Thomas,
Westland is good at this game, but the TR on the 101 clearly has them buffalo'd.

That teetering design has a square cut-out where the bearing sits, so the loads pass thru a square, not exactly the best way to do it. I would guess that the real life loads are higher on that rotor than the tests performed, cracks form at the edges of the square and at least once, the rotor came apart.

The 50 hour interval is the real concern, and the Canadians just gave up wrestling with it.

I would hazard a guess that Agusta/Westland have tried to patch up the existing design bit by bit, and this has cost them the last 18 months of heartache. Sometimes it is hard for a design team to take their wonderful baby (that innovative tail rotor) and just shoot it, and start anew. In defense of the patch up philosophy, to start anew would take a minumum of 2 years for a tail rotor, if they did it with no resource limits (plenty o' money) and had good luck. Who knows but that the new tail rotor is going thru trials now?

Having been manager when such decisions are being made, I can assure you it takes guts (and money) to be truly decisive, and it is possible that this kind of decisiveness is just rarer than it should be.

I think now the EH101/US101 has been chosen as the new presidents machine the t/r problems will be fixed quick smart it may be a complete redesign as Nick said or a fix that will work, as the US Military will not accept an aircraft to carry the President with an inherant fault!
Years ago when I worked on Australian S70A-9 Blackhawks the aussie version ran a larger Xmsn and rotorbrake not fitted to the UH60A, when we had oil filter /pressure problems on our xmsn, which was the same as was going to go into the VH60 the problem was fixed quick smart.....after we had had problems with filter bypass buttons popping for 2 years!!
The 101 will be fixed ,unfortunatly the Canadians ,Danish,UK, and Italy will have to put up with it until I believe the US101 fix comes through.

Another fix situation that springs to mind....is the 76 Main Rotor head....and a couple of crashes...and at least one attempt to modify the original design that failed. At least Sikorsky was successful after they figured out what the actual problem was.

Maybe someone needs to enact an Aviation Lemon Law?

It seems that sometimes the manufacturers need to be spurred into action to resolve safety isssues that injure or kill people, and destroy equipment. The typical resolution is through the Courts, but maybe there is a more practical way.

If there was a law of this type on the books, I am quite convinced that many of the problems we have to deal with would go away permanently - and we wouldn't have to pay for the fix either! :ooh:

Northern neighbors
 

So is this the same issue?


http://news.yahoo.com/s/cpress/20051...crash_report_1

Nick, I was wondering about the development part, with computer technology, I would guess that alot of " A model problems" get identified in simulation and reworked?

Have the smart guys lost an understanding of the problems relying on computers?

Not the same...
 

Havoc:

The CH-146 in the article is a Bell 412. Though not an expert on the aircraft I believe that the t/r problems are caused by debris that dent or otherwise compromise the strength of the blades themselves.

Perhaps if Heedm is nearby he can clarify.

The Cormorant, on the other hand, is not cracking at the blade, but rather the hub sections the blades attach onto. The cause of the cracking has not been determined but is most definitely not from FOD.

Nick L mentioned the square cutouts where the cracks appeared. It's interesting to note that EHI produced and distributed a 'new' half hub that had beefed up cutouts, improved QA, and without an interior titanium plate. These new half-hubs started to crack in a completely different area, in less that 50 hours.

It was at this point that the decision was made to scale back the fleet in order to prolong the supply of 'old' half hubs and the SAR base in Trenton lost out. The good thing is that now we have 2 Bell 412s to use for SAR in our region.:sad:

7 million square kilometers to cover with a fleet of two corporate helos. Nice:mad:

havoc,

That helo link is the Canadian Military 412 that had a scratched TR blade which cracked and eventually failed, causing tail boom separation and then the crash.

It is an example of why flaw tolerance is a wise idea, but it isn't the same mode as the EH-101 problem, which Labpilot explains a bit for us.

