Coastguard S92's
In fact, the down force is greatest when it is stalled.
Ah but according to St Nick, aerofoils tend to generate the most lift when they are stalled. Next time I fly a fixed-wing I must remember to keep the wings stalled at all times, thereby maximising the lift.
Whilst you are blessing us with your superior knowledge, could you explain why according to those that actually fly it (Mr 212) its more nose up in strong winds than in light winds (strong winds to a former N Sea pilot means 40kts +)
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The broad flat area of the horizontal tail, as well as the tailcone, present area for the main rotor downwash to act on, as vertical drag, even when the surface is stalled. In fact, the down force is greatest when it is stalled.
Even a lowly colonial understood what Nick meant, maybe because I actually read what he posted. Give it a rest man, you are so far behind you are actually deluded into thinking you are first.
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You know, I was wondering that myself.....
When you first started posting facts and figures about the 225 (and other EC models) I actually valued your opinions. Now however I see that you are so blinded and biased that I have to throw the baby out with the bath water. As I said, EC makes some fine a/c, as a matter of fact the 350 is one of my favorite and the 76 is one of my least (due to that stupid nose high hover to name one). However, that does not lower my opinion of Nick, he has the knowledge and experience to back up his claims. One does not get to where is on B**ls**t.
And by the way, now that you have used the name St. Nick in a degrading manner, don't be surprised if you find a lump of coal in your stocking this year
When you first started posting facts and figures about the 225 (and other EC models) I actually valued your opinions. Now however I see that you are so blinded and biased that I have to throw the baby out with the bath water. As I said, EC makes some fine a/c, as a matter of fact the 350 is one of my favorite and the 76 is one of my least (due to that stupid nose high hover to name one). However, that does not lower my opinion of Nick, he has the knowledge and experience to back up his claims. One does not get to where is on B**ls**t.
And by the way, now that you have used the name St. Nick in a degrading manner, don't be surprised if you find a lump of coal in your stocking this year
Ow
Rather than getting your kicks out of slagging me off, why not post something to explain why 212 thinks the nose attitude is higher in strong wind than in light wind. So far no-one has explained that. Its easy to snipe from the sidelines, somewhat harder to contribute something useful.
My explanation is spot on for the Super Puma family - you can feel the stabiliser stall as speed is reduced through around 20kts with a corresponding tuck in fuselage attitude, but that does not mean its necessarily correct for the S92 with its flatter section horizontal stabiliser and canted tail rotor. Looking at the photos, the 92 stabiliser looks more like a flat plate than an aerofoil and perhaps its sole job is to aid the otherwise dodgy longitudinal stability? Lets try to have some technical discussions without personal attacks. Now that would be a first for Pp
HC
Rather than getting your kicks out of slagging me off, why not post something to explain why 212 thinks the nose attitude is higher in strong wind than in light wind. So far no-one has explained that. Its easy to snipe from the sidelines, somewhat harder to contribute something useful.
My explanation is spot on for the Super Puma family - you can feel the stabiliser stall as speed is reduced through around 20kts with a corresponding tuck in fuselage attitude, but that does not mean its necessarily correct for the S92 with its flatter section horizontal stabiliser and canted tail rotor. Looking at the photos, the 92 stabiliser looks more like a flat plate than an aerofoil and perhaps its sole job is to aid the otherwise dodgy longitudinal stability? Lets try to have some technical discussions without personal attacks. Now that would be a first for Pp
HC
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Lets try to have some technical discussions without personal attacks.
Sorry, I am not an aeronautical engineer, so I would never presume to be able to explain anything that has to do with that. However, again if you read Nick's post he says:
The nose up for the 92 is greatest at about 10 to 15 knots of forward speed
10-15kts is light
OW yes but that is a light wind. When Mr 212 wakes up (he's on Borneo time) perhaps he will tell us at what wind speed the maximum hover nose up occurs (or if you like what forward airspeed in level flight. My guess is that it will be around 40kts or so.
You don't presume to have an opinion, but are you saying that no-one else except Nick is entitled to one? It would be a pretty dull forum if only he were allowed to post on technical or aerodynamic issues. The only other posts would be the cooing, gasping and re-posting his CV by his prostrators.
