ROBINSON FORUM NEEDED (URGENTLY)
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Helidrvr ,
Hi there....IMHO you are doing a !!!!! hot job of moderating this forum.Us helo pilots are so diverse in our opinions and thoughts due to the wide and varying tasks that helicopters are used for and I think you are dealing with things very well.
To the rest of the helo ppruners ,
We fly or work with the best aircraft in the world...the helicopter.....so lets respect each others opinions and views and stop throwing our toys out of the cot everytime someone says something that we may not like.
Just remember helo pilots rule and plankies drool...
rgds
The bear.
------------------
..AD ASTRA PER NOSTRUM..
(Dont pick your nose on finals)
Hi there....IMHO you are doing a !!!!! hot job of moderating this forum.Us helo pilots are so diverse in our opinions and thoughts due to the wide and varying tasks that helicopters are used for and I think you are dealing with things very well.
To the rest of the helo ppruners ,
We fly or work with the best aircraft in the world...the helicopter.....so lets respect each others opinions and views and stop throwing our toys out of the cot everytime someone says something that we may not like.
Just remember helo pilots rule and plankies drool...
rgds
The bear.
------------------
..AD ASTRA PER NOSTRUM..
(Dont pick your nose on finals)
Guest
Posts: n/a
When I first saw the comments made towards Lu I thought, thats a little harsh. Then I continued to read Lu's distorted understanding of physics and helicopter dynamics and how fiercely he defended this distorted view. Lu you really make youself look stupid. No one should argue so strongly on a subject that they know so little about. I agree that you should be free to post, but again, Lu, you have really embarrassed yourself to those of us who have a basic grasp on the subject of helicopter physics. Don't get me wrong, you obviously have a great deal of knowledge on many of the things we all discuss here and I enjoy reading many of your posts. But you made some statements that are just plain wrong.
[This message has been edited by helisphere (edited 13 January 2001).]
[This message has been edited by helisphere (edited 13 January 2001).]
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To: Helisphere
I checked out you website and looking at your picture I would place you in the late twenties or at the most in your early thirties. At the most, you were born in or around 1970. At that time I had been working as a mechanic or an engineer on helicopters for 21 years. Also, on your website you have a link to the Helicopter History Site. On that site you can click on Sikorsky and the history of their helicopter accomplishment. If you click on the first Coast Guard helicopter detachment you will see a group of individuals. One is listed as Boone, another as Brzcki,another named Erickson and another named Berry. These are the people that gave me my introduction to helicopter mechanics and I served with ADC Oliver Berry for three years and learned more about helicopters during that time than anyone else in the Coast Guard. After discharge I went to college and fresh out of college I was hired by Sikorsky and put into an intensive 14-month training program leading to a senior field engineer position.
I personally feel that you think I am an idiot because of your Robinson bias. If that is not true, then please tell me why I am an idiot and please tell me what I said is wrong and or stupid. I responded to your comments on another thread along with comments by two other individuals whom I think are wrong in their conclusions.
On a personal note I find it strange that a person that knows absolutely nothing about me or my background would have called me stupid based on his own personal bias
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The Cat
[This message has been edited by Lu Zuckerman (edited 13 January 2001).]
[This message has been edited by Lu Zuckerman (edited 13 January 2001).]
I checked out you website and looking at your picture I would place you in the late twenties or at the most in your early thirties. At the most, you were born in or around 1970. At that time I had been working as a mechanic or an engineer on helicopters for 21 years. Also, on your website you have a link to the Helicopter History Site. On that site you can click on Sikorsky and the history of their helicopter accomplishment. If you click on the first Coast Guard helicopter detachment you will see a group of individuals. One is listed as Boone, another as Brzcki,another named Erickson and another named Berry. These are the people that gave me my introduction to helicopter mechanics and I served with ADC Oliver Berry for three years and learned more about helicopters during that time than anyone else in the Coast Guard. After discharge I went to college and fresh out of college I was hired by Sikorsky and put into an intensive 14-month training program leading to a senior field engineer position.
I personally feel that you think I am an idiot because of your Robinson bias. If that is not true, then please tell me why I am an idiot and please tell me what I said is wrong and or stupid. I responded to your comments on another thread along with comments by two other individuals whom I think are wrong in their conclusions.
On a personal note I find it strange that a person that knows absolutely nothing about me or my background would have called me stupid based on his own personal bias
------------------
The Cat
[This message has been edited by Lu Zuckerman (edited 13 January 2001).]
[This message has been edited by Lu Zuckerman (edited 13 January 2001).]
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This is seems to have turned into a 'How much can we slag off Lu' debate.
I think that this is unfair and not justified.
Lu, you are obviously a very well educated man, who has worked hard for many years to develop such a broad and indepth knowledge. In my personal opinion, I think that the people who scathe your lengthy detailed replies perhaps do not understand to content, or wish that they were able to write in such a way.
Comparing knowledge, I am still very much a newbie. I could not even imagine knowing as much as it appears you do.
But, that is not a point of defeat, I hope that at some point in my career, I will be able to write such educational replies.
I think everyone should try to be a little more tolerant of each other and realise that we all have something valuable to give to all of these threads, whether it be in the depth of Lu's replies or not.
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THOSE WHO HAVE THE WILL TO WIN, CANNOT BE BEATEN!!
I think that this is unfair and not justified.
Lu, you are obviously a very well educated man, who has worked hard for many years to develop such a broad and indepth knowledge. In my personal opinion, I think that the people who scathe your lengthy detailed replies perhaps do not understand to content, or wish that they were able to write in such a way.
Comparing knowledge, I am still very much a newbie. I could not even imagine knowing as much as it appears you do.
But, that is not a point of defeat, I hope that at some point in my career, I will be able to write such educational replies.
I think everyone should try to be a little more tolerant of each other and realise that we all have something valuable to give to all of these threads, whether it be in the depth of Lu's replies or not.
---------------------------------------------
THOSE WHO HAVE THE WILL TO WIN, CANNOT BE BEATEN!!
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To Lu:
First of all, I never called you an idiot. I said you have made yourself look like one by the
statements you have made. Obviously you have a lot of credentials. That makes you look even
worse. It's like a scientist going around saying the earth is flat and the planets, sun, and stars all
rotate around it as the center of the universe.
