Bell 206: JetRanger and LongRanger
oldrotorhead:
Yes, leave it to a "test pilot" to complicate the issue. Vaqueroaero never mentioned N1. He was referring only to the apparent lack of N2/NR split in a practice auto. Which is normal. He said he (erroneously) expected that the N2 needle would drop to 65% "idle" position. Others chimed in with similar (and similarly wrong) expectations, and then our boy Nick sez that when you pull the throttle back on an S-76A the rpm goes to 65-70%. Oh yeah, he fails to mention whether that's N1 or N2. Hey, even I was confused by that statement, so I *KNOW* that vaqueroaero, who was expecting "65%" N2 during his practice auto, is too. The other thing I question is, if the C-30 idle speed is set properly (59-65% according to the RR manual), then why, with the FCL on the idle stop, is the N1 65-70% in an S-76A? In my C-20 equipped ships, rolling the throttle to idle gives me 62% N1, just like on the ground. Do S-76A pilots not pull all the way back to the idle-stop?
Lord, some of you are dense beyond belief. Here is what I have observed: Sometimes in a practice auto, if I make a turn or a flare, the NR will increase above 100%. The N2 will start to follow the NR up, but it will *then* split and go back to 100% or so. Governed? Maybe not, but the N2 for some reason does not always follow the rotor up to the 107% limit.
And in fact, this is *exactly* the situation vaqueroaero described.
Matthew Parsons says:
...Which would be good advice, IF THERE WERE A CLUTCH. But there isn't. It's called a "freewheeling unit." And calling a FWU a "clutch" is like saying there's a clutch on the back wheel of your bicycle. Which we don't say. There is no clutch on a helicopter with a free-turbine engine. If the NR goes above the N2, either in practice autorotation or upon shutdown, then the FWU is working properly. According to vaqueroaero's original post, there was never any indication that the FWU was doing anything other than what it's supposed to.
Some of you people really need to learn more about how 206B's behave before spouting off about stuff you do not know. But that is a constant source of irritation on this board. Someone will ask a legitimate and specific question, then he'll get responses that start out, "I don't know the answer to this, but I think..." Hey, if you don't know the answer, why not leave it for those who DO?
Live and learn, boys, live and learn. And hopefully, vaqueroaero has learned...well...*something*...from this thread and is back flying his inappropriately-grounded 206. (I'd love to see the write-up and sign-off on the maintenance log on this one!)
PPN#1F..where did you get the impression that Nick said any thing about the N2 being at 70% at idle? Come on now, you must be aware he was referring to the N1.
And by the way, if you are in any doubt as to whether the governor on an Allison or RR 250 is working when the throttle or power lever/s is or are back at idle (in autorotation of course), try pulling the bloody lever up climbing away and see how quick your "governed" N2 gives up. Haven't ya noticed what happens to the N2 during the terminationof a practice EOL, even at the hover?
And in fact, this is *exactly* the situation vaqueroaero described.
Matthew Parsons says:
In any case, ensure the clutch is working properly.
Some of you people really need to learn more about how 206B's behave before spouting off about stuff you do not know. But that is a constant source of irritation on this board. Someone will ask a legitimate and specific question, then he'll get responses that start out, "I don't know the answer to this, but I think..." Hey, if you don't know the answer, why not leave it for those who DO?
Live and learn, boys, live and learn. And hopefully, vaqueroaero has learned...well...*something*...from this thread and is back flying his inappropriately-grounded 206. (I'd love to see the write-up and sign-off on the maintenance log on this one!)
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Yes it is quite interesting seeing some of the views on this one,
Im still with PPF.! on this one regarding N2 split,
the B206 has a FWU which is a "sprag bearing" and is a nice tight fit, it has to be other wise when it comes to drive it will slip when engaging and wouldnt be healthy, so" there is drag on that "sprag bearing" when free wheeling, when the rpm rises, flaring lets say, there is a slight increase in N2, be it only small,
Balanced decent in an auto with a flare at the bottom and the nose Yaws left, transmission: drag. same kind of thing.
