Sikorsky S92 question

dermabrasion

Does anyone know if the S92 is rated to land (or can be rated) on an elevated platform such as a rooftop landing pad?
My understanding that it is not rated to land on an elevated platform, but I see that it operates for companies servicing oil-rigs, which I assume have elevated platforms.
Thanks

arubex

Off-shore ( rig & ship ) platform certification is a different category to that in populated zones.

On land, as far as I know the S-92 is only cleared for ground-level pads in populated zones. Of course if this is an operational question you'd be best to speak to a Sikorsky rep.

Chuck Aaron

The question is "is said elevated platform (3m above ground) able to take a Performance Class A (greater than 20,000 lbs) aircraft landing?" And not the other way around "can an S-92 land on an elevated platform".

A quick look in the Rotorcraft Flight Manual for the actual weight of the aircraft AUW and theN use iFly to calculate M&B.

If the platform can take the weight then grand job.

To make life that little bit easier there's Sikorsky's "Rig Approach" system, which is an offshore platform approach system for S-92's which when in place is a fully automated arrival and departure to the elevated platform.

Hit the button and she does it herself, nifty.

Sikorsky's iFly flight calculator app, which is free by the way, will work out Mass & Balance positions for crew and cargo also the performance of the aircraft taking into account the conditions at the offshore platform on the day, life just got easier for S-92 pilots.

The Nutty M

Sorry to hijack the thread but Chuck, would you know why the s92 is left to hoover with its booty low to the ground for the first 10-15 secs of lift-off from both Aberdeen and rigs? This is Scotia specific by the ways. Its frightnening sitting at the very back lol.

Chuck Aaron

The Nutty M wrote: »

Sorry to hijack the thread but Chuck, would you know why the s92 is left to hoover with its booty low to the ground for the first 10-15 secs of lift-off from both Aberdeen and rigs? This is Scotia specific by the ways. Its frightnening sitting at the very back lol.

It's a C of G thing, 7 tanks of fuel slushing about takes its toll.

They're usually taking the 15 seconds for some inflight checks as well as it's a SOP in case of a OEI situation.

The Nutty M

The Nutty M wrote: »

Sorry to hijack the thread but Chuck, would you know why the s92 is left to hoover with its booty low to the ground for the first 10-15 secs of lift-off from both Aberdeen and rigs? This is Scotia specific by the ways. Its frightnening sitting at the very back lol.

Like this https://m.youtube.com/watch?v=Qnv9gbQlryw ?

Chucks explaination makes perfect sense really.

The Nutty M

[Deleted User] wrote: »

Like this https://m.youtube.com/watch?v=Qnv9gbQlryw ?

Chucks explaination makes perfect sense really.

Yes like that but when you are sitting there it feels like a more extreme nose up pitch.

youtheman

For a helicopter to move forward the rotor disc has to be tilted forward in flight (to blow air backwards). So if the rotor mast is vertical relative to the cabin then this will mean that the cabin is also tilted forward in forward flight (causing some extra drag). Some modern helicopters have the rotor mast tilted forward relative to the cab, so this means that in flight the cabin is level with the rotor tilted forward. The downside of this is that in the hover, with the rotor disc level, the nose of the a/c is up. Its really down to the design, do you want the cabin level in the hover or in forward flight, you can't have both.

Chuck Aaron

youtheman wrote: »

For a helicopter to move forward the rotor disc has to be tilted forward in flight (to blow air backwards). So if the rotor mast is vertical relative to the cabin then this will mean that the cabin is also tilted forward in forward flight (causing some extra drag). Some modern helicopters have the rotor mast tilted forward relative to the cab, so this means that in flight the cabin is level with the rotor tilted forward. The downside of this is that in the hover, with the rotor disc level, the nose of the a/c is up. Its really down to the design, do you want the cabin level in the hover or in forward flight, you can't have both.

I have heard of the mast tilted slightly to the left to decrease tail rotor drift, never heard of manufactures tilted forward.

Can you link to an example?

I'd take point with the"blows air backwards" when in reality the spinning of the blade acts like an aeroplane wing and forces the air over the surface of the blade and then throws the air downwards after the trailing edge of the blade to the ground.

Just sayin'

EI-DOR

For a helicopter to move forward the rotor disc has to be tilted forward in flight (to blow air backwards).

For a Helicopter to move forward the pilot has to apply power first by increasing Collective thus changing the Rotor blade angle of attack and then applying forward Cyclic to tilt the disc forward. Once the Helicopter reaches a certain speed and gets enough relative air through the Rotor system it reaches Effective Translational Lift or ETL or the sweet spot if you want to call it that.

Once the machine goes through the ETL the Pilot can actually decrease power slightly while the Rotor system remains effective!

