Helicopter physics impressions - simplified

[jiltedjock 10]

yeah. If it werent for the fact that even shooting is lame, since ballistics and calibers and rifles are all over the place. But this is it, take or leave. I dont have the will to fight it anymore. I have A2 and have A3. I hoped the latter would be better -on every aspect- instead it's just different. And it's still a WIP, and there will be mods, and i still have A2+ACE, and many other games i liked to play before A2+ACE took all my gaming time. So we will live on.

If ACE was to incorporate I44's armour penetration system it would come as close to sim as we are likely to be able to manage with the engine.

[maffa 29]

It's the knowledge that is feasible that kills me.

But this is totally OT and nothing new.

[dmarkwick 261]

As I said:

My best guess for this mechanic is to give a cheap autorotation ability to AI.

I guess a way to "test" this out (somewhat) would be to setPos your position to 1000m altitude without starting engines & see what happens.

[nodunit 397]

....

In every game I've played with even the most basic flight controls such as battlefield 3 I've seen people manage to screw this up horribly, even the most simplification isn't going to help some people.

Helicopters are the most difficult vehicle to control and they should be as in the hands of the right pilot they can single handedly turn the tide of many battles.

TOH also had control variety based on the level of difficulty configured in its server settings and the control scheme drastically changed based on that difficult.

On the simplest difficulty the flight was very much like Arma 2 save for collective having a power ratio, there was no need to yaw to counteract torque.

As you step up the difficulty then you start to introduce things such as rotor disk influence, counter torque, wind and eventually the unforgiving wild bulls that helicopters are, they don't have to be set to that by default and you can bet that most servers will NOT have them set to that difficulty for that very reason.

The mentality of "Oh but then it will be too difficult" is nothing short of infuriating because it holds back so much potential, let me apply it to other scenarios.

We have a new armor system! Ammo type used will effect how tanks are damaged along with angle and its own armor and defense systems, MBT's will be able to bounce or simple absorb some anti tank projectiles if you hit them in the wrong spot...oh but then people will actually have to flank the armor and place their shots carefully, learn more about the projectiles drop so that they can attack it from afar..

We have a new driving system! Speed and weather effects the roads, if you turn the vehicle too sharply at high speeds and that vehicle has a high center of gravity then its very likely you'll flip it. Likewise turning abruptly at high speeds could potentially cause a loss of control...oh but then people will have to drive more carefully and at lower speeds if they want to do certain things, learning the nuances of the vehicle, which ones are more susceptible to flip..

We have a new infantry armor system! Different types of armor will effects all manners of things, from turn speed to running and acceleration as well as stamina! The heavier the armor the more mobility loss but the more project gained, from 9mm to 7.62 with even more effect at distance! Oh but then people will have to learn about the different armor types and identify them especially over distance so they can judge wether or not they should shoot that person and where to expose the weaknesses and could potentially due the battle out because the person in heavier armor can bunker down somewhere and expose only their chest and head..

Edited October 10, 2013 by NodUnit

[dharbert 0]

I guess a way to "test" this out (somewhat) would be to setPos your position to 1000m altitude without starting engines & see what happens.

If you use the editor and set yourself as the pilot in a helicotper, and start out at a height of 1000 m with the engine off, you will instantly nosedive to the ground at 400 km/hour. The helicopter won't even make the slightest attempt to auto-rotate.

---------- Post added at 22:19 ---------- Previous post was at 21:43 ----------

Something is definitely messed up. I did a little more testing and got some rather interesting results. Something is making the helicopter slow down between 350 to 300 meters. I ran several tests and got several different results. I'll attempt to explain my testing methodology.

I started out as a pilot in the RAH-66 Comanche, set my altitude at 1000 meters with the engine on. It took me 73 seconds from the time I shut off the engine until I landed. 1000 meters -> 500 meters took 25 seconds, which gives a rate of descent of 20 meters per second. However, from 500 meters -> ground level took 48 seconds, which gives a rate of descent of 10.4 meters per second. Interestingly 350 meters -> 300 meters took 10 seconds, which gives a rate of descent of only 5 meters per second.

So, it went like this. The helicopter dropped like a rock from 1000 m to 500 m, slowed down greatly between 350 m to 300 m, then picked up speed for the rest of the descent to the ground. Not only is it noticeable on the altimeter, you can actually hear the engine slow down, then speed back up again.