It ain't broken......
Im still with PPF.! on this one regarding N2 split,
the B206 has a FWU which is a "sprag bearing" and is a nice tight fit, it has to be other wise when it comes to drive it will slip when engaging and wouldnt be healthy, so" there is drag on that "sprag bearing" when free wheeling, when the rpm rises, flaring lets say, there is a slight increase in N2, be it only small,
Balanced decent in an auto with a flare at the bottom and the nose Yaws left, transmission: drag. same kind of thing.
It ain't broken......
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It is really enlightening to see the varied opinions from so many people. Let me put in my 2 cents worth. Before I get drilled from the other highly regarded participants, I am going to give what I know to be a likely possibility from years of maintenance experience as well as flying experience in the type.
This applies to a Bell 206 and the RR 250 engiine.
First: when the twist grip is rolled to flight idle the governor is out of the system.
Second: Once the twist grip is in the flight idle positionwhile in flight (autorotation), the N2 RPM will be TOTALLY dependant on what maintenance has the Fuel Control (N1) IDLE setting at. If the FCU idle is on the high side, there will be NO needle split in autorotation. For training ships, it is generally a good idea to set idle on the low side to get a good needle split in autorotation.
Third: Don't ever fly a machine if you suspect the freewheeling unit to be defective. The life you save may be your OWN! You can check it on the ground as others have stated by rotating the rotor both directions and listening/observing the 4th stage turbine wheel in the exhaust stack. Rotate the rotor IN the direction of rotation and the turbine should NOT rotate, and there should not be any rubbing/chattering noises. Rotate the rotor opposite the direction of rotoation, and the turbine SHOULD turn, and you MAY get some additional "whirring"noise from the engine.
Most importantly what I have drawn from this thread is if you have a maintenance question, ASK A MAINTENANCE TYPE!!!! Pilots are notorius for trying to baffle with BS when they aren't sure. Yes, I am an ATP. :-)
This applies to a Bell 206 and the RR 250 engiine.
First: when the twist grip is rolled to flight idle the governor is out of the system.
Second: Once the twist grip is in the flight idle positionwhile in flight (autorotation), the N2 RPM will be TOTALLY dependant on what maintenance has the Fuel Control (N1) IDLE setting at. If the FCU idle is on the high side, there will be NO needle split in autorotation. For training ships, it is generally a good idea to set idle on the low side to get a good needle split in autorotation.
Third: Don't ever fly a machine if you suspect the freewheeling unit to be defective. The life you save may be your OWN! You can check it on the ground as others have stated by rotating the rotor both directions and listening/observing the 4th stage turbine wheel in the exhaust stack. Rotate the rotor IN the direction of rotation and the turbine should NOT rotate, and there should not be any rubbing/chattering noises. Rotate the rotor opposite the direction of rotoation, and the turbine SHOULD turn, and you MAY get some additional "whirring"noise from the engine.
Most importantly what I have drawn from this thread is if you have a maintenance question, ASK A MAINTENANCE TYPE!!!! Pilots are notorius for trying to baffle with BS when they aren't sure. Yes, I am an ATP. :-)
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fostaire,
How nice to see a civilised, knowledgeable reply without a hint of condescension like those from PF#1.
Naturally, there is a clutch involved. In simplified terms, a sprag clutch is a freewheeling clutch which through a system of roller bearings allows a drive to be transmitted in one direction whilst, through its freewheeling mechanism, in the case of a helicopter, it allows the engine to run down to idle whilst the rotor RPM are not dragged down with it.
Nick may have omitted to mention that it is the N1 which go to idle, whilst the N2 stays loosely at the same value as the Nr, but be assured that his observations on PPRuNe will always carry more weight than those of PF#1 because we all know where Nick is coming from - after all he posts openly under his own name, unlike either PF#1 or myself and Nick is not insufferably pompous, arrogant and overbearing in his replies
How nice to see a civilised, knowledgeable reply without a hint of condescension like those from PF#1.
