rotor intersection IAS

[Raptor9]

@Fifou265, let me address some things that you've said to clarify some fact from fiction. I've been working on and flying helicopters for 13 years, of multiple types and different rotor systems.

 

It is true that rotor blades in general are not designed to operate in supersonic, or even transonic, speeds. However, the Kamov coaxial rotor design and the Sikorsky S-97 coaxial rotor design are quite different. The Kamov system uses a fully-articulated rotorhead, with hinges that allow each individual blade to flap up (when advancing into the wind) and flap down (when retreating from the wind) in forward flight. This large flapping motion, combined with the two rotor systems spinning in opposing directions, means the rotors will eventually meet on the right side of the Ka-50 if exposed to the right conditions. This is why the IAS VMax airspeed alarm goes off when the rotor systems are estimated to be approaching dangerously close. This assumes however a static flight condition, such as level flight, not over-G or overly-aggressive cyclic inputs. It is just an estimation, not a black-and-white solution.

 

The S-97 rotor system on the other hand utilizes a rigid rotor system. This system does not have flapping hinges. The blades themselves flex to absorb and compensate for aerodynamic effects associated with forward flight. This means the S-97's coaxial rotor system does not flap up and down like the Kamov design.

 

Moving on, every aircraft (to include combat aircraft) whether it be a fixed- or rotary-winged has a set of prescribed limitations that are declared by the engineers. In order to be qualified to fly that aircraft, the pilot must be well-versed in these limitations so he does not intentionally or unintentionally exceed them. If he does, "bad things" may happen, which is why the limit exists. Red lines are painted on gauges for a reason, as are aircraft limitations written in operator manuals.

 

Conventional helicopters have design limitations as well. The UH-1 Huey for example can experience mast bumping which can cause the entire rotor head to separate from the aircraft; mast-bumping is a common issue for semi-rigid rotor systems (and this is simulated in the DCS UH-1). Fully-articulated rotor systems can still have mid-air collisions with themselves if the blades flap downward enough to collide with the fuselage or tailboom (I've done this in the DCS Mi-8 as well). It doesn't mean these DCS products are broken, they just simulate their real-world counterparts.

 

Back to the DCS Ka-50. The Ka-50 in DCS is a simulation, not an arcade game. It simulates the weapons, cockpit, and limitations of the real Ka-50, in all its glory. The flight model is not broken, players can break the DCS Ka-50 just like they can a real helicopter. I've been playing DCS Black Shark since 2009, and I used to sever my rotors all the time. I kept practicing and now I can jink, dive, and turn without any problems. It just takes time and patience.

Edited January 20, 2016 by Raptor9

[Reagan505]

hi , yoyo himself :)

which hazard the alarm prevent then?

 

rotor intersection is fatal hazard , why the alarm can't tell me dangerous flight envelope kamov got the data

why can we fly at 500 km/h in game ? no way the real one can do that!

my opinion in high speed there is a margin difference between the real data and the game

 

the rotor anti ice alarm(ekran) is plague with similar bug , it trigger long time after your engine are already frozen

Edited January 20, 2016 by Reagan505

[Enduro14]

The alarm does only one thing - watching the speed. The pilot has to learn a lot of restrictions depending on flight parameters providing by Kamov company after study and tests.

If the pilotage in this video does not present combat helo ability, I think, you need an X-wing FM. :)

 

Yo-yo by chance is their a video of those maneuvers with the pit configuration and input display enabled. I would like to learn some of those maneuvers thank you.

[Migow]

@Fifou265, let me address some things that you've said to clarify some fact from fiction. I've been working on and flying helicopters for 13 years, of multiple types and different rotor systems.