I am not an aeronautical engineer either but I am an instructor and I have to be able to explain flight characteristics to my trainees.
If you look back at this thread (and many others) I think you will find that the first insulting post is from Nick. I just tend to react (even though my mother told me that was the wrong thing to do!)
HC
You don't presume to have an opinion, but are you saying that no-one else except Nick is entitled to one? It would be a pretty dull forum if only he were allowed to post on technical or aerodynamic issues. The only other posts would be the cooing, gasping and re-posting his CV by his prostrators.
I am not an aeronautical engineer either but I am an instructor and I have to be able to explain flight characteristics to my trainees.
If you look back at this thread (and many others) I think you will find that the first insulting post is from Nick. I just tend to react (even though my mother told me that was the wrong thing to do!)
HC
Chief Bottle Washer
First and last reminder!
HC (and others whose mothers may have given Good Advice):
Let me remind you of one of the terms and conditions to which you agreed when you registered with PPRuNe
Let me remind you of one of the terms and conditions to which you agreed when you registered with PPRuNe
Be Courteous!
Don't attack others. Personal attacks on others will not be tolerated. Challenge others' points of view and opinions, but do so respectfully and thoughtfully... without insult and personal attack.
Don't attack others. Personal attacks on others will not be tolerated. Challenge others' points of view and opinions, but do so respectfully and thoughtfully... without insult and personal attack.
HeliComparator
Quote:
Ah but according to St Nick, aerofoils tend to generate the most lift when they are stalled. Next time I fly a fixed-wing I must remember to keep the wings stalled at all times, thereby maximising the lift.
Quote:
Ah but according to St Nick, aerofoils tend to generate the most lift when they are stalled. Next time I fly a fixed-wing I must remember to keep the wings stalled at all times, thereby maximising the lift.
look at the Cl:
Regards.
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Staggering!! Yet again a thread has turned from the topic & become 'I know more than you do thread!'
Why??
The question was, I believe, how are the S-92's getting on with MCA!! (Or words to that affect!) But somehow we've found ourselves embroiled with Principles of flight!
In short....the S-92 is doing pretty well. It's new....so there are teething problems. But on the whole the guys operating it seem pretty damn happy!
I don't fly it, so I can't comment on all the things the other people who DON'T fly it are talking about! But I'm sure someone who knows will post eventually......if he can be bothered to wade through the me me me's!!
212man.....other than the downwash.....I think the answers to all your questions are very positive! The downwash is pretty severe!! But I'm sure the boys will adapt & overcome!
Fingers crossed for lots of stimulating on topic posts!
Why??
The question was, I believe, how are the S-92's getting on with MCA!! (Or words to that affect!) But somehow we've found ourselves embroiled with Principles of flight!
In short....the S-92 is doing pretty well. It's new....so there are teething problems. But on the whole the guys operating it seem pretty damn happy!
I don't fly it, so I can't comment on all the things the other people who DON'T fly it are talking about! But I'm sure someone who knows will post eventually......if he can be bothered to wade through the me me me's!!
212man.....other than the downwash.....I think the answers to all your questions are very positive! The downwash is pretty severe!! But I'm sure the boys will adapt & overcome!
Fingers crossed for lots of stimulating on topic posts!
Hence the nose down attitude.
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I've forgotten how to quote someone, so it doesn't quite look right sorry.
Tailtakeoff said:
I must say I think it is a bit much that CHC have registered their Sumburgh S-92 G-CGOC (Coast Guard Oscar Charlie). They are clearly trying to cash in on the good reputation that the last Coast guard Oscar Charlie (G-BDOC) had in Shetland for the last couple of decades.
This is probably going to sound VERY big headed, but I think that was my idea. When in a meeting with CHC in the Sumburgh hotel way back when, I suggested they keep the last two letters the same for the new aircraft. Whether they did that on my suggestion or not I dont know. Logic being everyone in the area doesn't get confused by callsigns, local's as well as people involved in the aviation bit. That and the fact it was a pain in the rear end everytime we changed A/C and forgot which one we were in. To be fair it wasn't the "senior's" only, us "junior" staff were as bad, as were air traffic sometimes.
Anyway just thought I would put my penny's worth in, que the smart comments by text and emails from Shetland.
