Question about autorotation for helicopter professionals

hi

all you now when motors go down what you must do '' To prevent RPM decay, the pilot must promptly lower the collective pitch control to reduce drag and incline the total aerodynamic force vector forward so it is near the axis of rotation. Remember in some helicopters you can go from normal operating rotor RPM to an unrecoverable blade stall condition in Under 10 Seconds.'' Why in DCS BS this is not correct ???

question is :

1.what happen when in autorotation RPM go below minimum unrecoverable RPM ?

2.is rotor stop running to zero and we continue to fall like brick or rotor still have some RPM but still fall like brick ? if has why me can't recover RPM to ''safe'' RPM?

3.i ask this questions because in DCS Black Shark you can always recover RPM in autorotaion. even i try some test and i realize DCS dont do job right in this simulation or i get wrong and i apologize in beginning :(

-i try vertical autorotation with collective all way UP from 1000m altitude and in this situation helicopter continue autorotation (RPM go to 40% of rotor and then stabilize on 50%) and vertical speed of decent was about 10-12 m/s and with landing gears down helicopter land only with damage of gear (i didnt touch no control at all :) in real life if i do this my RPM will go to zero or what ???

-another test was when i shot down motors collective was in middle position and helicopter continue in autorotaion with speed 100km/h and 60% rotor RPM. i didnt put down collective like in real situation all pilot WILL. and i use half way of collective to make clear land on runway :) this is very strange to me :(

-third test i shot down motors and i put collective all way UP and helicopter get in autorotation and stabilize on 70km/h with 50% rotor RPM. i take down landing gear and dont touch anything then. helicopter still fly in this autorotaion with 10m/s vertical decent and make crash landing with small damage EVERY time :) again very strange to me :(

-forth test was shot down motors and i put collective all way DOWN and helicopter get in autorotation and stabilize on 210km/h with 50% rotor RPM. i take down landing gear and dont touch anything then. helicopter still fly in this autorotaion with 16-18m/s vertical decent and make crash landing with small damage EVERY time but pilot always alive :) again i dont understand this ?????

-so pilot is no needed to fly in autorotaion in DCS because helicopter always land alone with no problem and pilot go home alive ? if someone touch commands heli crash :)

I love DCS BS but i need to see real FM model and behavior of helicopter and when i try some test in this SIMULATOR to make the same test in real life. For all this years only YOU made the first GOOD helicopter simulator! All other just try in this. For this i hope all who now helicopters aerodynamic , all REAL and VIRTUAL pilots and ED DCS will answer we on this question because i and all others pilots really need answer on this. It is possible or just bag in game or bad programing and what will happen in real life if i do all this?

THNKS for making my life better . . .

Post your tracks of your 4 tests.

Are you flying in "game" mode or "real" mode? check gameplay options. Upload those tracks, what you'r explaining doesen't happen to me. When autorotating, if I make a little mistake I go down like a brick and crash.

Remember in some helicopters you can go from normal operating rotor RPM to an unrecoverable blade stall condition in Under 10 Seconds.'' Why in DCS BS this is not correct ???

Rotor mass plays its role. You need to be quicker with collective if your helicopter has light rotor.

Are you flying in "game" mode or "real" mode?

Before you asking something like this you should know that Pirke is military helicopter pilot...:smilewink: I'm pretty much sure it was not game mod...

Before you asking something like this you should know that Pirke is military helicopter pilot...:smilewink: I'm pretty much sure it was not game mod...

Except there is a bug in some installations that when you install the simulator in real mode (the installer asks you), it switches to game mode. Anyway, tracks would be the best way, hard to say anything else without them.

He is getting different result that I experiences, I was having a hard time keeping helicopter flying in auto rotation, I need to go back and try this again.

I'm not sure about the real Ka-50 but I also think that DCS Blackshark is a bit too forgiving regarding (auto rotation) rotor stall.

On MAKS 2009 I found out how quickly a "real" helicopter can get in to a rotor stall.

I knew I had to lower the collective and I did, though not completely.

Here is a video of the "accident":

(engine cutoff at 08:35)

Can this be explained,maybe, by the fact that Ka-50 is much lighter aircraft and have coaxial rotors?

