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Serious Deviation between game and real ka50 flight model


Migow

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Yep, more speed...

 

q1iHCA7wIe0

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They would loose there heads, start a rumor Weta43. Ka-50 Black Shark 3 Confirmed.:) Then sit back and watch...

 

Now back on topic...lol

 

Fifou265,

 

Your still talking about this clearance of blades at speed, most of what you are taking about is theoretical. What are you asking here for ED to change in the flight model exactly?

 

What parameters do you think the Ka-50 should reach here, that its not reaching?

 

I was able to get the Ka-50 to around 340Km/h, than loaded the G force up and....Boom!

 

 

 

At this speed going by your charts you collected, the max +G force at this speed is only around 1.7 Gs. Do you know of a real Ka50 flying at this speed? Link to it, if you have please.

 

 

 

All is well flying very very carefully at 340Km/h

--

 

The danger zone, right before.....Boom. You can fly at these speeds and perhaps more? You needed to be very very careful with any G force load, as per diagram.

--

thanks for your investigation :thumbup:

 

ok , first i 'm not native english , so it likely hard for people to understand what i'm trying to explain ,the way etc...^^

 

330 km/h IAS in forward flight with 0 m/s VVI at 50m msl ,in your example you are diving a little at 4m/s not the same thing

 

i said 330 km/h to show you that the animation is sync with flight model , there is no bug in animation ( at least in forward flight)

 

the subject is mostly about rotor clearance , check the rotor clearance it must match the data

 

"Your still talking about this clearance of blades at speed, most of what you are taking about is theoretical"

 

not correct the data come from real flight test in all kind of maneuver even forward flight

 

please check the rotor clearance in your video ,fly at same parameter than kamov data full forward flight 0m/s VVI

 

the thread is about that ; if possible slow down the video look at rotor at 47° 107° like in document

90% time in your video must look at rotor clearance 47° 107°

 

you talk about flight enveloppe , i talk about rotor clearance , we dont talk about the same problem :)

 

i'l make video about that

 

like you say it is very unlikely that flight model will change .

still people and ED need to see that something is wrong with rotor clearance, and by the way flight model likely the deviation is about rotor Dissymmetry of lift


Edited by Fifou265

VEAF 735th - www.veaf.org - Formateur Ka50

Escadrille Francophone évoluant sur DCS.

En savoir plus : http://www.veaf.org/fr/735-escadrille-virtuelle-dcs-fancaise

Nous rejoindre : http://www.veaf.org/fr/nous-rejoindre

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thanks for your investigation :thumbup:

 

ok , first i 'm not native english , so it likely hard for people to understand what i'm trying to explain ,the way etc...^^

 

330 km/h IAS in forward flight with 0 m/s VVI at 50m msl ,in your example you are diving a little at 4m/s not the same thing

 

i said 330 km/h to show you that the animation is sync with flight model , there is no bug in animation ( at least in forward flight)

 

the subject is mostly about rotor clearance , check the rotor clearance it must match the data

 

"Your still talking about this clearance of blades at speed, most of what you are taking about is theoretical"

 

not correct the data come from real flight test in all kind of maneuver even forward flight

 

please check the rotor clearance in your video ,fly at same parameter than kamov data full forward flight 0m/s VVI

 

the thread is about that ; if possible slow down the video look at rotor at 47° 107° like in document

90% time in your video must look at rotor clearance 47° 107°

 

you talk about flight enveloppe , i talk about rotor clearance , we dont talk about the same problem :)

 

i'l make video about that

 

like you say it is very unlikely that flight model will change .

still people and ED need to see that something is wrong with rotor clearance, and by the way flight model likely the deviation is about rotor Dissymmetry of lift

 

 

the subject is mostly about rotor clearance , check the rotor clearance it must match the data

 

It’s all good Fifou265,

 

I know there is a bit of a language barrier here and I’m really trying to find out what you really think should be changed/fixed on the Ka-50. I like testing things out against known statistics and theoretical design/manufacturers limitations.

