Flight Dynamic Engine

[Sid6dot7]

I think something that has been overlooked untill now is the fact the KA-50 is a twin-rotor design.

 

And it has a real moveable rudder at the tail booms end to additionally support the yaw momentum generated by the coaxial rotors at high speed. Not many helos have this, most have a fixed vertical stabilizer that automaticly compensates the yaw momentum with higher airspeed to a certain amount. But as said it isn't directly adjustable.

Edited July 22, 2009 by Sid6dot7

[EinsteinEP]

Already posted earlier, but a life-size helicopter with dual contra-rotating coaxial rotors and an advanced hydraulic control sytem with a complex feedback control system should be expected to act differently than a conventional toy helicopter. In fact, if ED's Black Shark handled just like the bit of plastic in that youtube video, there'd be a lot more people crying foul about their dynamics engine!

 

I think if you start to really research your questions/concerns you'll find some very interesting things about the actual physics of the Ka-50 helicopter design, the idiosyncrasies of the pilot/helicopter interface, and ED's implementation of the whole shebang. Just like getting into RC choppers for the first time, the learning curve is the fun part!

[GGTharos]

maybe my initial comment of way wrong was a little harsh! I agree!

maybe what I'm trying to say is it still has that Pendulam on a string feel.

 

That is precisely how it should feel. Thank mother inertia.

 

the sim after all the trimming still feels to me to be Loose! The trim & Controls seem to change to much for no real reason. Like the maintenance guy forgot to tighten everything up.

 

It changes for very real reasons: Airspeed changes, collective changes, CoG changes.

 

I appologize for not being able to do that!

 

Go ahead and post your trackfile on an external site and then post a link to it.

Meantime I suggest you watch how a real Ka-50 flies on youtube.

I'm sorry to say that using an R/C Ka-50 will not back-up anything you say. It would be like saying that your honda civic can jump 100' into the air and then come back down in one piece because you made your R/C do the same (within scale, of course).

 

Using an R/C to compare the flight dynamics to a multi-metric-tonne combat helicopter is completely inappropriate. The only thing that is the same are the basic controls and flight surfaces, and this is where the similarity ends.

 

I fly R/C planes, and I've flown a real plane as well (A small light plane, at that) and I can tell you right now, if you attempt to fly it like an R/C, you will be dissapointed (or dead!). You can fly maneuvers that might look the similar, but that's about it. The feel is completely different.

[starbird]

I wouldn't dismiss the experience that smaller freeflight and r/c gives to designers and engineers. A number of full scale craft started out as chuck gliders and r/c to see if an idea could actually work. The m1-f1 lifting body started out as a r/c glider. The documentary for spaceship 1 has footage of foam models being thrown off the hangars roof to see which configuration would glide best. The same idea was used to see where the CG should be on the mercury space capsule so it would fly stable blunt end forward.

 

Of course, there is a limit to what you can test for, and there was a lot more testing done before hardware was flown.

 

I can't say whether DCS handles like the real thing, but it seems reasonable.

 

My limited flight time in a c172 says that if anything, its even more stable than the sim makes it to be.

[Yo-Yo]

And it has a real moveable rudder at the tail booms end to additionally support the yaw momentum generated by the coaxial rotors at high speed. Not many helos have this, most have a fixed vertical stabilizer that automaticly compensates the yaw momentum with higher airspeed to a certain amount. But as said it isn't directly adjustable.

 

The main task for large area rudder is to provide yaw controllability during autorotation because twin-rotor system is not good in it. The secondary task is to assist rotors yawing at high speed.

 

 

 

And concerning the R/C and RL planes/helos.... there is a great difference. If you scale down a plane, for example, 1/N the areas of aerodynamic elements scale down as N^2. MOIs scaled down more dramatically because the elements weight are scaled down as N^x *** and the inertia radius scaled down as N^2.

So the R/C planes become very agile.