 

It is true that rotor blades in general are not designed to operate in supersonic, or even transonic, speeds. However, the Kamov coaxial rotor design and the Sikorsky S-97 coaxial rotor design are quite different. The Kamov system uses a fully-articulated rotorhead, with hinges that allow each individual blade to flap up (when advancing into the wind) and flap down (when retreating from the wind) in forward flight. This large flapping motion, combined with the two rotor systems spinning in opposing directions, means the rotors will eventually meet on the right side of the Ka-50 if exposed to the right conditions. This is why the IAS VMax airspeed alarm goes off when the rotor systems are estimated to be approaching dangerously close. This assumes however a static flight condition, such as level flight, not over-G or overly-aggressive cyclic inputs. It is just an estimation, not a black-and-white solution.

 

The S-97 rotor system on the other hand utilizes a rigid rotor system. This system does not have flapping hinges. The blades themselves flex to absorb and compensate for aerodynamic effects associated with forward flight. This means the S-97's coaxial rotor system does not flap up and down like the Kamov design.

 

Moving on, every aircraft (to include combat aircraft) whether it be a fixed- or rotary-winged has a set of prescribed limitations that are declared by the engineers. In order to be qualified to fly that aircraft, the pilot must be well-versed in these limitations so he does not intentionally or unintentionally exceed them. If he does, "bad things" may happen, which is why the limit exists. Red lines are painted on gauges for a reason, as are aircraft limitations written in operator manuals.

 

Conventional helicopters have design limitations as well. The UH-1 Huey for example can experience mast bumping which can cause the entire rotor head to separate from the aircraft; mast-bumping is a common issue for semi-rigid rotor systems (and this is simulated in the DCS UH-1). Fully-articulated rotor systems can still have mid-air collisions with themselves if the blades flap downward enough to collide with the fuselage or tailboom (I've done this in the DCS Mi-8 as well). It doesn't mean these DCS products are broken, they just simulate their real-world counterparts.

 

Back to the DCS Ka-50. The Ka-50 in DCS is a simulation, not an arcade game. It simulates the weapons, cockpit, and limitations of the real Ka-50, in all its glory. The flight model is not broken, players can break the DCS Ka-50 just like they can a real helicopter. I've been playing DCS Black Shark since 2009, and I used to sever my rotors all the time. I kept practicing and now I can jink, dive, and turn without any problems. It just takes time and patience.

 

the flight model in game has limitation when exceeding 300 km/h IAS there is no flutter airframe damage no supersonic tip blade catastrophic failure if you go in dive

 

it seems there is margin difference between the dangerous flight enveloppe and the alarm

the alarm should start at 250 km/h not 315km/h

 

the documentation :

" Maximum airspeed km/h: IAS in gear-up and gear-down configuration

 

300

Blade’s stall, flutter and strength

 

"

"

Maximum rotor’s RPM, %:

 

 

 

Up to 190 km/h 190…245 km/h 245…265 km/h 265…280 km/h 280…300 km/h

98

95

93 91 90

 

Flutter

 

"

 

autoration has been questionned by mi8 pilot on the forum.

flight model has been tweaked in the past, i start questionned the flight model reliability in game since that.

the model are broken in those condition

 

 

so why there could not be a difference in flight model and the real data at high speed

 

the alarm trigger at lower speed when you go high altitude

the alarm must alert about rotor collision , not flutter itself.

currently it is useless:(

 

mig21 AOA alarm is useful

 

 

The rotor head on the Ka-50 is hingeless , rigid rotor

 

unlike the mi8 mi24(old rotor 5 blade) fully articulated

 

alphaonesix citation:

Merry Christmas. http://darrell.halo5.net/outpost/Ka-32_rotors_MM.zip (note this is for the Ka-32, but the rotor masts and swashplates are, as far as I can tell, identical...so it should be quite helpful for you.

 

Quick answers to 4 and 5...