Naturally, there is a clutch involved. In simplified terms, a sprag clutch is a freewheeling clutch which through a system of roller bearings allows a drive to be transmitted in one direction whilst, through its freewheeling mechanism, in the case of a helicopter, it allows the engine to run down to idle whilst the rotor RPM are not dragged down with it.
Nick may have omitted to mention that it is the N1 which go to idle, whilst the N2 stays loosely at the same value as the Nr, but be assured that his observations on PPRuNe will always carry more weight than those of PF#1 because we all know where Nick is coming from - after all he posts openly under his own name, unlike either PF#1 or myself and Nick is not insufferably pompous, arrogant and overbearing in his replies
anjouan:
And so by that standard, anjouan, we shouldn't pay any attention to anything you say either, eh?
I really detest this site and the way some of you gits get. You feel that it's okay to say anything at all (even if it's incorrect) as long as it's veddy, veddy polite. After all, if it's not said with just the proper temperament, then we don't want to hear it, eh what? Which is why, I guess, Nick Lappos can make conflicting and contradictory statements but nobody dares say anything.
Vaqueroaero posted his little issue. Nick replied with, "The condition isn't normal, I think." Later on, he sez, "The needles will split, virtually all the time, when you command the engine to idle with the throttle while the rotor is at 100%. If you just let the collective down and the rotor builds upward, the engine will still be governed, and will creep up to about 103%."
Let me see if I got this right: So the engine is not governed but then again it is, and the N2 will definitely split but will stay up around 100%, maybe as high as 103. According to Nick.
Oooookay. Clear as mud now!
Nick again: If you do not get a clean needle split when you roll the throttle to idle and the rotor stays at 100%, then land the aircraft and give it to pprune fan #1.
In other words, give it to a pilot who's actually qualified to fly it, knows something about it and knows improper conditions from proper ones. Yes, I'll buy that.
Here's a scenario for you self-appointed experts out there: What if you're solo and have minimum fuel when you do your auto rpm check? Even at flat pitch, the NR will decay from 100% to where it ought to be for that machine. As will the N2. Definite split? Not. Nope. No way.
And Matthew, every helicopter has a sprague clutch (FWU), that is a given. Pistons and fixed-turbine ships have other clutches that actually allow the engine to rev above the NR upon start-up. I have met many RR 250 pilots who really, truly thought that their steed had also had such a "clutch" in addition to the FWU. I was afraid you were one of them. See, we turbine pilots do not refer to the FWU as a clutch except as a conjunctive term.
Threads like this are actually a lot of fun. I'm sure there are a lot of pilot-readers out there going, "You mean turbines *don't* have clutches?" "You mean the N2 needle of a free turbine won't go to idle when you roll the throttle off in flight?" "You mean the N2 needle in a free-turbine engine might not even split in a practice auto?"
Nick may have omitted to mention that it is the N1 which go to idle, whilst the N2 stays loosely at the same value as the Nr, but be assured that his observations on PPRuNe will always carry more weight than those of PF#1 because we all know where Nick is coming from - after all he posts openly under his own name, unlike either PF#1 or myself.
I really detest this site and the way some of you gits get. You feel that it's okay to say anything at all (even if it's incorrect) as long as it's veddy, veddy polite. After all, if it's not said with just the proper temperament, then we don't want to hear it, eh what? Which is why, I guess, Nick Lappos can make conflicting and contradictory statements but nobody dares say anything.
Vaqueroaero posted his little issue. Nick replied with, "The condition isn't normal, I think." Later on, he sez, "The needles will split, virtually all the time, when you command the engine to idle with the throttle while the rotor is at 100%. If you just let the collective down and the rotor builds upward, the engine will still be governed, and will creep up to about 103%."
Let me see if I got this right: So the engine is not governed but then again it is, and the N2 will definitely split but will stay up around 100%, maybe as high as 103. According to Nick.
Oooookay. Clear as mud now!
Nick again: If you do not get a clean needle split when you roll the throttle to idle and the rotor stays at 100%, then land the aircraft and give it to pprune fan #1.