 

*** You have to calculate it by yourselves. :)

 

Re number is not the same as well.

Edited July 23, 2009 by Yo-Yo

[AndyHill]

And concerning the R/C and RL planes/helos.... there is a great difference. If you scale down a plane, for example, 1/N the areas of aerodynamic elements scale down as N^2. MOIs scaled down more dramatically because the elements weight are scaled down as N^x *** and the inertia radius scaled down as N^2.

So the R/C planes become very agile.

 

*** You have to calculate it by yourselves. :)

 

Re number is not the same as well.

 

Unsurprisingly, here is the answer in all of its simplicity. Small scale models can be a very useful tool even in modern aircraft design, but you have to calculate in all the factors that change when you have a model that is for example 1/4 of the size of the real thing. When flying model airplanes trying to make them look as real as possible you have to put a lot of effort into flying it just the right way, which usually means making everything look like it's happening much more slowly than the plane would really like to go. For relatively light models inertia is only a fraction of what it is on the real thing, which makes realistic flight with models quite difficult and gives them the incredible handling characteristics seen on your video for example.

 

Here's a pretty impressive video of what a model chopper can do:

Needless to say, you shouldn't expect something like this from a real helicopter.

[Oldflyer2]

Hello All

 

It is early Thur mornig and I have not had time to really look at all the posts.

 

I really hope that I have a chance to get some trk. file made to show what I am really talking about here!

 

And please lets drop the R/C referance. I am getting a little sore about people making referancs to toys or the difference in size! I know this.

 

These so called toys are 1000's of dollars in highend radio and electric equipment and do not in any way feel, fly, or ressemble TOY's. and alot of what you fly in the real world started out as R/C! as mentioned in one response here.

 

It was just a referance point! nuff said.

 

One simmer brought up an interesting point about outside weather influences. Good Point here. Only because the whole Coaxial rotor was designed to elimnate some of these outside forces on the airframe. Read your Wiki on the KA-50. And also that the KA-50 does wiegh in the range of 8000 KG. It should not be flaling around in the sky like a bobble head.

I have also watched many video's on aircraft in flight.

 

Now, If you watch any of the Ka-50 flight videos! once in a foward flight do you see it bobing up and down or swaying side to side like it's on some sort of string in a huricane? well that's what I am getting here! even with all the vortex effects and inertia, and auto everything turned OFF.

 

Maybe I got a bad copy of this software or something! I do not know. That is why I started this thread. Which I might add I should be getting some thanks because it sure has sturred up some great debate!...LOL

 

Well I will finish this later. I do want to continue this and get more responce for sure it's awesome!

 

 

Sincerely: oldflyer2

[element1108]

It's not a bad copy of the software, sounds like a control settings issue. What setup are you using? I know a few users on the forum have commented initially of not being able to control their helicopter smoothly and this is the best place to fix that..guys in here are super helpful.

 

I'm not trying to toot my own horn, but I can control the helicopter in a very smooth manner. Most guys I fly with online are all very smooth flyers as well even in a combat environment.

 

I'm not the best to fix those problems as I'm still understanding what and how everything works outside of the actual practice of it. Auto pilot/auto direction issue possibly or a joystick dampening issue perhaps?

 

We'll figure it out mate!

[nemises]

Hello All

 

 

Now, If you watch any of the Ka-50 flight videos! once in a foward flight do you see it bobing up and down or swaying side to side like it's on some sort of string in a huricane? well that's what I am getting here! even with all the vortex effects and inertia, and auto everything turned OFF.

 

 

Sincerely: oldflyer2

 

I do remember it bobbing up and down and swaying side to side like a broncho! ... it was when I was still learning how to fly it ! .... it used to seem to fight me at every step, and get out of control for no good reason!

 

99% of your issue (I'm sure, unless it is some sort of control input problem), is not realising how the Auto stabalisers interact with the trim, and the fact that the trim also effects Rudder input.

