Sikorsky S-92: Operations
Design Nit Picking
HC,
Hiding behind the " Waffle " term to express displeasure with a non Eurocopter design just leads to endless debate regarding design choices that individual OEM's make based upon their own trade-offs.
Thus we have such differences as a wider landing gear tread on the S-92 for easier taxi and resistance to rollover. Fairly significant larger flapping hinge offset which results in higher hinge moment, thus a better slope landing capability and higher main rotor control power ( slightly higher gust sensitivity but that is easily handled by the AFCS) for better manuevering. And the differences go on. I notice the newest AW machine looks like it has a canted tail rotor-I bet that decision came after some interesting internal meetings at AW. Some are hardly esoteric, as in what the president of the company likes!
At the 1991 Paris Airshow Guy Dabadie gave Nick Lappos and I demo rides in the prototype Super Puma MkII and I gave him and extended ride in a new UH-60 ( had to make up for the two rides he gave us ). Nick and I were very impressed with what Eurocopter had come up with and I know that Guy was similarly impressed with the Blackhawk. Different machines with different basic missions, but one could still evaluate the underlying technology, and the different design choices. ( Suffice to say we didn't see anywhere near 193 KIAS or +3.5 G in the Puma but Guy certainly did in the Hawk. I had an old fashioned G-meter installed in the blank space below the blade de-ice panel. ).
After the flight I asked Guy what he thought of the Hawk and he said " C'est formidable". That about sums up our report on his new Super Puma as well.
Thanks,
John Dixson
Hiding behind the " Waffle " term to express displeasure with a non Eurocopter design just leads to endless debate regarding design choices that individual OEM's make based upon their own trade-offs.
Thus we have such differences as a wider landing gear tread on the S-92 for easier taxi and resistance to rollover. Fairly significant larger flapping hinge offset which results in higher hinge moment, thus a better slope landing capability and higher main rotor control power ( slightly higher gust sensitivity but that is easily handled by the AFCS) for better manuevering. And the differences go on. I notice the newest AW machine looks like it has a canted tail rotor-I bet that decision came after some interesting internal meetings at AW. Some are hardly esoteric, as in what the president of the company likes!
At the 1991 Paris Airshow Guy Dabadie gave Nick Lappos and I demo rides in the prototype Super Puma MkII and I gave him and extended ride in a new UH-60 ( had to make up for the two rides he gave us ). Nick and I were very impressed with what Eurocopter had come up with and I know that Guy was similarly impressed with the Blackhawk. Different machines with different basic missions, but one could still evaluate the underlying technology, and the different design choices. ( Suffice to say we didn't see anywhere near 193 KIAS or +3.5 G in the Puma but Guy certainly did in the Hawk. I had an old fashioned G-meter installed in the blank space below the blade de-ice panel. ).
After the flight I asked Guy what he thought of the Hawk and he said " C'est formidable". That about sums up our report on his new Super Puma as well.
Thanks,
John Dixson
Last edited by JohnDixson; 20th Nov 2011 at 16:39. Reason: Added typo correction
I want to meet the Design Team that can make the "perfect" helicopter.
There are very successful machines out there built by many different teams...all who have different but successful design philosophies.
The one thing they all have in common are sorry excuses for Pilot Seats.
The seat in my old Ford pickup with over 300,000 miles on it....beat the hell out any helicopter seat I ever sat upon....even if brand new.
There are very successful machines out there built by many different teams...all who have different but successful design philosophies.
The one thing they all have in common are sorry excuses for Pilot Seats.
The seat in my old Ford pickup with over 300,000 miles on it....beat the hell out any helicopter seat I ever sat upon....even if brand new.
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Sikorsky Seats
The famous cartoon of a helicopter pilot at work in the cockpit shows the seat manufacturer's data plate. It says.
That anecdote says it all.
G,
THE ACME SCREEN DOOR AND WINDOW COMPANY
Serial number 6100001234
Serial number 6100001234
That anecdote says it all.
G,
SAS - Yes both 92 and 225 have had "handbrake" incidents, and I would be the first to say that it was only luck that the 225 came out of it completely unscathed, whereas the 92 was moderately trashed. I was talking about "foolproof design" if that is a technical term? With anything as complex as a helicopter, it is very difficult to design it so that an incorrect action by the pilot is not catastrophic. However it is somewhat easier to design so that in some cases an inaction by the pilot is not catestrophic. Put it another way, a heli designed so that something MUST be done by the pilots at a critical time, when other similar helis don't require this, is the poorer design from a safety point of view. There are a number of examples of this in the 92 vs 225 debate.