 

It is theoretical to when something will "exactly" break in the structural limitations of the Ka-50 design.

 

Forget blade clearance and blade whipping and self-collision for one moment Fifou265.

 

attachment.php?attachmentid=164483&stc=1&d=1497861503

 

Let’s pretend these (Dots) above in figure 12 are accurate proven flown flight test results. I managed to hit all these parameters before any structural failure happened. Even the one way out near 380Km/h.

 

This is what I have tested my results on here Fifou265. Why do you think there is a limitation of 1.5G at 350km/h on chart 12? Are you sure the blades are colliding every time you break the Ka-50 because of the blade animation flies off? Or are you just putting too much stress (Speed and G Force load) on the rotor hub assembly and ED only shows the same structural blade animation failure in sim? So you automatically think that the blades must have collided when past these limits.

 

So, what do you think the Ka-50 limitations should be compared to chart 12?

Are you asking ED to allow the Ka-50 to "theoretically" go past the limitations of outlined in figure 12, because the blades should be further apart?

For all we know, ED may have used a chart similar to chart 12, to limit the Ka-50. We can only theoretically guess what will fail here at these extreme edge of flight conditions on the Ka-50, there is no documented failures, that we know of anyway. Are you saying the blades are not what should theoretically fail on the Ka-50 when past these limits on chart 12?

 

Even in the most sophisticated combat helicopter simulation has limitations Fifou265, for what theoretically will happen when at these limits are hit or hit with a 23mm round. ED uses all information that is documented on each subject when and where available, including ballistic penetration data to theoretically workout what might fail on the aircraft.

 

So just explain here to me what exactly should be the limitations in manufacturer chart "Fig12 picture" should be changed to allow the Ka-50 to have better structural limitations. Just remember, It's not all about blade clearance for these manufacturer limitations, it may well be the sophisticated hub assembly limitations too in chart 12. You see the blades fly off, perhaps because the rotorhub completely failed first, in some flight situations.

 

From what I can see from testing, the DCS Ka-50 does match the manufacturers structural limitations of Fig. 12 (Structural Qualification). What this structural limitation is doesn't really concern us here really, as this could be many potential theoretical things at play. We only know the manufacturers structural limitations from chart 12, that something could "potentially" can fail when this limit is reached or crossed. Having the blade further apart is not going to help make the Ka-50 more reliable at these marginal edge of the most extreme flying conditions. Something needs to fail here when these limits are crossed, in this simulated aircraft. Rotor-hub, rotor blades, my underwear if I was the test pilot IRL really doing these test stunts.

 

The faster you go, the more careful on the controls you need to be, the sweet spot is at 170Km/h to 270Km/h to maximized maneuvering ability 3.5Gs, at a max of 9800Kgs. This means you will need to reduce down the fuel load, when taking a full load of ammo into battle.

 

--


Edited by David OC
Changed speed sweet spot 170 to 270Km/h
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Great post David OC, i was a bit worried things would turn ugly here.. :thumbup:

 

You make some really good points so thank you for explaining them.

 

In simple terms you could say the flight model is quite accurate but DCS's interpretation of structural limitations of the airframe are modeled with a blade collision, where as in real life any number of failures could occur. Makes sense to me anyway :D

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FYI: In-game the Ka-50 can dive at +/-450km/h and get out of the dive in 1 piece !

 

Still, nice find !

 

Yes.... You can do all the things when you push collective down.

 

Doing backside flip at 300km/h speed starting at 20m altitude ain't a problem when you only initiate the maneuver with collective and immediately push it down while the fuselag and wings completes the backflip.

 

Then it is only critical to know at what point you start to pull collective again to avoid crashing ground after quick dive.

 

But what is talked in the manuals is the distance between rotor disks while you are actually pulling collective instead having them just autorotating.

 

The skill required to master is to know how much collective you need at what maneuvers and speeds so you have the controllability but you do not collide blades.