 

do this from a stable hover:

 

- press ctrl Enter to bring up the control input screen, this will display where you are trimmed at neutral...make sure to CANCEL out any rudder trim at all by pressing and holding trim and applying reverse rudder input..once it is centralised (on the control screen), release the trim button and recenter the control's immediately.

- now you are trimmed nicely, PRESS AND HOLD the trim button, apply some forward pitch and some roll and translate to a banking turn ...KEEP HOLDING the trim button down!

- Now, correct roll and stabalise on a heading with some forward speed...STILL with the trim button held....

- Check the control input screen again...are the rudders centralised?...is the Shark flying forward completely stable at the speed you want? .. good!..RELEASE the trim button

- make sure you are not heading for a mountain or loosing alititude (get the VSI on 0 as well with collective), and go make a cup of tea....

 

HOLDING the trim and checking the ctrl-enter screen may be the secret you are missing out on (I know it completely changed the way I fly the shark)

[GGTharos]

It was just a referance point! nuff said.

 

It was a bad one ;)

 

One simmer brought up an interesting point about outside weather influences. Good Point here. Only because the whole Coaxial rotor was designed to elimnate some of these outside forces on the airframe.

 

It wasn't. The coaxial frame just happens to provide greater lift which is useful in hilly terrain.

 

 

Now, If you watch any of the Ka-50 flight videos! once in a foward flight do you see it bobing up and down or swaying side to side like it's on some sort of string in a huricane? well that's what I am getting here! even with all the vortex effects and inertia, and auto everything turned OFF.

 

With Auto-everything turned OFF, no wonder the nose is all over the place. There's a reason why the stabilization channels are called ... stabilization channels.

I'd make a claim that:

1. You don't quite know how to fly this thing yet

2. It has a lot of inertia. It's not going to stop a movement just because you think it should

3. You might not have a good control setup - specifically, perhaps you're missing rudder pedals? I am, and it makes things bad

4. You're fighting the AP when its on, and inertia when it's off. Two different things, two different ways of handling them

5. Smooth inputs get smooth results. If I can do it, so can you ;)

6. The above takes some time to accomplish

7. Almost ANY control input you make will cause nose movement

8. Learn to play nice with the auto-stabilization. It'll do you well and fly very straight

9. Do not exceed Vne. Bad things happen, usually preceded by 'nodding' of the helicopter.

 

Maybe I got a bad copy of this software or something! I do not know. That is why I started this thread. Which I might add I should be getting some thanks because it sure has sturred up some great debate!...LOL

 

There's no debate. Most of us know you're just not used to flying the thing right ;)

[G3]

I would think we would have to know something about flight dynamics

i would have thought so :thumbup:

 

have done a little rc heli myself, great fun, full focus time that's for sure.

also spent a far bit of time now just hacking around in the virtual shark,

and find it can pull some pretty aggressive maneuvers when required.

 

as for the flight dynamics, i can only judge by what i think it should feel like,

have been in a few heli's but never on the sticks, so no real world experience,

but for a bloke with a funny hat on and a whole lot of other computer

crap all around me, the flight model feels pretty dam good to me.

 

great thread, got me in :)

Edited July 23, 2009 by G3

[EtherealN]

Now' date=' If you watch any of the Ka-50 flight videos! once in a foward flight do you see it bobing up and down or swaying side to side like it's on some sort of string in a huricane? well that's what I am getting here! even with all the vortex effects and inertia, and auto everything turned OFF.[/quote']

 

Auto everything turned off? You do realize that a real Ka-50 pilot could very well see his career finished if he flew with "auto everything off"? They do train for it, and they can do it, but basically the only time they're allowed to do so is when they are making an expedited return-to-base after having said systems fail. ;)

 

The Ka-50 is an extremely stable aircraft when the correct systems are active and it is correctly trimmed, but it also has a lot of agility when handled correctly.

