, so just hearing they will revisit it as a pretty big win, in my opinion.

Thank you. I think the video linked offers better evidence than my track files. I've learned to fly the module as it is, and I really had to try to force it in the track files. I don't know if that's me just adapting, or evidence the modelling is pretty darn close, but is still off enough to feel quite wrong to someone familiar with the phenomenon. I've really tried to kick around is this broken, or am I not an objective observer, and I can't quite say anymore. As I mentioned anecdotally somewhere in the post, my first encounter with VRS in the HIP I had to google what was trying to be modeled, because it felt so absolutely foreign. I think the moddelling of the phenomenon is quite good, Induced from an OGE hover it is spot on. But the parameters where you are susceptible to it need the relook. I have experienced and seen far too many DCS Mi-8 crashes that the flight profile just isn't enough for the ensuing disaster that follows.

I'm not sure your meaning? The DCS Mi-8 is easy to get into VRS or the actual aircraft is easy to enter VRS. If you scroll up to the start of the topic, you will see: I started the thread by asking that very question to an active MI-8 instructor friend of mine. "Is the Hip more prone to VRS than other helicopters?" His answer was pretty definitively "No." I'd ask you to read through the whole thread, where I wage a fairly lengthy war on why VRS isn't realistically modeled in DCS, the Hip specifically, and upon what experience base I draw those conclusions upon. I'm a retired U.S. army heavy lift standardization helicopter pilot who used to demonstrate VRS. And I know it sounds self serving to come here and tout credentials, but I am an expert on rotary wing aerodynamics and VRS in particular and because I want to make the point: it's not even required to be demonstrated to new pilots. Virtually no one gets a demonstration of VRS going through flight school, or did at least, unless it was because their instructor went out of his or her way to teach it. It is for most pilots purely book knowledge. I certainly didn't receive a demonstration. Then I got into it once in real life, survived the test, to learn the lesson if you will, and it became a pet peeve of mine, that we didn't teach it. I went out of my way to demonstrate it because, although exceedingly rare, VRS can absolutely kill you, and very quickly. So, in addition to being an expert, It falls into the category of one of my pet peeves, I went out of my way to demonstrate to pilots that it is deadly, even though it wasn't required. But how it works in DCS is sketchy at best. VRS kills people the way sticking a fork into the toaster kills people. And that is only if they don't know about the hazard or are operating in extreme high G.W. high D.A. situations and get careless. I'm glad they tried to model it, but I also think it's worth the time to get it right. It's also why mine is the umpteenth thread about VRS, from other real pilot's who say the same exact thing.

12:40 seconds: There is no way that flight profile should result in a VRS accident. The Vortices would be shed because he is not descending into them. Here you can see the difference. At about 1 minute in. Notice how the bird flies fine, even backwards in a descent. It isn't until he tries to descend vertically into his own rotorwash does VRS happen.

@NineLine Here are a couple of track files. My beef is it seems you can get into VRS, in the MI-8 without one critical element. But it is the most important element, vertical or near vertical descent. If I had to guess, I'd say the VRS algorithm is looking for parameters of flight associated with a Pilot's rule of thumb for avoiding VRS. In other words, if the manual says use caution below 40 KIAS, that doesn't mean the phenomenon can happen at 40 knots. They throw in fudge factors for tailwinds etc. A big grey area to stay out of. VRS can happen, and can only happen, when the helo is descending vertically into it's own downwash, and with sufficient rate of decent. You have to be going straight down into your rotorwash. That appears to be the piece that is improperly coded. It should be absolutely impossible to encounter VRS with an approach angle less than about 32 degrees as indicated on the VRS diagram. I believe on track 2, the first signs of VRS start occurring in the 30 knots range, and it is fully developed with 20 knots of forward speed. 1.trk 2.trk

Sorry for the delay. I got burned out on this thread. Indeed, the fact we are arguing about it speaks volumes of the simulator, as does the fact about half of the responders or more won’t take at face value, the multiple real life pilots telling the community it’s wrong. It’s a great sim. I’d go the trackfile route, if it seemed there was any enthusiasm for fixing it, but it feels like the only enthusiasm is to find a way to impugn what several of us are saying, and that is, it isn’t correct. There is a tiny window in landing profile where you can be descending directly in your own downwash. You have to be in that downwash descending vertically or near vertically for this phenomenon to occur. I did try a few tests with smoke on the ground and I was hoping the airflow was modeled in the smoke, so I could see the vortex, unfortunately it doesn’t seem to be. You have to find a very precise attitude and descent angle to encounter VRS because by definition if you are not going directly down into your downwash, the vortices are washed away. I’ve also rewatched the VRS accident videos and will offer two more pieces of anecdotal evidence from viewing them: There appears to be no attempt at corrective action, indicating VRS is rare in the hip, and not some boogeyman waiting for the slightest inattention to rate of descent. if it was as bad as depicted in DCS, it would be known in the community and they’d have reacted with some form of corrective action. I can see none. The fact there are recoded accidents points, ironically, to it not being crazy deadly. I.E. we haven’t seen an R22 mast bumping crash in years because it is a known and well fleshed out hazard. In my estimation, they crashed not knowing what was wrong with their aircraft. Secondly, both accidents happened in essentially vertical profiles and one actually was drifting backwards. thats what it takes to get into VRS, you have to be going straight down into your downwash, who’s angle is dictated by the surface winds and your relation to them. With a 15 knot tailwind I can get into VRS at 15 knots, but otherwise, no, you just can’t. Because I can’t simultaneously be going both fifteen knots forward and in a vertical descent. Its not unless you find that one perfect pitch, power and airspeed setting and deliberately hold it there, and even then you have to descend too fast. And I’d just reiterate, I would like to test this, but I’m burned out fighting with people, developer has yet to chime in, and I largely feel stupid for thinking I could break through the nonsense, when so many have already failed. None of that is directed at you, it’s just explaining why I’m accepting defeat over learning how to do trackfiles and conducting more extensive flight testing. No one cares, and to many it’s a badge of honor they can fly the “deadly” hip.

Roger, same as 47 before we got fadec controls. We had Incr / dincr to set but rrpm but it was governed by some fairly simple flywheel governors and manipulating fuel control.

I gotta look at what to see what it’s called but I’m assuming it’s being controlled by my slider which is how I go from idle to flight rrpm. Thanks for the replies. That’s a fairly significant difference in rrpm at takeoff settings. That could certainly be a cause I’d thus far not considered. It may be the 47 is just really better than average similar bird regarding VRS because in any given profile that extra RRPM and lack of rail rotor would and could be the difference. And it’s the lack of upflow that feels off, as I stated somewhere up there in the post. But that much difference in RRPM on its face, might be the difference I’m feeling. There would be noticeably less upflow. And at the end of the day that’s a decent answer for why at least. it would also explain why tweaking the throttle levers works in the sim to make it feel more “right” to me, even if it is incorrect procedure.