It stems from the belief by EC that pilots only recently evolved from chimpanzees, they design accordingly. Our American cousins of course don't even believe in evolution, but assume that all heli pilots are descended from Chuck Yeager or his relatives. Any that are not steely superheroes have no business flying their products. Personally, being closer to a chimp than a Yeager, I prefer EC's philosophy.
John - the point of my "waffle" comment was that an argument that having such a limitation built into the design of a commercial heli is a "good thing", is a poor argument in my view.
I agree that both manufacturers have good and bad points, stemming to some extent from where they are starting from (viz my second para)
HC
It stems from the belief by EC that pilots only recently evolved from chimpanzees, they design accordingly. Our American cousins of course don't even believe in evolution, but assume that all heli pilots are descended from Chuck Yeager or his relatives. Any that are not steely superheroes have no business flying their products. Personally, being closer to a chimp than a Yeager, I prefer EC's philosophy.
John - the point of my "waffle" comment was that an argument that having such a limitation built into the design of a commercial heli is a "good thing", is a poor argument in my view.
I agree that both manufacturers have good and bad points, stemming to some extent from where they are starting from (viz my second para)
HC
It stems from the belief by EC that pilots only recently evolved from chimpanzees
Collectives, Brakes and Seats
Hc,
You wrote:
" John - the point of my "waffle" comment was that an argument that having such a limitation built into the design of a commercial heli is a "good thing", is a poor argument in my view."
The point of my observations was to suggest that " things " such as narrow gear tread and low flapping hinge offset were not necessarily " good " attributes to incorporate in any helicopter.
HC, you may be a bit too harsh on the EC designers. They may have had my first superior at SA in mind. That person had, in his flying CV, both an S-58 brake handle assembly and an H-3 brake handle assembly, both of which he removed, in toto, during normal brake applications. We used to wonder how on earth he did that!
SAS, your point on seats is on target. I think, over the years, only three seats impressed me as being comfortable: CH-53E, CH-47A and the CH-21C. And nowadays, even the aces like Martin-Baker, who made the original S-92 seats, seemed unable to follow simple requests like " Make it like the 53E seat and everyone will be ecstatic".
Lastly a note re chimpanzees, et al..Perhaps some of the EC designers infiltrated SA early on, as the S-61 models had 14 inch fore/aft stick throws and it was commonly observed that a simian must have been used as a design model. Led to problems if a short armed pilot adjusted his seat forward in cruise, to make his flying arm position more comfortable, forgot he had done so, and if at near the forward CG limit, had to really scramble coming into a hover.
Thanks,
John Dixson
You wrote:
" John - the point of my "waffle" comment was that an argument that having such a limitation built into the design of a commercial heli is a "good thing", is a poor argument in my view."
The point of my observations was to suggest that " things " such as narrow gear tread and low flapping hinge offset were not necessarily " good " attributes to incorporate in any helicopter.
HC, you may be a bit too harsh on the EC designers. They may have had my first superior at SA in mind. That person had, in his flying CV, both an S-58 brake handle assembly and an H-3 brake handle assembly, both of which he removed, in toto, during normal brake applications. We used to wonder how on earth he did that!
SAS, your point on seats is on target. I think, over the years, only three seats impressed me as being comfortable: CH-53E, CH-47A and the CH-21C. And nowadays, even the aces like Martin-Baker, who made the original S-92 seats, seemed unable to follow simple requests like " Make it like the 53E seat and everyone will be ecstatic".
Lastly a note re chimpanzees, et al..Perhaps some of the EC designers infiltrated SA early on, as the S-61 models had 14 inch fore/aft stick throws and it was commonly observed that a simian must have been used as a design model. Led to problems if a short armed pilot adjusted his seat forward in cruise, to make his flying arm position more comfortable, forgot he had done so, and if at near the forward CG limit, had to really scramble coming into a hover.
Thanks,
John Dixson
Tip for pilots. watch out when doing anything that interupts the power supply. eg forgetting to start the apu after doing cross bleed start checks and trying to shut down! ive had to run away a couple of times because of that!
incase it wasnt clear to you.
John,
Re Chinook seats....if you recall there were too MK cushions...one which was a solid red color and one that was a dark red in some kind of material that could have been used for Window Curtains or a very cheap Marks and Sparks suit. The solid red cushion was comfortable....and the other an Engineers revenge for a pilot having stolen his wife and had an intimate relationship with his daughter in the passing. Horrible things they were!
The Chinook seat was the most comfortable of all the helicopter seats I sat in...Bell Seats purely sucked and ruined more backs than any other torture device ever made.
