Great video graphics. But you missed to explain how the 'flapping to equality' in forward flight causes flapback. And you also missed to explain how the (undesired) flapback is controlled in forward flight, which is by a forward cyclic control input.
If you fly forward, then retreating blade is flapping down, so increasing angle of attack, and compensating lift dissymetry, so it means that the blade would have the highest positio over the nose ? But if you push cyclic forward, then blade pitch need to be channged on the retreating side, and that means it will start producing more lift and flups up, so the highest position will be over tail ?
Wow. Just a few errors here. First, the flapping from the inequality will tilt the disc BACK, not cause a roll. You even showed that the advancing blade flaps up and the retreating blade flaps down. This is the result of NOT moving the cyclic. The disc tilts back, the aircraft stops moving forward, and then goes backward. The reverse then happens and the disc flaps forward, but the inertia of the fuselage swinging below the disc causes it to flap even lower. Aircraft accelerates forwards faster, flaps higher, and the sequence will go for 3 or 4 oscillations before the aircraft crashes. However! If the pilot introduces forward cyclic to stop the flapback, he is using cyclic feathering to stop the flapback, lift is the same on both sides, and the aircraft keeps going forwards. The tendency to roll to the advancing side is from Inflow Roll, a different aerodynamic effect. Nice animations, but wrong explanations.
Or you can say; "advancing and retreating blades!" The advancing blades will have more downward flow, than the retreating blades. This is the "rotor disk," area. This is caused by the tilting angle of the swashplate. In any direction of the cyclic lever, or handle for directional control.
I’m a new CFI and would like to use a video like this for teaching. Would it be possible to get a video made with only one of the helicopters that you presented here? Specifically looking for a Copter with three blades, rotating right-side back. Fenestron tail rotor. (Guimbal Cabri G2)
The stall starts at retreating blade side the effect of G Precession is felt 90° from stall in direction of wing travel being aft torque from the RBS causes roll to that side G Precession cause torque down aft causing the front to pitch up during the RBS roll.
But if the retreating blade flaps down too much, the angle of attack can surpass the stall angle and caused retreating blade stall. So the helicopter must fly slow enough that the forward motion does not cancel out the lift from the retreating half of the rotor disc.
If you are flying forward, then the retreating blade is flapping UP, so that the overall disc is tilted forwards. The cyclic has been moved forwards to stop the flapback. There is no "flapping to equality" in forward flight. Yes, if you go fast enough, or are heavy enough, or are high enough, the stall angle will be reached, but remember that the inner part of the retreating blade is stalled anyway.
Umm...no. Inflow roll is caused by the inflow (at speed) at the rear being higher than at the front. Flapping to equality only happens at low speeds, with the cyclic held fixed, and soon fixes itself by crashing the aircraft.
Great video graphics. But you missed to explain how the 'flapping to equality' in forward flight causes flapback. And you also missed to explain how the (undesired) flapback is controlled in forward flight, which is by a forward cyclic control input.
If you fly forward, then retreating blade is flapping down, so increasing angle of attack, and compensating lift dissymetry, so it means that the blade would have the highest positio over the nose ?
But if you push cyclic forward, then blade pitch need to be channged on the retreating side, and that means it will start producing more lift and flups up, so the highest position will be over tail ?
Nice explanation! Now i finaly understand the lift Dissymmetry and the rotor flapping.
Wow. Just a few errors here.
First, the flapping from the inequality will tilt the disc BACK, not cause a roll. You even showed that the advancing blade flaps up and the retreating blade flaps down. This is the result of NOT moving the cyclic. The disc tilts back, the aircraft stops moving forward, and then goes backward. The reverse then happens and the disc flaps forward, but the inertia of the fuselage swinging below the disc causes it to flap even lower. Aircraft accelerates forwards faster, flaps higher, and the sequence will go for 3 or 4 oscillations before the aircraft crashes.
However! If the pilot introduces forward cyclic to stop the flapback, he is using cyclic feathering to stop the flapback, lift is the same on both sides, and the aircraft keeps going forwards.
The tendency to roll to the advancing side is from Inflow Roll, a different aerodynamic effect.
Nice animations, but wrong explanations.
CHOPPERS DON'T FLY, THEY BEAT THE AIR INTO SUBMISSION...
THEY SAY NO TO GRAVITY
Loved the animation.
Top work.
I will have all that into account.
You understand a lot about physics.
Huge Likeeeeeeeeeeeeeee 👍😉
the best vidoe ever for understanding Lift Dissymmetry
Or you can say; "advancing and retreating blades!" The advancing blades will have more downward flow, than the retreating blades. This is the "rotor disk," area. This is caused by the tilting angle of the swashplate. In any direction of the cyclic lever, or handle for directional control.
I’m a new CFI and would like to use a video like this for teaching.
Would it be possible to get a video made with only one of the helicopters that you presented here?
Specifically looking for a Copter with three blades, rotating right-side back. Fenestron tail rotor. (Guimbal Cabri G2)
contact me with details.
Don't undersand how the helicopter will roll sidewards. Due to gyroscopic precession, shouldn't it roll backwards?
The stall starts at retreating blade side the effect of G Precession is felt 90° from stall in direction of wing travel being aft torque from the RBS causes roll to that side G Precession cause torque down aft causing the front to pitch up during the RBS roll.
It was the spanish Juan De La Cierva who came up with the solution to the problem when he invented the autogiro by putting hinges in the rotorhead.
But if the retreating blade flaps down too much, the angle of attack can surpass the stall angle and caused retreating blade stall. So the helicopter must fly slow enough that the forward motion does not cancel out the lift from the retreating half of the rotor disc.
If you are flying forward, then the retreating blade is flapping UP, so that the overall disc is tilted forwards. The cyclic has been moved forwards to stop the flapback. There is no "flapping to equality" in forward flight. Yes, if you go fast enough, or are heavy enough, or are high enough, the stall angle will be reached, but remember that the inner part of the retreating blade is stalled anyway.
Awesome work
And thanking you for such a great understanding video
I'm curious to know if this problem of lift dissymmetry is automatically cancelled out in helicopters with counter rotating rotor blades.
Yes
Disymmetry of lift creates inflow roll which is overcome by flapping to equality
Umm...no. Inflow roll is caused by the inflow (at speed) at the rear being higher than at the front. Flapping to equality only happens at low speeds, with the cyclic held fixed, and soon fixes itself by crashing the aircraft.
Fucking great video mate
Yeah i watched it twice and, great video 😬
Thanks, it was perfect
It will pitch not roll... because gyroscopic precession affect.
No, not to aerodynamics
Thank you a lot
What if wind is not horizontal but inclined?
Thank you
What if the wings are not shaking
Awsome!
Great work!
Good job..problem is only 13 of us get it. Oh well. Heli most amazing piece of machinery
Cool
Google Bo-105 rotor head. It's rigid. No flapping.
You did not explain how it is done.
Yes he did. But if you want the mechanism that allows it it’s the swashplate.
Machines that shouldn't fly... Has to fix every law of motion and aerodynamics
G-d bless
I hate robot voice overs…. Everyones trying to do TH-cam automation
Horrible. It’s not explained properly. Plus, the robot voice and music are disgusting
.
Way over my head