Yes I am biased. I happen to think that Frank Robinson has done as much to better the helicopter
industry as Sikorsky, Hiller, Piasecki, Young, Kaman or any of the other helicopter pioneers.
However, any bias, be it good or bad, cannot alter the physical laws of nature. My bias has nothing
to do with calling you on false statements.
On to your false statements. I'll start with your post to helo teacher on 04 Jan 2001 04:57.
Your statements are in capitals.
THE PURPOSE OF THIS ILLUSTRATION IS TO DISPROVE FRANK ROBINSONS'
PREMISE OF CONSIDERING A 90-DEGREE PITCH HORN IN THE DESIGN OF THE
ROBINSON ROTORHEAD.
IF HE HAD THE OPPORTUNITY TO CHOSE A 90-DEGREE PITCH HORN THEN ANY
VERTICAL MOVEMENT OF THE BLADE (CONING) WOULD TURN THE BLADE INO A
FIRST CLASS LEVER WITH THE CONE HINGE AS THE FULCRUM. IN THIS CASE,
WHEN THE BLADE CONED UPWARDS, THE PITCH HORN WOULD MOVE
DOWNWARDS AGAINST A FIXED PITCH LINK.
THIS RELATIVE MOVEMENT WOULD CAUSE THE BLADE TO INCREASE PITCH AS IF
THE PITCHLINK HAD BEEN MOVED RELATIVE TO THE BLADE.
Ok, here I agree, this is pitch cone coupling. And with a 90 degree pitch horn it would certainly be a
factor.
IN ORDER TO CONE, THE PILOT HAD TO PUT IN ENOUGH PITCH TO LIFT THE
HELICOPTER OFF THE GROUND.
False. Any increase in collective pitch will produce coning. Coning is a function of centrifugal
force and lift produced by the blade. Therefore any amount of lift produced by even the smallest
amount of collective will produce a certain amount of coning.
AT THE SAME TIME, THE CONING ACTION WITH A 90-DEGREE PITCH HORN WOULD
PRACTICALLY DOUBLE THE PITCH RESULTING IN BLADE STALL OR VERY CLOSE
TO BLADE STALL. IF THE PILOT HAD SUFFICIENT POWER TO GET THE HELICOPTER
OFF THE GROUND AND MOVED THE CYCLIC IN ANY DIRECTION HE COULD ADD
ANOTHER 5-6 DEGREES OR MORE TO THE ALREADY HIGH PITCH IN THE ROTOR
SYSTEM.
Wrong again. It would not double the amount of pitch in the blade as you will see later in this post.
You are saying this as if the blades won't cone at all until pilot has pulled in enough collective to
lift off, and then suddenly the blades will cone increasing the pitch just as suddenly nearly stalling
the blades and producing so much drag the engine can't produce enough power to maintain RPM.
This is ludicrous.
As for the cyclic. If the R22 had a 90 degree pitch horn there would be no pitch FLAP coupling.
When you apply cyclic the rotor tilts "flaps" in a direction. This means one blade goes up when the
other is down or vice versa. When this happens the coning hinges DO NOT move. The
TEETERING hinge DOES moves but our 90 degree pitch horns are in line with the teetering axis.
Therefore, there is NO resultant change in blade pitch from anything other than the actual cyclic
control input made by the pilot.
Now lets look at what would really happen if we were to try lifting off into a hover in an R22 with
a 90 degree pitch horn.
I am going through this step by step so there is no question about how I will arrive at my
conclusion. And it will be there for anyone to see in case I have made any errors.
First of all we need to establish some parameters.
1. how much do the blades actually cone when the R22 is in a hover?
2. how much will blade pitch increase from a given amount of coning with a 90 degree pitch horn.
Unfortunately I do not have the detailed specs for an R22 that I need to establish these parameters,
so they will be off a little, but they will be very close and if anyone wants to get the exact numbers
and run them, be my guest.
To calculate the coning we need to know two things.
1. the amount of centrifugal force acting on a single R22 blade at flight RPM
2. the amount of lift produced by a single R22 blade.
I will assume that an R22 blade weighs approx. 40 lbs. and that its spanwise center of mass is at
50% of the span.
Centrifugal force = Mass x Velocity squared. There are a couple of extras to go with that.
Velocity will be in the angular velocity unit of radians per second. And to put our blade weight into
the proper unit of mass we must divide the number of lbs by the acceleration force of 1g which is
32.2 ft/sec squared.
40 lbs divided by 32.2 = 1.2422
The R22 flight manual says, if I am not mistaken, that the 12.5 ft radius rotor has a tip velocity of
672 ft/sec at flight RPM.
Radians/sec = tip velocity divided by the rotor radius = 53.76 radians/sec
53.76 is of course the velocity so we have to square it.
2890.1376
multiply this by our mass.
1.2422
and we get
3590.1289
one last step, we must multiply this by the radius of the blade center of mass.
6.25 feet
Centrifugal force = 22,438.3058 lbs per blade
Now the lift part is simple, if we are at max gross weight that 1370 lbs. There are 2 blade so we
divide by two and find that we need to produce 685 lbs of lift per blade in order to hover.
Technically we need slightly more than that initiate the ascent into a stabilized hover.
Now we need some trig to figure out the coning angle from these two factors.
Lift divided by centrifugal force = 0.0305 ATAN = 1.7486 degrees of coning per blade.
whew! That solves our first problem. Now we need to know the pitch cone coupling ratio so we can
figure out how much more blade pitch we have at a hover with a 90 degree pitch horn.
Now, instead of running through exact numbers like: if the blade goes up 1.7486 degrees then the
pitch link will go down xx.xxx inches but since it can’t go down due to the swash plate then it will
rise relative to the blade feathering axis causing x.xxx number of degrees increase in blade pitch.
What I WILL do is establish a ratio for coning to feathering. And since I do not know the exact
dimensions of the pitch horn in relation to the coning and feathering axes. This will let us play with
a range of possibilities.
