Gazelle and VRS

People are trying to offer constructive feedback not complain. They have even gone as far as posting links on a very technical issue to illustrate the problem. VRS is modeled just not correctly. I'm another one who has stopped using the gazelle until it's flight model is improved to obey the laws of physics. See my other thread regarding lateral tail rotor thrust and cyclic stability for example. I'm currently filled with hope and dread for the bo105. I want the Polychop helicopters to be the best in DCS. In spite of the fantastic rendering and good systems modeling in my opinion the Gazelle is currently the worst helicopter in DCS due to the poor flight model. If I want to just look at well rendered helicopters that don't fly right I'd install P3d or FSX.

Spot on...

Why do you complain,all of you simmers,about some differencies between a real hélicopter and the model simulated?

Do you think that behind your monitors while playing,with your body seated and feets set down on ground,you are flying?

Even with force feedback or stuff like that and now the VR headset,you stay on the ground.

So another word is about comparison of FM.

I do regret for all of you but when you are playing on a simulator,nothing is real.

It's the background that will follows your acts on joystick to simulate move in every direction,not the sprite or 3D object that you are playing.

In real flight background stills unmoving.

You are speaking about flight model of a 3D environment,not a plane or helo.

In the game nothing is aerodynamic nor physic,just code.

So What will do with this kind of analogy.

Only one thing to do is play the game.

A game is made for entertainment not for engineering.

What do you care about vortex or other stupid legends?

For my own i did a lot of mountain rescue flights on SA342.And army flights on SA341.

Never been,or seen other pilot,face to face with the "VRS" as you call that.

Maybe i'm lucky or after more of 7000 flying hours i did not enough.

The module is close real Gazelle and as long you are not able to make your computers take off the ground and fly around,you will never end the topic.

Never been,or seen other pilot,face to face with the "VRS" as you call that.

Maybe i'm lucky or after more of 7000 flying hours i did not enough.

Well pilots are trained to avoid VRS in the first place. It certainly exists, I've been in the back of an Mi-17 on training flights where we've done it on purpose several times. I suppose you should be thankful that none of the pilots you flew with ever got you into that situation.

It's similar to mast bumping in a way. It's a phenomenon that certainly exists in helicopters with teetering main rotor systems, but how many people have had it happen to them? An extremely small number, since all pilots of the affected aircraft are taught early on how to avoid it.

Why do you complain,all of you simmers,about some differencies between a real hélicopter and the model simulated?

Do you think that behind your monitors while playing,with your body seated and feets set down on ground,you are flying?

Even with force feedback or stuff like that and now the VR headset,you stay on the ground.

So another word is about comparison of FM.

I do regret for all of you but when you are playing on a simulator,nothing is real.

It's the background that will follows your acts on joystick to simulate move in every direction,not the sprite or 3D object that you are playing.

In real flight background stills unmoving.

You are speaking about flight model of a 3D environment,not a plane or helo.

In the game nothing is aerodynamic nor physic,just code.

So What will do with this kind of analogy.

Only one thing to do is play the game.

A game is made for entertainment not for engineering.

What do you care about vortex or other stupid legends?

For my own i did a lot of mountain rescue flights on SA342.And army flights on SA341.

Never been,or seen other pilot,face to face with the "VRS" as you call that.

Maybe i'm lucky or after more of 7000 flying hours i did not enough.

The module is close real Gazelle and as long you are not able to make your computers take off the ground and fly around,you will never end the topic.

That's all well and good, but you should always strive to get as close as possible to the real deal. And I'm sure Polychop intends to do just that.

Constructive criticism is good.

For my own i did a lot of mountain rescue flights on SA342.And army flights on SA341.

Never been,or seen other pilot,face to face with the "VRS" as you call that.

Maybe i'm lucky or after more of 7000 flying hours i did not enough.

The module is close real Gazelle and as long you are not able to make your computers take off the ground and fly around,you will never end the topic.

Are you a pilot or a passenger? Because if you're a pilot and you don't know basic helo aerodynamics... omg.

