"I hear some rumours about a fire in an S-92"

Sikorsky seem to have catered for every luxury with that aircraft!

Is the large bay at the rear where they keep the logs? ;)

Nick / HeliComparator,

Thanks for the explanations:

"The vibe system on the S-92 ... solid state electric motors with extreme precision rpm control ..."
&
"EC225 ... more like a loudspeaker voicecoil"

On rereading these, i'm slighly puzzled as to the location of the force-generators. Are these located near the rotor hub or on the floor? I'm puzzled since i would have though that the nearer the accelerometer to the motor, the better the feedback to counter the vibration (unless it is a predictive system).

I still find myself slightly puzzled why the gearbox does not use compliance control mounting (hydromounts allow critical damping for ideal 2nd order HF roll-off). Using aerodynamic convention the ideal for a "rigid" rotor would be:

X & Y - soft to reduce fore/aft and side/side rotor vibration input.
Z - stiff to allow fast collective response
RX & RY - stiff to allow fast cyclic response
RZ - soft to decouple engine torque fluctuations from cab.

This is achievable by using 3 hydromounts around powertrain that are soft in X & Y and stiff in Z. The difficulty is that the engine(s) would ideally be rigid to the gearbox, requiring a seperate subframe, hence some additional mass. In practice the stiff RX mounting would reduce torsional flex for an isolated installation.

The "stiff" direction magnitude could still be chosen to allow isolation below the airframe 1st bending eigenmode frequency. These mounts are then the ideal position for the force-generators, whether linear or rotary motor...

Mart

Graviman

Steady - you're getting a bit technical here for us mortal pilots. However I think that what you are describing as "compliance control mounting" is more like what is fitted to the EH101 family - ie active struts attaching the transmission to the airframe. This is a reasonably elegant solution as it removes the vibration before it reaches the airframe, but is not a simple (hence cheap or light) solution as these same struts carry all the lifting forces for the airframe, plus as you say there are problems with the interface between airframe and transmission eg flight control pushrods and engines. Someone flying these beasts might tell us more.

In comparison, the active vib systems on the 92 and 225 are relatively simple in that there are no dire consequences of failure modes, and certainly in the case of the 225 its just the icing on the cake as its already a smooth aircraft.

Generally the actuators are mounted on the cabin walls, and of course the anti-vibe effect is fairly localised. Not sure where the accelerometers are, but surely they shouldn't be right next to the generators because they are predictive - the great advantage of helicopter is that the rotor rpm is (hopefully) constant, and the flight regime changes relatively slowly - and if they are some way away from the generators that is likely to increase the sphere of vibration reduction.

Better stop now 'cause you can tell I barely know what I am talking about!

HC

S 92 Fire?

Anyone got info on the cause of fire in one of PHI`s S92`s??
Rumours says it happened during ground run.

Rotorbrake perhaps? Wouldn't be the first and certainly not the last!

HC; you are too modest! Hope the 225 is going well :ok:

HeliComparator,

"Steady - you're getting a bit technical here for us mortal pilots."

Hehehe, sorry 'bout dat. I live in awe of you folks who not only routinely fly these amazing machine, but somehow manage to make 'em pay! I have to join the computer dots, and simulate dynamics for my dinner.

"Better stop now 'cause you can tell I barely know what I am talking about!"

Hehehe, the answers are much appreciated and well noted. I will read up on the EH101 active mounting system. In automotive applications Lotus did some work on predictive algorithms for sound/vibration absorption. I'll have a root around for some info on this, but the acc position would be less critical.

I am singularly impressed with heli pilots, since they always seem to have a good understanding of the mechanics of their flying machine. I think you have demonstated this point nicely... :ok:

Mart

PHI S92
 

During a maintenance run, a hydraulic line had a pin hole leak, fluid atomized and caught fire.

Not offical by no means.

PHI S92 fire
 

I kind of hoped it was the rotorbrake...

Engine anti ice wire chaffed thru, subsequently arced to a hydraulic line causing a pinhole and igniting the fire.

Bargain! Just what you need when in IMC at FL90!

after all those years ... respite from the constant Merlin moans at last!

Nice new Heliliner anyone?

:p

Sikorsky not having a very good time at the moment with the S92 problems, the S76 losing part of a blade in the Southern N Sea killing crew and pax and the recent Baltic S76 crash.

332M

it has not been a picnic for eurochopper , some high profile accidents with EC120's recently.

I heard about the pictures of the PHI Hydraulic line fire...

It was very small, and apparently the aircraft looks very "ugly" with the firefighting material they sprayed on.

You have to remember EVERY new helicopter has teething problems.

Look at the S-76; it was PLAGUED with problems, engine fires, engine explosions

Now take a look at the S-76... you can't touch it! It's one of the best selling helicopters, and in 2004 Sikorsky sold the most S-76's then ever!