The pitch cone coupling ratio will depend upon two distances. The first distance is: from, the center
of the pitch link upper rod end bearing, to, the center axis of the coning hinge. The second distance is:
from, this same pitch link upper rod end bearing, to, the feathering axis about which the blade
changes pitch. I also must clarify that these distances are to be measured normal to, or
perpendicular to, the respective axes. By the way, if this gets hard for anyone to visualize from reading alone, draw it out, most of you probably know basically what a R22 rotorhead looks like.
The first distance decides how much the feathering axis will move below the pitch horn for a given
coning angle change. The longer the distance the more it would want to move. The second distance
decides how many degrees the blade will change pitch due to the feathering axis moving below the
pitch horn. The longer the distance the less the pitch angle will change. So if both distances are
equal, then one degree of coning will increase the pitch by one degree. If however the first distance
is let’s say half of the second, then 1 degree of coning will only produce 0.5 degrees of pitch
increase. So we can say that the ratio of the second distance to the first equals the ratio of coning to
pitch. Now, I don’t know the actual distances for the R22 but I would say from memory that the
pitch horn is farther away from the feathering axis than a 90 degree one would be from the coning
hinge axis. If this is the case then there would be less pitch change for an amount of coning. But lets
go with worst case and say they are the same. 1.7486 degrees of pitch would be compensated for by
the pilot unknowingly raising the collective I would guess about an inch and a half to 2 inches less
than he would for the 72 degree pitch horn without the pitch cone coupling properties. And of
course if the aircraft were to be certified this way they would simply have the controls rigged slightly
different. Remember I’m not using the real dimensions here, and more than likely the pitch cone
coupling ratio would actually be less and the pilot would probably have less than 1 inch collective
difference between the different pitch horn angles. If you must, find the actual dimensions and run
the numbers. See what you get.
[This message has been edited by helisphere (edited 14 January 2001).]
First of all, I never called you an idiot. I said you have made yourself look like one by the
statements you have made. Obviously you have a lot of credentials. That makes you look even
worse. It's like a scientist going around saying the earth is flat and the planets, sun, and stars all
rotate around it as the center of the universe.
Yes I am biased. I happen to think that Frank Robinson has done as much to better the helicopter
industry as Sikorsky, Hiller, Piasecki, Young, Kaman or any of the other helicopter pioneers.
However, any bias, be it good or bad, cannot alter the physical laws of nature. My bias has nothing
to do with calling you on false statements.
On to your false statements. I'll start with your post to helo teacher on 04 Jan 2001 04:57.
Your statements are in capitals.
THE PURPOSE OF THIS ILLUSTRATION IS TO DISPROVE FRANK ROBINSONS'
PREMISE OF CONSIDERING A 90-DEGREE PITCH HORN IN THE DESIGN OF THE
ROBINSON ROTORHEAD.
IF HE HAD THE OPPORTUNITY TO CHOSE A 90-DEGREE PITCH HORN THEN ANY
VERTICAL MOVEMENT OF THE BLADE (CONING) WOULD TURN THE BLADE INO A
FIRST CLASS LEVER WITH THE CONE HINGE AS THE FULCRUM. IN THIS CASE,
WHEN THE BLADE CONED UPWARDS, THE PITCH HORN WOULD MOVE
DOWNWARDS AGAINST A FIXED PITCH LINK.
THIS RELATIVE MOVEMENT WOULD CAUSE THE BLADE TO INCREASE PITCH AS IF
THE PITCHLINK HAD BEEN MOVED RELATIVE TO THE BLADE.
Ok, here I agree, this is pitch cone coupling. And with a 90 degree pitch horn it would certainly be a
factor.
IN ORDER TO CONE, THE PILOT HAD TO PUT IN ENOUGH PITCH TO LIFT THE
HELICOPTER OFF THE GROUND.
False. Any increase in collective pitch will produce coning. Coning is a function of centrifugal
force and lift produced by the blade. Therefore any amount of lift produced by even the smallest
amount of collective will produce a certain amount of coning.
AT THE SAME TIME, THE CONING ACTION WITH A 90-DEGREE PITCH HORN WOULD
PRACTICALLY DOUBLE THE PITCH RESULTING IN BLADE STALL OR VERY CLOSE
TO BLADE STALL. IF THE PILOT HAD SUFFICIENT POWER TO GET THE HELICOPTER
OFF THE GROUND AND MOVED THE CYCLIC IN ANY DIRECTION HE COULD ADD
ANOTHER 5-6 DEGREES OR MORE TO THE ALREADY HIGH PITCH IN THE ROTOR
SYSTEM.
Wrong again. It would not double the amount of pitch in the blade as you will see later in this post.
You are saying this as if the blades won't cone at all until pilot has pulled in enough collective to
lift off, and then suddenly the blades will cone increasing the pitch just as suddenly nearly stalling
the blades and producing so much drag the engine can't produce enough power to maintain RPM.
This is ludicrous.
As for the cyclic. If the R22 had a 90 degree pitch horn there would be no pitch FLAP coupling.
When you apply cyclic the rotor tilts "flaps" in a direction. This means one blade goes up when the
other is down or vice versa. When this happens the coning hinges DO NOT move. The
TEETERING hinge DOES moves but our 90 degree pitch horns are in line with the teetering axis.
Therefore, there is NO resultant change in blade pitch from anything other than the actual cyclic
control input made by the pilot.
Now lets look at what would really happen if we were to try lifting off into a hover in an R22 with
a 90 degree pitch horn.
I am going through this step by step so there is no question about how I will arrive at my
conclusion. And it will be there for anyone to see in case I have made any errors.
First of all we need to establish some parameters.
1. how much do the blades actually cone when the R22 is in a hover?
2. how much will blade pitch increase from a given amount of coning with a 90 degree pitch horn.
Unfortunately I do not have the detailed specs for an R22 that I need to establish these parameters,
so they will be off a little, but they will be very close and if anyone wants to get the exact numbers
and run them, be my guest.
To calculate the coning we need to know two things.
1. the amount of centrifugal force acting on a single R22 blade at flight RPM
2. the amount of lift produced by a single R22 blade.
I will assume that an R22 blade weighs approx. 40 lbs. and that its spanwise center of mass is at
50% of the span.
