Engine power discrepancy between Russian helicopters

[some1]

When following the limits displayed on the Engine Power Indicator, Ka-50 shows much worse performance than Mi-8 and Mi-24. For example here's a test hovering with engine power at 'H' setting (max continuous). Same conditions, same weight (9.9 t). Antiice and air filters off:

Ka-50, with supposedly the most efficient rotor system: barely lifts off the ground at 1m/s and can only hover in ground effect. PTIT: 855C, EPI 7.5, engine RPM 96%

Mi-24 with supposedly the same TV3-117VMA engines, climbs initially at 6 m/s, still climbs above 1 km altitude at 4 m/s:  PTIT 920C, EPI 7.8, engine RPM 97%. 

Mi-8 with the weaker TV3-117VM engines, goes like a rocket at 10 m/s and barely slows down, at 1 km altitude climbs 2x faster than Mi-24. PTIT 890C, EPI 8.2, engine RPM 96%. 

The same is with horizontal flight, max speed at 'H' max continuous power is roughly:

Mi-24: 160 kts

Mi-8: 155 kts

Ka-50: 135 kts

Note the much lower PTIT temperature in Ka-50 at 'H' setting. Looks like either the power limits displayed on the indicator are too low, or some helicopters in DCS are over/underpowered. 

 

climbTest_mi24.trk climbTest_mi8.trk climbTest_Ka50.trk

Edited January 14, 2023 by some1

[zerO_crash]

You cannot compare the performance of helicopters like that. There are far too many factors to account for in order to get a relative idea of performance difference (performance in what part of the flight envelope?). Ka-50 and Mi-24 have rotor blade-airfoils designed for high speeds, whereas Mi-8 has one optimized for lift/hovering. Furthermore, total area of rotor blades matter, as well as rpm. Whilst it might seem logical at first to set a definite load (9.9 tonnes in this case), you have to compare that to maximum weight of the airframe. Ka50 is the lightest, its blades are desgined for its own purpose.

 

Same goes for the RPM, PTIT and EPI-values that you are seeing. They depend on a multitude of factors; build of the helicopter, tuning of the engines, etc... Don't forget that for example both Ka-50 and Mi-24 have wings for armament. Those wings reduce thrust produced by the main rotor/rotors in hover due to it acting as an obstruction to the airflow. On the other hand, in forward speed, they reduce the power needed. Mi-8 has hardpoints, but they are not nearly as obstructing as the wings on Ka-50 or Mi-24. Don't forget such factors as for example engine heat dissipators, which by default are installed on Ka-50, and completely optional on Mi-8 and Mi-24. Those heat dissipators, do in fact reduce airflow of the engine (due to obstructive elements at the rear, whether you engage it or not), thus making it run hotter and less efficiently, but at the gain of reduced IR-signature. You have to keep in mind things like onboard computers and systems which will need electricity to run, and that increases engine RPM and thus PTIT, without any gains to the physical performance of the aircraft. Again, there are many, many factors to count. That's why, you simply cannot compare completely different aircraft like that.

 

Using your logic, you could ask; how come that the Mi-8, while having the weakest engines, also happens to have the highest maximum load of them all? Purpose and design. With that said, don't attempt doing any of the maneuvers you can with either Ka-50 or Mi-24, otherwise you'll see the end of the flight-envelope for that helicopter. For reference, Mi-8's top speed is 250 km/h, +- a couple of km/h in straight flight, a Ka-50 or Mi-24 will gladly do 300 km/h, and more in level flight. I'm not even mentioning the 3.5G that Ka-50 will do...

Edited March 6, 2023 by zerO_crash

[some1]

I am aware of the engineering differences between airframes and engines installations, I don't expect them all to perform the same. However, that still does not explain the weird power figures in DCS. Or maybe just the power indicator pointers are off. You posted a lot of text, but hardly on topic.

2 hours ago, zerO_crash said:

Don't forget such factors as for example engine heat dissipators, which by default are installed on Ka-50, and completely optional on Mi-8 and Mi-24.

If you cared to download and check the tracks I uploaded, which you obviously did not, the tests are performed with heat dissipators on all helicopters.

2 hours ago, zerO_crash said:

Those heat dissipators, do in fact reduce airflow of the engine (due to obstructive elements at the rear, whether you engage it or not), thus making it run hotter

If you actually read my first post, which I'm starting to doubt, Ka-50 engine runs much cooler at max continuous setting.

3 hours ago, zerO_crash said:

You have to keep in mind things like onboard computers and systems which will need electricity to run, and that increases engine RPM and thus PTIT

Again, Ka-50 engines run colder and slower than other helicopters, not hotter. 