 

As mentioned by mvsgas, the Ka-50 rotor head has no hinges. Flapping and feathering movements are permitted through the use of a torsion bar assembly...actually it looks to me like a strap pack assembly as developed by the former Hughes company in the U.S. and seen on aircraft like the MD-500 series and the AH-64 series of helicopters. For more info on how strap packs work, look up rotor info on those helicopters, there will be plenty of info on the Internet. The Ka-50 rotor head does not have a drag hinge, either, and it does not appear to allow leading or lagging of the blades, only flapping and feathering. As far as limits go, feathering is limited by the pitch change links. Lead/lag doesn't appear to be allowed at all, so no limit there. Flapping upward does not appear to be limited mechanically, although it might be (and I just can't tell) or centrifugal force prevents excessive upward flapping. Downward flapping is prevented by droop stops, but those won't be necessary in-flight, only at low rotor speeds during startup and shutdown.

 

Most rotor heads are secured to the mast with split cones and a mast nut. Not sure if this is the case with the Ka-50, though. I would bet that it's identical to the Ka-32 in this respect, so should be in the rotor maintenance manual I linked for you on my website. I am too lazy to look it up myself right now.

 

Good luck! And feel free to ask any more questions...I know we have several maintenance engineers/technicians on these forums, including myself, so ask away!

Yeah, semi-rigid (as far as I know) only refers to two-bladed teetering rotor systems. The rotor system on the Ka-50 would best be described as "rigid". The rotor head on the Ka-50 is hingeless, although feathering and flapping are possible through the use of a torsion plate (like a flex beam on a Bell 412) or strap pack (as used on the OH-6/MD-500 series and the AH-64).

Edited January 21, 2016 by Fifou265

[Migow]

Just so we're really, absolutely on the same page: You are not saying ED got it wrong, you're saying Kamov got it wrong, right?

 

In which case, why are we even talking about this?

 

Edit:

 

Jayne: Testing. Testing, Captain, can you hear me?

Mal: I'm standing right here.

Jayne: You're coming through good and loud.

Mal: Coz' I'm standing right here.

Jayne: Yeah, well, but, the transmitters...

 

:D

 

i 'm not questionning Kamov but ED implementation :smilewink:

[Raptor9]

it seems there is margin difference between the dangerous flight enveloppe and the alarm

the alarm should start at 250 km/h not 315km/h

 

The IAS Vmax alarm is an estimation that the blades are flapping dangerously close to each other based on airspeed and air density only, not poor pilot technique. If I wanted to, I could sheer the rotors off a Huey, Mi-8 or Ka-50 on the ground if I made large enough control inputs in a boneheaded way.

 

the alarm trigger at lower speed when you go high altitude.

 

That's because at higher elevations the blades flap more due to air density. The IAS Vmax is a dynamic value, it goes up and down based on atmospheric conditions.

 

currently it is useless:(

 

It is not useless. An alarm not sounding is not the cause of rotors sheering off, poor piloting is. That's like saying that a pilot flew into the ground because the "Low Altutude" warning never went off.

 

The rotor head on the Ka-50 is hingeless , rigid rotor

 

unlike the mi8 mi24(old rotor 5 blade) fully articulated

 

alphaonesix citation:

 

Okay, fair enough, the Ka-50 doesn't have hinges (my mistake), but there is nothing in that citation that explicitly says the Ka-50 rotor system is a rigid-head, aside from a person's characterization of how it works. The AH-64 rotorhead is an articulated rotor with a strap-pack system (without hinges), but it is an articulated rotor head nonetheless.

 

Regardless, the point I was trying to make at the conclusion of my last post is this: it is completely possible to fly and fight with the Ka-50 in DCS without sheering off the rotor blades due to blade intersection. Full aerobatic maneuvers are possible, as are high speed or high-G maneuvers. If you cannot perform these maneuvers without losing your blades, I'm simply suggesting you practice more, and not make wild assumptions about the Ka-50 flight model being "broken". This is not a personal attack, it is simply an observation on the nature of a flight simulation.

 

To this day, I cannot successfully perform a takeoff in a P-51, and every other landing I make in the MiG-21 ends up in a cartwheel. Do I blame the flight model? No, because I see other players around me performing those same maneuvers with no problems or issues. All that tells me is I need to practice in those aircraft more.

