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Helicopters lack mass, permitting impossible/destructive maneuvers.
Assigned, WishlistPublic


-Helicopters are capable of yawing 90 degree to left/right while travelling at airspeeds in excess of 200kph. This is not possible, would destroy any real aircraft, and causes game aircraft to flip when their physics envelope is exceeded in an impossible manner.
-helicopters are capable of hairpin turns, slowing from 200kph (my standard testing speed) before entering uncontrolled spins as airspeed and torques instantly become unmatched.
-helicopters when perform dives/climbs slow impossibly fast with negligable altitude change, result in aircraft spins/flips due to suddenly mis-matched torques.


Legacy ID
Advanced Flight Model
Steps To Reproduce

(perform all maneuvers with initial velocity of 200kps)

  1. Establish level flight. Yaw to either left/right 90 degrees. Aircraft will flip.
  1. Establish level flight. Rapid jerk back/push cyclic forward. Aircraft airspeed will change by 100+ kph instantaneously before entering spins.
Additional Information


Event Timeline

Worldsprayer edited Additional Information. (Show Details)
Worldsprayer set Category to Advanced Flight Model.
Worldsprayer set Reproducibility to Always.
Worldsprayer set Severity to None.
Worldsprayer set Resolution to Open.
Worldsprayer set Legacy ID to 3925860425.May 7 2016, 7:10 PM
Bohemia added a subscriber: AD2001.Aug 6 2014, 4:13 PM
vicx added a subscriber: vicx.May 7 2016, 7:10 PM
vicx added a comment.Aug 8 2014, 6:26 AM

Is this a particular A3 heli or all of them?

All of them, though with the latest patch to dev branch via 08-08-2014
EXE rev. 126636 (game)
EXE rev. 126634 (launcher)
Size: ~157 MB

the issue is much better. However the Mi-48 still suffers the issue completely since the change they made effected the tail rotor forces somehow, and the mi-48 has no tail rotor to adjust. In it you can still go 250kph, pull a 90 degree yawing turn and hit 0kph almost instantaneously. It's also heavy enough that it doesnt really flip, so it actually survives the maneuver too.

The yawing should be toned down but the concept in itself is realistic and occurs because of screwed up stress damages.

vicx added a comment.Aug 8 2014, 8:23 PM

EspressoLyle, there a few points. From what Worldsprayer and other commentators have said is that there are a few circumstances where the flight models have been ignoring the force of air at 200kph that should make yawing with rudder harder. You can only force the heli to yaw by a very small percentage before the aerodynamic forces cancel out whatever you are applying via the rudder. Helis should be more stable at higher speeds in a lot of ways - you probably shouldn't be able to yaw your way out of the sky at 200kph.

Failure modes at high speed would be:

  • exceeding it's speed limit at which point you should crash in a predictable fashion (look up vne)
  • exceeding mechanical limits where parts of the heli break then of course it should crash more randomly. But this shouldn't happen via yawing by itself.

Good to hear Worldsprayer. I am flying the Pawnee right now and it is feeling much improved.

The Mi-48 is such a different case. (Shouldn't it be a Ka-100?) It does need to be treated separately to the other models. BIS can probably get away with applying some stablising hacks to mi-48 to make it not do impossible things. They could just call it a fly-by-wire feature and it wouldn't really be wrong for them to do that.

He mentions the yawing caused when jerking the stick back and forth thus changing airspeed by 100kph. This should cause yawing but also break the helicopter, and since this feature isn't implemented it looks like a bug. You took my comment the wrong way, vicx.

Bassicaly what vicx said in the first part: Basic aerodynamics applying, a plane (which is what a helo is a speed) should not be capable of yawing like that (unless it has an absurdly powerful transmission and airframe I suppose) as the aircraft should windsock into the wind. the 48 has those 4 canted stabilators in the back that are intended to stabilize forward flight (or would if it was real). Just like with every other helicopter in the game now, if you put in full left/right pedal, the helo should yaw a certain amount and then bounce back to a neutral point.

And that's not what I'm talking about espresso: The yawing I'm talking about is player inputted shouldn't permit a 90 yaw just like the rest of the helos now.

The 100kph thing is about climbing and diving. Go to 200+ kph. Quickly nose over until you point straight down and then back up. I just did it and my airspeed went from 200 to 0 and back to 200 when I leveled back out. That is what I'm talking about, and implies that the helo simply has no "inertia", or no system to make it look like it has inertia.

vicx added a comment.Aug 9 2014, 1:38 PM

Sorry Espresso if I took it the wrong way, I am in agreement with you on the subject that in air heli damage is missing. I think that causes sim problems.

If you can't damage the heli (in the air) this lets you put the heli in unusual positions where it behaves a lot more wierdly because you totally exceed the limits of sim model. This is bad because it feels random. It would be better if parts of the heli would break off and then you would have a new aerodynamic model to deal with.


As far as the yawing at speed *note:I am not a pilot* it feels like at 200kph on any heli with stablisers or a big fin at the back that yaw should not exceed 5%. If you wanna yaw you gotta climb (bleed speed)and then yaw (like they do in all the youtube videos).


Worldsprayer I have been experiencing the odd velocity changes but it is hard to pin them down.

  • I feel that when I yaw at high speeds the heli loses way too much forward speed but the heli shouldn't be able to yaw at high speeds (so fix that and maybe problem goes away).
  • I feel that when I stab the cyclic forward or back at 200kph it changes the velocity BUT doesn't change the altitude enough. I feel like it should change the alitude more and the velocity should be a function of the delta in altitude.