Sikorsky S-92: From Design to Operations
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mtoroshanga, no helicopter has blade anti-ice, ALL helicopters have blade de-ice, where the ice is formed then shed. The power needs of an anti-ice system would be perhaps ten times that of the de-ice systems, far beyond the ability of any power system on board the machine. The heat needed to melt a razor thin section of the ice next to the blade is small, especially when the ice above it (also a thin skin, unlike mtoroshanga's imaginary vibration inducing massive chunk) shields the heated section from the Mach .5 cold air blast. The ice detector determines the timing for the pulses, where they come at more frequent intervals as the ice accretion rate is higher, so that the thin skin of ice is blasted off before it grows too thick.
Engine bellmouths have de-ice because any shed would harm the engine. Typical de-ice requirements are from 5 to 10 watts per square inch. If a Puma/Black Hawk had deiced blades, it would need over 140 KW of power continuously just on the main blades! That is perhaps 5 Black Hawk generators saturated just for the blades.
I have no idea how mtoroshanga thinks he knows otherwise, it would be interesting to find out.
Regarding the difference between Design Engineers and Mechanic-Engineers, both professions are necessary. I am sure mtoroshanga is a pro at maintaining a safe, operable helo, but he is clearly lost designing a helicopter system, as lost as a design engineer would be determining how to overhaul a helicopter.
Engine bellmouths have de-ice because any shed would harm the engine. Typical de-ice requirements are from 5 to 10 watts per square inch. If a Puma/Black Hawk had deiced blades, it would need over 140 KW of power continuously just on the main blades! That is perhaps 5 Black Hawk generators saturated just for the blades.
I have no idea how mtoroshanga thinks he knows otherwise, it would be interesting to find out.
Regarding the difference between Design Engineers and Mechanic-Engineers, both professions are necessary. I am sure mtoroshanga is a pro at maintaining a safe, operable helo, but he is clearly lost designing a helicopter system, as lost as a design engineer would be determining how to overhaul a helicopter.
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Clarifying mtoroshanga's point:
The fatal accident on the AS332L mentioned was to Helikopter Service aircraft LN-OPG 10 years ago.
The HUMS did NOT give prior notice because the sensor had not been repaired having been unservicable for for a couple of months. So fixing the sensor was ignored not a the HUMS analysis.
http://www.havarikommisjonen.no/defa...&V_ITEM_ID=247
The aircraft was at a remote base flying 50 hours a week with one engineer.
However you would think that a decade on new aircraft would be better at detection!
The fatal accident on the AS332L mentioned was to Helikopter Service aircraft LN-OPG 10 years ago.
The HUMS did NOT give prior notice because the sensor had not been repaired having been unservicable for for a couple of months. So fixing the sensor was ignored not a the HUMS analysis.
http://www.havarikommisjonen.no/defa...&V_ITEM_ID=247
The aircraft was at a remote base flying 50 hours a week with one engineer.
However you would think that a decade on new aircraft would be better at detection!
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zalt,
They are better now for modern helicopters. That accident was a chain, like all accidents. The position of the engines on ancient helicopters makes it such that an engine burst will cut the primary flight controls, which is the real cause of that accident. Modern regulations require that any turbine will burst, and the aircraft's design must account for that by withstanding that burst.
The Super Puma family cannot be redesigned to prevent this, in fact, the 225 does not meet this new turbine burst requirement. Instead, regardless of the requirement to withstand a burst, the engines are said to not be able to burst. The regulation is not met, however.
The S92, and the other more modern helicopters, are designed so that a turbine burst does not allow engine chunks to cut primary flight controls. The A-139 has similar design features, I believe.
They are better now for modern helicopters. That accident was a chain, like all accidents. The position of the engines on ancient helicopters makes it such that an engine burst will cut the primary flight controls, which is the real cause of that accident. Modern regulations require that any turbine will burst, and the aircraft's design must account for that by withstanding that burst.
The Super Puma family cannot be redesigned to prevent this, in fact, the 225 does not meet this new turbine burst requirement. Instead, regardless of the requirement to withstand a burst, the engines are said to not be able to burst. The regulation is not met, however.
The S92, and the other more modern helicopters, are designed so that a turbine burst does not allow engine chunks to cut primary flight controls. The A-139 has similar design features, I believe.
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So how did the better tail rotor on the S92 still cause a run on landing?
How were the chip detectors made better so that they did not detect a bearing failure?