3 hours ago, zerO_crash said:

With that said, don't attempt doing any of the maneuvers you can with either Ka-50 or Mi-24, otherwise you'll see the end of the flight-envelope for that helicopter. For reference, Mi-8's top speed is 250 km/h, +- a couple of km/h in straight flight, a Ka-50 or Mi-24 will gladly do 300 km/h, and more in level flight.

When was the last time you flew these helicopters in DCS? Mi-8 is quite sporty as long as it does not carry any cargo, and almost as fast as Mi-24. Ka-50 is a dog if you try to follow the limits on the engine indicators. 

Re-read my first post. Mi-8 does 290 km/h on continuous engine setting, it will exceed 300 km/h with takeoff power. Ka-50 barely does 250 km/h, good luck getting it to 300 in level flight without exceeding engine limits. 

[zerO_crash]

14 hours ago, some1 said:

I am aware of the engineering differences between airframes and engines installations, I don't expect them all to perform the same. However, that still does not explain the weird power figures in DCS. Or maybe just the power indicator pointers are off. You posted a lot of text, but hardly on topic.

If you cared to download and check the tracks I uploaded, which you obviously did not, the tests are performed with heat dissipators on all helicopters.

If you actually read my first post, which I'm starting to doubt, Ka-50 engine runs much cooler at max continuous setting.

Again, Ka-50 engines run colder and slower than other helicopters, not hotter. 

When was the last time you flew these helicopters in DCS? Mi-8 is quite sporty as long as it does not carry any cargo, and almost as fast as Mi-24. Ka-50 is a dog if you try to follow the limits on the engine indicators. 

Re-read my first post. Mi-8 does 290 km/h on continuous engine setting, it will exceed 300 km/h with takeoff power. Ka-50 barely does 250 km/h, good luck getting it to 300 in level flight without exceeding engine limits. 

I didn't check the tracks because the original complaint is based on invalid testing, plain and simple. I would expect you to understand that without me specifiying. The heat dissipators are of different construction, thus different air throughput levels. Ka-50 engine running cooler can be explained by different tuning of the engine ("can", not "definitely"). I haven't flown DCS for a while now, which doesn't change the fact that I know how they behave (I doubt you have as much time as me in DCS or any of these modules, but that is besides the point). You claiming Ka-50 is a "dog", is your impression, not a fact. My experience is very much the opposite. Furthermore, I can back it up with specifications within the manuals. Mi-8 is sporty for a machine of that size, but it is nowhere near a Ka-50 in terms of dynamics. I suggest you learn to fly the Ka-50 properly (within limits), and you'll see what a nonsense it is to compare the two. 

 

I further suggest you learn to read, because as far as I see, you claim to adhere to engine-limitations, yet you exceed the permissable speed limits in the Mi-8. Selectively chosing what limitations to follow, only proves your ignorance and incompetence. Flying a Mi-8 constantly at 280 km/h+ , induces for example vibrations, which the airframe is not built to tolerate long-term. A single sortie within DCS might accept this, but let me inform you very clearly, that you are indeed reducing the service life of the airframe at an accelerated rate. Want to talk logic, then accept the fact that Mi-8 is permitted circa 250 km/h as top cruising speed, and anything above for prolonged time, is you showing incompetence. IRL, you would not be a pilot for long! Ka-50 and Mi-24 were built with those speeds in mind, maintained, mind you! Hopefully, I'm not exceeding your word count capacity!

 

No dev will respond to your testing, because it simply is flawed and bears very little in common with objective and relevant analytics. You want to test something, then use a testbed engine, or at least design a test which makes sense. Even the values you state, have firmly been confirmed before to have been components of e.g. engine tuning (Higher pressure in the compressor - higher torque for improved maintaining of rotor RPM. After all, EPR/EPI gives you an idea of how much pressure is exerted within the engine (example)). What I am saying here is, there might be a fault, or not, with the system (Ka-50 is a old module, newly revised), but your testing doesn't cut it. It appears as very little more than a few values (far too few and irrelevant), and a rant at most.

 

Mi-8 will not do much more than 280 km/h (we are talking here about indicated airspeed) in level flight due to aerodynamic drag. In dive, sure, but not level maintained. I have tested it a couple of times (in short intervals). Ka-50 and Mi-24 alike, will easily do above 300 km/h within the realm of 60-minute power limit. I will remind you that the manuals for all three aircraft show engine limitations of test-bench setup, not aircraft-mounted configuration (I have posted the engine limitations for all TV3-117VM/A engines that we have, as installed on the aircraft, in this forum). Also, top speeds are momentary, not prolonged. Not sure where you get it from that a helicopter is supposed to maintain it's top speed prolonged...