Why do you complain,all of you simmers,about some differencies between a real hélicopter and the model simulated?

Do you think that behind your monitors while playing,with your body seated and feets set down on ground,you are flying?

Even with force feedback or stuff like that and now the VR headset,you stay on the ground.

So another word is about comparison of FM.

I do regret for all of you but when you are playing on a simulator,nothing is real.

It's the background that will follows your acts on joystick to simulate move in every direction,not the sprite or 3D object that you are playing.

In real flight background stills unmoving.

You are speaking about flight model of a 3D environment,not a plane or helo.

In the game nothing is aerodynamic nor physic,just code.

So What will do with this kind of analogy.

Only one thing to do is play the game.

A game is made for entertainment not for engineering.

What do you care about vortex or other stupid legends?

For my own i did a lot of mountain rescue flights on SA342.And army flights on SA341.

Never been,or seen other pilot,face to face with the "VRS" as you call that.

Maybe i'm lucky or after more of 7000 flying hours i did not enough.

The module is close real Gazelle and as long you are not able to make your computers take off the ground and fly around,you will never end the topic.

Rivet counting, my friend! Also very prevalent among the scale modelling community. :thumbup:

I think a big problem the testers encounter is that they can only comment on what they experienced while flying the real helicopter. Alot of the stuff that is criticized, is not done with the real aircraft or is avoided at any cost.

So in a way a real pilot is limited when it comes to testing a sim.

I'm a real pilot,and you are right.

When learning fly an aerodyne all situations are study and we are aware.

And the art of flying is to make our work and the same time avoid all that could be dangerous or fatal to us and passengers.

Simmers do prefer search all the ways acrobatic to get sensations.

Unfortunately a simulator cannot faithfully transpose the real flight angular acceleration.

To know what i mean just compare something easily to do by all of us:

make a low flight with your simulator at 100 knots and compare with you in a car at 100 knots.

Will see that the speed rendering is very low in your simulator.

That's it and we have to wait for a long long time before our computers will able to render a correct speed.

Part of the test requirements for getting a CAA PPL(H) for a Gazelle (SA-341G) includes showing a pilot can recognise, induce and recover from a VRS at a safe altitude.

JAR-FCL 2 Subpart C lists a series of exercises, numbered 1 to 28 which form the syllabus for training for the PPL(H), exercise 28 being for night flying.

 

Exercise 15

Hover out of ground effect (OGE), vortex ring

• establishing hover OGE
  
• drift/height/power control
  
• demonstration of incipient stage of vortex ring, recognition and recovery (from a safe altitude)
  
• loss of tail rotor effectiveness
  

I doubt military training and testing is any less rigorous.

I think a big problem the testers encounter is that they can only comment on what they experienced while flying the real helicopter. Alot of the stuff that is criticized, is not done with the real aircraft or is avoided at any cost.

So in a way a real pilot is limited when it comes to testing a sim.

I was talking about the flipping and other stuff. as i said before, the VRS is not optimal.

Iwonder why they changed it. when the Gazelle first came out, VRS was verry brutal. I was hiding behind a tall building once and got into VRS. I fell like a stone and died.

It would be great if we got an explanation to why that change was made. Right now when i enter VRS the Gazelle slips right out of it and the altitude loss isn't as great.

It might be how the FM is build. BST is programming they FM like ED from ground up and in extreme detail. And that costs a lot. Remember F15C FM was given as example that it costs 100 000$

3rd Party devs don't have those money to throw upfront so they can use "shortcuts" to achieve best possible without ruining them. Polychop said before the lauch that the FM is build as and EFM using a sort of plugin made for scientific analysis or something (iirc). So this "interface" might have limitations when connecting to DCS.

Is my only explanation why they often try to "establish the perception" that the FM is pretty much done although some strange behaviors are reported. VRS, AP on/off being almost the same, stability in flight.

I am not sure if that is right. IIRC they said they will use a middleware to design the Bo-105's FM but not the one for the Gazelle. I might be wrong though.