In other words, give it to a pilot who's actually qualified to fly it, knows something about it and knows improper conditions from proper ones. Yes, I'll buy that.
Here's a scenario for you self-appointed experts out there: What if you're solo and have minimum fuel when you do your auto rpm check? Even at flat pitch, the NR will decay from 100% to where it ought to be for that machine. As will the N2. Definite split? Not. Nope. No way.
And Matthew, every helicopter has a sprague clutch (FWU), that is a given. Pistons and fixed-turbine ships have other clutches that actually allow the engine to rev above the NR upon start-up. I have met many RR 250 pilots who really, truly thought that their steed had also had such a "clutch" in addition to the FWU. I was afraid you were one of them. See, we turbine pilots do not refer to the FWU as a clutch except as a conjunctive term.
Threads like this are actually a lot of fun. I'm sure there are a lot of pilot-readers out there going, "You mean turbines *don't* have clutches?" "You mean the N2 needle of a free turbine won't go to idle when you roll the throttle off in flight?" "You mean the N2 needle in a free-turbine engine might not even split in a practice auto?"
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pprunefan#1,
It is clear from your adrenalin-fueled rants that whatever crawled up your butt remains there. I do think most readers will get more out of this with less storm, and more discourse.
Regarding what someone with an open mind could have learned here:
1) The engine is NOT governed when the throttle is at idle. It is set to a relatively fixed fuel flow. (BTW - For CECO fuel controls, it is an absolutely fixed fuel flow, changable only by maintenance setting. Once, 25 years ago, we had to shim the idle metering valve, because we ran out of turns on it, and could not get a start.)
2) The Nr/N2 needles will split most of the time in a 206, and MUST split all of the time in a Sikorsky, when the rotor is at 100% in auto, and the engine(s) throttle(s) are at idle. SOME 206's might not show a split if their fixed idle settings are on the high side.
3) If you don't get a split while at idle in an auto, ask questions, because it could be a bad thing in a 206, and always is a bad thing in most other helicopters.
4) If you want a clean, carefully thought out answer, don't ask Pprune fan #1. He doesn't like to share his info, he likes to whack you in the head with a shovelful of it.
It is clear from your adrenalin-fueled rants that whatever crawled up your butt remains there. I do think most readers will get more out of this with less storm, and more discourse.
Regarding what someone with an open mind could have learned here:
1) The engine is NOT governed when the throttle is at idle. It is set to a relatively fixed fuel flow. (BTW - For CECO fuel controls, it is an absolutely fixed fuel flow, changable only by maintenance setting. Once, 25 years ago, we had to shim the idle metering valve, because we ran out of turns on it, and could not get a start.)
2) The Nr/N2 needles will split most of the time in a 206, and MUST split all of the time in a Sikorsky, when the rotor is at 100% in auto, and the engine(s) throttle(s) are at idle. SOME 206's might not show a split if their fixed idle settings are on the high side.
3) If you don't get a split while at idle in an auto, ask questions, because it could be a bad thing in a 206, and always is a bad thing in most other helicopters.
4) If you want a clean, carefully thought out answer, don't ask Pprune fan #1. He doesn't like to share his info, he likes to whack you in the head with a shovelful of it.
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PF#1 is the only person who in his rantings will eventually be ignored just because of the unpleasantness of his manner. If you detest this site so much I suggest you stay off it in future - you will not be missed.
I did not say that posts from anyone who posts anonymously should not be paid attention to, merely that we all know who Nick is and that, therefore we know where he's coming from and how well qualified he is when he makes his informative comments on technical matters.
The main one who is confused around here seems to be you. For example
. So there isn't a clutch, yet every helicopter has one?! 