Centrifugal force = Mass x Velocity squared. There are a couple of extras to go with that.
Velocity will be in the angular velocity unit of radians per second. And to put our blade weight into
the proper unit of mass we must divide the number of lbs by the acceleration force of 1g which is
32.2 ft/sec squared.
40 lbs divided by 32.2 = 1.2422
The R22 flight manual says, if I am not mistaken, that the 12.5 ft radius rotor has a tip velocity of
672 ft/sec at flight RPM.
Radians/sec = tip velocity divided by the rotor radius = 53.76 radians/sec
53.76 is of course the velocity so we have to square it.
2890.1376
multiply this by our mass.
1.2422
and we get
3590.1289
one last step, we must multiply this by the radius of the blade center of mass.
6.25 feet
Centrifugal force = 22,438.3058 lbs per blade
Now the lift part is simple, if we are at max gross weight that 1370 lbs. There are 2 blade so we
divide by two and find that we need to produce 685 lbs of lift per blade in order to hover.
Technically we need slightly more than that initiate the ascent into a stabilized hover.
Now we need some trig to figure out the coning angle from these two factors.
Lift divided by centrifugal force = 0.0305 ATAN = 1.7486 degrees of coning per blade.
whew! That solves our first problem. Now we need to know the pitch cone coupling ratio so we can
figure out how much more blade pitch we have at a hover with a 90 degree pitch horn.
Now, instead of running through exact numbers like: if the blade goes up 1.7486 degrees then the
pitch link will go down xx.xxx inches but since it can’t go down due to the swash plate then it will
rise relative to the blade feathering axis causing x.xxx number of degrees increase in blade pitch.
What I WILL do is establish a ratio for coning to feathering. And since I do not know the exact
dimensions of the pitch horn in relation to the coning and feathering axes. This will let us play with
a range of possibilities.
The pitch cone coupling ratio will depend upon two distances. The first distance is: from, the center
of the pitch link upper rod end bearing, to, the center axis of the coning hinge. The second distance is:
from, this same pitch link upper rod end bearing, to, the feathering axis about which the blade
changes pitch. I also must clarify that these distances are to be measured normal to, or
perpendicular to, the respective axes. By the way, if this gets hard for anyone to visualize from reading alone, draw it out, most of you probably know basically what a R22 rotorhead looks like.
The first distance decides how much the feathering axis will move below the pitch horn for a given
coning angle change. The longer the distance the more it would want to move. The second distance
decides how many degrees the blade will change pitch due to the feathering axis moving below the
pitch horn. The longer the distance the less the pitch angle will change. So if both distances are
equal, then one degree of coning will increase the pitch by one degree. If however the first distance
is let’s say half of the second, then 1 degree of coning will only produce 0.5 degrees of pitch
increase. So we can say that the ratio of the second distance to the first equals the ratio of coning to
pitch. Now, I don’t know the actual distances for the R22 but I would say from memory that the
pitch horn is farther away from the feathering axis than a 90 degree one would be from the coning
hinge axis. If this is the case then there would be less pitch change for an amount of coning. But lets
go with worst case and say they are the same. 1.7486 degrees of pitch would be compensated for by
the pilot unknowingly raising the collective I would guess about an inch and a half to 2 inches less
than he would for the 72 degree pitch horn without the pitch cone coupling properties. And of
course if the aircraft were to be certified this way they would simply have the controls rigged slightly
different. Remember I’m not using the real dimensions here, and more than likely the pitch cone
coupling ratio would actually be less and the pilot would probably have less than 1 inch collective
difference between the different pitch horn angles. If you must, find the actual dimensions and run
the numbers. See what you get.
[This message has been edited by helisphere (edited 14 January 2001).]
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Posts: n/a
I am fairly certain that I posted the first rotary topic on PPRUNE, when Danny used to individually email us the day's topics and replies. (There was only one forum in those days). I can't prove it as the site server crashed in 1996 and most of the stuff got lost forever. Since then the website has exploded logarithmically in both numbers, content and presentation. We are lucky to have our own forum now.
I kept away from this topic after the first few postings as I thought it would probably go rapidly downhill to a slanging match. Well I wasn't wrong was I?
I can see both sides of Lu's arguments. He has shown some courage in speaking out to many who can't believe that they may be flying an aircraft with quite severe limitations. I am one who will no longer fly in that particularly unforgiving type of helicopter, either as a pilot or as pax. My own decision, made a long time ago. However, IMHO Lu does "go on a bit" as my old mother would say..zzz.... It is obvious he is quite passionate about the subject...zzz.
As I am ex-military, I was one of the ones who complained when HELIDRVR suddenly appeared as if from nowhere and got a bit heavy-handed about the military stuff when it was mainly WE who got the rotorheads forum going in the first place...He is now forgiven; especially as he apologised and admitted his mistake! He did say that military stuff could come back, but some people prefer to forget that.
I am now a civvy professional pilot of thirty years experience, flying both fixed and rotary wing but mainly rotary at the moment. I am a qualified instructor, having graduated from both RAF Central Flying Schools (separate fixed wing and rotary wing instructor schools). However, I am not a mathematician and although I can follow the deeply theoretical stuff regarding heavy numbers, I do not enjoy reading it. For that reason I don't often comment on such matters but don't complain about its presence on the forum either. I certainly wouldn't email the moderator and request it to be removed, as HELIDRVR knows, see above about previous complainers on the military stuff.
I think we should just allow everyone to post whatever they like. If an individual doesn't like what is posted the best option is to ignore it. Without any dialogue the post goes to the bottom of the page and eventually drops off into an archive.
What I do find irritating lately is that so often a good topic begins but degenerates as contributor's egos get dented. Let's leave the forum as intended - to discuss matters rotary. Slagging off is catered for on a separate forum called Jetblast.
P.S. I've "gone on a bit" too. I don't want to moderate either - Helidrvr offered it me once and I turned it down. Just having my ten-penny worth.
[This message has been edited by Skycop (edited 14 January 2001).]
I kept away from this topic after the first few postings as I thought it would probably go rapidly downhill to a slanging match. Well I wasn't wrong was I?
