Helicopter Urban Myths
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212man,
I lead the team and gave many of the press interviews, I know what we said, and it was nowhere near what you proport.
I do object to you stealing this thread, it is a fun one. Why don't you start your own thread?
I lead the team and gave many of the press interviews, I know what we said, and it was nowhere near what you proport.
I do object to you stealing this thread, it is a fun one. Why don't you start your own thread?
212man....
Trust me young feller....on this side of the pond....we care even less about class distinctions than you might surmise. To borrow an idea from a great American Hero....Forrest Gump...."Class is as Class does!" It may be learned but it is not inherited. I do believe that is not the way it works on your side of the salt water divide.
How does that old saw go....no offense meant here Nick..."Never trust a Jewish guy with an attorney, a Frenchman with a snag tooth, a Greek wearing tennis shoes, don't do business with a Chinese, and never let an English Gentleman owe you money."
Trust me young feller....on this side of the pond....we care even less about class distinctions than you might surmise. To borrow an idea from a great American Hero....Forrest Gump...."Class is as Class does!" It may be learned but it is not inherited. I do believe that is not the way it works on your side of the salt water divide.
How does that old saw go....no offense meant here Nick..."Never trust a Jewish guy with an attorney, a Frenchman with a snag tooth, a Greek wearing tennis shoes, don't do business with a Chinese, and never let an English Gentleman owe you money."
Resisting the temptation to respond further, in defference to the original thread starter, a couple more comments that are heard from time to time (maybe not urban myths, but certainly innacuracies believed by some as true):
Regarding flight planning: "it doesn't matter that the wind is stronger than we planned for, as what we lose on the way there, we'll make up for on the way back"
Regarding max take off weight (when using a WAT graph): "we can take off a bit heavier than the graph as we have loads of runway", or "we can take off a bit heavier than the graph as there's a strong wind."
Regarding flight planning: "it doesn't matter that the wind is stronger than we planned for, as what we lose on the way there, we'll make up for on the way back"
Regarding max take off weight (when using a WAT graph): "we can take off a bit heavier than the graph as we have loads of runway", or "we can take off a bit heavier than the graph as there's a strong wind."
Another thread gave me the idea. I heard that early in my training and it is still teached to new CP students.
"When flying inadvertly into IM conditions, you should immediately enter autorotation."
I had the opportunity to see in real life that this would be very, very dangerous. A few years ago I was sitting in the class room at my university and I could see an EMS helicopter flying low over the town right into a cloud. Fortunately he did not autorotate but made 180. He came out of the cloud after a few seconds very nose low. If he had autorotated he would have crashed, because the cloud touched the ground.
But here is the question, is it save to autorotate through a cloud deck? Provided you are sure that there is enough space below the clouds to continue the flight in VMC.
"When flying inadvertly into IM conditions, you should immediately enter autorotation."
I had the opportunity to see in real life that this would be very, very dangerous. A few years ago I was sitting in the class room at my university and I could see an EMS helicopter flying low over the town right into a cloud. Fortunately he did not autorotate but made 180. He came out of the cloud after a few seconds very nose low. If he had autorotated he would have crashed, because the cloud touched the ground.
But here is the question, is it save to autorotate through a cloud deck? Provided you are sure that there is enough space below the clouds to continue the flight in VMC.
JimL,
You place way. way, way too much faith in the FAA when it comes to things like that.
Engines do not quit on singles when you are IMC...dont'cha know...it is the single generator and other lack of redundancies that make me wonder.
It is odd how the FAA can have one view on issues if it is a three hundred seat airliner or a five seat JetRanger. Is it the sheer number of lives that matter?
Last year the EMS industry killed more people than did the airlines in this country.....and how many of them were single engined aircraft in IMC conditions?
You place way. way, way too much faith in the FAA when it comes to things like that.
Engines do not quit on singles when you are IMC...dont'cha know...it is the single generator and other lack of redundancies that make me wonder.
It is odd how the FAA can have one view on issues if it is a three hundred seat airliner or a five seat JetRanger. Is it the sheer number of lives that matter?
Last year the EMS industry killed more people than did the airlines in this country.....and how many of them were single engined aircraft in IMC conditions?
Ah, ups, sorry, I was talking about europe and VFR pilots. If I am not totaly wrong, the FAA training does not (yet) require a helicopter pilot to do any instrument training. The argument for entering autorotation immediately when flying inadvertly into IMC was that in an autorotation the helicopter is more stable.
Flying SE in IMC has been done for years with planks and I can see no reason why not in a helicopter. I is up to the pilot to consider all factors and a lot of SE plank drivers set their limits in a way that they don't fly IFR when they have no chance land in the event of an engine failure.
BTW in a helicopter I can not fly SEIFR commercialy and there aren't many private SEIFR helicopters around. I would probably be very difficult to find an accident report about an engine failure while flying SEIFR in a helicopter.
Flying SE in IMC has been done for years with planks and I can see no reason why not in a helicopter. I is up to the pilot to consider all factors and a lot of SE plank drivers set their limits in a way that they don't fly IFR when they have no chance land in the event of an engine failure.