A clutch is merely a device for connecting two rotating shafts of which there are, of course, many in a helicopter. A sprag clutch is a clutch mechanism which incorporates a freewheeling unit so that the two rotating shafts can be disengaged if the inner one slows down. In a turbine, this allows the engine compressor and it's associated gas generator to be at idle, without dragging down the rotor. Naturally, on the ground the rotor will slow down if it is not being driven at a flight rpm power setting, whilst its rpm in autorotation will vary depending the factors altering the autorotative force. So as fostaire and Nick have pointed out, the N1 and N2 will depend on the maintenance settings on the CECO FCU, whilst the Nr will vary depending on whether the aircraft is in a steady state autorotation or is being manoeuvred, which could cause an increase or a decrease. If the steady state auto are too low, they can be increased by engineering making adjustments to the blade pitch.
Naturally PF#1 will now write a 10 page rant explaining how all of the above is rubbish, especially as
, or maybe
. Confused? You will be 
I did not say that posts from anyone who posts anonymously should not be paid attention to, merely that we all know who Nick is and that, therefore we know where he's coming from and how well qualified he is when he makes his informative comments on technical matters.
The main one who is confused around here seems to be you. For example
IF THERE WERE A CLUTCH. But there isn't.
every helicopter has a sprague clutch (FWU), that is a given.
Oooookay. Clear as mud now!
Naturally PF#1 will now write a 10 page rant explaining how all of the above is rubbish, especially as
I really detest this site and the way some of you gits get.
Threads like this are actually a lot of fun.
anjouan, you have contributed exactly ZERO to this thread. I suggest you simply stay out of it unless you have something positive to contribute.
There. Short enough for you?
EDIT: Oops! I just went back and re-read your post, old bean. You wrote:
See what I mean about people who don't know what they're talking about? Let's go back to Turbines 101. Sonny, the COMPRESSOR/GAS GENERATOR can speed up and slow down at will with absolutely no effect on the NR. It is only "gas coupled" to the rotor.
It is the N2 shaft that is the one connected to the trans. The sprague clutch allows the N2 wheels/shaft to do slow down without effecting the NR. (Not exactly ten pages but it will have to do.)
Don't you people understand this subject? I thought you guys were smarter than this. Guess I was wrong. Gosh I hate that.
Oh Nick!
Nick, you ought to stick to Sikorskys. Or Gulfstreams. Or Mooneys. Or whatever it is you're flying these days. You evidently don't know much about 206s if you say something like getting a split "most" of the time in a 206. Wrong!
It is not *always* a bad thing in a H-500. It is not *always* a bad thing in an E-480. It is not always a bad thing in a S-333. It is not *always* a bad thing in a Twinstar. It is not *always* a bad thing in a BO105. Did I leave any RR-250 ship out?
If anyone is doing anything with a shovel, it ain't me. But yeah, there sure is a lot of shovelling going on here.
There. Short enough for you?
EDIT: Oops! I just went back and re-read your post, old bean. You wrote:
A sprag clutch is a clutch mechanism which incorporates a freewheeling unit so that the two rotating shafts can be disengaged if the inner one slows down. In a turbine, this allows the engine compressor and it's associated gas generator to be at idle, without dragging down the rotor.
It is the N2 shaft that is the one connected to the trans. The sprague clutch allows the N2 wheels/shaft to do slow down without effecting the NR. (Not exactly ten pages but it will have to do.)
Don't you people understand this subject? I thought you guys were smarter than this. Guess I was wrong. Gosh I hate that.
Oh Nick!
2) The Nr/N2 needles will split most of the time in a 206, and MUST split all of the time in a Sikorsky, when the rotor is at 100% in auto, and the engine(s) throttle(s) are at idle. SOME 206's might not show a split if their fixed idle settings are on the high side.
3) If you don't get a split while at idle in an auto, ask questions, because it could be a bad thing in a 206, and always is a bad thing in most other helicopters.
If anyone is doing anything with a shovel, it ain't me. But yeah, there sure is a lot of shovelling going on here.