Edited March 4, 2023 by zerO_crash

[some1]

10 hours ago, zerO_crash said:

I haven't flown DCS for a while now, which doesn't change the fact that I know how they behave (I doubt you have as much time as me in DCS or any of these modules, but that is besides the point). You claiming Ka-50 is a "dog" is your impression, not a fact. My experience is very much the opposite

Then I suggest you go back to DCS and compare the aircraft yourself again before trying to start a pissing contest. Maybe a thing or two have changed since then. 

 

10 hours ago, zerO_crash said:

Ka-50 and Mi-24 alike, will easily do above 300 km/h within the realm of 60-minute power limit.

Absolutely not. Here's Ka-50 on a standard Caucasus day, at 60-minute power limit on the power indicator, with no weapons and almost empty tanks, and it can't even do 270 km/h TAS.

In the same conditions, Mi-8 with 100% fuel in the tanks, IR supressors and external pylons is still faster by ~15 km/h. Even though it's almost 2 tonnes heavier than Ka-50 as shown here. Mi-24 also has similar top speed.

null

[zerO_crash]

You are flying the Ka-50 below it's maximum 60 minute limit! Check the values! Your PTIT is 860*C (955*C PTIT is maximum for 60 min.), your engine RPM is 95% (97.5% is the maximum for 60 min.). Your EPR, is also below the 60 min. threshold. You are looking at the gauge from the pilot's angle. If you look at it from above (lean in), then you'll notice that your are actually below the "M" (60 min.) readout. Due to perspective, you are actually below the readout. When you are on point with EPR, the indicators should indicate values above the destined, from pilot's perspective. Check that again! 

 

Also, are you flying the Ka-50 3-pylon version, or 2 in this case? With the 2-pylon version, I have made 300 km/h+ (indicated - not HUD (GS)) maintained on 60 min. power rating, though without loadout. Go to 6 min. contingency, and you are well above. I have been at 345 km/h+ in the Ka-50 in contingency-setting, for very short durations (couple seconds), but could maintain that for at least 6 min. if I didn't bother with the limitations.

 

Finally, there is one thing that you can do, to both increase fuel economy as well as fly very much faster in the Ka-50 (aiming for engine maximums aside). Control selector for re-adjustment of the free-turbine (rotors) RPM governor. Set that from "Nominal" (default) to "Low". It is primarily used for when you dive down at very high speeds so as not to stress the rotor. However, it can also be used for economic flight. In simple terms, it will gear down your engines, relative to the blade AOA. The thing you have to monitor here, is not letting the rotor RPM drop too much (not below 83% during maneuvers as per manual #13-3). Just to specify, the Mi-8 and Mi-24 have very similar functionality, but they have it purely for trimming the engines manually to their optimal setting, prior to take-off (it is not used as dynamically as in Ka-50). In Ka-50, it works a bit different, and is used both for deep diving and improved fuel economy.

 

For reference, you won't do more than 280 km/h (indicated airspeed) maintained in level flight with the Mi-8, as stated earlier. You see the proof in your own picture of the Mi-8.

Edited March 4, 2023 by zerO_crash

[some1]

14 minutes ago, zerO_crash said:

You are flying the Ka-50 below it's maximum 60 minute limit! Check the values! Your PTIT is 860*C (955*C PTIT is maximum for 60 min.), your engine RPM is 95% (97.5% is the maximum for 60 min.). Your EPR, is also below the 60 min. threshold. You are looking at the gauge from the pilot's angle. If you look at it from above (lean in), then you'll notice that your are actually below the "M" (60 min.) readout. Due to perspective, you are actually below the readout. When you are on point with EPR, the indicators should indicate values above the destined, from pilot's perspective. Check that again! 

As I stated in the first post, which you still seem to ignore, these are not the numbers the Ka-50 shows at the  60 min. threshold. I moved my head to verify that the pointers are on the 'H' mark during the test. Besides, I mostly fly in VR and the gauge is better visible there.

That's Ka-50 (III) btw. 

23 minutes ago, zerO_crash said:

For reference, you won't do more than 280 km/h (indicated airspeed) maintained in level flight, as stated earlier. You see the proof in your own picture of the Mi-8.

All the speeds I give are TAS. You're mixing the two. Never claimed Mi-8 will do 300 IAS. 

[zerO_crash]

34 minutes ago, some1 said:

As I stated in the first post, which you still seem to ignore, these are not the numbers the Ka-50 shows at the  60 min. threshold. I moved my head to verify that the pointers are on the 'H' mark during the test. Besides, I mostly fly in VR and the gauge is better visible there.

