Dynamic Rollover Demo

A work in progress demonstrating some of the factors leading to dynamic rollover in helicopters.

Category:

Education

Tags:

• helicopter
• aerodynamics

[kz4506]

to let me get this right , lack of power , verses to much colective , blades bog on lift , causes the c of e to roll , when the tail rotor lets go = tipping the body over , so he should have lower collective and right peddle to stay straight ,and cycle to suite correct , please

[WonderingMindfully]

@kz4506: Critical angle of lateral tilt is achieved due to lateral force of fuselage is resisted by opposite force on skid produced by nonmoving object (taxiway light here). Before critical lateral tilt is reached, correction can be achieved by opposite cyclic because the lateral force vector of the rotor is opposite the direction of tilt. Once the critical angle is achieved, however, even full opposite cyclic does not get the lateral component of lift going in the right direction.

[WonderingMindfully]

@kz4506: Critical angle of lateral tilt is achieved due to lateral force of helicopter movement is resisted by opposite force on skid produced by nonmoving object (taxiway light here). Before critical lateral tilt is reached, correction can be achieved by opposite cyclic because the lateral force vector of the rotor is opposite the direction of tilt. Once the critical angle is achieved, however, even full opposite cyclic does not get the lateral component of lift going in the right direction.

[WonderingMindfully]

2) I guess

[WonderingMindfully]

1) Can anybody suggest a simple way to demonstrate the relationship between roll rate and critical angle?

[deviantphoenix31]

Just a heads up, but a "rapid" collective reduction can lead to dynamic rollover in and of itself if you have a pivot point established... a smooth and moderate collective reduction is your best bet.

[paintball321]

pay for a new taxi light and a conversation with the FAA on why your dumbass hit the light in the first place

[gordonjj]

You say this is "A work in progress..." I say, you're done. You have given me an excellent demonstration of dynamic rollover. No further info is needed.

Thanks for the education!

[stetson6]

@WonderingMindfully Lateral component of lift, or t/r thrust, or crosswinds, are what create a roll rate. Control the roll rate (minimum) and critical angle is maximum, typically the static rollover angle. The critical angle is that point where when lift is removed totally, with the collective bottomed, the roll rate carries the fuselage around the pivot point to where the static rollover angle is attained.

[stetson6]

@stetson6 It's not a bad demo that you have here, if I implied that I apologize. Just thought it was missing some points that cover all types of rollover scenarios.