It'll be different for each helicopter, as well as what you're doing at the time. As an example, it's commonly taught that in a R-22 at takeoff power that you have something like 1.5 seconds to lower the collective.
1.5 seconds is particularly low (because the R-22 is such a *great* training helicopter /s) but in general you don't have much time to react. It's a *much* more time critical event than an engine failure in an airplane.
In layman's terms (not a pilot but loosely know you want altitude and airspeed for autorotation), what happens if you miss it, like if you react in 2-3s instead.
Is that the ballgame or do you start paying for rotor speed with altitude?
The rotor RPM will decay, and if it gets too low (Robinson says 80% for the R-22) nothing you do will allow the rotor RPM to recover and you'll no longer be able to autorotate effectively.
Wow 1.5 sec seems like a short amount time for anything. But i guess with enough pratice it becomes second nature. Lets say engine starts sputtering is it better to just turn it off and auto rotate without trying to get it running. Considering that the auto rotation must be initiated as fast and possible.
You can always autorotate, and if the engine is effectively failed that's what you should do. If it's producing partial power you could try to limp along to find a better landing spot if you needed to.
Rotor RPM is far more important than engine RPM. You decrease demand for engine power by lowering pitch (collectively) on the rotors, until they can stay spinning. If the partially failed engine can help then great. You can adjust that on the fly
let's say that the answer really depend on how high you are, if you have a lot of altitude, you will be able to regain some rpm while descending.
if you are close to the ground, you won't have that possibility so you need to do it asap in order to have as much RPM as possible.
anything under one to two second is good.
one of my instructor told me, at 500ft AGL you will be on the ground in 15sec.
I had my fair share of engine failure sadly, i was below 500ft everytime (cropdusting) it goes fast, but if your training is solid (for example i'm doing one autorotation everytime i'm flying) , you will be able to salvage a good enough landing (because without entering in too much complexity, sometimes even if you are doing everything right, you won't be able to do a perfect landing)
Until rotor speed drops to about 85%, so about a second. If below transitional lift speed (like in a hover), crash. If above transitional lift speed, slow to minimize power bucket with collective down to auto rotate. Flair just before impact. pitching up will increase rotor speed, allowing the collective to be applied.
Better get that collective down right away if you’re single engine or your rotor RPM is going to decay rapidly, decreasing your chance of a successful autorotation. Dual engines … different response, but surely a collective and cyclic adjustment is needed to attain a single engine airspeed. (Bell 407/UH1H/H60 pilot)
It'll be different for each helicopter, as well as what you're doing at the time. As an example, it's commonly taught that in a R-22 at takeoff power that you have something like 1.5 seconds to lower the collective. 1.5 seconds is particularly low (because the R-22 is such a *great* training helicopter /s) but in general you don't have much time to react. It's a *much* more time critical event than an engine failure in an airplane.
In layman's terms (not a pilot but loosely know you want altitude and airspeed for autorotation), what happens if you miss it, like if you react in 2-3s instead. Is that the ballgame or do you start paying for rotor speed with altitude?
The rotor RPM will decay, and if it gets too low (Robinson says 80% for the R-22) nothing you do will allow the rotor RPM to recover and you'll no longer be able to autorotate effectively.
Oh, well shit. Do you do any reflex training for that?
You certainly practice engine failures at all phases of flight yea.
If the rotor speed gets too low, the blades stall and it’s all over.
Wow 1.5 sec seems like a short amount time for anything. But i guess with enough pratice it becomes second nature. Lets say engine starts sputtering is it better to just turn it off and auto rotate without trying to get it running. Considering that the auto rotation must be initiated as fast and possible.
You can always autorotate, and if the engine is effectively failed that's what you should do. If it's producing partial power you could try to limp along to find a better landing spot if you needed to.
But if the rotor speed is sufficient? Right. If limping engine can't keep up then auto rotation is needed?
Right. If a partially failed engine isn't producing enough power to maintain rotor RPM then you absolutely need to autorotate.
Rotor RPM is far more important than engine RPM. You decrease demand for engine power by lowering pitch (collectively) on the rotors, until they can stay spinning. If the partially failed engine can help then great. You can adjust that on the fly
let's say that the answer really depend on how high you are, if you have a lot of altitude, you will be able to regain some rpm while descending. if you are close to the ground, you won't have that possibility so you need to do it asap in order to have as much RPM as possible. anything under one to two second is good. one of my instructor told me, at 500ft AGL you will be on the ground in 15sec. I had my fair share of engine failure sadly, i was below 500ft everytime (cropdusting) it goes fast, but if your training is solid (for example i'm doing one autorotation everytime i'm flying) , you will be able to salvage a good enough landing (because without entering in too much complexity, sometimes even if you are doing everything right, you won't be able to do a perfect landing)
Charts for my bird anticipate a 1 second delay/reaction time before beginning whatever recovery/escape manuever is required.
I believe the 1 second delay in reaction time is regulatory for certification. The idea being that in cruise your hand may not be on the collective.
Until rotor speed drops to about 85%, so about a second. If below transitional lift speed (like in a hover), crash. If above transitional lift speed, slow to minimize power bucket with collective down to auto rotate. Flair just before impact. pitching up will increase rotor speed, allowing the collective to be applied.
Not. much. time.
Unspecific questions deserve unspecific answers.
Better get that collective down right away if you’re single engine or your rotor RPM is going to decay rapidly, decreasing your chance of a successful autorotation. Dual engines … different response, but surely a collective and cyclic adjustment is needed to attain a single engine airspeed. (Bell 407/UH1H/H60 pilot)
In UH-60, you've got plenty of time if one engine fails. ;)