Re Chinook seats....if you recall there were too MK cushions...one which was a solid red color and one that was a dark red in some kind of material that could have been used for Window Curtains or a very cheap Marks and Sparks suit. The solid red cushion was comfortable....and the other an Engineers revenge for a pilot having stolen his wife and had an intimate relationship with his daughter in the passing. Horrible things they were!
The Chinook seat was the most comfortable of all the helicopter seats I sat in...Bell Seats purely sucked and ruined more backs than any other torture device ever made.
Seats
SAS, I only flew 4 CH-47A's: 3 were production prototypes ( 414, 450, 451 ) and one a new 1964 production machine, in which we put a 2000 gal pillow tank and flew it non-stop over a 1000 mile closed course. Very good seats in all, so must have been the good ones you referred to.
Thanks,
John
Thanks,
John
A couple of design aspects of the Chinook stick with me...
The Cyclic Stick Postioning system....that trim wheel device that allowed you to position the cyclic to a comfortable position. Which one had to remember to center again prior to ground ops.
The other was the ability for the old Girl to jack the Aft Pylon off the airframe if the FE left the Ramp Control lever in the down position and the Pilots forgot to re-engage the Cyclic Force Trim. The problem occurred when the cyclic moved forward...the ramp went down as the tail rose....and the Pilot finally waking up and realizing a problem existed....pulled the Cyclic back to where it should have been all along.....to discover the ramp was firmly planted on Planet Earth which was not going to shift out of its orbit despite the pilot trying to make it do so with the cyclic pull.
The Cyclic Stick Postioning system....that trim wheel device that allowed you to position the cyclic to a comfortable position. Which one had to remember to center again prior to ground ops.
The other was the ability for the old Girl to jack the Aft Pylon off the airframe if the FE left the Ramp Control lever in the down position and the Pilots forgot to re-engage the Cyclic Force Trim. The problem occurred when the cyclic moved forward...the ramp went down as the tail rose....and the Pilot finally waking up and realizing a problem existed....pulled the Cyclic back to where it should have been all along.....to discover the ramp was firmly planted on Planet Earth which was not going to shift out of its orbit despite the pilot trying to make it do so with the cyclic pull.
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From the thread on the failure of the IHST:
Isn't that a good reason for better design rather than OEMs just sitting back and hoping that Darwinian selection will make pilots more error tolerant but in the meantime sending arrogant recommendations to their customers to do better?
Sikorsky safety specialist Steve Gleason summed up the data-driven conclusions: "We're not finding new ways to crash helicopters. We're just doing the same thing over and over."
Squibb,
Having been involved in efforts to improve the safety record of the American EMS industry....the one thing that became very plain is helicopter pilots are not very innovative in the ways they kill themselves, their med crew,. and their patients.
OEM organizations are not able to correct "Judgement" issues and poor airmanship.
All one has to do is throw in night flight in marginal weather conditions over inhospitable terrain....and the best designed helicopter often comes to grief because of the lack of brains between the headset found in some many aircraft.
Perhaps if we converted to UAV's....which would be a technical solution to a human failure....the OEM's could have a huge role to play.
I hold little hope of that ever happening as the human pilot is much cheaper than the digital version that would be required.
We all know the "system" would never allow that.
Gleason summed up the data-driven conclusions
OEM organizations are not able to correct "Judgement" issues and poor airmanship.
All one has to do is throw in night flight in marginal weather conditions over inhospitable terrain....and the best designed helicopter often comes to grief because of the lack of brains between the headset found in some many aircraft.
Perhaps if we converted to UAV's....which would be a technical solution to a human failure....the OEM's could have a huge role to play.
I hold little hope of that ever happening as the human pilot is much cheaper than the digital version that would be required.
We all know the "system" would never allow that.
Yes one could argue the stud issue has been solved.
But interestingly, with the underlying complete failure of the gearbox when any lubrication component on the MGB side of the cooler fails and subsequently leaks, the s92 is still to this day a certified part 29 helicopter. It really looks as if there is nothing that could happen to revoke that certification at this point.
But interestingly, with the underlying complete failure of the gearbox when any lubrication component on the MGB side of the cooler fails and subsequently leaks, the s92 is still to this day a certified part 29 helicopter. It really looks as if there is nothing that could happen to revoke that certification at this point.
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I think you will find that the stud issue was sorted a long time ago.
The S 92 is a positive step forward in heli design and a lot of pilots prefer it to EC products. I fly it and did not design it!