That's Ka-50 (III) btw. 

All the speeds I give are TAS. You're mixing the two. Never claimed Mi-8 will do 300 IAS. 

I am fully aware of what you are going at. In most cases, PTIT and engine RPM will not be the limiting factors, EPR is typically the first one to limit one's operation. However, as stated, it seems to me that your EPR is below that of the maximum for 60 min. limit. Even so, EPR will vary with atmospheric pressure, termperature - generally weather. Flown in different types of weather, you will find out that EPR is not always the first to limit out of the three. Aditionally, you are running then 3-pylon Ka-50 (I haven't tested it yet), but that does not matter at all. A reduction in performance is to be expected from a larger wing with an extra pylon and more equipment onboard (helicopters). Try the original Ka-50 with 2-pylon wings and you'll see the performance is better.

 

Let me put you apart right here. First, I am not mixing up anything. You failed to detail what type of speeds you have checked in your inital post. I am clearing that up. While IAS will be close to TAS at ground level, you are not at ground level. In the Ka-50, you are at approx. 200m QNH and in the Mi-8 you are at 270m QNH, all extracted from your altimeters (assuming that your barometric pressure is set correct?!). When claiming differences of "15 km/h" between two helicopters, then that falls into the realm of error for the inaccurate measurement you have done. 70m of altitude difference, plus inaccurate IAS readout (you cannot tell +-1 on the IAS-gauges) will give you that margin for error, and more. Thirdly, you claimed speeds of 290 km/h which, a couple of posts later, you are specifying to be TAS, yet you haven't shown one single readout which confirms this. Furthermore, as backup to your supposedely TAS readout, you post cockpit pictures of one helicopter that can readout GS, and the other which only gives you IAS (with margin for error, might I add). Your test it utterly flawed. I haven't tested Ka-50 BSIII yet, but comparing two helicopters together has nothing to do with that. If you want to post any metrics, use DCS-metrics from within a replay and editor, not inside the modules. Lastly, in your "test", you load all aircraft to the same weight, without taking into account their; a) different roles and b) different designs. A Ka-50 at 10.8 tonnes will start to feel somewhat sluggish (compared to it's empty configuration, still more responsive than Mi-8), whilst the Mi-8 still has almost 2 tonnes of payload before reaching it's maximum weight. It's rotor-, control-system and all there-around is designed for such a load! Comparatively, you are testing two planes against each other, you load a cessna to it's maximum and test it's performance against a small jet aircraft... The difference isn's as big, but the proof of concept still stands. You are making pointless comparisions. The only thing these helicopters have in common, are the engines (and some of the sub-systems), the whole design is simply different.

 

If you want to compare anything, at least make sure you extract your metrics out reliably, then we can discuss whether Mi-8 should be the attack helicopter with Vikhrs and Ka-50 a utility one...

Edited March 4, 2023 by zerO_crash

[some1]

1 hour ago, zerO_crash said:

I haven't tested Ka-50 BSIII yet

Another lengthy post and you still haven't even fired DCS to check if your bookworm knowledge actually applies to the current state of the sim. 

We're in DCS BS3 "bugs and problems" section, not "real world aviation", or "what I did in DCS 5 years ago" section.

2 hours ago, zerO_crash said:

In the Ka-50, you are at approx. 200m QNH and in the Mi-8 you are at 270m QNH, all extracted from your altimeters (assuming that your barometric pressure is set correct?!). When claiming differences of "15 km/h" between two helicopters, then that falls into the realm of error for the inaccurate measurement you have done. 70m of altitude difference, plus inaccurate IAS readout (you cannot tell +-1 on the IAS-gauges) will give you that margin for error, and more.

The speed readouts I give you are from the DCS status bar in the external view, not from the cockpit gauges. If you think 70 meters difference would reverse the situation drastically, better check you math.

2 hours ago, zerO_crash said:

Thirdly, you claimed speeds of 290 km/h which, a couple of posts later, you are specifying to be TAS, yet you haven't shown one single readout which confirms this.

These are not the same conditions I used when testing speeds several months ago, so I'm not surprised the numbers are different than in my first post. Like it or leave it.

 

1 hour ago, zerO_crash said:

Lastly, in your "test", you load all aircraft to the same weight

Nope, as I clearly stated, Ka-50 on the screenshot was as light as possible, no stores and little fuel, while Mi-8 on a screenshot was full tanks, IR supressors and pylons. Since you've complained that in the first post in this thread I tested the aircraft at the same weight, now you have them at two tonnes difference. Around 8800kg for Ka-50, around 10800 kg for Mi-8. Mi-8 is still faster when flying on the 60 min. engine limit, and no, neither Ka-50 (nor Mi-24 for that matter) won't easily do 300 km/h at that engine setting, despite your claims. At full take-off power, yeah, barely.