Si
P.S. I KNOW I'm easily confused LOL
Tailtakeoff said:
I must say I think it is a bit much that CHC have registered their Sumburgh S-92 G-CGOC (Coast Guard Oscar Charlie). They are clearly trying to cash in on the good reputation that the last Coast guard Oscar Charlie (G-BDOC) had in Shetland for the last couple of decades.
This is probably going to sound VERY big headed, but I think that was my idea. When in a meeting with CHC in the Sumburgh hotel way back when, I suggested they keep the last two letters the same for the new aircraft. Whether they did that on my suggestion or not I dont know. Logic being everyone in the area doesn't get confused by callsigns, local's as well as people involved in the aviation bit. That and the fact it was a pain in the rear end everytime we changed A/C and forgot which one we were in. To be fair it wasn't the "senior's" only, us "junior" staff were as bad, as were air traffic sometimes.
Anyway just thought I would put my penny's worth in, que the smart comments by text and emails from Shetland.
Si
P.S. I KNOW I'm easily confused LOL
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I must say I think it is a bit much that CHC have registered their Sumburgh S-92 G-CGOC (Coast Guard Oscar Charlie). They are clearly trying to cash in on the good reputation that the last Coast guard Oscar Charlie (G-BDOC) had in Shetland for the last couple of decades.
Coastguard 100 - Stornoway Duty
Coastguard 101 - Stornoway Standby
Coastguard 102 - Sumburgh Duty
Coastguard 103 - Sumburgh Standby
Coastguard 104 - Lee Duty
etc etc..
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blast beaten to it. However Biggles I think there are others who may make the claim about keeping the OC part of the reg. At the end of the day I reckon the majority of the islanders don't care either way. Just look at the flood of letters of support that appeared when Bristows lost the contract. NOT!!
Regards
Wiretensioner
Regards
Wiretensioner
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S92 Sar
There is a lot of whinging about the S92 on this thread. Mostly, I guess, from non S92 operators. Just about all the S92 SAR pilots are very pleased 
with the aircraft. The nose up attitude and the poor seat do not seem to be a problem, the only area that is different from exisiting SAR aircraft is the rotor wash but there are ways around that and, after all, it is a big aircraft (AUM upto 26500 lbs). There is always resistance to new things but if people that think the S61 or Sea King are so much better because "we have always done it that way" need to pull them selves into the current century, the S92 is new technology. We could always go back to a single engine aircraft with a 100ft winch like the Whirlwind!!!!
with the aircraft. The nose up attitude and the poor seat do not seem to be a problem, the only area that is different from exisiting SAR aircraft is the rotor wash but there are ways around that and, after all, it is a big aircraft (AUM upto 26500 lbs). There is always resistance to new things but if people that think the S61 or Sea King are so much better because "we have always done it that way" need to pull them selves into the current century, the S92 is new technology. We could always go back to a single engine aircraft with a 100ft winch like the Whirlwind!!!!
Nick Dear Boy,
Maybe I have had a few too many Egg Nogs (note.....means VSOP coloured by the essence of Egg Nog) but as I read your post it seems quite clear to me....but not to HC that what you refer to as a stalled surface is in fact the non-moving tail bits and not the rotor blades.
Heavens knows even a Redneck knows a wing creates the most lift just at stall....but also provides for max drag as well.....and what with drag being the force that gets strongest quickest, it has the more noticeable effect. (or so I dredged up out of the deepest reaches of my alcohol ravanged brain).
Maybe I have had a few too many Egg Nogs (note.....means VSOP coloured by the essence of Egg Nog) but as I read your post it seems quite clear to me....but not to HC that what you refer to as a stalled surface is in fact the non-moving tail bits and not the rotor blades.
Heavens knows even a Redneck knows a wing creates the most lift just at stall....but also provides for max drag as well.....and what with drag being the force that gets strongest quickest, it has the more noticeable effect. (or so I dredged up out of the deepest reaches of my alcohol ravanged brain).
Is this thread creep?
SAS
Why are you on the computer on Christmas Day? Oh all right then, escaping the rellies just like me!
I don't think anyone (even me) thought that NL was referring to the rotor system when he was talking about drag. He was talking about the horizontal stabiliser.