Let the S-92's teething problems play out... in 30 years you'll be wondering why Sikorsky wants to replace such a good working machine. :ok:

Imagine a dark stormy winter night in the north sea with 60 kts+ of wind and 10m waves,and a "teething problem" like a small hydraulic line fire or loss of main gearbox lubrication pressure...

Shell Brunei orders three S-92's
 

Good choice. Overshadows the purchase announced the same day, that EGAC has also ordered one! Nice work there.

Brunei Shell Petroleum Purchases Three S-92s


SERIA, Brunei, Sept. 14 /PRNewswire-FirstCall/ -- Sikorsky Aircraft announced today that Brunei Shell Petroleum (BSP) has contracted to buy three S-92 helicopters for offshore oil service.
With this contract, BSP becomes the first oil company in Asia to select the S-92 for fleet operations. BSP and Sikorsky announced the deal in a signing ceremony here today at the Oil and Gas Discovery Centre before an audience of government officials, BSP representatives and other guests.
"We're confident that the S-92 will provide BSP excellent performance, reliability, and safety operating in the challenging offshore environment of the South China Sea," said Pete Saloomey, Sikorsky's Regional Executive for Asia.
Sikorsky and BSP have a business relationship that dates back to 1967 when the company put into service its first S-61N for offshore oil service. Since then BSP has accumulated more than 139,000 flight hours with its S-61N fleet.
"With the S-92, Brunei Shell has selected an aircraft that will build upon the S-61's legacy," Saloomey said. "On behalf of Sikorsky Aircraft, I'd like to thank BSP for selecting the S-92 for this vital mission and demonstrating continued confidence in our company and this great aircraft."
Since first deliveries began in 2004, the S-92 has quickly made its mark in the offshore oil industry. S-92s are currently providing offshore revenue service for four operators in the North Sea, the Gulf of Mexico, and off Nova Scotia, Canada, with more than 4,500 fleet hours combined.
The S-92 helicopter was the first rotorcraft in the world certified by the FAA to FAR Part 29 Transport Rotorcraft, Amendment 47, the latest US safety regulations, as well as the equivalent European Aviation Safety Agency/Joint
Aviation Authorities (EASA/JAA) standards.
Sikorsky Aircraft Corporation, based in Stratford, Conn., is a world leader in helicopter design, manufacturing and service. Sikorsky is a subsidiary of United Technologies Corporation (NYSE: UTX), of Hartford, Conn., which provides a broad range of high-technology products and support services to the aerospace and building systems industries.


Eastern General Aviation to Purchase One Sikorsky S-92 Offshore Oil Helicopter


SHANGHAI, China, Sept. 15 /PRNewswire-FirstCall/ -- Eastern General Aviation Corporation (EGAC) has agreed to purchase one Sikorsky S-92 helicopter to serve offshore oil support missions in the Bohai Bay area. Delivery is anticipated in late 2006.

EGAC, a subsidiary of China Eastern Air Holding Company, signed the agreement today with Sikorsky. This S-92 is configured to carry 19 passengers and two crew.
"The S-92 has quickly become the aircraft of choice in the offshore oil market worldwide and we are happy to add EGAC to the growing list of customers for this aircraft," said Stephen Estill, Sikorsky's Vice President for Worldwide Sales.
"Sikorsky helicopters are proven to be the best offshore helicopters and we are adding this S-92 to complement the two S-76C++ helicopters we just ordered a month ago," said Mr. LI Jianmin, President of EGAC.

EGAC is one of the three largest offshore helicopter operators in China and the one with the longest operating history. Based in Tianjin, China, EGAC has been supporting oil companies in northern China, especially in the Bohai Bay area, for the past 20 years.

Sikorsky Aircraft Corporation, based in Stratford, Conn., is a world leader in helicopter design, manufacturing and service. Sikorsky is a subsidiary of United Technologies Corporation (NYSE: UTX), of Hartford, Conn., which provides a broad range of high-technology products and support services to the aerospace and building systems industries.

Reading this in the Schipol SIA lounge en-route Brunei. Should be fun!:ok:

More news here:

http://www.brudirect.com/DailyInfo/N...905/nite05.htm

Good news.
Good decision.
Wish I was still there.
Good luck to all in SAV.

Good luck 212man!!Keep us up to date!

S 92`s grounded again
 

-Both Norsk 92`s grounded due to cracks in mr dampers
-2 of CHC HS 92`s, one with due to cracks in mr dampers and on the other the suport strut for the horizontal stab is broken off. due to lack of spare parts its been grounded allmost a week, same aircraft was in the hangar for a month due to a avc generator broke loose waiting for repair solution from Sikorsky.

Puma pilots flying their butts off...