Regarding how these things happen, it is not easy to engineer anything, and especially a helicopter. I believe computers have made things far better, by a long shot. For that, and other reasons, I believe these incidents are fewer and fewer than they used to be (there were over 75 main rotor separations in Hueys, folks!) but that is still no real explanation. I guess I could wax on about our collective inability to be perfect, but we all know that already. Most folks have their mistakes show up in a file drawer, or a mailbox, or perhaps in a courtroom. Aviation is so very unforgiving, far more so than even the Sea, and so even the minor mistakes good people make end up very badly. Is it any consolation that in the world of aviation, three accidents occur for crew error for every one that is the fault of the machine or designers? I think not, because we all share the blame when an aircraft goes in.

Labpilot, thanks for the details about the 101 TR, I am sure my friends there are working hard to fix this.

Nick,

You left out all of the Sikorksy problems. The going joke on the UH-60 and S-76 was that they had the most advanced rotors in the world because they could routinely convert from four bladed to three bladed in flight.

How many died in the 60 and 76 because of this problem?

How many have died in the EH-101 because of tail rotor cracks?

The Sultan

"How many have died...............? " asked The Sultan


You are way off base, get a life.

How many hours are on the high time EH-101 these days? What about the EH-101 fleet time today? All the advertising used to highlight the fleet hours on the EH-101, but suddenly this ceased. I wonder if it might be because the fleet hours are barely rising due to the continued grounding (sorry, limited availability ;) ) of the aircraft?

What is the current status of the EH-101 fleets with the various operators? What is the status of the of the Danish deliveries? How about availability and serviceability rates?

I find it quite remarkable how well the topic seems to be lost in the aviation press, and that no-one has the balls to go and get the real story. They are either true experts on keeping information quiet, or maybe all the journalists are part of the conspiracy? :p I mean, surely a systemic failure (and grounding, or not ;)) on an entire new fleet of helicopters is worthy of some questions and reporting?

As for the Sultan's comments. Which aircraft are you manufacturing? I would be interested to see a safety comparison on your products. I have seen some horrifying problems with a variety of helicopter types and manufacturers, and I truly doubt that you are exempt.

Norsk Passes 1,000 Flight Hours With Both Their S-92 Helicopters

October 2005 - Bergen, Norway - Norsk Helikopter has achieved another industry milestone by becoming the first S-92 operator in the world to reach 1,000 fleet hours on both their S-92 helicopters. The aircraft was made by Sikorsky, a United Technologies Corp (NYSE: UTX) company.

As recently as this past June, Norsk celebrated the achievement of reaching 1,000 flight hours on both their S-92 helicopters, transporting more than 20,000 passengers to and from North Sea oil fields in the process.

Norsk's two S-92 helicopters began revenue service in February and March 2005.

"The overall performance of the S-92 has been in accordance to the high expectations we and our customer had for this new generation aircraft. We are pleased to have reached 1,000 hours on our first two S-92s, and we expect that the average annual utilization of our S-92s will be more than 2,000 hours per helicopter the first year of operation," said Geir Tynning, Norsk's Commercial Director.

"Norsk's achievement of 1,000 flight hours with just one of their aircraft demonstrates the confidence that Norsk places in the S-92. Its robust design, new technology and demonstrated reliability have made the S-92 more than ready to meet the demanding needs of our Norwegian offshore oil customers," said Jeff Pino, Sikorsky's Senior Vice President for Corporate Strategy and Commercial Programs.

Norsk's two S-92 helicopters are used by Statoil for crew change missions from Bergen, Norway, throughout the North Sea area. They replaced two AS332 Super Pumas.

In addition to these milestone fleet hour achievements, Norsk was the first offshore oil S-92 operator in Europe, making its maiden revenue flight at 7:30 am on 21 February.