Unfortunately a simulator cannot faithfully transpose the real flight angular acceleration.

To know what i mean just compare something easily to do by all of us:

make a low flight with your simulator at 100 knots and compare with you in a car at 100 knots.

Will see that the speed rendering is very low in your simulator.

That's it and we have to wait for a long long time before our computers will able to render a correct speed.

What do you mean by speed rendering? If the sim is running at 30-60 fps, do the objects not move by and change perspective as they should?

I think I understand what you mean by things seeming slow...but, I have always attributed this to less detail in the simulator environment (grass, ground texture, etc.) to give the impression of movement.

The FM should absolutely be improved...It's ridiculous to say a good flight model is impossible. Maybe floaty and rail-ey are the best you can expect in FSX, but we know what DCS is capable of.

I also remember Polychop mentioning using a third party software system for their FM. I wonder if this has much to do with the limitations we are hoping to see improved...

Does the SA342 use the Medusa code for calculations as per Fragger''s post or it not installed in the SA342 code but only in the BOH105?

We plan to intergrate the MEDUSA calculation system the first time with the

BO105PAH1 which will run through integration tests later this year after the release of the SA342M and as soon TOWSIM has finished

last code lines of the calculation tool.

In short again about the MEDUSA system it includes the flightmodel configurations for all types of helicopters, which includes,

configuration of the bladecount of main and tail rotor, weight of the helicopter, RPM, measurments of the airframe and various other

factors that are vital for a helicopter flight. The MEDUSA system calculates the FM based on factor as stated and

autorotation landings are also calculated as factor.

Does the SA342 use the Medusa code for calculations as per Fragger''s post or it not installed in the SA342 code but only in the BOH105?

The Gazelle uses the AFM.

That's a generic term. Su-25T uses also AFM. Not same thing.

3rd party devs are using what is called EFM which stands for "External FM" as in not made by Eagle Dynamics (or Belsimtek), ED had initially SFM for all planes that were LOMAC/FC2-3 era. After Su25T arived (with Flaming Cliffs1) its FM was named AFM... as in Advanced FM. Now ED uses the term PFM as in Professional FM.

Basically naming a FM "AFM" is just a way of delimiting from SFM. So any third party dev that doesn't use SFM uses an EFM. And that EFM can be called whatever they please. Medusa... AFM... etc. I

Vortex Ring State

I have had 4000hrs real life flying in a British Army Gazelle and have never experienced VRS once.

As a pilot you are taught not to put yourself into a position to be in that condition. If you want to fly the Gazelle as realistically as possible why would you put yourself in that position ?. beats me :smilewink:

and yes I do have the gazelle module, No it's not perfect but is pretty good nonetheless.

There are Old pilots and there are Bold pilots but NO Old Bold pilots........Gravity sucks

As a pilot you are taught not to put yourself into a position to be in that condition. If you want to fly the Gazelle as realistically as possible why would you put yourself iin that position ?. beats me :smilewink:

It is not so much about what we do or not do to fly an aircraft realistically. It is more about what the aircraft does or does not do to fly realistically. Smalll, but important difference! I mean, that is the beauty of simulations: we can experiment and try out things we would never do in real life. That "What If..."-factor ... it starts with "What if I were a pilot?" and continues with "What if i try this or that maneuvre" over "What if I try to kill F-15s with my Gazelle?" to "What happens if I eject while flying NoE ... inverted.":D

"What happens if I eject while flying NoE ... inverted.":D

:lol:

It is not so much about what we do or not do to fly an aircraft realistically. It is more about what the aircraft does or does not do to fly realistically. Smalll, but important difference! I mean, that is the beauty of simulations: we can experiment and try out things we would never do in real life. That "What If..."-factor ... it starts with "What if I were a pilot?" and continues with "What if i try this or that maneuvre" over "What if I try to kill F-15s with my Gazelle?" to "What happens if I eject while flying NoE ... inverted.":D

Not saying you do, but what is the point of picking holes in the module and expecting the devs to make it as realistic as possible if all you need is an arcade version which would probably be a lot cheaper.