I remember that video Frazer,exelent stuff ...DCS pilot???!!! WTF is that???!!!:D

i play on simulation mod but and i can crash if i like but here is some bug or bad programing :) in real life my minimum % of rotor RPM is 89% for 30s and if i go under this i am dead man :( here is something i dont understand :( maybe is some coaxial rotor magic :)

i will upload all my track of testing

in real life my minimum % of rotor RPM is 89% for 30s and if i go under this i am dead man :( here is something i dont understand :( maybe is some coaxial rotor magic :)

KA-50:

1. Maximum allowed rotor RPM – 98%

2. Minimum safe RPM in flight – 83%

shows an autorotation-landing (begins at 4:20m). There RPM is between 79% and 72% most of the time. But it differs from 61 - 79% during the whole autorotation landing.

KA-50:

1. Maximum allowed rotor RPM – 98%

2. Minimum safe RPM in flight – 83%

 

shows an autorotation-landing (begins at 4:20m). There RPM is between 79% and 72% most of the time. But it differs from 61 - 79% during the whole autorotation landing.

i talk about MIL-8 in real life. and point of all is here you can make autorotation with 50% and land safe :) i will upload track later. in you tube video you do autorotation with plane approach.

this you can do only on RUNWAY if you try it on some other terrain you will be dead. to much speed in approach. its 3 type of autorotation : plane aproach with speed over 100km/h (when helicopter was invented this was only way to land in autorotation and its needed terrain about 500m) , vertical autorotation with speed below 50km/h and combined with speed 60-100km/h. now in all helicopters pilot do combined (combination of this 2) because is safer then other 2.

Rotor RPM itself doesn't say all that much about the amount of lift the rotor is generating. Blade angle and speed, (in any direction) significantly influences lift. The Coaxial design is probably a benefit when auto rotating whit speed,

Though probably a disadvantage when in a hover since the upper rotor will be operating in the turbulence of the lower one.

So safe landing whit 50% rotor RPM and 0 airspeed seems highly unlikely to me.

Safe landing whit 50% rotor RPM and lets say 80km/h forward seems might just be possible.

Also bear in mind the loadout of the helicopter has an influence on how well the landing gear can absorb the shock of impact.

If you have full fuel load, and are fully armed you will get different results then when testing whit lets say 400kg of fuel and no weapons......

Though i must agree whit Frazer, auto-rotating is quite easy in DCS:BS.

http://www.2shared.com/file/XWzVl38Y/Pirke_BS_test_track.html

http://www.2shared.com/file/Td4ZD-DN/maxweight_autorotation.html

http://www.2shared.com/file/6g4OColN/maxweight_vertikal_autorotatio.html

scroll all way down and

click on ''click here'' in right down corner on ''Save file to your PC''

ok look this tracks and I wait comments.

in folder ''strange autorotation TEST'' is 3 situation i ask in questions.

on second link is TEST of 3 situation with MAX LOAD.

on 1 colective all way UP and no touching commands, on 2 collective half way up and normal landing , 3 collective all way down and didnt touch to the end of landing only use cyclic this time because vertical speed and progressive speed is to big for safe landing without touching commands.

on third link i make vertical autorotation with zero speed with max load and landing gear do job again :) here look the safest way to crash land in combat area ;) pilot always ok and only landing gaer damaged :)

from this test i see its again the same problem again with collective all way UP :)

all in all i see from this TEST if you have vertical speed about 15m/s and speed about 100 km/h you can safe crash land without touching commands and pilot survive :) and if you have engines failure you dont need to lower collective all way down to make good autorotation and safe RPM and your LIFE. All this is very weird ;(

THNKS

 

Though i must agree whit Frazer, auto-rotating is quite easy in DCS:BS.

yes VERY easy :(

pls look track and you will see what i taking about.

one autorotation was do at collective all way UP and no touching any commands. second coletive all way DOWN and no touching any commands . third was do at half way UP collective and i use commands to land safe. very strange ;( if RPM fall below minimum why stay there with all way UP collective??? why RPM didnt fall to zero because driven and stall region on rotor is bigger then driving region and rotor dont get increasing force to keep spinning??? and in one time when spinning rotor is to low centifugal force of rotor blades is smaller and rotor blades go up and its look like funnel when helicopter going down and we wait crash on rotor blades like umbrella.