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PF#1, you really are a most obnoxious person and it's not surprising you were thrown off when you were using your other name. I am not, nor ever will be any b*astard son of yours - I'd kill myself if I were, but as I'm almost certainly older than you I think it unlikely. What exactly, pray, do you feel you have contributed to this thread? You spotted my small error (freely admitted) and then rant on and on in your usual arrogant and condescending fashion. Yes I'm human, I make errors, but you just hate to be wrong don't you? Wow, a perfect pilot - you must be the first one ever then. You wind yourself up so quickly, it's probably just as well you're a manager now - someone as unstable as you would probably be a danger to all when flying. Your English, which unlike mine is probably your native language is not much better either. It's a sprag clutch SONNY
Okay.... so there isn't a clutch in there, but the one which isn't there allows the N2 shaft to do slow down without affecting the Nr.
So have you decided yet whether there is or isn't a clutch in there somewhere? You're such an obnoxious git, it's not worth commenting further. I'll leave you to finish off with another of your tirades.
IF THERE WERE A CLUTCH. But there isn't.
The sprague clutch allows the N2 wheels/shaft to do slow down without effecting the NR
So have you decided yet whether there is or isn't a clutch in there somewhere? You're such an obnoxious git, it's not worth commenting further. I'll leave you to finish off with another of your tirades.
Something I used to do before doing an autorotation in a strange aircraft......while setting on the ground at full chat....pull an arm full of collective...getting the aircraft light on the skids....then roll the throttle off....checking for the right indications which included a needle split. Alternatively, a hovering auto will do the same but requires you to be "airborne".
anjouan:
Oh anjouan. If it makes you feel better...superior?...makes you feel like MORE OF A MAN to criticize my spelling/grammar, then have at it. Frankly, I would have expected more maturity from the PPRUNE group and only expected such childish behaviour from that from the bunch over at Just Helicopters but you have proved me wrong. AGAIN! Good job, old sod! It is interesting though that you harp on *my* alleged mistakes whilst seemingly glossing over your own as if they were inconsequential. Curious, that. But there you go.
Oh, and you call yours a "small error?" Son, confusing N1 and N2 is not a "small error." It shows a real, basic, solid lack of understanding of how turbine engines work.
Any why you keep harping on my previously getting banned is also curious. Wishful thinking on your part now? Would you prefer that all people with whom you disagree be somehow banished from your lofty presence? That posters whom you deem "unpleasant" be permanently removed from this board? Get off the banning issue, you Board Nazi. The mods know full well that if they ban someone, that someone will just change identities and come back. I've got more email addresses than Frank R. has lawsuits.
SASless:
During such procedure, performed in a 206, the MR decay will be too fast to notice any N2/NR needle-split, so I'm not sure what good that would do. BZZZZZT! But good try, thanks for playing.
So at the end of the day, what have we (vaqueroaero) learned from this thread? Well, according to people who actually fly them, 206's do *not* always show a definite N2/NR needle-split in a practice autorotation. In fact, *most* times they won't. There is hardly any noticeable difference in a 206 between flat-pitch/full-throttle and flat-pitch/idle-throttle. Which is what I've said FROM THE BEGINNING. Any questions?
pprune fan #1, your personal attacks and general manner are not what we all want on pprune. I must caution you about this. None of us want this site to go the way of others. Behave or be gone.
PedalStop
as unstable as you would probably be a danger to all when flying. Your English, which unlike mine is probably your native language is not much better either.
Oh, and you call yours a "small error?" Son, confusing N1 and N2 is not a "small error." It shows a real, basic, solid lack of understanding of how turbine engines work.
Any why you keep harping on my previously getting banned is also curious. Wishful thinking on your part now? Would you prefer that all people with whom you disagree be somehow banished from your lofty presence? That posters whom you deem "unpleasant" be permanently removed from this board? Get off the banning issue, you Board Nazi. The mods know full well that if they ban someone, that someone will just change identities and come back. I've got more email addresses than Frank R. has lawsuits.
SASless:
Something I used to do before doing an autorotation in a strange aircraft......while setting on the ground at full chat....pull an arm full of collective...getting the aircraft light on the skids....then roll the throttle off....checking for the right indications which included a needle split.