BTW in a helicopter I can not fly SEIFR commercialy and there aren't many private SEIFR helicopters around. I would probably be very difficult to find an accident report about an engine failure while flying SEIFR in a helicopter.
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I learned to fly instruments in a SE helicopter, and logged lots of instrument time in them. The UH1 was a decent instrument platform (and still is) and the Army flies in IMC routinely in the TH57(?), or whichever number the 206 has these days. They launch into 1/4 mile IMC all the time in training, and AFAIK have had few, if any, accidents attributable to engine failure. I had far rather fly IMC in a turbine helicopter than in a light piston SE airplane, and they fly IMC all the time. Single-engine IMC in commercial operations is another matter, though. The FAA's view is that you can kill yourself whenever you want, you can kill 9 passengers if you exercise a little care, but you can't kill 10 without jumping through more hoops - thus the 9 or few pax rules, and the 10 or more rules. Then when you get to 20 it's more stringent. This is why you'll never see 20-passenger helicopters in the GOM - 20 pax requires a paid and trained flight attendant. Whether this makes sense is moot, because the bureaucracy has to have rules, and any number they pick is arbitrary.
Ever been night flying away from the airport TT?
If you cannot see it....you can fly into it without knowing it ahead of time.
If you cannot see it....you can fly into it without knowing it ahead of time.
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Sure.
maybe if you are flying in the middle of nowhere with no visual cues you are IMC anyway and therefore need the skills and/or kit.
If you do have visual cues/ambient/celestial light etc you are night VMC and then maybe there is no excuse.
maybe if you are flying in the middle of nowhere with no visual cues you are IMC anyway and therefore need the skills and/or kit.
If you do have visual cues/ambient/celestial light etc you are night VMC and then maybe there is no excuse.
There is always an excuse for spatial disorientation when flying during the night, even if it is VMC. During a night flight I had a false impression, that the terrain was climbing. I new it was flat, but my brain gave me another impression. There where lights everywhere but no moon. That happend about 10 miles from my home airport. I was very, very happy when I saw the airport with all those lights. That was a very disturbing experience.
Our brain produces that image of our environment and not the eye. That depends a lot from what we have learned to see or even what we want to see. It is very easy to confuse the brain.
Our brain produces that image of our environment and not the eye. That depends a lot from what we have learned to see or even what we want to see. It is very easy to confuse the brain.
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VRS in differently loaded helicopter
Great thread, got a lot ideas confirmed. Anyway, back to VRS:
If you have a helicopter with a pilot and some fuel weighing 1000kg and go out and at altitude gets VRS at 800fpm. After that you go back and fill it up to MAUW at 2000kg and try the same thing. At what descent-rate will VRS occur?
With my understanding of VRS, I would say that it will happen at a greater descent-rate, say 1400fpm. The reason beeing that a higher weight must generate a stronger downwash, so you need to go faster downwards to catch it and enter VRS.
What actually makes me wonder is that I've read in a book (can't remember wich one) that states it's easier to encounter VRS if ligtly loaded in same machine.
So... am I right or how wrong am I?
Cheers!
/2beers
If you have a helicopter with a pilot and some fuel weighing 1000kg and go out and at altitude gets VRS at 800fpm. After that you go back and fill it up to MAUW at 2000kg and try the same thing. At what descent-rate will VRS occur?
With my understanding of VRS, I would say that it will happen at a greater descent-rate, say 1400fpm. The reason beeing that a higher weight must generate a stronger downwash, so you need to go faster downwards to catch it and enter VRS.
What actually makes me wonder is that I've read in a book (can't remember wich one) that states it's easier to encounter VRS if ligtly loaded in same machine.
So... am I right or how wrong am I?
Cheers!
/2beers
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2beers,
You are right about the higher weight requiring more descent rate. Higher altitude also requires more descent rate, both of these are counter to the urban myth.
You are right about the higher weight requiring more descent rate. Higher altitude also requires more descent rate, both of these are counter to the urban myth.
And what about VRS in an autorotation or in a quick stop?
I remember a film that was shown at the Robinson Safety Course. It was during certification where they entered autorotation very low and landed very hard.
I am not quite sure if it was acctualy VRS.
Is it possible to get VRS during a flare? What conditions should one avoid to get into VRS during the flare? (If I had a choice)
I remember a film that was shown at the Robinson Safety Course. It was during certification where they entered autorotation very low and landed very hard.
I am not quite sure if it was acctualy VRS.
Is it possible to get VRS during a flare? What conditions should one avoid to get into VRS during the flare? (If I had a choice)
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Some early morning thoughts - forgive the smart a**, it is early!
The dreaded VRS cannot be experienced anywhere except when the rotor is forced to eat its own downwash, at descent speeds that are near zero forward speed and near 75% of the downwash speed (relative to the rotor axis). Nowhere else in the rotor flow regime will VRS occur.