 

At higher speeds helicopters fly like an airplane and having a turning tail assists a lot as we can even more do all kind turns and flips without using so much the rotors as we do have slight gliding capabilities.

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Yes.... You can do all the things when you push collective down.

 

Doing backside flip at 300km/h speed starting at 20m altitude ain't a problem when you only initiate the maneuver with collective and immediately push it down while the fuselag and wings completes the backflip.

 

Then it is only critical to know at what point you start to pull collective again to avoid crashing ground after quick dive.

 

But what is talked in the manuals is the distance between rotor disks while you are actually pulling collective instead having them just autorotating.

 

The skill required to master is to know how much collective you need at what maneuvers and speeds so you have the controllability but you do not collide blades.

 

At higher speeds helicopters fly like an airplane and having a turning tail assists a lot as we can even more do all kind turns and flips without using so much the rotors as we do have slight gliding capabilities.

 

It's not only the collision of the blades here, it's also the G force tolerance on other parts of the rotor hub. If you were to ask ED to change anything here, it would be just the animation of the blades and how close they are seen perhaps at the higher speeds.

 

Have the blades further apart and still exploded them when the structural limit is reached (Something failed). Doesn't bother me, I'm not hanging out the door looking at the hub when doing 330km/h.:) Oh that's close....Boom!

 

 

ka50_3.jpg

 

The


Edited by David OC
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  • ED Team

 

in game at 280km/h it looks like less than 100mm , about to collide

 

irl :

at 0 km/h clearance is 1400mm

 

I guess you should have double checked your measurements before claiming the "great errors" for the community.

 

First of all, the clearance is 1500 mm (Fig 10, ERF1998-vol1-AD05.pdf) for 0 kph.

 

Then, I can not see your "100 mm" at 280. The valued researcher would fly a mission with steady speed then start the track and using slow-mo catch the moment of two blades are at the closes distance. Just one under another or close to it. Then, moving the camera as far as it is possible he would set the neccessary zoom (FOV) and place the camera using both F2 and Alt-F2 rotations just between the rotors on the pole.

 

And he would take a ruler and using inter-hub distance as a reference he would get approx. 610 mm and not the "100 mm" (600% error!!!).

 

The thing the valued researcher can not do is to obtain real blade tip log from the simulation, but I can.

This log obtained form in vitro tool is for 280 kph and the collective pitch rotor AoA close to the simulation. Later I can obtain it just from the simulation that uses just the same calculation model as the tool.

 

Of course, the REAL TIME model used in Ka-50 (for average PC of 2005, by the way) did not use true aeroelasticity and detailed wake model as non-real time models used in the references by Kamov company...

 

But it does use true aerodynamic and mechanical simulation of each blade using the shortest dt we can afford.

 

But the result of it is quite good for the real time, single PC simulation.

If the simulated helicopter performs the same aerobatics as real without blade collisions - it's a good FM, right?

 

 

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Ніщо так сильно не ранить мозок, як уламки скла від розбитих рожевих окулярів

There is nothing so hurtful for the brain as splinters of broken rose-coloured spectacles.

Ничто так сильно не ранит мозг, как осколки стекла от разбитых розовых очков (С) Me

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It's called a helicopter that's been sitting out on some god forsaken FARP for who knows how long, with the occasional odd replacement of parts and maintenance. Probably closer to REAL life than we think.

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Thanks for the info about the Black Shark's FM modeling Yo-Yo, always interesting to see how these FM's are modeled.

 

She is one very elegant lady, more than just physics equations, the FM is true SimArt, as seen here in the video you posted.

 

This guy has some awesome skills.:)

 

QFGjSqQzDXs

 

 

.


Edited by David OC

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What a masterpiece of smooth flying skills !

 

After hundreds of hours in the Ka-50 I am still miles away from those smooth skills.

 

A delight to watch, a true landmark for any Ka-50 Pilot out there indeed.

 

 

Bit

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