About differences with mi-8, might be the combo of having two rotors and short blades perhaps? I don't really know

Also being unloaded and with only 5% fuel in the track might help.

I have hard times doing good autorotations, but I have to say your tracks are kind of weird, never seen an autorotation done with so much weirdness but also so much ease and so little input. Said that, I've never tried to do an autorotation wrong on purpose (when it gets ugly I overreact and I crash XD). But I must add, there are real autorotations in youtube that seem very easy (from the safety of an screen lol).

I guess somebody from ED can have a good explanation of coaxials and autorotations.

Maybe high alpha/stall situations is where the current aerodynamics model reaches some limitations. This is just guesswork on my end, but i suppose that turbulent airflow is still impossible to calculate on a desktop PC in realtime.

pls ED do you have some contact with real Ka-50 pilot to ask him to explain is this good or bad ? if you can do this in real life then this helicopter is MEAN MACHINE and you dont need eject seat :) If you try this in MI8(russain helicopter) and Gazella (french helicopter) (this 2 helicopters i fly) you will be dead man :(

THNKS

Do you play with version 1.0.1 or the latest version 1.0.2?

It would not surprise me if this is an issue of the latest version 1.0.2 and the version 1.0.1 got it right. But i am too leasy to check this out.

Edit

OT: just watched some of your other tracks (first person view of a-10/f-16 vs ka-50 etc.) ... speed dive into the city-area to hide and manoeuver behind buildings, wow man (;

pls ED do you have some contact with real Ka-50 pilot to ask him to explain is this good or bad ? if you can do this in real life then this helicopter is MEAN MACHINE and you dont need eject seat :) If you try this in MI8(russain helicopter) and Gazella (french helicopter) (this 2 helicopters i fly) you will be dead man :(

 

THNKS

Well, real ka-50 pilots helped make this simulator, and they use it in the military so it must be pretty convincing to the real deal. Check the credits in the flight manual. Anyway, I hope somebody can explain the technicalities about this, at least it would be informative.

This thread,and Pirke's track files, really makes me wondering is flight model of ka-50 exact copy of original software previously developed for russian military pilots or is it just "heavily modified" to meet expectations of average sim lover...:noexpression:

Hi, this -sounds- to me like a terrain modeling issue with respect to impacting a runway and surviving.

For the rest (specific rotor RPM etc) I cannot tell. I will PM Yo-Yo to look at this thread.

I'm not sure about the real Ka-50 but I also think that DCS Blackshark is a bit too forgiving regarding (auto rotation) rotor stall.

 

On MAKS 2009 I found out how quickly a "real" helicopter can get in to a rotor stall.

 

I knew I had to lower the collective and I did, though not completely.

 

Here is a video of the "accident":

(engine cutoff at 08:35)

That sim looks awesome. :) I think you dive too much for speed, that takes out RPM with the collective up too like you said. Still it was pretty quickly. I can only talk about the R22 and R44, in the R22 it's really quick losing RPM but it is also quick to get them back. The R44 is slower in losing and gaining RPM. AS350 it has also lots of inertia. I don't know about Mi-8 but it was really quick.

About the Ka-50 in the sim, I also think it's very forgiving. Although I don't have any knowledge on Ka-50 as I never flown one, so I don't know how the real one acts.

Regards.

That sim looks awesome. :) I think you dive too much for speed, that takes out RPM with the collective up too like you said. Still it was pretty quickly. I can only talk about the R22 and R44, in the R22 it's really quick losing RPM but it is also quick to get them back. The R44 is slower in losing and gaining RPM. AS350 it has also lots of inertia. I don't know about Mi-8 but it was really quick.

 

About the Ka-50 in the sim, I also think it's very forgiving. Although I don't have any knowledge on Ka-50 as I never flown one, so I don't know how the real one acts.

 

Regards.

Yea that sim looks very neat, a little bit like the best of DCS and FSX combined, at the highest setting without any FPS issues. Definitely something you want to have in your garage :joystick: :D

About the rotor stall, it was a very good lesson. It is very good to make that mistake in a simulator and not in reality ;)

My conclusion about DCS Blackshark & real flying:

BS helped me a lot flying this mi-8 sim well and I'm sure it is also a good training for any other helicopter, but I don't think you can fly any other helicopter without any mistakes as every aircraft has their own user manual.