How, and I really want to know this, was the software programmed to be better to assume that 1043mb is the maximum that can be encountered?
How were the chip detectors made better so that they did not detect a bearing failure?
How, and I really want to know this, was the software programmed to be better to assume that 1043mb is the maximum that can be encountered?
was the software programmed to be better to assume that 1043mb is the maximum
I wonder how the aircraft would behave if you took off on a standard day and descended to -1000 ft Hp (Israel e.g.)? Could be interesting
Regarding the TR bearing, the fix to ensure future vibration detection is in hand, and will probably involve repositioning the accelerometer.
Bristow IHUMS detected a crack in a high speed shaft adaptor that was ignored and subsequently caused a fatal accident
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Deicing myths
Could not hold back here.
Deicing the S-92, or any other rotor, is, as Nick points out, a matter of encouraging the ice to shed when you want it to rather than preventing it or melting it.
To actually determine when to shed the ice is a matter of determining what size chunks you wish to shed. Once you determine that, the cloud water content, drop size and temperature tell you how often to zap the blade. -i.e the time and timing vary with conditions to keep the pieces the same size.
Then you show those pieces can't hurt you if they hit - and voila! you have a deicing system - be it Super Puma, S-92 or AW139.
Note - the 609 has anti-ice.............
Nick I do wish you would stop lying about the EC225. You said
which you know to be a lie because you have seen the TCDS - even posted it on Pprune- you know there is no grandfathering on the engines, and you know that its not possible to grandfather on a new engine (which the Makila 2A is). Or perhaps you are not lying, perhaps you are just as thick as mince?
As you well know, the certification requirement is met by the blade shedding technology whereby in an overspeed situation not contained by the electronic shutdown system, the N2 blades are dumped into the containment shield and then the N2 turbine discs cannot go any faster (and start to slow down). This in my opinion is far better than the Sikorsky system where the turbine disc is allowed to explode, with the hope that there is sufficient protection within the airframe to prevent serious damage.
Amusingly Sikorsky's slide showing this wonderous innovation shows the bits of turbine debris can fly through the rotor disc. Unless you are going to tell me that the rotor blades are impervious to turbine disc that was doing 50,000 rpm an instant ago, I would say that the EC system is far better and safer.
- Yea, pity about the rotor blades. Flight controls don't work too well without those.
Even you once described EC's idea as "cool" - how times and bitterness have changed you.
Your constant and irrational lying in a pathetic attempt to make the EC225 look worse than your baby just means that you lose all credibility. Get a grip!
HC
The Super Puma family cannot be redesigned to prevent this, in fact, the 225 does not meet this new turbine burst requirement. Instead, regardless of the requirement to withstand a burst, the engines are said to not be able to burst. The regulation is not met, however.
As you well know, the certification requirement is met by the blade shedding technology whereby in an overspeed situation not contained by the electronic shutdown system, the N2 blades are dumped into the containment shield and then the N2 turbine discs cannot go any faster (and start to slow down). This in my opinion is far better than the Sikorsky system where the turbine disc is allowed to explode, with the hope that there is sufficient protection within the airframe to prevent serious damage.
Amusingly Sikorsky's slide showing this wonderous innovation shows the bits of turbine debris can fly through the rotor disc. Unless you are going to tell me that the rotor blades are impervious to turbine disc that was doing 50,000 rpm an instant ago, I would say that the EC system is far better and safer.
The S92, and the other more modern helicopters, are designed so that a turbine burst does not allow engine chunks to cut primary flight controls.
Even you once described EC's idea as "cool" - how times and bitterness have changed you.
Your constant and irrational lying in a pathetic attempt to make the EC225 look worse than your baby just means that you lose all credibility. Get a grip!
HC
I found the slide that Nick presented to me in the days when I thought he was credible. It shows the S92's rotor blades being taken out by a turbine burst
HC
HC
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helicomparitor it is you who try to mislead by misrepresenting the law. The regulation is NOT met by the 225, because the 225's design cannot and does not meet the turbine burst requirements, laws that were changed after the terrible Super Puma turbine burst accident that cost so many lives.
helicomparitor said, "Nick I do wish you would stop lying about the EC225. You said "the 225 does not meet this new turbine burst requirement"...which you know to be a lie because you have seen the TCDS - even posted it on Pprune- you know there is no grandfathering on the engines."