I can see both sides of Lu's arguments. He has shown some courage in speaking out to many who can't believe that they may be flying an aircraft with quite severe limitations. I am one who will no longer fly in that particularly unforgiving type of helicopter, either as a pilot or as pax. My own decision, made a long time ago. However, IMHO Lu does "go on a bit" as my old mother would say..zzz.... It is obvious he is quite passionate about the subject...zzz.
As I am ex-military, I was one of the ones who complained when HELIDRVR suddenly appeared as if from nowhere and got a bit heavy-handed about the military stuff when it was mainly WE who got the rotorheads forum going in the first place...He is now forgiven; especially as he apologised and admitted his mistake! He did say that military stuff could come back, but some people prefer to forget that.
I am now a civvy professional pilot of thirty years experience, flying both fixed and rotary wing but mainly rotary at the moment. I am a qualified instructor, having graduated from both RAF Central Flying Schools (separate fixed wing and rotary wing instructor schools). However, I am not a mathematician and although I can follow the deeply theoretical stuff regarding heavy numbers, I do not enjoy reading it. For that reason I don't often comment on such matters but don't complain about its presence on the forum either. I certainly wouldn't email the moderator and request it to be removed, as HELIDRVR knows, see above about previous complainers on the military stuff.
I think we should just allow everyone to post whatever they like. If an individual doesn't like what is posted the best option is to ignore it. Without any dialogue the post goes to the bottom of the page and eventually drops off into an archive.
What I do find irritating lately is that so often a good topic begins but degenerates as contributor's egos get dented. Let's leave the forum as intended - to discuss matters rotary. Slagging off is catered for on a separate forum called Jetblast.
P.S. I've "gone on a bit" too. I don't want to moderate either - Helidrvr offered it me once and I turned it down. Just having my ten-penny worth.
[This message has been edited by Skycop (edited 14 January 2001).]
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Lu seems always trying to reduce the helicopter to a mathematical and exact computer produced bunch of formulae.If you read Prowty he most refreshingly admits that even the most modern machines are made to fly by trial and error.The final product most often bears no relation to the brilliantly formulatd drawing board model.Even Prowty himself admits that rotor blades do the darndest of things (quote) and trying to analyze their performance made him dizzy!
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To:Cullcov
I try to read Ray Proutys’ columns in Rotor & Wing and find them extremely difficult to understand. He tries to bring his descriptions down to the lowest common denominator so that even helicopter pilots can understand. I would place myself in the middle or of average intelligence and with all of my experience still can’t understand much of what he says.
I used to have long conversations with him when I worked at Lockheed on the Cheyenne. When we talked about aerodynamics and the dynamic systems of the Cheyenne I understood everything he said. Maybe over time he did get a bit dizzy trying to solve the problems of helicopter aerodynamics.
------------------
The Cat
I try to read Ray Proutys’ columns in Rotor & Wing and find them extremely difficult to understand. He tries to bring his descriptions down to the lowest common denominator so that even helicopter pilots can understand. I would place myself in the middle or of average intelligence and with all of my experience still can’t understand much of what he says.
I used to have long conversations with him when I worked at Lockheed on the Cheyenne. When we talked about aerodynamics and the dynamic systems of the Cheyenne I understood everything he said. Maybe over time he did get a bit dizzy trying to solve the problems of helicopter aerodynamics.
------------------
The Cat
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To: Helisphere
If you will note I made a post on another thread and I changed the wording relative to how coning is introduced. I also allowed that with coning, the blades would lead slightly but under those or any other condition would the leading cause the rotor system to accelerate enough to read the difference on your tach or percentage of power or, whatever.
What difference does it make how much the blades cone when the pilot puts the helicopter in a hover and 90-degree pitch horns are installed? And what difference does it make how much the pitch would be increased over the amount input by the pilot when he pulled collective when a 90-degree pitch horn is installed? You are trying to prove me wrong through the use of your calculations, which may in themselves be valid (excepting the figures used in those calculations).
You are beating the proverbial dead horse. Frank Robinson could never have considered the use of a 90-degree pitch horn on his rotorhead and if he did the FAA would not approve it. Aside from the collective pitch coupling adding pitch why don’t you run your calculations considering cyclic pitch change? I believe that either you or another individual stated that re-rigging the helicopter could solve the problem. The rigging procedures, as bad as they are, have been approved by the FAA. You want to change the the FAA approved rigging to accommodate a 90-degree pitch horn that the FAA would not approve of if Frank Robinson proposed it.
Another point made by you or another individual, related to the coning, once set by pulling collective would stay the same when cyclic was introduced causing the head to teeter and the coning relationship would remain the same relative to the head. First of all, the head is underslung just like on a Bell and this is done to minimize lead and lag. However the Bell just teeters but it does not have cone hinges. So, this underslinging works for the Bell. But, since the Robinson blades can flap on their cone hinges then you get lead and lag. However, the Robinson rotorhead does not have Lag hinges so the leading and lagging takes place via spanwise bending of the blades. This bending is reacted by the cone hinges and the teeter hinge which causes them to wear egg shape. Another reason for the cone hinge is to relieve blade bending and minimize the transmission of flapping loads into the airframe. So, if this is true then Frank Robinson admits to the blades flapping and we all know that when blades flap they lead and lag.
The cone angle does not remain constant. It changes due to cyclic input and blade loading and when this happens, the blades will try to lead and lag.
Your turn.
------------------
The Cat
If you will note I made a post on another thread and I changed the wording relative to how coning is introduced. I also allowed that with coning, the blades would lead slightly but under those or any other condition would the leading cause the rotor system to accelerate enough to read the difference on your tach or percentage of power or, whatever.
What difference does it make how much the blades cone when the pilot puts the helicopter in a hover and 90-degree pitch horns are installed? And what difference does it make how much the pitch would be increased over the amount input by the pilot when he pulled collective when a 90-degree pitch horn is installed? You are trying to prove me wrong through the use of your calculations, which may in themselves be valid (excepting the figures used in those calculations).