This was just a short 10 min test to show you that the numbers which you claim do not match with what happens in DCS right now. If you don't believe me, or think the test method is flawed, fire up DCS and you'll have all the answers to your questions in 10 minutes. Certainly would have been quicker than writing all of this.

 

[zerO_crash]

First and foremost, apparently, you seem to be the only one having the issue, thus, it seems that my recent memory is still more accurate than your mixed conclusions based on a multitude of metric-extracts, where nothing is neither sorted nor presented cleanly. Goes to show your competence. I stated once already, that me not having flown in the recent year, has nothing to do with your lack of analysis and concrete metrics. Furthermore, you draw conclusions on flawed logic and comparisons, which are at this point demeaning. Why you even post the pictures of inside cockpit (when what you extract is clearly from a different source), is beyond me... Additionally, 70m altitude difference will not make immediate impact, but adding multiple factors together can change it. In professional analysis, one of the first rules that you learn, is to investigate any potential faults and/or components that can result in a skewed outcome, and preferably discard them by analyzing their impact on the subject. Additionally, all of a sudden, you start pulling in speeds that have been obtained in different conditions, without even stating so. At this moment, the topic is incredibly messy on all levels, and at the bottom of it all, lies your "feeling" that Ka-50 is not attaining your desired outcome. When I get the chance, I'll see for myself, though I haven't heard anyone claim that the performance regime is in any way altered. At this point, you haven't presented anything that reliably states anything other than my personal experience with the Ka-50 nor any significant deviation from the original product. Out!

[some1]

 

9 hours ago, zerO_crash said:

Why you even post the pictures of inside cockpit (when what you extract is clearly from a different source), is beyond me...

I posted these pictures to further illustrate the issue since you've complained about the methods used in the first post. So I used a different method, with different weights. If you want something super scientific to satisfy your curiosity, you have to do it yourself, sorry. At this moment I doubt you would be satisfied with anything I'd upload, anyway.

10 hours ago, zerO_crash said:

When I get the chance, I'll see for myself, though I haven't heard anyone claim that the performance regime is in any way altered

Well, that would be great if you'd finally stopped talking about your memories and launched the game. It not like in BS3 there's any harm from flying constantly at takeoff power or above it. Most people won't care about power limits until the engines start to blow up.

[zerO_crash]

On 3/5/2023 at 10:58 AM, some1 said:

 

I posted these pictures to further illustrate the issue since you've complained about the methods used in the first post. So I used a different method, with different weights. If you want something super scientific to satisfy your curiosity, you have to do it yourself, sorry. At this moment I doubt you would be satisfied with anything I'd upload, anyway.

Well, that would be great if you'd finally stopped talking about your memories and launched the game. It not like in BS3 there's any harm from flying constantly at takeoff power or above it. Most people won't care about power limits until the engines start to blow up.

We are not "talking", we are chatting, just to clear that off. Also, flying at 6-minute power limit can break your engines within one session in DCS. There are plenty of posts asking "why the engine quit all of a sudden". That typical DCS-pilot doesn't care about limits, it due to the nature of a simulator. You make out of it what you want, and most sadly treat it as a "game with good physics- and systems-modelling". I don't care about those, I care about people that actually fly somewhat realistic within the realm of the simulator (there is plenty of personell with IRL experience here).

 

Regardless of your impressions, as stated before, no dev will take such a "report" seriously. They are more than enough "bug" being reported, which stem from lack of knowledge and interest in reading the manual. Without any subsequent testing, this currently falls within the parameters of that.

Edited March 6, 2023 by zerO_crash

[some1]

Looking forward to your thorough testing then, when you finally launch BS3 for the first time.

Edited March 6, 2023 by some1

[AeriaGloria]

On 3/5/2023 at 12:21 PM, zerO_crash said:

We are not "talking", we are chatting, just to clear that off. Also, flying at 6-minute power limit can break your engines within one session in DCS. There are plenty of posts asking "why the engine quit all of a sudden". That typical DCS-pilot doesn't care about limits, it due to the nature of a simulator. You make out of it what you want, and most sadly treat it as a "game with good physics- and systems-modelling". I don't care about those, I care about people that actually fly somewhat realistic within the realm of the simulator (there is plenty of personell with IRL experience here).