The S 92 is a positive step forward in heli design and a lot of pilots prefer it to EC products. I fly it and did not design it!
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I think you will find that the stud issue was sorted a long time ago.
So whats your take then on gearbox bypass, foot cracking, cockpit ergonomics and noise?
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I agree that the tragic loss should not have happened, but other current types also have a Land Immediately instruction following a total MGB oil pressure loss. Emergency Checklists like Normal Checklists are written to cover the operating issues with that type. There is no perfect heli design. How many helicopters can you think of with a single stop go switch to make life easy? You pay a lot of money for a car and expect perfection, you pay many times that for a helicopter and they still leak water when it rains and no carpets as standard! There has always been a EC and SK divide, what about slagging off the EC product after the tragic North Sea crash? Sincere apologies to any families or friends of the people involved in that sad incident who may be reading this post.
On the ergonomics seems ok to me but then I am used to SK aircraft, cockpit noise yes but a good fitting headset or flying helmet?? helps. However, the autopilot and other advantages make up for the noise for me.
On the ergonomics seems ok to me but then I am used to SK aircraft, cockpit noise yes but a good fitting headset or flying helmet?? helps. However, the autopilot and other advantages make up for the noise for me.
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Engine chip warnings
Seasons greeting to all
Question for the AMEs, is it normal to see both engine #1 and # 2 chip detection on the same aircraft within the space of one week?
We've just had one of our buses over here get two chip faults, engine #2 on Dec 27, was changed out and placed back in service, then engine #1 had a chip fault two days later (Dec 29). Splinters were deemed within limits for a serviceability check. From what I've read in the customer flight notification bulletin the serviceability check will take approximately 4 hours after which the aircraft will require a ½ hr ground run, ½ hour hover check followed by an inspection of the chip detector.
I would have assumed that engines are ran to stagger operational hours, so is there a shared lubrication system on the S92 that could cause cross-contamination, I would have assumed not?
Safe flying
Max
Question for the AMEs, is it normal to see both engine #1 and # 2 chip detection on the same aircraft within the space of one week?
We've just had one of our buses over here get two chip faults, engine #2 on Dec 27, was changed out and placed back in service, then engine #1 had a chip fault two days later (Dec 29). Splinters were deemed within limits for a serviceability check. From what I've read in the customer flight notification bulletin the serviceability check will take approximately 4 hours after which the aircraft will require a ½ hr ground run, ½ hour hover check followed by an inspection of the chip detector.
I would have assumed that engines are ran to stagger operational hours, so is there a shared lubrication system on the S92 that could cause cross-contamination, I would have assumed not?
Safe flying
Max
Gaspode,
Bad seats, rainwater leaks, and spartan upholstry is just a fact of life in the helicopter world!
If it is glitzy and glitter you want....get your MBA from Wharton or Havard and work your way up to the Gulfstream Jet world.
Max,
Engine chips can be caused by any number of things and usually are benign events. As the aircraft are flown...over time a new aircraft will encounter a need to change one engine ahead of the other and thus a find itself with different hours on the engines.
I am not knowing of the 92 design in particular...but I would imagine the two engine lubrication systems are completely separate and even if they shared a common cooler...it would be partitioned so the oils did not mix and in reality be a single unit but made up of independent modules.
Engine chips are not something to get too concerned about as the magnetic plugs are designed to discover "wear" kinds of material. It is the gear boxes that are the more important concern than the engines re potential failures as the 92 is designed to fly well on a single engine.
Jim L has provided statistical data that shows two engines failing almost simultaneously is so remote a possibility as to be of almost no concern.
Bad seats, rainwater leaks, and spartan upholstry is just a fact of life in the helicopter world!
If it is glitzy and glitter you want....get your MBA from Wharton or Havard and work your way up to the Gulfstream Jet world.
Max,
Engine chips can be caused by any number of things and usually are benign events. As the aircraft are flown...over time a new aircraft will encounter a need to change one engine ahead of the other and thus a find itself with different hours on the engines.
I am not knowing of the 92 design in particular...but I would imagine the two engine lubrication systems are completely separate and even if they shared a common cooler...it would be partitioned so the oils did not mix and in reality be a single unit but made up of independent modules.
Engine chips are not something to get too concerned about as the magnetic plugs are designed to discover "wear" kinds of material. It is the gear boxes that are the more important concern than the engines re potential failures as the 92 is designed to fly well on a single engine.
Jim L has provided statistical data that shows two engines failing almost simultaneously is so remote a possibility as to be of almost no concern.
Last edited by SASless; 31st Dec 2011 at 17:28.