You are beating the proverbial dead horse. Frank Robinson could never have considered the use of a 90-degree pitch horn on his rotorhead and if he did the FAA would not approve it. Aside from the collective pitch coupling adding pitch why don’t you run your calculations considering cyclic pitch change? I believe that either you or another individual stated that re-rigging the helicopter could solve the problem. The rigging procedures, as bad as they are, have been approved by the FAA. You want to change the the FAA approved rigging to accommodate a 90-degree pitch horn that the FAA would not approve of if Frank Robinson proposed it.
Another point made by you or another individual, related to the coning, once set by pulling collective would stay the same when cyclic was introduced causing the head to teeter and the coning relationship would remain the same relative to the head. First of all, the head is underslung just like on a Bell and this is done to minimize lead and lag. However the Bell just teeters but it does not have cone hinges. So, this underslinging works for the Bell. But, since the Robinson blades can flap on their cone hinges then you get lead and lag. However, the Robinson rotorhead does not have Lag hinges so the leading and lagging takes place via spanwise bending of the blades. This bending is reacted by the cone hinges and the teeter hinge which causes them to wear egg shape. Another reason for the cone hinge is to relieve blade bending and minimize the transmission of flapping loads into the airframe. So, if this is true then Frank Robinson admits to the blades flapping and we all know that when blades flap they lead and lag.
The cone angle does not remain constant. It changes due to cyclic input and blade loading and when this happens, the blades will try to lead and lag.
Your turn.
------------------
The Cat
Guest
Posts: n/a
Back to Lu:
Again, your words are capitalized.
IF YOU WILL NOTE I MADE A POST ON ANOTHER THREAD AND I CHANGED THE
WORDING RELATIVE TO HOW CONING IS INTRODUCED.
I am not going to go trying to find what you have edited.
I ALSO ALLOWED THAT WITH CONING, THE BLADES WOULD LEAD SLIGHTLY BUT
UNDER THOSE OR ANY OTHER CONDITION WOULD THE LEADING CAUSE THE
ROTOR SYSTEM TO ACCELERATE ENOUGH TO READ THE DIFFERENCE ON YOUR
TACH OR PERCENTAGE OF POWER OR, WHATEVER.
What does that have to do with the price of tea in China?
WHAT DIFFERENCE DOES IT MAKE HOW MUCH THE BLADES CONE WHEN THE
PILOT PUTS THE HELICOPTER IN A HOVER AND 90 DEGREE PITCH HORNS ARE
INSTALLED?
Duh!? YOU are the one who said pitch cone coupling was going to practically double the amount
of actual pitch in the blade. Obviously, if we want to figure out the ACTUAL amount of exess pitch
then we need to know how much coning there is, because the amount of exess pitch is directly
dependent upon the amount of coning, hence, the term pitch-cone coupling. Have you been checked
lately for the possibility of alzheimers disease?
AND WHAT DIFFERENCE DOES IT MAKE HOW MUCH THE PITCH WOULD BE
INCREASED OVER THE AMOUNT INPUT BY THE PILOT WHEN HE PULLED
COLLECTIVE WHEN A 90-DEGREE PITCH HORN IS INSTALLED?
YOU are the one who said pitch would practically double, remember? In fact, here is your exact
quote:
AT THE SAME TIME, THE CONING ACTION WITH A 90-DEGREE PITCH HORN WOULD
PRACTICALLY DOUBLE THE PITCH RESULTING IN BLADE STALL OR VERY CLOSE
TO BLADE STALL. IF THE PILOT HAD SUFFICIENT POWER TO GET THE HELICOPTER
OFF THE GROUND AND MOVED THE CYCLIC IN ANY DIRECTION HE COULD ADD
ANOTHER 5-6 DEGREES OR MORE TO THE ALREADY HIGH PITCH IN THE ROTOR
SYSTEM.
And you are asking me what difference it makes? Well, Lu, explain to me how something that
makes no difference can result in “BLADE STALL” or very close to it. If it makes no difference
then what was your reason for pointing this out in the first place?
YOU ARE TRYING TO PROVE ME WRONG THROUGH THE USE OF YOUR
CALCULATIONS, WHICH MAY IN THEMSELVES BE VALID, (ACCEPTING THE
FIGURES USED IN THOSE CALCULATIONS).
I have already proven you wrong, you just refuse to accept it. Who is beating the dead horse here?
YOU ARE BEATING THE PROVERBIAL DEAD HORSE. FRANK ROBINSON COULD
NEVER HAVE CERTIFIED THE USE OF A 90-DEGREE PITCH HORN ON HIS
ROTORHEAD AND IF HE DID THE FAA WOULD NOT APPROVE IT.
Yes Lu, I've heard you say that like ten different times now, but you have given no valid evidence to
substantiate this claim. In fact the very reasons you did give as evidence that it could not be certified
are above and you are now asking me what difference they make. I don’t know, that is a good
question. What difference does it make?
ASIDE FROM THE COLLECTIVE PITCH COUPLING ADDING PITCH WHY DON’T YOU
RUN YOUR CALCULATIONS CONSIDERING CYCLIC PITCH CHANGE? I BELIEVE
THAT YOU OR ANOTHER INDIVIDUAL STATED THAT RE-RIGGING THE
HELICOPTER COULD SOLVE THE PROBLEM. THE RIGGING PROCEDURES, AS BAD
AS THEY ARE, HAVE BEEN APPROVED BY THE FAA. YOU WANT TO CHANGE THE
FAA APPROVED RIGGING TO ACCOMMODATE A 90-DEGREE PITCH HORN THAT
THE FAA WOULD NOT APPROVE OF IF FRANK ROBINSON PROPOSED IT.
First of all, I am not talking about rigging PROCEDURES, I am talking about the rigging itself.
The PROCEDURE for setting up the length of control rods and the actual resulting lengths are two
different things. No, I don't want to change the rigging to accommodate a 90 degree pitch horn. I
am saying that if it had been done that way, the rigging would be slightly different. Actually, with
as little difference as the 90 degree horn makes it may not even need to be rigged differently.
Run my calculations considering cyclic pitch change? There is nothing to calculate in regards to
cyclic inputs as the flapping they produce does NOT induce a pitch change with a 90 degree pitch
horn. However, with the 72 degree horn, which it has actually been certified with, pitch change will
be induced by cyclic flapping. This is called Delta 3. The R22 flies just fine with it as have some
other helicopters.