So at the end of the day, what have we (vaqueroaero) learned from this thread? Well, according to people who actually fly them, 206's do *not* always show a definite N2/NR needle-split in a practice autorotation. In fact, *most* times they won't. There is hardly any noticeable difference in a 206 between flat-pitch/full-throttle and flat-pitch/idle-throttle. Which is what I've said FROM THE BEGINNING. Any questions?
pprune fan #1, your personal attacks and general manner are not what we all want on pprune. I must caution you about this. None of us want this site to go the way of others. Behave or be gone.
PedalStop
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From and ole mech's point of view:
1. I don't mean to be critical, but I wouldn't ground or unground an aircraft based on information from the internet. Suggest you consult your local Bell CSR or Product Support Engineering if you are that concerned.
2. Nick's wrong and PF#1 is correct, though Nick did relent and say they may not split: There won't be a split as there is enough airflow from the engine at idle to keep the turbine up to rotor speed during an auto. The only time that I can remember seeing a split is after shutting down the engine you will see a split if you don't use the rotor brake and let the engine spool down.
3. PF#1 is wrong and Nick is correct: At idle the N2 governor is inoperative. Don't believe me, use the N2 governor beep switch to beep up or down, note the N2 doesn't change. I've disconnected the N2 beep actuator to adjust the rod end and moved the N2 governor lever back and forth, it had no effect.
4. Regarding N1 idle speed setting, we always set the idle speed to the max side due to the fact that when operating in hot weather, if the idle speed was on the slow side we would sometime get a flickering Xmsn Gbx Oil Press. light
5. As mentioned before, if you rotate the rotor by hand in one direction and it turns the turbine and then in the other direction and it doesn't you don't have a stuck clutch.
6. The 206 has a free wheeling unit that allows the rotor to turn free in one direction and locks the shaft in the other direction. Inside of that free wheeling unit, is a "Sprag Clutch". So yes there is a clutch on the 206, but it is not a series of roller bearing. It's hard to explain what the Sprag looks like but they don't roll, but act more like wedges so that they lock the shaft to the outer coupling when the engine is producing more torque than the rotor. If the rotor produces more torque, such as in an auto rotation then the outer coupling can rotate freely around the engine output shaft.
So after all this diatribe, what did "vaqueroaero" do with his aircraft, did he change the free wheel unit, call Bell PSE or just keep flying his aircraft? Stay tuned folks for tomorrow there will be a new episode of "As the Rotor Turns"
Chuck
1. I don't mean to be critical, but I wouldn't ground or unground an aircraft based on information from the internet. Suggest you consult your local Bell CSR or Product Support Engineering if you are that concerned.
2. Nick's wrong and PF#1 is correct, though Nick did relent and say they may not split: There won't be a split as there is enough airflow from the engine at idle to keep the turbine up to rotor speed during an auto. The only time that I can remember seeing a split is after shutting down the engine you will see a split if you don't use the rotor brake and let the engine spool down.
3. PF#1 is wrong and Nick is correct: At idle the N2 governor is inoperative. Don't believe me, use the N2 governor beep switch to beep up or down, note the N2 doesn't change. I've disconnected the N2 beep actuator to adjust the rod end and moved the N2 governor lever back and forth, it had no effect.
4. Regarding N1 idle speed setting, we always set the idle speed to the max side due to the fact that when operating in hot weather, if the idle speed was on the slow side we would sometime get a flickering Xmsn Gbx Oil Press. light
5. As mentioned before, if you rotate the rotor by hand in one direction and it turns the turbine and then in the other direction and it doesn't you don't have a stuck clutch.
6. The 206 has a free wheeling unit that allows the rotor to turn free in one direction and locks the shaft in the other direction. Inside of that free wheeling unit, is a "Sprag Clutch". So yes there is a clutch on the 206, but it is not a series of roller bearing. It's hard to explain what the Sprag looks like but they don't roll, but act more like wedges so that they lock the shaft to the outer coupling when the engine is producing more torque than the rotor. If the rotor produces more torque, such as in an auto rotation then the outer coupling can rotate freely around the engine output shaft.
