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•The factory uses this to come up with the auto rotation airspeeds R22/R44 60-70 kts (65 kts is what we teach as it’s the center of that range)

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•What the factory did is they took the 3 sources of energy (see the autorotation slide for more detail) and back figured it to the amount of horse power for how many seconds they need to be able to get you safely back down to the ground.

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•But you actually need more  energy than this as coasting back down to the ground is not enough….as we need enough energy to stop our decent so that we don’t just pile into the ground.

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•Consider now the 65kts of speed as you start to flare you are requiring less and less energy for a short period of time. So while you are trading the forward airspeed for more lift (higher angle of attack)  you are actually requiring less lift to sustain your autorotation. So what is the extra energy used for? TO STOP YOUR DECENT

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•Now  consider an airspeed of 45kts as you start to flare you are requiring MORE and MORE energy. So while you are trading the forward airspeed for more lift (higher angle of attack)  you are actually requiring MORE lift to sustain your autorotation. So the question becomes where do you get the energy to stop your decent? The Answer is you will not fully stop your decent with that amount of airspeed….in other words you are going to hit the ground hard

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•Being on the front side of the power curve is critical to the survival of the aircraft (and your survival as well).

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•If you cant get to the front side of the power curve by time you go to flare get as much airspeed as you can flare as hard as you can and as low as you safely can and keep it level and pull collective

 

•The helicopter is designed to absorb the impact. In Robinson the skids are designed to spread and the seats are designed to collapse ….but since helicopters are expensive we would prefer if you learned about the power curve, stay on the front side when going into the flare and you not only walk away but the helicopter survives to fly another day

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•Who knew all that was in the total drag curve….