Klunk001

The Nutty M wrote: »

Yes like that but when you are sitting there it feels like a more extreme nose up pitch.

The S-92 has its main gearbox tilted forward by 5 degrees. This causes it to sit in the hover with a noses up attitude, anything from 4 to 6 degrees.
This is offset by making the aircraft more comfortable when in the cruise with a nose level attitude.

The vertical departure you see in the youtube clip carried out by the 92 requires the aircraft to go wheel light on the ground before pulling power. This ground cushion effect greatly assists with this departure and getting you to your Take off decision point quickly

The 92 usually has 2 fuel tanks, left and right sponson. It can be equipped with 2 aux tanks.

The Nutty M

Klunk001 wrote: »

The S-92 has its main gearbox tilted forward by 5 degrees. This causes it to sit in the hover with a noses up attitude, anything from 4 to 6 degrees.
This is offset by making the aircraft more comfortable when in the cruise with a nose level attitude.

The vertical departure you see in the youtube clip carried out by the 92 requires the aircraft to go wheel light on the ground before pulling power. This ground cushion effect greatly assists with this departure and getting you to your Take off decision point quickly

The 92 usually has 2 fuel tanks, left and right sponson. It can be equipped with 2 aux tanks.

Scotia's 92s are anything but comfortable in the cruise from a passenger perspective, while it is level it is extremely vibey compared to their 225s

Klunk001

The Nutty M wrote: »

Scotia's 92s are anything but comfortable in the cruise from a passenger perspective, while it is level it is extremely vibey compared to their 225s

All 92`s are like that. It`s amazing what an extra main blade can do.
The 225 is smoother, but a lot of people just don`t want to fly in it.

Chuck Aaron

My apologies regarding the 7 fuel tanks, I've been going over Super Puma techs recently in dept and literally had brain melt and mixed up the S-92 and the 225.

Rumours are the 225's aren't as safe regarding some of the maintaince.

Interesting to hear of the MRGB tilted 5 degrees forward, surely that would tilt the nose down???

If C of G is directly under the main rotor mast, in the hover, she should hover horizontally.

If forward, in hover, she'd hover nose down.

If aft, of mast ,in hover, she'd hover tail down.

Correct?

youtheman

Chuck Aaron wrote: »

Interesting to hear of the MRGB tilted 5 degrees forward, surely that would tilt the nose down???

No. If the MRGB is tilted forwards by 5 degrees then this means that in the hover, when, by definition, the rotor disc is horizontal, the nose if 5 degrees up. In forward flight if the disc is 5 degrees nose down (at the front) then the cabin is horizontal.

The idea of titling the gear box forward is to try achieve the optimum orientation and drag of the fuselage for the cruise, at the expense of the hover position.

Klunk001

youtheman wrote: »

No. If the MRGB is tilted forwards by 5 degrees then this means that in the hover, when, by definition, the rotor disc is horizontal, the nose if 5 degrees up. In forward flight if the disc is 5 degrees nose down (at the front) then the cabin is horizontal.

The idea of titling the gear box forward is to try achieve the optimum orientation and drag of the fuselage for the cruise, at the expense of the hover position.

👍

Chuck Aaron

youtheman wrote: »

No. If the MRGB is tilted forwards by 5 degrees then this means that in the hover, when, by definition, the rotor disc is horizontal, the nose if 5 degrees up. In forward flight if the disc is 5 degrees nose down (at the front) then the cabin is horizontal.

The idea of titling the gear box forward is to try achieve the optimum orientation and drag of the fuselage for the cruise, at the expense of the hover position.

Well put sir!

The Nutty M

Klunk001 wrote: »

All 92`s are like that. It`s amazing what an extra main blade can do.
The 225 is smoother, but a lot of people just don`t want to fly in it.

True, the older generation seem to be more vocal on their hatred of the 225's but Step Change is making headway in changing that view a little bit. The younger generation by all means give out too but I've never yet seen anybody refuse to board a flight when we find out its a 225 before the briefing.

Psychlops

https://www.boards.ie/discussion/comment/94207652#Comment_94207652

Wrong, its a standard bounce into ground effect, they hover
the helicopter then drop her low before applying power & departing,
what happens is rotorwash at the lower height coupled with the cantered
blades gives extra lift. On the way up a certain power is applied &
the aircraft will lift vertically to a
height that allows safe flight away from obstacles, & in the event
of an engine failure before forward flight the aircraft would land back
on the pad/ground safely, & if the same happened when forward flight
is achieved the aircraft would safely fly away. This is used in
helicopter sites that are near big buildings/confined areas for safe
operations to the aircraft & the people or buildings around the
site.