Anyway, a quick point of aerodynamics for you and Aser (nice graph, Aser!). You can stop reading now if you already understand it!
Once you get to the top of Aser's graph at the stall line, an aerofoil (other than one tethered in a wind tunnel) tends to find the region to the right of the stall line quite unstable due to the fact that lift reduces as angle of attack increases. (angle of attack being defined as the angle between the relative airflow and the chord line). Take a fixed-wing wing - as the angle of attack exceeds that stall line the wing loses lift and starts to drop. The very fact that the wing is descending through the air increases the angle of attack further, which reduces its lift, which makes it descend faster, which increases its angle of attack further still etc.
The same applies to a horizontal stabiliser. In forward flight its pushing the tail down but as airspeed reduces, the angle of attack increases due to the increasing angle of downwash from the main rotor and at some point it gets to the top of Aser's graph and lift starts to decrease. As soon as that happens, the tail starts to come up and that increases the angle of attack, losing (downward) lift which further increases the angle of attack etc. That's why the hover attitude suddenly takes a step change as the stall is reached, rather than a gradual change as might be implied by Aser's graph
So although it looks as though you could function happily just to the right of the stall line, in reality you couldn't, and you fall off the right-hand side of the graph as soon as you touch the stall line.
This phenomena is very noticeable on the Super Puma family. The auto-hovering AS332L2 could get into an oscillating syndrome where the hover attitude varied between level and about 7 degrees nose up when hovering in about 40 kts of wind as the stabiliser cycled through stalling / unstalling.
Possibly it doesn't happen on the S92 but I think the chances are it does and that is why 212 says the hover attitude is more nose high in strong wind than in light wind.
Nick will no doubt argue but we should remember that whilst Eurocopter, Sikorsky etc are the experts in designing and building the aircraft, Bristow, CHC, Bond, Norsk, Cougar, PHI, (even Shell!) etc are the experts in operating them and the total hours ever flown by Sikorsky on the S92 is exceeded by the operators every month.
HC
Why are you on the computer on Christmas Day? Oh all right then, escaping the rellies just like me!
I don't think anyone (even me) thought that NL was referring to the rotor system when he was talking about drag. He was talking about the horizontal stabiliser.
Anyway, a quick point of aerodynamics for you and Aser (nice graph, Aser!). You can stop reading now if you already understand it!
Once you get to the top of Aser's graph at the stall line, an aerofoil (other than one tethered in a wind tunnel) tends to find the region to the right of the stall line quite unstable due to the fact that lift reduces as angle of attack increases. (angle of attack being defined as the angle between the relative airflow and the chord line). Take a fixed-wing wing - as the angle of attack exceeds that stall line the wing loses lift and starts to drop. The very fact that the wing is descending through the air increases the angle of attack further, which reduces its lift, which makes it descend faster, which increases its angle of attack further still etc.
The same applies to a horizontal stabiliser. In forward flight its pushing the tail down but as airspeed reduces, the angle of attack increases due to the increasing angle of downwash from the main rotor and at some point it gets to the top of Aser's graph and lift starts to decrease. As soon as that happens, the tail starts to come up and that increases the angle of attack, losing (downward) lift which further increases the angle of attack etc. That's why the hover attitude suddenly takes a step change as the stall is reached, rather than a gradual change as might be implied by Aser's graph
So although it looks as though you could function happily just to the right of the stall line, in reality you couldn't, and you fall off the right-hand side of the graph as soon as you touch the stall line.
This phenomena is very noticeable on the Super Puma family. The auto-hovering AS332L2 could get into an oscillating syndrome where the hover attitude varied between level and about 7 degrees nose up when hovering in about 40 kts of wind as the stabiliser cycled through stalling / unstalling.
Possibly it doesn't happen on the S92 but I think the chances are it does and that is why 212 says the hover attitude is more nose high in strong wind than in light wind.
Nick will no doubt argue but we should remember that whilst Eurocopter, Sikorsky etc are the experts in designing and building the aircraft, Bristow, CHC, Bond, Norsk, Cougar, PHI, (even Shell!) etc are the experts in operating them and the total hours ever flown by Sikorsky on the S92 is exceeded by the operators every month.
HC