The above proves your ignorance about regulations, hc, because the requirement is for the airframe, not the engines, to take the brunt of a burst. The 225 does NOT meet the requirement, the EC 225 ducks the requirement by claiming that the engine does not burst, and not by assuring that the aircraft can withstand the burst. This is the same old story they gave before the Super Puma accident that caused the regulation to be changed!
The shot you give of the S92 (thank you for that, it is my slide!) shows that the S92 engine burst zone avoids the controls, transmission and servos. You are not capable of knowing that the rotor blades are qualified to take a 23mm HEI hit in the worst angle, and so are not threatened by the burst, but that is just another piece of your ignorance, so we understand.
Here is a shot of the Super Puma's burst zone, for comparison. Note that the controls, blades, servos and transmission are all threatened by the engines:
helicomparitor said, "Nick I do wish you would stop lying about the EC225. You said "the 225 does not meet this new turbine burst requirement"...which you know to be a lie because you have seen the TCDS - even posted it on Pprune- you know there is no grandfathering on the engines."
The above proves your ignorance about regulations, hc, because the requirement is for the airframe, not the engines, to take the brunt of a burst. The 225 does NOT meet the requirement, the EC 225 ducks the requirement by claiming that the engine does not burst, and not by assuring that the aircraft can withstand the burst. This is the same old story they gave before the Super Puma accident that caused the regulation to be changed!
The shot you give of the S92 (thank you for that, it is my slide!) shows that the S92 engine burst zone avoids the controls, transmission and servos. You are not capable of knowing that the rotor blades are qualified to take a 23mm HEI hit in the worst angle, and so are not threatened by the burst, but that is just another piece of your ignorance, so we understand.
Here is a shot of the Super Puma's burst zone, for comparison. Note that the controls, blades, servos and transmission are all threatened by the engines:
Nick
The 225 airframe engine combination does meet the requirements. If it didn't, the TCDS would show it as you well know. Do stop trying to mislead.
I agree that if you fitted a crappy old pair of CT7s it would no longer be compliant, but the TCDS refers to a particular airframe and engine combination, so that point is irrelevant.
I am sure the S92 blades can take
but what happens if the bits are bigger than 23mm?
Another photo on the same slide of yours that I stole (can't be bothered to post it), shows the turbine disc in 3 large chunks which are much, much larger than 23mm. The blades could not take a hit from that.
Mind you, with only 4 blades I suppose there is a moderate chance that the chunk would miss the blades altogether. Perhaps its this luck that you are relying on to keep your occupants alive?
HC
The 225 airframe engine combination does meet the requirements. If it didn't, the TCDS would show it as you well know. Do stop trying to mislead.
I agree that if you fitted a crappy old pair of CT7s it would no longer be compliant, but the TCDS refers to a particular airframe and engine combination, so that point is irrelevant.
I am sure the S92 blades can take
a 23mm HEI hit in the worst angle,
Another photo on the same slide of yours that I stole (can't be bothered to post it), shows the turbine disc in 3 large chunks which are much, much larger than 23mm. The blades could not take a hit from that.
Mind you, with only 4 blades I suppose there is a moderate chance that the chunk would miss the blades altogether. Perhaps its this luck that you are relying on to keep your occupants alive?
HC
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again, your ignorance shows through. Why don't you either give up, or at least learn something about those things before you speak up.
hc asked, "what happens if the bits are bigger than 23mm?" and he further opined, "the turbine disc in 3 large chunks which are much, much larger than 23mm. The blades could not take a hit from that."
When you expose all of us to your ignorance it is actually disappointing, because you talk such a good game, some folks might actually begin to believe you know something about designing aircraft. You don't, and you are getting deeper and deeper into your own BS! The struggles ae amusing, however.
The issue with tolerating a flying chunk is the energy of the chunk, not its diameter. As I am quite sure you have heard a few times, that size doesn't matter.
The energy of a 23MM projectile is approximately twice that of the engine disk chunk when it flies from the engine. I know, because I helped issue the report that said so.
While we are on the subject, the airframe must withstand the burst, and the 225 does not. Every engine manufacturer says his engine will not burst. They are born with that phrase on their lips, even if the phrase is in French. They said so before that terrible Super Puma fatal accident, and they (and you) still say so.
Too bad the EC 225 does not meet the latest regulations in so many ways, in spite of your misunderstanding of the laws.
hc asked, "what happens if the bits are bigger than 23mm?" and he further opined, "the turbine disc in 3 large chunks which are much, much larger than 23mm. The blades could not take a hit from that."
