Helicopter damper

[brightspark]

its facts read it

 

[Tinbasherdan]

https://www.hse.gov.uk/research/misc/helicoptersafety.pdf

Seems to me, on a skim read to be a report on the likelihood of a heli ditching, not the survivability

 

[Maker]

One on left is how it is, on right one I have dissected it allows the blade to lead and lag..

Why do the blades need to lead and lag? I'd have thought they'd be rigidly fixed to the "hub".

 

[Parm]

Why do the blades need to lead and lag? I'd have thought they'd be rigidly fixed to the "hub".

Is that not what gives it lift?

An expert will be along soon

 

[brightspark]

because the leading blade is traveling through the air faster than the the lagging blade.ones going forward while the other is going backwards while rotating even though they are both creating lift

 

[AVI_8]

Is that not what gives it lift?

An expert will be along soon

Angle of attack gives lift, controlled by the collective

What is lead-lag? - Helicopter Study Guide

Lead-lag or leading and lagging is the horizontal movement of the rotor blades forwards and backwards along a vertical hinge.

www.thehelicopterstudyguide.com

 

[Tinbasherdan]

The way I understand it, it’s to do with the inherent “flapping motion” of the blades, as a blade rises it’s centre of mass edges closer to the mast, causing the blade to accelerate akin to an ice skater pulling their arms in to accelerate a spin. Again I’m no heli mech so I could be completely wrong

 

[500e]

#26
There are a few ridged rotor heads

 

[AVI_8]

All that's holding a CFM56 engine onto the wing of a 737 are 8 relatively small bolts. I've got a couple u/s ones, I'll take a photo.

Thankfully they’re not known for departing the wing as they’re my working donkeys

 

[cardiffrob]

The blades are angled (coned) upwards slightly due to them having to lift the Heli. The 'retreating' blade, when fly forwards, is not flying through the airstream as fast as the other side, which is rotating at the same speed but also being driven forwards in the same direction as the Heli. The retreating blade thus is more able to be centrifuged outwards. This means the rettreating blade also lowers more perpendicular to the rotor shaft, thus flopping downwards.
I started my ATPL(H) course with Bristows in about 1990 where I was able to watch an Autorotating landing by a Robinson 22 Heli that rolled over and chopped itself into 1000 pieces. I moved onto fixed-wing after that!
I recently managed an S61 Heli Sim (Circa £10M) that was built from the wreck of a crashed Heli that fell from the BNrent Spar rig and was later recovered. Those that survived the impact with the water drowned. With engines in the roof, along with the heavy gearbox and rotors, it is most likely to roll quickly over. This is why the invented those scary dunk tanks for the Oilies to train in.

 

[cardiffrob]

My employer moved some RB211 engines on their shiny new 10 ton overhead hoist. Turns out the bolts on the engine cradle were just cheap Grade 5 'shipping' bolts and not the ones needed to lift it. I had to give a quick lesson in reading the markings on bolts to the Apprentices.

 

[Eric the chicken]

When I was working I had occasion to fly out to St Kilda, just off the Outer Hebrides on a couple of times. I noted that whilst we, the passengers were obliged to wear survival suits the pilot just wore his normal flying overalls. Maybe he'd come to terms with the survival statistics.

 

[mtt.tr]

i couldn't imagine lasting long in the north sea

 

[CompoSimmonite]

no your not. if the engine fails you can disengage the rotor and come down and feather the blades and land ok .its standard practice every year was in my mates copter when he did one just tough **** if your over the sea

I once saw a heli fall out of the sky and was about to call 999 when it recovered. This happened a couple more times and was told it was a military training area and they were practicing auto rotation. Still shocking to see as the rate of fall was quite fast

 

[James1979]

I once saw a heli fall out of the sky and was about to call 999 when it recovered. This happened a couple more times and was told it was a military training area and they were practicing auto rotation. Still shocking to see as the rate of fall was quite fast

Got a couple of friends in the industry one of whom is a pilot. I’m sure he said they used to do this on an annual check flight but nowadays it’s every year on a sim and then every other in an aircraft.

Either way he doesn’t look forward to it.

 

[CompoSimmonite]

Nothing to do with that but helicopters reminds me , They call the nut holding the rotor on the "Jesus Nut" as if it fails the only thing that can save you is jesus

I think the same would apply to a weight shift hang glider

 

[slim_boy_fat]

Well, this thread took a cheery turn quite quickly.....

 

[bourbon]

I once saw a heli fall out of the sky and was about to call 999 when it recovered. This happened a couple more times and was told it was a military training area and they were practicing auto rotation. Still shocking to see as the rate of fall was quite fast

Shawbury by any chance?

 

[CompoSimmonite]

Shawbury by any chance?

Can't remember exactly where but it was middle of nowhere, I think, in York area

 

[Robotstar5]

I once saw a heli fall out of the sky and was about to call 999 when it recovered. This happened a couple more times and was told it was a military training area and they were practicing auto rotation. Still shocking to see as the rate of fall was quite fast

I saw similar at RNAS Culdrose, came in steep and fast over the perimeter fencing then flared and dropped gently onto the grass.