For the rotary wing pilots

[Screamtruth]

Alright, I am a frequent flyer on helos.....We use PHI for all of our transportation to and from the offshore rigs in the gulf of Mexico. I was talking with one of the S92 pilots and asking him about auto rotation. I do not understand the whole concept behind this. I mean, if you loose engine power, what keeps those wings a spinning? Is it the inertia of the blades themselves or what? We are feet wet for almost 120 nM until we hit the rig, so I was wondering how effective would the auto rotation be, just in case, you know.

 

[gregsivers]

It didn't make any sense to me until I learned about it in aero class. When we do it here in the training command we immediately put the collective down, which preserves the rotor RPM. In normal flight the flow of air goes down thru the rotor blades, while in autorotative flight its reversed and going up. While descending to the ground you're building up the rotor RPM to stop the descent just before touchdown. You pull up on the collective just before hitting the ground, and all the built up rotor RPM turns into enough lift to allow you to stop the descent and settle to the deck. It would be better than just dropping and crashing into the water. I'm sure someone else can explain it in more detail, but thats the gist of it.

By autoing to the water, you'd be able to let the helo settle into the water more gently than just crashing into it, which might allow you to egress before it sinks.

 

[Screamtruth]

That makes sense. We have had a few birds go down this past year or so. One of which was an S92, I think. It is still a fairly new bird, kind of looks like a 53, but has cabin class type seating, but I think there are still a few kinks in the bird. We had one blow an engine last week and was disabled on the rig; they had to replace the engine of the pad of the platform. Not ideal I would think.

 

[HH-60H]

gregsivers is absolutely correct.
To put it a little more simply:
helo falls, wind turns propeller thingy, generates small amount of lift, slows helo fall, near ground inertia of propeller thingy helps helo land softly.

 

[Screamtruth]

gregsivers is absolutely correct.
To put it a little more simply:
helo falls, wind turns propeller thingy, generates small amount of lift, slows helo fall, near ground inertia of propeller thingy helps helo land softly.

I know I was a grunt, but do you have to make it so painfully obvious? LOL :icon_smil

 

[petescheu]

By autoing to the water, you'd be able to let the helo settle into the water more gently than just crashing into it, which might allow you to egress before it sinks.

Love that helo dunker... not.

 

[gregsivers]

gregsivers is absolutely correct.
To put it a little more simply:
helo falls, wind turns propeller thingy, generates small amount of lift, slows helo fall, near ground inertia of propeller thingy helps helo land softly.

Thats what I was trying to get at, but that whole blade element diagram thing is still in my head, I'm not too long out of fams.

 

[phrogpilot73]

Thats what I was trying to get at, but that whole blade element diagram thing is still in my head, I'm not too long out of fams.

Blade element, huh? Don't remember much of that...

 

[petescheu]

By autoing to the water, you'd be able to let the helo settle into the water more gently than just crashing into it, which might allow you to egress before it sinks.

Love that helo dunker... not.

 

[gregsivers]

Love that helo dunker... not.

Oh come on I had fun. You know deep down inside you did too.

 

[HH-60H]

Oh come on I had fun. You know deep down inside you did too.

It's even better the second time.

 

[Chubby]

It's even better the second time.

Everything is better with wings. Or so I'm told.

 

[HH-60H]

Well, it's better and worse.
The 2nd dunker time all 4 rides are blindfolded, but you get to use HABD on the last 2.

 

[ChunksJR]

The Helo goes up and down....and around...it's circular...circular.

The easiest way I've ever heard it explained is putting a fan in a window...then shutting off the fan. On a breezy day, the fan will continue turning as the air flow hits the blades causing just the slightest amount of wind (lift) and "autorotation."

~D

 

[Screamtruth]

We have to do the tank every 2 years as well. Blindfolded, or rather blanked out goggles and all. Did it in the Corps as well, so now it is just an annoyance.