Now, having said that, not all tests turned out the same. In that test it took me 73 seconds to hit the ground from a height of 1000 meters. In another test it only took 36 seconds to hit the ground from a height of 1000 meters under the same conditions. So, something is screwy with the game code or they decided to just throw some random variable in there to give the appearance of functioning auto-rotation. And no, air resistance is not a factor. There isn't any wind interference either, as the chopper falls in the exact same spot on the ground every single time.

---------- Post added at 23:11 ---------- Previous post was at 22:19 ----------

I did a bit more testing and the results are even more hilarious and random. Turning off the engine at a height of 1000 meters results in a relatively slow fall back to Earth with no damage whatsoever. However, turning off the engine at a height of only 300 meters will result in severe damage and/or death. So, a fall from a great height is perfectly safe, yet a fall from a much lower altitude will disable your chopper and/or kill you. How's that for realism?

And the Littlebird, from a height of 1000 meters, when you shut the engine off it falls (quite literally) like a feather to the ground. It's comical how long it takes for it to fall to the ground. Also, if you are in the Comanche, you can shut off the engine at 1000 meters, let it free fall to a height of 100 meters, then turn the engines back on and it will save the helicopter about 50 meters off the ground.

Edited October 10, 2013 by dharbert

[relain 1]

If I read this correctly,

http://en.wikipedia.org/wiki/Autorotation_(helicopter)

an easy autorotation maneuver should be impossible even in Vanilla ARMA, because it is one of the most difficult situations a helicopter pilot could imagine.

Also: To get the autorotation effect you also need to glide forward to get enough "air under your blades".

So I think we should classify this as a bug - not a feature.

[FredAirland 14]

I think ARMA helicopter flight model is spot on for the purpose it serves, i.e. use by non expert helicopter pilots, flying at low level in a battlefield.

Implementing a realistic autorotations is no easy task since it involves several calculations (as I did in my Helicopter Total Realism FSX extension) which are IMHO way too complex for the above purpose.

I will be doing some advanced helicopter aerodynamics in ARMA sometimes in the future, then you can have fun!

I bet it will be way better than TKOH....

[maffa 29]

wish you do fred, i may change my mind to not devote myself in any vehicle related activity in my clan :D

in any case, even if @dhalbert tested again the situation, i have still not decided if it's a crude representation of "automatic" autorotation or just a bug.

[[evo] dan 79]

In every game I've played with even the most basic flight controls such as battlefield 3 I've seen people manage to screw this up horribly, even the most simplification isn't going to help some people.

Helicopters are the most difficult vehicle to control and they should be as in the hands of the right pilot they can single handedly turn the tide of many battles.

TOH also had control variety based on the level of difficulty configured in its server settings and the control scheme drastically changed based on that difficult.

On the simplest difficulty the flight was very much like Arma 2 save for collective having a power ratio, there was no need to yaw to counteract torque.

As you step up the difficulty then you start to introduce things such as rotor disk influence, counter torque, wind and eventually the unforgiving wild bulls that helicopters are, they don't have to be set to that by default and you can bet that most servers will NOT have them set to that difficulty for that very reason.

The mentality of "Oh but then it will be too difficult" is nothing short of infuriating because it holds back so much potential, let me apply it to other scenarios.

I remember this happening with TOH, they ended up dumbing it down so K&M players could play on expert, even though it should be difficult too. I guess BIS just ditched the whole idea of TOH because they felt it pointless after the dumbing down (and the 10fps hit).

But I do agree that it would have been very nice for them to add it in, as well as the other features such as SL and FR. They didn't get them to work in MP though, BUT, Neo did and he's a BIS team member now as I recall so its certainly possible.

[gatordev 219]

If you use the editor and set yourself as the pilot in a helicotper, and start out at a height of 1000 m with the engine off, you will instantly nosedive to the ground at 400 km/hour. The helicopter won't even make the slightest attempt to auto-rotate.

Which is exactly how it should be. There's something called "catastrophic loss of Nr" which means the blades slow down to a point where no amount of air rushing up will make them spin again. It can happen to a perfectly healthy and flyable helicopter if the pilot holds the collective up too much and loses turns before recovering.

an easy autorotation maneuver should be impossible even in Vanilla ARMA, because it is one of the most difficult situations a helicopter pilot could imagine.