No matter how hard the devs FM the gazelle or any other module, you will never have it work just like the real thing especially for £50.

Most helis are flown very much by feel through the seat and sound of the mechanics. :pilotfly:

I have had 4000hrs real life flying in a British Army Gazelle ...

That makes you the expert on the topic of flight model accuracy. Can you go into more detail what is modeled well and what is off?

Questions I have in particular are:

Is the Gazelle really that dead stable in forward flight? It needs zero pedal input, even when yanking the collective from idle to full.

Is it true that there will be no jolt going thru the airframe, when yanking the collective from 50% to full in forward flight? Even the rpm doesn't go down.

I have the feeling when pulling in a lot of collective that the torque needle climbs quickly, but the helo gains altitude only slowly. Do you think climbrate for torque input in modeled correctly?

Can you maybe answer this guys question regarding stick position in fast flight: https://forums.eagle.ru/showpost.php?p=3012623&postcount=16

Would be really interested in your opinion to see if it is actually worth putting hours into mastering this aircraft. To me it's only worth it if it is a good representation of the real thing. I admit to me it feels a bit too arcade mode. That might be down to a bad FM or the SAS/Autopilot. But I don't know. You are the one qualified to give a statement on that.

Thanks

I've given the Gazelle about 4hrs in the last couple of days in 2.0. It is undoubtedly an excellent little helicopter and I am really warming too it. I can force VRS if I try too and it will drop like a stone and cannot be recovered with collective alone. If you build up any lateral or forward momentum it does self recover though. Given the small rotor disc it inevitably exits VRS on its own.

I would be very interested to read mickt014s opinion on a few little issues that have been mentioned in the various flight model threads and which don't make sense to me.

- no need to compensate with collective when performing pedal turns in the hover. (I'd expect turning against the torque would require some slight collective to maintain altitude and less collective pitch required when turning with torque).

- no overspeed of the rotor when performing rapid fast stops from high speed. Shouldn't the rotor spool up rapidly if not managed due to the increased airflow presented to the rotor disc and the low collective pitch setting?

- no bogging of the rotor or any change in yaw when making large collective changes in forward flight.

The thing I've been practicing most and trying to get my head around the last few days is precise circuits. I'm finding it very unusual how the Gazelle turns. Keeping the VSI at zero while maintaining an exact desired airspeed requires really very precise pedal input and cyclic control. It's so much harder than anything else I've flown in a simulator and just feels very... different. It's like the aircraft is fighting you and wants to either self level or slide (EDIT: both with SAS on or off). Sven has assured me that this is how the military Gazelle turns so I've decided to just learn to master it. There is no tendency for the tail to weather vein at all. It takes a while transitioning back to any of the Dreamfoil Creations helicopters in x-plane or other helicopter modules in dcs (I know, I know.. all helicopters are different, but this is REALLY different lol).

I'm glad I'm warming to the module again. A family friend was an Irish Air Corps instructor on Gazelles when they used them for pilot training many moons ago. It was also the first helicopter I was ever in. Sorry to go off topic from VRS but it's hard not to ask a few questions when someone with 4,000 hrs on type chimes in.

vrs

That makes you the expert on the topic of flight model accuracy. Can you go into more detail what is modeled well and what is off?

 

The Gazelle I have flown is a different beast to the French model in that it does not have SAS fitted, so it's very much hands on all the time. I believe there are different blades fitted and the Brit gaz is not armed. There is a sight fitted but only for obs in the recce role so the AUW is probably different.

 

Questions I have in particular are:

 

Is the Gazelle really that dead stable in forward flight? It needs zero pedal input, even when yanking the collective from idle to full.

 

Do not know how effective SAS is, but on the Brit ver No, every move of the collective needs an input from the pedals dependant on the amount of power pulled. [Yaws left when you pull power so right pedal needed and viceversa]. In forward flight the large rear fin acts as a wing so helps prevent yaw. If you pulled from flight idle to full you would probably over torque the transmission and not have enough right pedal to keep it straight.