When you expose all of us to your ignorance it is actually disappointing, because you talk such a good game, some folks might actually begin to believe you know something about designing aircraft. You don't, and you are getting deeper and deeper into your own BS! The struggles ae amusing, however.
The issue with tolerating a flying chunk is the energy of the chunk, not its diameter. As I am quite sure you have heard a few times, that size doesn't matter.
The energy of a 23MM projectile is approximately twice that of the engine disk chunk when it flies from the engine. I know, because I helped issue the report that said so.
While we are on the subject, the airframe must withstand the burst, and the 225 does not. Every engine manufacturer says his engine will not burst. They are born with that phrase on their lips, even if the phrase is in French. They said so before that terrible Super Puma fatal accident, and they (and you) still say so.
Too bad the EC 225 does not meet the latest regulations in so many ways, in spite of your misunderstanding of the laws.
The issue with tolerating a flying chunk is the energy of the chunk, not its diameter. As I am quite sure you have heard a few times, that size doesn't matter.
Where the item has sufficient energy to pass right through, only a small part of that energy is transferred into damaging the rotor blade. If instead I sent a 230mm chunk through with the same amount of energy (going a lot slower of course) it would be quite capable of severing the rotor blade.
I know, because I helped issue the report that said so.
Saying size doesn't matter is sooo 90s. In the noughtys sized definitely does matter. But I guess you will never know...
Once again, stop your blatant lying! The 225 does meet the certification requriements for FAR and CS 29 regarding turbine burst protection. Have a look at the tcds if your memory is so poor that you can't remember. The AS332L does not meet them, neither does the S76, S61 etc, because the regs have been changed since they were certified.
HC
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hc, what you don't know about the last post has built an industry. What training have you ever had and what experience on ballistics and ballistic tolerance? Stop the bull, please.
Your crackpot theory about "mach 3 bullets" makes no sense! First off, do you actually think the folks who made the 23mm didn't want it to do any damage? It is designed to shed its maximum energy into the structure it strikes, like a hollow-point bullet! Secondly, the 23mm that the blade is designed and tested to withstand is a High Explosive Incendiary (HEI) and the energy of its explosive content is not included in my brief discussion below.
Again, you have no idea what your are talking about, none, zip squat. Time to just quiet down, cut the caffeine and learn something from your peers (I use the term "peers" term very loosely here.)
BTW, I sent you a Christmas card, did you get it yet?
Your crackpot theory about "mach 3 bullets" makes no sense! First off, do you actually think the folks who made the 23mm didn't want it to do any damage? It is designed to shed its maximum energy into the structure it strikes, like a hollow-point bullet! Secondly, the 23mm that the blade is designed and tested to withstand is a High Explosive Incendiary (HEI) and the energy of its explosive content is not included in my brief discussion below.
Again, you have no idea what your are talking about, none, zip squat. Time to just quiet down, cut the caffeine and learn something from your peers (I use the term "peers" term very loosely here.)
BTW, I sent you a Christmas card, did you get it yet?
By the way Dan, I may have my faults (surely not, I hear you say?) but pathetic jealousy of the S92 or Nick is certainly not one of them. I just don't like to see some big fish in a little pond use his reputation fraudulently.
HC
HC
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Helicomparitor (or should I call you Mach 3 Bullets!), are you saying that this is a little pond to you, do you denigrate pprune so easily?
And regarding reputation, one earns that, and it hard for you to do so as you hide behind an anonymous label!
I will send your erudite analysis about "Mach 3 bullets" through the design community along with your real name, it will get some belly laughs! I will cc you a copy, too!
And regarding reputation, one earns that, and it hard for you to do so as you hide behind an anonymous label!
I will send your erudite analysis about "Mach 3 bullets" through the design community along with your real name, it will get some belly laughs! I will cc you a copy, too!
I will send your erudite analysis about "Mach 3 bullets" through the design community along with your real name, it will get some belly laughs! I will cc you a copy, too!
Happy Christmas St Nick!
HC
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Back to deice/anti ice
Go to the Eurocopter website regarding ice problems on rotor blades and you will see that they have a theory that heating the main rotor blades is a better path than pulses of power which have to recover heat lost then hope that all the ice comes off at one time is better. Please do not talk down to people you do not know,.