 

As has been mentioned, if you are having weird responses to control inputs there might be a problem with your control setup.

 

When the aircraft bobs side-to-side and up-and-down, are you absolutely certain you are not overcompensating in your control inputs? It sounds like you are expecting a much more snappy response to inputs, and this is something the human mind is very good at detecting and reacting to. Problem is, the reactions can very well be involuntary and will usually only perpetuate the problem. I know: that is a problem I spent several flights (though fixed-wing) IRL trying to remove from my system. I kept trying to adjust for every small oscillation and since there is some delay from controller input to the control surfaces having an actual effect I overcompensated and thereby perpetuated the problem. It took my instructor forcing me to just set up trim and completely remove my hands and feet from the controls to get it in - the aircraft oscillated a few times and then settled into a stable attitude. (Also, this phenomenon is what helped cause the first two crashes of JAS-39 Gripen aircraft.)

 

Also, on the note of being sore about the reference to those R/C's being toys... Well sir, 1000's of dollars of a few KG of equipment isn't even close to 15 million dollars and 7800 kilogrammes (empty) and 10800 kilogrammes (max takeoff) of equipment. And it was you that used references to how R/C's worked as an argument seeking to prove that something is wrong with the flight model in DCS:BS. Though I do have to mirror the kudos you are getting for having the stones to do that. :P

 

So to my mind (and I recently crashed my R/C Cessna into a tree during an aerobatics display :( ) it really is borderline to toys. That may seem a bit offensive to those that are heavily invested in the hobby, but then again there are people here that are heavily invested into this hobby and they might have taken offense to being told that an R/C helo proves that a flight model vouched for by actual military operators of the actual aircraft being modeled is wrong... See the point?

[159th_Viper]

....And also that the KA-50 does weigh in the range of 8000 KG. It should not be flaling around in the sky like a bobble head....

 

Aye M8

 

I can say with absolute certainty that the Kamov does not/is not simulated to act as above, at least not with my install :)

 

To begin to speculate as to why you are experiencing the issues as per your posts is also probably not the most productive way of addressing the issue I would have thought. Reasons could be a Myriad of issues from Flightstick Input deviations to..........Hell, anything really!

 

I would advise that you (or someone else) put together a simple mission in the editor with an Airstart incorporating a couple of rudimentary obstacles or the like that, if flown in a designated sequence, will incorporate Basic Flight Maneuvers and the like. Once the Mission is Flown and the track submitted, one can then have a look and see what, if anything, is amiss and proffer advice on any aspects if needed.

 

Again - The Bird's Rock-Solid in the Air, doing what she is asked for 99.9% of the time. As for the 0.1%, well.....we all have our days!

 

You just gotta treat her right is all :D

[ZaltysZ]

We just need a track or this surely will extend beyond 20 pages.

 

P.S: What is wrong with usage of "toys"? Men are just kids, whose toys are getting more and more expensive as they grow. :)

Edited July 23, 2009 by ZaltysZ

[beers]

OldFlyer, do forgive the harsh tone of some of these posts. Many of us have been flying this thing for months and patience with humans is not a trait of sim'ers. (we have enormous patience with technology, just not humans)

 

I bet that you're just trying to fly around and take a look at the world thru BS. Military aircraft... not intended for joy-riding, intended to lift off from A, go to B, blow up C, return to A, no detours, no pit-stops.

 

So, I think you can get your rocks off by:

1) TURN ON stabilzation controlls

2) TURN ON flight director

 

Flight director will provide the stablization functions, but will allow you to point yourself where ever you want and go. Without flight director on the helo wants to go to B and if you try to detour you will feel like you're riding an angry bull.

[GGTharos]

Without flight director on the helo wants to go to B and if you try to detour you will feel like you're riding an angry bull.

 

 

... unless you know how to do it. Short of some valid points that have been brought up with the difference in controls between the RL and virtual setup that you have, maneuvering the aircraft with FD OFF is merely a matter of understanding what the AP is doing and why, and how you can play nice with it, and it with you.