Uh, no. It's something that is practiced all the time in various different kinds of helicopters. Depending on how big it is, some helos will "stop" the auto in a hover. Smaller helicopters can take it all the way to the deck with the engine not providing any benefit. I can't tell you how many times I've autoed a Bell 206 to the deck with the engine at idle.

There's a lot of fail in this thread, but that doesn't mean that the flight model in A3 is perfect by any means. I completely understand why BIS did what they did. If they're able to put the ToH engine in later and make it optional, I think that would be a great addition.

Another thing people need to keep in mind is that losing an engine (or two) isn't the end of the world. Losing your transmission is what ends the day very quickly. While I don't want to experience either, I'd rather lose my tail rotor than lose my main tranny. Once the tranny is gone, everything stops spinning and you have the rest of your life to watch it unfold. The good news is that main transmissions in military aircraft are very rugged, so it's not necessarily something that needs to be modeled in game.

[progamer 14]

You guys can provide feedback on the autorotation issue here: http://feedback.arma3.com/view.php?id=10283 as well for the developers to see. It does seem like its too easy at the moment and has no risk.

[CaptainAzimuth 714]

Well other than the fact you may break the heli's engine, hull, ar even die on impact, but the heli minorly damaged. Or blow up entirely. It depends on who is auto rotating. If you do it right, worst that can happen is it would leave you severely fucked up, and heli damaged.

[maffa 29]

again as i said, i dont think this magic/rough autorotation is an issue altogether. Medics heal magically, tank drivers turn every system on and nominal in 5 seconds and are ready to go, even non pilot roled players can jump in an aircraft and fly it around the map, so i dont see why anyone shuoldnt benefit from magic autorotation. If it can be done, it will be done magically -although i remember clearly there used to be an "emergency landing manoeuvre tutorial" in A2, so maybe things are not that simple to handle.

[oukej 2911]

The auto-rotation behavior is otherwise very similar to A2 state, with the lack of helicopter's instability (some sort of auto-stabilizer, if you want ;)), it truly is very easy to land safely without any input if you shut down the engine mid-air & with initially stabilized position.

The drag factor of the rotor - in an hypothetical ideally-stabilized situation when the helicopter falls straight down - is similar to a parachute of the same size. Irl you'd be slowed down as well.

But the descend rate you achieve during that "maneuver" should be probably high enough to damage your helicopter beyond repair-ability. Therefore, this issue can be more related to actual helicopters' hit-point values. We'll definitely try to look into that.

The stability is otherwise beneficial for ease of use of the helicopters, the "vertical auto-rotation" is a sort of a minor exploitation of it. Moreover, there are no mechanics in game to simulate the instability or air currents properly. Changing the current behavior could have consequences in completely breaking the possibility to auto-rotate in other situations (as in early Alpha dev. stage). Little tweaks to how much energy is stored in the spinning could also have consequences in less realistic standard auto-rotation. The model is very simplified, such changes are always trade-offs. That does not mean they are a priori rejected ;)

I'll monitor & look into that, but please understand, that it may receive lower priority (we have limited manpower, a fine tuned helicopter can mean a forgotten flying tank somewhere else;))

[relain 1]

Uh, no. It's something that is practiced all the time in various different kinds of helicopters. Depending on how big it is, some helos will "stop" the auto in a hover. Smaller helicopters can take it all the way to the deck with the engine not providing any benefit. I can't tell you how many times I've autoed a Bell 206 to the deck with the engine at idle.

There's a lot of fail in this thread, but that doesn't mean that the flight model in A3 is perfect by any means. I completely understand why BIS did what they did. If they're able to put the ToH engine in later and make it optional, I think that would be a great addition.

Thanks for sharing your RL knowledge - interesting stuff. :)

[FredAirland 14]

I'll monitor & look into that, but please understand, that it may receive lower priority (we have limited manpower, a fine tuned helicopter can mean a forgotten flying tank somewhere else)

If you wish additional manpower for this I think I can help..(free) I am already working on an advanced FM using scripts, see here but if needed I can go way deeper than that...

Fred

[gatordev 219]

Words.

Completely understandable. While not how you'd do it in real life, I always appreciated the auto characteristics in A2 because it was repeatable and consistent. Like I said earlier, if down the road we get the option of a ToH FM in A3, great, but in the mean time, the A3 FM is still so much better than A2. Thanks for continuing to work it.

[Hunter Rose 10]

In every game ... chest and head.

Yeah, waiting for ACE.