 

Regardless of your impressions, as stated before, no dev will take such a "report" seriously. They are more than enough "bug" being reported, which stem from lack of knowledge and interest in reading the manual. Without any subsequent testing, this currently falls within the parameters of that.

 

You can’t break the engines if TV3-117 in DCS. The 6 minute power limit is for increasing lifetime. Head of belsimtek ex-Mi-8 pilot has said you can run engines at take off power all flight and not notice any change in power at the end. They are similarly unbreakable in DCS unless the governors are disengaged. 
 

In my experience the inition OP has something right. There is something very weird beyond tuning in the TV3-117VMA of the Mi-24/Ka-50, and TV3-117V of Mi-8. In Ka-50/Mi-24 engine model is identical. Gearbox is different. Engine limits, RPM, EPR, and PTIT, should be identical. Yeah a suppressor will decrease performance, but what the engine cares about is PTIT/RPM, with EPR only as a reference for pilot/data recorder 
 

In Mi-8 for example, the EPR seems to be perfectly at 100% take off power much more then Ka-50, Mi-24. In addition, there has been alotnof tuning of the TV3-117VMA engines it seems since release of Mi-24/BS3. But Mi-8 soldiers on without any changes to its 117V. In itself the only difference to the pilot between engines should be higher temperature and power, not overall EPR behavior. 
 

Anyways, I haven’t done as thorough a test as OP, but I’m glad OP has. And I might look at the tracks and test myself. I assume there’s a few things that lay on a sliding scale of “almost completely finished,” “requiring tweaks,” and “from a decade ago when the game had less fidelity.” 

On 1/14/2023 at 8:36 AM, some1 said:

When following the limits displayed on the Engine Power Indicator, Ka-50 shows much worse performance than Mi-8 and Mi-24. For example here's a test hovering with engine power at 'H' setting (max continuous). Same conditions, same weight (9.9 t). Antiice and air filters off:

Ka-50, with supposedly the most efficient rotor system: barely lifts off the ground at 1m/s and can only hover in ground effect. PTIT: 855C, EPI 7.5, engine RPM 96%

Mi-24 with supposedly the same TV3-117VMA engines, climbs initially at 6 m/s, still climbs above 1 km altitude at 4 m/s:  PTIT 920C, EPI 7.8, engine RPM 97%. 

Mi-8 with the weaker TV3-117VM engines, goes like a rocket at 10 m/s and barely slows down, at 1 km altitude climbs 2x faster than Mi-24. PTIT 890C, EPI 8.2, engine RPM 96%. 

The same is with horizontal flight, max speed at 'H' max continuous power is roughly:

Mi-24: 160 kts

Mi-8: 155 kts

Ka-50: 135 kts

Note the much lower PTIT temperature in Ka-50 at 'H' setting. Looks like either the power limits displayed on the indicator are too low, or some helicopters in DCS are over/underpowered. 

 

climbTest_mi24.trk 2.96 MB · 0 downloads climbTest_mi8.trk 2.11 MB · 0 downloads climbTest_Ka50.trk 710.69 kB · 0 downloads

 

I’ll run my own tests using your figures as a comparison and get back 

Edited March 27, 2023 by AeriaGloria

[zerO_crash]

On 3/27/2023 at 7:02 PM, AeriaGloria said:

You can’t break the engines if TV3-117 in DCS. The 6 minute power limit is for increasing lifetime. Head of belsimtek ex-Mi-8 pilot has said you can run engines at take off power all flight and not notice any change in power at the end. They are similarly unbreakable in DCS unless the governors are disengaged. 
 

In my experience the inition OP has something right. There is something very weird beyond tuning in the TV3-117VMA of the Mi-24/Ka-50, and TV3-117V of Mi-8. In Ka-50/Mi-24 engine model is identical. Gearbox is different. Engine limits, RPM, EPR, and PTIT, should be identical. Yeah a suppressor will decrease performance, but what the engine cares about is PTIT/RPM, with EPR only as a reference for pilot/data recorder 
 

In Mi-8 for example, the EPR seems to be perfectly at 100% take off power much more then Ka-50, Mi-24. In addition, there has been alotnof tuning of the TV3-117VMA engines it seems since release of Mi-24/BS3. But Mi-8 soldiers on without any changes to its 117V. In itself the only difference to the pilot between engines should be higher temperature and power, not overall EPR behavior. 
 

Anyways, I haven’t done as thorough a test as OP, but I’m glad OP has. And I might look at the tracks and test myself. I assume there’s a few things that lay on a sliding scale of “almost completely finished,” “requiring tweaks,” and “from a decade ago when the game had less fidelity.” 

