R22 rolls over when pushing cyclic forward

[bastian74]

Is this real world behavior or a flight model bug?

If you porpus downward while in forward flight it rolls over 180 degrees into inverted.

[drhotwing1]

If you are using 'Expert' mode you almost require the use of rudder pedals. The R22 reacts very closely to the real-life counterpart . If you are having difficulty flying the R22 be sure to run in novice mode where you will recieve some help stabilizing the tail.

Jeff (IPACS Development Team)

[bastian74]

I'm in expert mode, I'm not talking about yaw I'm talking about roll. Just fly fast forward flight, initiate a climb and then push forward. You'll be upside down in a moment as it initates a hard "aileron roll." It's the only real odity I've experienced.

On a bug note, in VR when cycling through the views, one of them consistently crashes the game / locks up. I have to end-task to get out.

[Jan (IPACS)]

This is a realistic behavior of the aircraft and that is the reason for the label on the cyclic: low g maneuvers prohibited.
To exit the roll increase collective and pull aft cyclic to load the rotor disk again to regain control. (just like the real thing)

[bastian74]

LOW-G PUSHOVERS - EXTREMELY DANGEROUSPushing the cyclic forward following a pull-up or rapid climb, or even fromlevel flight, produces a low-G (weightless) flight condition. If the helicopter isstill pitching forward when the pilot applies aft cyclic to reload the rotor, therotor disc may tilt aft relative to the fuselage before it is reloaded. The mainrotor torque reaction will then combine with tail rotor thrust to produce apowerful right rolling moment on the fuselage. With no lift from the rotor,there is no lateral control to stop the rapid right roll and mast bumping canoccur. Severe in-flight mast bumping usually results in main rotor shaftseparation and/or rotor blade contact with the fuselage.The rotor must be reloaded before lateral cyclic can stop the right roll. Toreload the rotor, apply an immediate gentle aft cyclic, but avoid any large aftcyclic inputs. (The low-G which occurs during a rapid autorotation entry is nota problem because lowering collective reduces both rotor lift and rotor torqueat the same time.) Never attempt to demonstrate or experiment with low-G maneuvers,regardless of your skill or experience level. Even highly experienced test pilotshave been killed investigating the low-G flight condition. Always use greatcare to avoid any maneuver which could result in a low-G condition. Low-G mast bumping accidents are almost always fatal

[bastian74]

I had always assumed that they were prohibited purely to avoid boom-strikes. That's interesting!

[bastian74]

I also found this reddit post of a student pilot who found out the hard way:
https://www.reddit.com/r/Helicopters/comments/4simx5/r22_low_g_pushover_close_call_today_shook_me_up_a/

[md500f]

In reality, the blades will generally strike the cabin or the boom before the mast gets severed but of course at that point it doesn't really matter. I've had the onset of mast bumping in turbulence a number of years ago. It happens quickly but not quickly enough that you can't react to save it. I have to say that although the breakup isn't simulated in FS2, they've got it spot on in terms of how it happens. The whole thing about aft cyclic to reload the disc is a bit daft, there's no rotor thrust being produced, the disc is unloaded, so aft cyclic doesn't do a lot. Removing the reason for the yaw (tail rotor thrust) is the best thing to do. Lowering the collective and removing the anti-torque takes away most of the yaw and subsequent roll and if you're doing that you should be going aft cyclic anyway. This thinking is slowely making it's way into the flight training world.

[bastian74]

I'm having a hard time conceptualizing where the roll comes from. Gyroscopic procession of pulling aft on the unloaded rotor? If that's so, why doesn't it roll when loaded as well?

Another question, when they say cabin strike, are they talking about the glass canopy or the tail boom?

[bastian74]

I answered my own question at 6:32 in this video.
This is a phenomene I never knew existed and I considered myself pretty familiar with helicopters! (I've flown in an R22, and flown/assembled gas powered rc helicopters for more than a decade) but with the benefit of gigantic thrust to weight and rigid rotor systems.

https://youtu.be/_QkOpH2e6tM?t=391

[md500f]

The roll mainly comes from parasite drag on the fuselage. On paper it comes from the torque couple also. Blades will come through the cockpit during excessive flapping and in reality that'll happen at the same time as the tail gets cut off