ANOTHER POINT MADE BY YOU OR ANOTHER INDIVIDUAL, RELATED TO THE
CONING, ONCE SET BY PULLING COLLECTIVE WOULD STAY THE SAME WHEN
CYCLIC WAS INTRODUCED CAUSING THE HEAD TO TEETER AND THE CONING
RELATIONSHIP WOULD REMAIN THE SAME RELATIVE TO THE HEAD.
Exactly! You’ve finally made a true statement but you don't even agree with it.
FIRST OF ALL, THE HEAD IS UNDERSLUNG JUST LIKE ON A BELL AND THIS IS DONE
TO MINIMIZE LEAD AND LAG. HOWEVER THE BELL JUST TEETERS BUT IT DOES
NOT HAVE CONE HINGES. SO, THIS UNDERSLINGING WORKS FOR THE BELL. BUT,
SINCE THE ROBINSON BLADES CAN FLAP ON THEIR CONE HINGES THEN YOU GET
LEAD AND LAG.
True, the Bell does not have coning hinges. But does this mean that the Bell blades do not cone? Of
course they cone. They cone by bending. Now you tell me, is it the coning hinge or coning itself
that generates the coriolis force to lead or lag the blade?
As for which hinges the movement will occur on due to cyclic flapping on an R22? Imagine if we
took an R22 and hooked a cable onto each blade tip. Then we fastened the lose end of one cable to
a point up high on a wall. Then we hooked the other cables free end to some sort of winch that can
pull 22 thousand lbs on the cable. We have set the fastening point and the winch at some height
above the top of the helicopter so that as we put tension on the cables the helicopter will lift off of the
ground. The tension on the cables connected to the blade tips will simulate the centrifugal force at
flight RPM. By picking the whole thing up we are simulating the lift that would be created in a hover.
Now, if you were to climb into the helicopter, coning would increase, movement would occur at the
coning hinges but not the teetering hinge (ok, the cg change from you getting in would cause
movement at the teeter hinge, but you see my point, and if we added the weight right where the cg is
then it would not move the teeter hinge). Now lets think about cyclic inputs. Cyclic tilts the rotor
tip path plane. That means that when one blade goes up the other goes down. If we could then tilt
our contraption holding the tension on the cables we would simulate tilting the tip path plane. With
this picture in your mind, which hinges do you think will have the movement? I think it is obvious
that the teeter hinge will move and the coning hinges will not. Imagine how much force it would
take to misalign the hub from the tip path plane with all of the centrifugal force pulling on it. Just as
a rotor blade gains stiffness from centrifugal force, so do the coning hinges gain stiffness. If they
didn’t the blades would simply fold up as the helicopter tried to attain flight. Granted, there
probably is a VERY small amount of movement at the coning hinges. But not I think any more then
there would be on the bell from flexing.
HOWEVER, THE ROBINSON ROTORHEAD DOES NOT HAVE LAG HINGES SO THE
LEADING AND LAGGING TAKES PLACE VIA SPANWISE BENDING OF THE BLADES.
This is true, but also true for the bell and all teetering rotor systems. Underslinging reduces the coriolis effect but does not
eliminate it. And coriolis force is what causes lead lag forces.
THIS BENDING IS REACTED BY THE CONE HINGES AND THE TEETER HINGE WHICH
CAUSES THEM TO WEAR EGG SHAPE. ANOTHER REASON FOR THE CONE HINGE IS
TO RELEIVE BLADE BENDING AND MINIMIZE THE TRANSMISSION OF FLAPPING
LOADS INTO THE AIRFRAME.
True, the coning hinge is there to reduce blade bending from coning. But where did you come up
with them minimizing flapping loads into the airframe? As for the coning hinges wearing, can you
name a helicopter that does not have wearing parts?
SO, IF THIS IS TRUE THEN FRANK ROBINSON ADMITS TO THE BLADES FLAPPING
AND WE ALL KNOW THAT WHEN BLADES FLAP THEY LEAD AND LAG.
Of course the blades flap, but they flap on the teetering hinge. And yes they will lead and lag just
like they do on a bell or any other two-bladed teetering rotor system.
THE CONE ANGLE DOES NOT REMAIN CONSTANT. IT CHANGES DUE TO CYCLIC
INPUT AND BLADE LOADING AND WHEN THIS HAPPENS, THE BLADES WILL TRY
TO LEAD AND LAG.
Coning does not change from just a cyclic input, it’s only when the cyclic input causes rotor
thrust (loading) to change. And also, with CONING, both blades lead at the same time or lag at the
same time which translates into RPM changes not bending stress. And in fact the RPM doesn’t
change much because the governer compensates.
Final Note:
My purpose here is not to prove you wrong. I was trying to get you to stop making a fool of
yourself. You were presenting theories that were so blatantly flawed and with little evidence to back
them up and then so strongly defending them. Multiple people on this forum tried to straighten you
out. But you just kept getting yourself in deeper. Then you present your credentials as evidence
that what you say must be true. Now that really makes you look like the buffoon that someone
called you earlier. But the fact is I’ve let myself get drawn into this silliness, and I see now that it is
pretty pointless. So I’m not going to keep going on with you. Besides, I don’t know enough to really do justice to how complex helicopter dynamics are in reality.
I’m just a high school drop out without a college education trying to make a living flying these silly
contraptions (I say that with the utmost affection). So, what do I really know anyway. I know how
much credentials mean to you, so I doubt I could carry much weight in your mind in convincing you
of your errors. Dealing with your irrationality is too frustrating as you can tell by the tone of my
responses. Everyone else has figured this out already, that is why no one is posting on this thread
anymore, I’m just a late comer, but I finally get it.
Bye Lu.
Again, your words are capitalized.
IF YOU WILL NOTE I MADE A POST ON ANOTHER THREAD AND I CHANGED THE
WORDING RELATIVE TO HOW CONING IS INTRODUCED.
I am not going to go trying to find what you have edited.
I ALSO ALLOWED THAT WITH CONING, THE BLADES WOULD LEAD SLIGHTLY BUT
UNDER THOSE OR ANY OTHER CONDITION WOULD THE LEADING CAUSE THE
ROTOR SYSTEM TO ACCELERATE ENOUGH TO READ THE DIFFERENCE ON YOUR
TACH OR PERCENTAGE OF POWER OR, WHATEVER.