[Reagan505]

i 'm not questionning Kamov but ED implementation :smilewink:

 

Dude.... The KA-50 isn't broken... Bottom line, this is a video game.

 

Man, all this, "I think this should do this" & "I heard from a guy who heard, from a guy who heard, from a guy who watched a video" fuss about the alarm is a non-issue. If the alarm went off every time the aircraft was in a condition where there was a possibility of a blade strike / intersection.. the alarm would be on almost continuously.. All this fuss over the alarm, I'd hate to see your reaction to a XMNS chip light illuminating.

 

I believe ED has a way better understanding, along with access to the people and documentation involved with modeling the KA-50. With that in mind, remember this is a video game for entertainment purposes only.. It will never be perfect.

 

The KA-50 is fine and this is a video game... Everything will be alright... I promise

Edited January 21, 2016 by Reagan505

[Enduro14]

Dude.... The KA-50 isn't broken... Bottom line, this is a video game.

 

Man, all this, "I think this should do this" & "I heard from a guy who heard, from a guy who heard, from a guy who watched a video" fuss about the alarm is a non-issue. If the alarm went off every time the aircraft was in a condition where there was a possibility of a blade strike / intersection.. the alarm would be on almost continuously.. All this fuss over the alarm, I'd hate to see your reaction to a XMNS chip light illuminating.

 

I believe ED has a way better understanding, along with access to the people and documentation involved with modeling the KA-50. With that in mind, remember this is a video game for entertainment purposes only.. It will never be perfect.

 

The KA-50 is fine and this is a video game... Everything will be alright... I promise

 

Well said, their has been allot of my uncles fathers uncle and the oracle Google says this about flight models throughout this forum lately. On flip side of something is broken cool make a ticket but I fly the shark quite a bit and she feels good to me but then again I'm not a real world pilot yet.

[Migow]

The IAS Vmax alarm is an estimation that the blades are flapping dangerously close to each other based on airspeed and air density only, not poor pilot technique. If I wanted to, I could sheer the rotors off a Huey, Mi-8 or Ka-50 on the ground if I made large enough control inputs in a boneheaded way.

 

 

 

That's because at higher elevations the blades flap more due to air density. The IAS Vmax is a dynamic value, it goes up and down based on atmospheric conditions.

 

 

 

It is not useless. An alarm not sounding is not the cause of rotors sheering off, poor piloting is. That's like saying that a pilot flew into the ground because the "Low Altutude" warning never went off.

 

 

 

Okay, fair enough, the Ka-50 doesn't have hinges (my mistake), but there is nothing in that citation that explicitly says the Ka-50 rotor system is a rigid-head, aside from a person's characterization of how it works. The AH-64 rotorhead is an articulated rotor with a strap-pack system (without hinges), but it is an articulated rotor head nonetheless.

 

Regardless, the point I was trying to make at the conclusion of my last post is this: it is completely possible to fly and fight with the Ka-50 in DCS without sheering off the rotor blades due to blade intersection. Full aerobatic maneuvers are possible, as are high speed or high-G maneuvers. If you cannot perform these maneuvers without losing your blades, I'm simply suggesting you practice more, and not make wild assumptions about the Ka-50 flight model being "broken". This is not a personal attack, it is simply an observation on the nature of a flight simulation.

 

To this day, I cannot successfully perform a takeoff in a P-51, and every other landing I make in the MiG-21 ends up in a cartwheel. Do I blame the flight model? No, because I see other players around me performing those same maneuvers with no problems or issues. All that tells me is I need to practice in those aircraft more.

 

 

mig21 is dangerous to fly , too much accident ,they add useful AOA alarm especially in combat to avoid stall.