I’ll run my own tests using your figures as a comparison and get back 

 

 

I have never killed, nor tried to do an engine in DCS, thus I haven't checked what DCS will permit you in terms of engine durability. Again, depending on how long a mission is, what engine wear is set to (default is 90%, though you can set it manually lower in the mission editor), I wouldn't be surprised if it could be broken nowadays. Updates on singular components and damage modelling is beingn pushed through without concrete feedback through patch-notes.

 

Remember that engine model being identical, does can, and will IRL be geared different. With such complex machines, being hand made and tuned before leaving factories, you will absolutely never have the exact same feedback. Never. There will be nuances and some aircraft will be able to withstand more whereas others will not. The specification calls for minnimum demands, but what is normal in what aircraft will be somewhat different. This applies within a specific aircraft make, the difference is even greater when you start comparing different types of aircraft. I don't see anything here that is outside of what different tuning could result in (pure metrics). Actually, EPR is more than just for reference, as EPR actually counts in the specific atmospheric difference, thus showing you what pressure is being built up within the engine. In a sense, if you exert too high pressures in the engine, you will stress the materials to a higher degree than the limits permit. That's why you have the EPR-limits to go by. In Russian helicopters you have three instruments to control with regards to engine limitations in order to maintain within specified control. It's more than just a reference-indicator mate

 

I cannot really fly DCS atm. due to the sim performance having been altered since 2.8.0 (will need to get a new PC), however from the very little testing I did (2-3 hrs), I was able to attain TAS (as per editor metrics) of 275-280 km/h with a pure Ka-50 BSIII (two-pylon wing) and approximately 50% fuel. It was standard atmospheric conditions (default editor setting, again, need a new PC for anything specific) with no wind and between 10-20m ASL. I cannot see anything wrong. I might have reached close to 300 km/h if it was even lower on fuel, and less amunition, although 280 km/h is still really fast for this helicopter. 

 

The discussion of the qualitative anatomy of Ka-50 vs Mi-8MTV2 is a completely different one, and I have stated earlier why. Mi-8 will simply never attain the speeds and flight dynamic (turns, loops, instant change of bearing, etc...) that Ka-50 will do. One other should be stated, accelerating up to a max speed is one thing, attaining a top speed (e.g. dive), and then attempting to keep it as best as one can. Ka-50 has favourable qualities when it comes to maintaining the attained speed at a lower power setting once it has achieved the speed. It ought to be considered as well.

[AeriaGloria]

55 minutes ago, zerO_crash said:

 

I have never killed, nor tried to do an engine in DCS, thus I haven't checked what DCS will permit you in terms of engine durability. Again, depending on how long a mission is, what engine wear is set to (default is 90%, though you can set it manually lower in the mission editor), I wouldn't be surprised if it could be broken nowadays. Updates on singular components and damage modelling is beingn pushed through without concrete feedback through patch-notes.

 

Remember that engine model being identical, does can, and will IRL be geared different. With such complex machines, being hand made and tuned before leaving factories, you will absolutely never have the exact same feedback. Never. There will be nuances and some aircraft will be able to withstand more whereas others will not. The specification calls for minnimum demands, but what is normal in what aircraft will be somewhat different. This applies within a specific aircraft make, the difference is even greater when you start comparing different types of aircraft. I don't see anything here that is outside of what different tuning could result in (pure metrics). Actually, EPR is more than just for reference, as EPR actually counts in the specific atmospheric difference, thus showing you what pressure is being built up within the engine. In a sense, if you exert too high pressures in the engine, you will stress the materials to a higher degree than the limits permit. That's why you have the EPR-limits to go by. In Russian helicopters you have three instruments to control with regards to engine limitations in order to maintain within specified control. It's more than just a reference-indicator mate

 

I cannot really fly DCS atm. due to the sim performance having been altered since 2.8.0 (will need to get a new PC), however from the very little testing I did (2-3 hrs), I was able to attain TAS (as per editor metrics) of 275-280 km/h with a pure Ka-50 BSIII (two-pylon wing) and approximately 50% fuel. It was standard atmospheric conditions (default editor setting, again, need a new PC for anything specific) with no wind and between 10-20m ASL. I cannot see anything wrong. I might have reached close to 300 km/h if it was even lower on fuel, and less amunition, although 280 km/h is still really fast for this helicopter. 

 

The discussion of the qualitative anatomy of Ka-50 vs Mi-8MTV2 is a completely different one, and I have stated earlier why. Mi-8 will simply never attain the speeds and flight dynamic (turns, loops, instant change of bearing, etc...) that Ka-50 will do. One other should be stated, accelerating up to a max speed is one thing, attaining a top speed (e.g. dive), and then attempting to keep it as best as one can. Ka-50 has favourable qualities when it comes to maintaining the attained speed at a lower power setting once it has achieved the speed. It ought to be considered as well.

