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!
Thank you so much for sharing. I just started taking lessons in an R-22. The Robinson R-22 controls are VERY touchy. I see lots of Dynamic roll overs, But this sums it up Very clearly!
@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.
@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.
@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.
However, thrust(lift)is not critical to obtain a rolling moment. Typically obtained with a positive collective, but fully articulated rotors can generate a rolling moment at flat collective pitch if the cyclic is moved laterally.
That's why it's important to slowly get light on the skids, do your hover checks n then lift off. Regardless of how the dynamic roll over is created, be quick to lower the collective. That is what will save your ass and the helicopter. Ground resonance is a totally different animal. To recover from that you quickly raise the collective to lift off before the helicopter self destructs n disintegrates...😳
I think you're missing some elements in this demonstration. Most critical is the roll rate and exceeding the critical angle. I think it would be important to show how the roll rate decreases the critical angle, more than showing any sideways component of the lift vector.
@stetson6 Your demonstration only shows what happens when a corrective control application fails to keep the tip path plane level either due to pilot error or hitting control limits, and the sideways drift continues against the pivot point (either from crosswinds or too much drift speed)
this seems to happen a lot on my RC Blade helicopters ...I have learned to pop them up into the air quicker.....I guess it's not the same with the real ones.....
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
Come on it just leans left(viewed from tail to nose), so you just have to lean it right. Whether you actually fly in the real thing, or fly rchelicopter(harder, especially inverted). You just can't control all those factors to control it. Just give it a hard cyclic right, then back/forth to balance. Enough said.
@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.
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!
Thank you so much for sharing. I just started taking lessons in an R-22. The Robinson R-22 controls are VERY touchy. I see lots of Dynamic roll overs, But this sums it up Very clearly!
@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.
@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.
@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.
However, thrust(lift)is not critical to obtain a rolling moment. Typically obtained with a positive collective, but fully articulated rotors can generate a rolling moment at flat collective pitch if the cyclic is moved laterally.
Very educative… thanks …….. if there’s another animation of LTE…. 🙏🚁🚁🙏
That's why it's important to slowly get light on the skids, do your hover checks n then lift off. Regardless of how the dynamic roll over is created, be quick to
lower the collective. That is what will save your ass and the helicopter.
Ground resonance is a totally different animal. To recover from that you quickly raise the collective to lift off before the helicopter self destructs n disintegrates...😳
I think you're missing some elements in this demonstration. Most critical is the roll rate and exceeding the critical angle. I think it would be important to show how the roll rate decreases the critical angle, more than showing any sideways component of the lift vector.
@stetson6 Your demonstration only shows what happens when a corrective control application fails to keep the tip path plane level either due to pilot error or hitting control limits, and the sideways drift continues against the pivot point (either from crosswinds or too much drift speed)
this seems to happen a lot on my RC Blade helicopters ...I have learned to pop them up into the air quicker.....I guess it's not the same with the real ones.....
good to know:-D
1) Can anybody suggest a simple way to demonstrate the relationship between roll rate and critical angle?
What software did you use to simulate this?
Blender3D
+WonderingMindfully Thanks! So, you did not use any physics engine here, right?
Right.
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
This is one of the many reasons that coaxial rotor heads are better.
Come on it just leans left(viewed from tail to nose), so you just have to lean it right. Whether you actually fly in the real thing, or fly rchelicopter(harder, especially inverted). You just can't control all those factors to control it. Just give it a hard cyclic right, then back/forth to balance. Enough said.
2) I guess
share in fb helicopter safety
@WonderingMindfully pm me
@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.
Very educative… thanks …….. if there’s another animation of LTE…. 🙏🚁🚁🙏