 

Is it true that there will be no jolt going thru the airframe, when yanking the collective from 50% to full in forward flight? Even the rpm doesn't go down.

 

Yow can induce a jolt by rapid application of the collective up or down. Engine and rotor rpm is governed but there can be over or under swing . Rotor rpm in Auto is controlled by collective movement.

 

I have the feeling when pulling in a lot of collective that the torque needle climbs quickly, but the helo gains altitude only slowly. Do you think climbrate for torque input in modeled correctly?

 

rate of climb will mainly depend on ...weigth of heli, temperature, altitude and pressure. A heavy heli will pull a lot of torque and climb slowly

 

Can you maybe answer this guys question regarding stick position in fast flight: https://forums.eagle.ru/showpost.php?p=3012623&postcount=16

 

without SAS fitted the heli goes faster the more the cyclic is moved forward and held in place, it will not return to centre. Power will also be reqd and an input from the pedals. All 3 controls have to be coordinated at all times. The gaz is a lovely heli to fly and very manouverable needing only small inputs.

 

Hope this helps you

 

Would be really interested in your opinion to see if it is actually worth putting hours into mastering this aircraft. To me it's only worth it if it is a good representation of the real thing. I admit to me it feels a bit too arcade mode. That might be down to a bad FM or the SAS/Autopilot. But I don't know. You are the one qualified to give a statement on that.

Thanks

..

I've given the Gazelle about 4hrs in the last couple of days in 2.0. It is undoubtedly an excellent little helicopter and I am really warming too it. I can force VRS if I try too and it will drop like a stone and cannot be recovered with collective alone. If you build up any lateral or forward momentum it does self recover though. Given the small rotor disc it inevitably exits VRS on its own.

 

I would be very interested to read mickt014s opinion on a few little issues that have been mentioned in the various flight model threads and which don't make sense to me.

 

- no need to compensate with collective when performing pedal turns in the hover. (I'd expect turning against the torque would require some slight collective to maintain altitude and less collective pitch required when turning with torque).

 

Again I can only speak for the Brit ver with no SAS fitted. In a hover outside ground effect you will constantly be making small adjustments to all 3 controls. In ground effect its similar but you will use less power due to the ground cushion effect

 

 

- no overspeed of the rotor when performing rapid fast stops from high speed. Shouldn't the rotor spool up rapidly if not managed due to the increased airflow presented to the rotor disc and the low collective pitch setting?

 

There can be severe overspeed of the head if collective dropped rapidly ie Practice engine failure

 

- no bogging of the rotor or any change in yaw when making large collective changes in forward flight.

 

This will happen depending on your forward speed at the time, yaw will be more severe at low speed due to the fin not having as much effect

 

The thing I've been practicing most and trying to get my head around the last few days is precise circuits. I'm finding it very unusual how the Gazelle turns. Keeping the VSI at zero while maintaining an exact desired airspeed requires really very precise pedal input and cyclic control. It's so much harder than anything else I've flown in a simulator and just feels very... different. It's like the aircraft is fighting you and wants to either self level or slide. Sven has assured me that this is how the military Gazelle turns so I've decided to just learn to master it. There is no tendency for the tail to weather vein at all. It takes a while transitioning back to any of the Dreamfoil Creations helicopters in x-plane or other helicopter modules in dcs (I know, I know.. all helicopters are different, but this is REALLY different lol).

 

The gaz can be very prone to cross winds due to the large tail. It does take a lot of effort to master any heli. You need to think when climbing and descending PAT power attitude Trim APT Attitude Power Trim. (google it)

 

Hope this helps :pilotfly:

 

I'm glad I'm warming to the module again. A family friend was an Irish Air Corps instructor on Gazelles when they used them for pilot training many moons ago. It was also the first helicopter I was ever in. Sorry to go off topic from VRS but it's hard not to ask a few questions when someone with 4,000 hrs on type chimes in.

..

I don't think you needed to double post that, we got it..