 

well training irl will not tell you how to avoid ka50 dangerous flight envelope , if you enter you die, it is like black hole event horizon :D

of course in game you can train about dangerous flight envelope :thumbup:

coaxial detractor might be right in the end, it is too dangerous to operate with such flaw :(

 

 

yoyo told me there is no chart about rotor collision hazard :(

 

at high altitude 3000 m 20°C at sea level 760 QNH dangerous flight envelope start 150 km/h

 

it make the helo very slow to keep agility :(

 

rotor collision hazard require 4 variable charts which depend on speed , altitude , temperature, pressure.

many charts , and in dynamic meteo even worse :(

[AlphaOneSix]

The AH-64 rotorhead is an articulated rotor with a strap-pack system (without hinges), but it is an articulated rotor head nonetheless.

 

Careful, the AH-64's rotor head has feathering, flapping, and lead/lag (drag) hinges. The strap packs just keep it from flying apart.

[Raptor9]

Whatever :surrender: (In my haste when typing the previous response I meant to refer to the Ka-50, proofreading is still something I forget) I will admit I muddied the waters with some incorrect terminology and flawed information, and that led to a topic digression on airframe-specific hardware. My point is still that the DCS Ka-50 is not as limited and flawed as some people attest, despite the constant rhetoric. I am still more combat-effective when flying the Ka-50 than any other DCS module. I resign myself from this discussion, as it has gone nowhere in changing anybody's views on the DCS Ka-50 or the "unavoidable" rotor intersection.

[AlphaOneSix]

My point is still that the DCS Ka-50 is not as limited and flawed as some people attest, despite the constant rhetoric.

 

I strenuously agree! :)

 

It should be noted that I do disagree with the original post in this thread.

[RvETito]

Relax, there's nothing wrong in the Ka-50 model. You have little idea, if any, how much science is lying behind it. Don't forget that it's still a model, it ain't the real thing. But a very, very authentic model.

 

The overspeed alarm triggered by the EKRAN is not a pre-alert for rotor collision as this depends on other parameters like R/H pedal input and g-load. As someone mentioned above the warning depends on air density so one could figure that it's warning for high Mach number on the advancing blades tips.

 

Fly the Ka-50 and just enjoy it. It's still so much rewarding - ever since I was testing it back in 2007-2008 till today I never stopped to enjoy it.

[Migow]

ok then no bug ? then where are the chart?:) it 'll try to make chart.

 

thx for answer:)

[rinkerbuck]

Super old thread but I just got the KA50 and I need help avoiding blade destruction. I've never once had it happen when I am getting the overspeed or overtorque warning. It has happened several times at high speed (250-300kmh) in either completely level flight, or when I go into a very gentle dive without first lowering collective. It's really hard to tell how far I can push the envelope when there is ZERO WARNING of these catastrophic failures. So far I've never hurt the KA pulling 3.5 G's out of a dive or doing a really hard turn, its only in these situations where I am going fast, but without the IAS warning, and just do a very gentle forward push on the stick. I do have a video but I need to edit it for uploading if anyone wants to see it happen from external perspective when I was showing 120kts in the external view, at around 1500meters alt. As for this being realistic or not, all I can say is that I've flown A LOT of sim helicopters in my time (in XP11, FSX), and this is the only one I've ever had this happen with. It's also the only coax sim copter I've flown though.

Edited February 6, 2020 by rinkerbuck

[randomTOTEN]

You'll figure it out. I used to snap the rotors of the UH-1H when I first got it too.

 

 

Been several years since I've done either, and have mostly forgotten about these threats.. just handle them nice an gently. Other simulators have surely taught you bad habits.

[rinkerbuck]

You'll figure it out. I used to snap the rotors of the UH-1H when I first got it too.

 

 

Been several years since I've done either, and have mostly forgotten about these threats.. just handle them nice an gently. Other simulators have surely taught you bad habits.

 

maybe for a Coax chopper... but XP11 isn't exactly forgiving when it comes to detaching parts either. I'll have to focus on never even thinking of pushing the nose down at high speed before lowering collective.