Like Typhoid Mary, VRS has been blamed for crimes where it wasn't even in the neighborhood, but the mythology earns it the blame:
If you are in autorotation, you can't get VRS
If you do a power recovery from an auto, and you are too low, you will hit the ground. In Test Piloting circles, we have a name for that. We call it hitting the ground (HTG). HTG occurs if you encounter the ground and you have any vertical velocity.
Now, some instructor, armed with Her Majesty's Best Helicopter Aerodynamics Manual (or George Bush's Best Aerodynamic Manual) will find on page 73 that you can get VRS while asleep on Tursdays, as well as while performing a power recovery auto. No you can't. You can however get HTG, call it VRS and nobody will stop you.
The ability to establish a descent at 8 knots forward and 1200 fpm downward to get VRS is clearly outside the power recovery and quick stop regime, but that does not prevent people from declaring it to be VRS anyway.
What can happen in the recovery or quick stop is that you demmand too much thrust from the rotor, by flaring too aggressively, and you then find yourself saturating the engiine's ability to cover your tracks. This makes the rotor rpm droop, and the MP or Torque go sky high,. Shortly afterward, you get HTG.
Try this:
Do a series of quick stops, strating very gently, from the same speed, say 25 knots. At each one, note the peak MP or torque.
Use the flare angle and the rate of nose up to make the quick stop a bit more aggressive each time. Don't get silly with this, just carefully get a little more agressive with each one, until you hit your power limits (or your personal limits, which shows intelligence). Note that each ever more rapid decel requires more power. Duh. Who needs VRS when we can have a HTG the old fashioned way?
The dreaded VRS cannot be experienced anywhere except when the rotor is forced to eat its own downwash, at descent speeds that are near zero forward speed and near 75% of the downwash speed (relative to the rotor axis). Nowhere else in the rotor flow regime will VRS occur.
Like Typhoid Mary, VRS has been blamed for crimes where it wasn't even in the neighborhood, but the mythology earns it the blame:
If you are in autorotation, you can't get VRS
If you do a power recovery from an auto, and you are too low, you will hit the ground. In Test Piloting circles, we have a name for that. We call it hitting the ground (HTG). HTG occurs if you encounter the ground and you have any vertical velocity.
Now, some instructor, armed with Her Majesty's Best Helicopter Aerodynamics Manual (or George Bush's Best Aerodynamic Manual) will find on page 73 that you can get VRS while asleep on Tursdays, as well as while performing a power recovery auto. No you can't. You can however get HTG, call it VRS and nobody will stop you.
The ability to establish a descent at 8 knots forward and 1200 fpm downward to get VRS is clearly outside the power recovery and quick stop regime, but that does not prevent people from declaring it to be VRS anyway.
What can happen in the recovery or quick stop is that you demmand too much thrust from the rotor, by flaring too aggressively, and you then find yourself saturating the engiine's ability to cover your tracks. This makes the rotor rpm droop, and the MP or Torque go sky high,. Shortly afterward, you get HTG.
Try this:
Do a series of quick stops, strating very gently, from the same speed, say 25 knots. At each one, note the peak MP or torque.
Use the flare angle and the rate of nose up to make the quick stop a bit more aggressive each time. Don't get silly with this, just carefully get a little more agressive with each one, until you hit your power limits (or your personal limits, which shows intelligence). Note that each ever more rapid decel requires more power. Duh. Who needs VRS when we can have a HTG the old fashioned way?
And another myth cleared. Thank's
Could have found that out by myself - no downwasch - no VRS (and we all agree now, that this is NOT settling with power).
But the book is wrong with tuesday, it's monday, because on sunday at 3 pm you get that terrible light that pulls you down and you try to recover on monday.
I should really ask for a refund for the ground school I got. But that was during the stone age of helicopter flying.
In that video I mentioned it went like this. Jump out of the ship - or wreck, whichever applys - ,throw your helmet on the ground and say nasty words. I am not sure, if they had that on the test card in this sequence.
Btw: It was NOT anybody from RHC who said it was VRS, it was my instructor. He is flying planks now anyway.
Could have found that out by myself - no downwasch - no VRS (and we all agree now, that this is NOT settling with power).
But the book is wrong with tuesday, it's monday, because on sunday at 3 pm you get that terrible light that pulls you down and you try to recover on monday.
I should really ask for a refund for the ground school I got. But that was during the stone age of helicopter flying.
The obvious question is Nick, once you have encountered HTG what is the immediate action and recovery sequence
Btw: It was NOT anybody from RHC who said it was VRS, it was my instructor. He is flying planks now anyway.
Last edited by Rotorbee; 31st Jan 2005 at 06:21.
I just realised something very odd in Nick's list.
# 10!!!!!
Isn't Nick one of "Them"? Ha! Gotcha!
What are you trying to hide from us, Nick? Are the 15 myths acctualy true? Is the Queens rotorcraft manual right!
# 10!!!!!
Isn't Nick one of "Them"? Ha! Gotcha!
What are you trying to hide from us, Nick? Are the 15 myths acctualy true? Is the Queens rotorcraft manual right!