So after all this diatribe, what did "vaqueroaero" do with his aircraft, did he change the free wheel unit, call Bell PSE or just keep flying his aircraft? Stay tuned folks for tomorrow there will be a new episode of "As the Rotor Turns"
Chuck
Last edited by chuckolamofola; 16th Jul 2005 at 05:41.
pprune fan #1, your personal attacks and general manner are not what we all want on pprune. I must caution you about this. None of us want this site to go the way of others. Behave or be gone.
So go ahead, ban me if you want. Yep, you sure wouldn't want to criticize Nick (LAST NAME DELETED) for putting out bad poop and then clouding the issue by bringing N1 into it (sort of). Oh nooooo. Meh- this thread has run it's course anyway, who really cares.
Wait- I mean ban this SN. I'm shortly going to be switching internet providers at the house anyway. So in the words of the great Ah-nold Schwollenpekka, I'll be Bach.
pprune fan #1,
This is a moderated group, either conform or get out. Your choice. I find others who can disagree with each other and not use the same rude and denigrating manner. This is not a warning, it is a 3 day ban.
PedalStop
Last edited by PedalStop; 17th Jul 2005 at 16:35.
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Jetranger LTE
I have noticed that most accidents relating to Loss of Tailrotor Effectiveness (LTE) seem to involve the Bell 206. It is not very often if at all that i have heard of an LTE accident involving any other type. Is there a reason for this or is it my imagination. Are B206's more susseptable to this condition than other types.
John
John
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Fan #1
No one has a problem with the fact that you disagree or agree with anyone else. It is your delivery.
Vaqueroaero is not some helpless idiot. He is not going to go out and ground a machine because of one person's opinion. Nor is he going to go fly around on something he is questioning becasue you say it is ok. He is looking for some opinions or maybe some input if others have had a similar experience. With this input, and the advice of others he trusts, he will make a decision. No different than decisions people make every day.
No one has a problem with the fact that you disagree or agree with anyone else. It is your delivery.
Vaqueroaero is not some helpless idiot. He is not going to go out and ground a machine because of one person's opinion. Nor is he going to go fly around on something he is questioning becasue you say it is ok. He is looking for some opinions or maybe some input if others have had a similar experience. With this input, and the advice of others he trusts, he will make a decision. No different than decisions people make every day.
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I've learned something really useful from this.
My CV that would have been addressed to PHI is now going in the bin.
If Prunefan#1 is typical of the management attitude prevailing there, I want no part of it.
My CV that would have been addressed to PHI is now going in the bin.
If Prunefan#1 is typical of the management attitude prevailing there, I want no part of it.
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We used to own a Hughes 269B. It could be very short on left peddle authority. In a strong wind near max gross you couldn't do a 360 in the hover using the left peddle. The Schweizer/Hughes 300C is a much different beast however and has lots of tail rotor effectiveness.
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Theoretically, any helicopter could experience LTE. Modern designs tend not to experience LTE in typical flight conditions.
Jetrangers are high in numbers, have been around for a while, and are used in places where maximum power is frequently demanded. Because of all this, I'd expect to see more LTE problems with a Jet ranger.
And yes, they are more susceptible compared to many types.
Jetrangers are high in numbers, have been around for a while, and are used in places where maximum power is frequently demanded. Because of all this, I'd expect to see more LTE problems with a Jet ranger.
And yes, they are more susceptible compared to many types.
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Big_J,
You'll find that the majority (if not all!) of 206 LTE cases are in the earlier models with the smaller tail-rotor. There isn't alot of authority there especially at or close to max gross and you really have to be on the ball. Found it most dangerous when scanning fires, not a pleasant feeling when the tail steps out when you're heavy low and slow!
You'll find that the majority (if not all!) of 206 LTE cases are in the earlier models with the smaller tail-rotor. There isn't alot of authority there especially at or close to max gross and you really have to be on the ball. Found it most dangerous when scanning fires, not a pleasant feeling when the tail steps out when you're heavy low and slow!