1. In DCS it can’t be broken as long as governor works. This is true as of current open beta 

2. I’m well aware the EPR takes temeprsture and pressure into cosnsideration. You say it isn’t a reference, but then you say it’s for the pilot to see their power level? No systems in the engine depend on EPR. It is purely a measurement made only for the pilot to monitor power and for data recorder. That’s why it’s odd that certian aircraft straight up can’t reach full takeoff power at sea level, but the Mi-8 has no trouble and Ka-50 seems to reach full takeoff power much easier then Hind as well. I don’t see how your description is any different then a reference-indicator that you insist it’s not. The only consequences of exceeding the limits other then decreased engine lifetime will be consequences that come from the pilots superiors 
 

3. You should try the current OB. With multi threading many people have a 20-40% boost in frames. I don’t need to spend computer money for a while now 

 

4. I am not concerned with speed as much as I am with the EPR/PTIT/RPM relationship between the different modules 

[some1]

Checked the engine numbers at Max Continuous mode again, this time in level flight at 50m altitude. Standard day, 20C, no wind. All helicopters set to 50% fuel, with IR supressors installed, no weapons and no gun ammo. 

Ka-50 engines achieve ~850C PTIT at 'H' setting, 262 km/h TAS in level flight.

Mi-8 engines achieve ~890C PTIT at 'H' setting, 270 km/h TAS in level flight.

Mi-24 engines achieve ~910C PTIT at 'H' setting, 285 km/h TAS in level flight.

The limits on the Ka-50 EPR indicator seem to be very conservative compared to other two machines. It's quite interesting that Mi-8 is still the faster one even though it has all external appendages installed (armor, pylons, suppressors) and is 1 tonne heavier than Ka-50 in this test.

 

speedKa50_262.trk speedMi24_285.trk speedMi8_270.trk

Edited May 25, 2023 by some1

[AeriaGloria]

On 5/25/2023 at 9:51 AM, some1 said:

Checked the engine numbers at Max Continuous mode again, this time in level flight at 50m altitude. Standard day, 20C, no wind. All helicopters set to 50% fuel, with IR supressors installed, no weapons and no gun ammo. 

Ka-50 engines achieve ~850C PTIT at 'H' setting, 262 km/h TAS in level flight.

Mi-8 engines achieve ~890C PTIT at 'H' setting, 270 km/h TAS in level flight.

Mi-24 engines achieve ~910C PTIT at 'H' setting, 285 km/h TAS in level flight.

The limits on the Ka-50 EPR indicator seem to be very conservative compared to other two machines. It's quite interesting that Mi-8 is still the faster one even though it has all external appendages installed (armor, pylons, suppressors) and is 1 tonne heavier than Ka-50 in this test.

 

speedKa50_262.trk 3.42 MB · 0 downloads speedMi24_285.trk 3.39 MB · 0 downloads speedMi8_270.trk 3.54 MB · 0 downloads

 

 Very awesome test! 
 

Also, in H setting I believe both engines have identical power of 1700 HP, which makes it a good test. 

According to manuals, the TV3-117VM engine in Mi-8MT should be 845 degree Celsius PTIT at H (nominal) mode. If you use PSS, it goes up to 855. 
 

For TV3-117VMA in Ka-50/Mi-24P, PTIT at H/nominal should be 910-955 degrees Celsius according to some manuals (which also say 880-910 for cruise), but other manuals says 910 for cruise and 955 for nominal so perhaps some manuals are just more detailed then others. 
 

So it seems Mi-24 is on lower end, 910 in your test against 910-955 in manuals.

Ka-50 is at 850 when it should be 60-105 degrees higher.
 

Mi-8 too high at 890 by 35-45 degrees. 
 

As for how temperature should affect PTIT, I believe it does, but all the graphs I can find in Mi-24 and Mi-8 manuals are partial acceleration checks that won’t reach full heat, or are for relation of RPM to temperature, not PTIT. 

Also look at the placement of H/nominal tag, on both Mi-24P and Ka-50 it seems identical, about 7.5 atmospheres. But on Mi-8 it’s much higher, at between 8-8.5 atmospheres. Perhaps that is becuase, in reality Atleast in nominal mode it produces more power with less heat and perhaps has more pressure? Idk 

  Interesting if you compare max takeoff mode in VMA to max rated in VM, both equaling 2200 HP, the temperature is 960-990 for VMA and 9150-920 for VM. 

Edited June 8, 2023 by AeriaGloria