The S-92 is the first helicopter in the world certified by the European Aviation Safety Agency/Joint Aviation Authorities (EASA/JAA) to the latest and most rigorous safety standards. The S-92 was also the first helicopter certified by the FAA to FAR Part 29 Transport Rotorcraft, Amendment 47, the latest US safety regulations, which mirror the European standards.

What a load of ******s***t
 

All this backward and forward backbiting and sniping will never disguise the fact that history shows us that a helicopter can be like a fine wine. With time and care it will mature into something worthy of true greatness. The only question is 'how long'; and will the right degree of care (read financial support) will be available?

There is nothing to touch the 101 in its class but whether it will ever reach its full potential remains to be seen. The concept seems to be pretty future-proof if the problems can be resolved.

The S92 is made by the people that built the dear old S61, a machine that is capable of being re-born if only it gets the support required. I can't believe that they (Sikorsky) can be a long way from a winning formula - but its in a different class from the 101. I see the US president agrees with me. (oh dear!..... maybe that's not much of a recommendation????????) Still, poor jokes aside, can we please stop this juvenile much-chuckin' and get back to some professional quality feedback.

This thread has seen some enlightening technical stuff coming to light - lets keep it to that level guys, please!

:ok:

Geoffersincornwall

As the former Program Manager for the S-92, I have to agree that this is an EH-101 thread and not the place for chest-beating about other machines, even those ostensibly "better"! (Can't agree with some of the rest, but that is subject to someone forming another thread!)

I did hear that the US was re-commissioning the crash test rig at NASA Langley so that the fully redesigned fuselage of the US EH-101 could be crash tested, since the current version falls far short of US military crashworthiness. The new fuselage is said to have virtually every frame stiffened to meet the full 20 g's, vice the 8 to 15 the EH-101 now has.

Nick
 

Thanks for heading things back in the right direction.

You will be amused to learn that many years ago when the 101 had its maiden flight a story circulated that as CH pulled into the hover for the first time the left pedal went smack against the stop and a muffled "oh f**k!!" came from the RHS. The stuff legends are made of but given the subsequent history it makes the hair on the back of your neck stand up.

One of the other wonderful stories circulated at the time was that it was the secretary that typed the fax inviting the press to the 'launch' party that actually christened the new helicopter.

It was meant to be called the EHI-01 after the consortium that builds it but a typo meant that it became the EH-101. True or not - it's a good tale.


G

:)

Eh 101
 

Hi,

Can anyone point me in the right direction to find some info on the EH 101 blade tip design, B.E.R.P., I believe it's called?

Googled and asked Jeeves without much luck.

Also, if there's any information available regarding the US Navy's research into airfoils designed with uneven leading edges, based on hump-backed whales fin shapes (mentioned in Rotor & Wing a few months back), I'd be very interested to read it.

Thanks

Re: Eh 101
 

If you run through Google 'westland BERP' you will get a number of results [including ... http://www.whl.co.uk/history_timeline4.cfm ] that refer to the BERP being developed and introduced.

Were you perhaps after tecnical material? That I would expect to be commercial confidential even now.

The Putnam book on Westland by Derek N James has a fair bit on the BERP but again lots of images, general references and a timeline but no hard and fast technical stuff to speak of.

Re: Eh 101
 

For BERP, try this for starters.

Re: the 'knee'd' aerofoil studies, I remember seeing something back in the 1994/5 timeframe but will need to have a dig around.

I/C

Re: Eh 101
 

Thanks guys, appreciate the info :ok:

I wasn't looking for anything overly technical, I was just interested in reading about the basic aerodynamics and engineering, purely personal curiousity. So of course pprune is the best place to find out!

RAF Merlin
 

Can the Merlin helicopter fly upside down like the Apache? Can any other RAF helicopters?

The Puma did it or a while...........then the grown up's (one now a Wg Cdr and one a Gp Capt............pair of strokers:}) found out and boy did the sh!t hit the fan:p

all spelling mistakes are "df" alcohol induced

Only once...... (well almost only once).:\