[EtherealN]

Agreed with GG. As long as you have the stabilisation channels active (court martial if you don't) getting directly from where you are to where you want to be is a matter of pointing yourself in the right direction (allow for wind) and trimming the chopper. As has been mentioned in this thread, it is actually possible to go off to take a smoke, raid the fridge for a beer and have a leak just on a correct trim. (Assuming that weather is good.)

 

I do, in fact, pretty much never use the FD. I did turn it on once to look at it and decided I don't need it, but that's it. Which probably is an error, I should investigate it further to figure out when it would be useful to me, but it should not be a requirement for achieving a stable flight track.

[JimMack]

I had the pleasure of meeting Ed Macy recently. As you know he was very impressed with our flight model. He told me that the "acid test" that he used was to trim correctly and then let the Ka-50 fly "hands off", which it did.

[EtherealN]

JimMack, I am officially extremely envious of you. :P

 

EDIT:

But yes, Ed Macy's review of DCS:BS is a good place to go if you want to find out what a decorated attack helicopter pilot that is otherwise not connected to the game thought of the sim. Unfortunately, my memory is fail and I don't even recall which magazine contracted him to do the review...

[old_red_eyes]

And please lets drop the R/C referance. I am getting a little sore about people making referancs to toys or the difference in size! I know this.

 

Well, the fact is you presented this reference as justification for your view, so I think you put it on the table for discussion. And definitely, the difference in size is crucial, so it is not irrelevant to state this.

 

Have you considered that all the sims you have flown so far may actually not be very good simulations? It may be that when you simulate to sufficiently finer detail the flight characteristics become qualitatively different, and this is why BS is different? You should not assume that your experience with other sims is a good reference.

 

My point of reference is that I work on high speed control systems (e.g for 60,000 RPM turbo pump). The behaviour of the control system becomes completely different depending on the resolution, I can tell you the control system for our 11kW pumps will not work on turbopumps :smilewink:

 

Certainly, if you selling flight sim software you don't necessarily want to make it as hard to fly as the real thing, these are sold for entertainment purposes. If most users end up paying in "game" mode, then a lot of development effort is wasted.

 

Frankly, I would only seriously consider the opinion of real helicopter pilots, preferably with military experience. But, without wanting to have a go at you, have you many hours flying full-size helicopters?

[JimMack]

JimMack, I am officially extremely envious of you. :P

 

EDIT:

But yes, Ed Macy's review of DCS:BS is a good place to go if you want to find out what a decorated attack helicopter pilot that is otherwise not connected to the game thought of the sim. Unfortunately, my memory is fail and I don't even recall which magazine contracted him to do the review...

 

Review attached - it is from the Royal Aeronautical Society magazine.

Black Shark PC Review.pdf

[Oldflyer2]

hey Folks!

 

I am trying to get these tracks files that I have made but for some reason I can not see them in the folder except in the sim itself. They are not listed in the file folders when I view from my system?

 

I am running Win 7 RC Therfore I have been looking into some folder permisson settings but I really wonder why that would be an issue.

 

The ones supplied by the sim are there when viewed both in the Sim and my system view?

 

???????

 

Sincerely: Oldflyer2

[Zembla]

I noticed that - using Vista - I had to change the permissions on my folders to authorize users to write to my DCS installation folder. Otherwise no screenshots would show up, so taking pictures was useless :p

 

Maybe it's the same with tracks?

 

-Z

[RvETito]

Like it was already posted scaled flying models can't be used as criteria to compare flight dynamics, mostly because of the different Raynolds and Mach numbers. I'm not going to question your R/C experience but just out of curiousity- on how many actual flight hours of 'manual' flight in BS you base your conclusions?

[Panzertard]

At least when flying online the tracks end up in your \Ka-50\Temp folder as *.MIZ.TRK files.