What does that have to do with the price of tea in China?
WHAT DIFFERENCE DOES IT MAKE HOW MUCH THE BLADES CONE WHEN THE
PILOT PUTS THE HELICOPTER IN A HOVER AND 90 DEGREE PITCH HORNS ARE
INSTALLED?
Duh!? YOU are the one who said pitch cone coupling was going to practically double the amount
of actual pitch in the blade. Obviously, if we want to figure out the ACTUAL amount of exess pitch
then we need to know how much coning there is, because the amount of exess pitch is directly
dependent upon the amount of coning, hence, the term pitch-cone coupling. Have you been checked
lately for the possibility of alzheimers disease?
AND WHAT DIFFERENCE DOES IT MAKE HOW MUCH THE PITCH WOULD BE
INCREASED OVER THE AMOUNT INPUT BY THE PILOT WHEN HE PULLED
COLLECTIVE WHEN A 90-DEGREE PITCH HORN IS INSTALLED?
YOU are the one who said pitch would practically double, remember? In fact, here is your exact
quote:
AT THE SAME TIME, THE CONING ACTION WITH A 90-DEGREE PITCH HORN WOULD
PRACTICALLY DOUBLE THE PITCH RESULTING IN BLADE STALL OR VERY CLOSE
TO BLADE STALL. IF THE PILOT HAD SUFFICIENT POWER TO GET THE HELICOPTER
OFF THE GROUND AND MOVED THE CYCLIC IN ANY DIRECTION HE COULD ADD
ANOTHER 5-6 DEGREES OR MORE TO THE ALREADY HIGH PITCH IN THE ROTOR
SYSTEM.
And you are asking me what difference it makes? Well, Lu, explain to me how something that
makes no difference can result in “BLADE STALL” or very close to it. If it makes no difference
then what was your reason for pointing this out in the first place?
YOU ARE TRYING TO PROVE ME WRONG THROUGH THE USE OF YOUR
CALCULATIONS, WHICH MAY IN THEMSELVES BE VALID, (ACCEPTING THE
FIGURES USED IN THOSE CALCULATIONS).
I have already proven you wrong, you just refuse to accept it. Who is beating the dead horse here?
YOU ARE BEATING THE PROVERBIAL DEAD HORSE. FRANK ROBINSON COULD
NEVER HAVE CERTIFIED THE USE OF A 90-DEGREE PITCH HORN ON HIS
ROTORHEAD AND IF HE DID THE FAA WOULD NOT APPROVE IT.
Yes Lu, I've heard you say that like ten different times now, but you have given no valid evidence to
substantiate this claim. In fact the very reasons you did give as evidence that it could not be certified
are above and you are now asking me what difference they make. I don’t know, that is a good
question. What difference does it make?
ASIDE FROM THE COLLECTIVE PITCH COUPLING ADDING PITCH WHY DON’T YOU
RUN YOUR CALCULATIONS CONSIDERING CYCLIC PITCH CHANGE? I BELIEVE
THAT YOU OR ANOTHER INDIVIDUAL STATED THAT RE-RIGGING THE
HELICOPTER COULD SOLVE THE PROBLEM. THE RIGGING PROCEDURES, AS BAD
AS THEY ARE, HAVE BEEN APPROVED BY THE FAA. YOU WANT TO CHANGE THE
FAA APPROVED RIGGING TO ACCOMMODATE A 90-DEGREE PITCH HORN THAT
THE FAA WOULD NOT APPROVE OF IF FRANK ROBINSON PROPOSED IT.
First of all, I am not talking about rigging PROCEDURES, I am talking about the rigging itself.
The PROCEDURE for setting up the length of control rods and the actual resulting lengths are two
different things. No, I don't want to change the rigging to accommodate a 90 degree pitch horn. I
am saying that if it had been done that way, the rigging would be slightly different. Actually, with
as little difference as the 90 degree horn makes it may not even need to be rigged differently.
Run my calculations considering cyclic pitch change? There is nothing to calculate in regards to
cyclic inputs as the flapping they produce does NOT induce a pitch change with a 90 degree pitch
horn. However, with the 72 degree horn, which it has actually been certified with, pitch change will
be induced by cyclic flapping. This is called Delta 3. The R22 flies just fine with it as have some
other helicopters.
ANOTHER POINT MADE BY YOU OR ANOTHER INDIVIDUAL, RELATED TO THE
CONING, ONCE SET BY PULLING COLLECTIVE WOULD STAY THE SAME WHEN
CYCLIC WAS INTRODUCED CAUSING THE HEAD TO TEETER AND THE CONING
RELATIONSHIP WOULD REMAIN THE SAME RELATIVE TO THE HEAD.
Exactly! You’ve finally made a true statement but you don't even agree with it.
FIRST OF ALL, THE HEAD IS UNDERSLUNG JUST LIKE ON A BELL AND THIS IS DONE
TO MINIMIZE LEAD AND LAG. HOWEVER THE BELL JUST TEETERS BUT IT DOES
NOT HAVE CONE HINGES. SO, THIS UNDERSLINGING WORKS FOR THE BELL. BUT,
SINCE THE ROBINSON BLADES CAN FLAP ON THEIR CONE HINGES THEN YOU GET
LEAD AND LAG.
True, the Bell does not have coning hinges. But does this mean that the Bell blades do not cone? Of
course they cone. They cone by bending. Now you tell me, is it the coning hinge or coning itself
that generates the coriolis force to lead or lag the blade?
As for which hinges the movement will occur on due to cyclic flapping on an R22? Imagine if we
took an R22 and hooked a cable onto each blade tip. Then we fastened the lose end of one cable to
a point up high on a wall. Then we hooked the other cables free end to some sort of winch that can
pull 22 thousand lbs on the cable. We have set the fastening point and the winch at some height
above the top of the helicopter so that as we put tension on the cables the helicopter will lift off of the
ground. The tension on the cables connected to the blade tips will simulate the centrifugal force at
flight RPM. By picking the whole thing up we are simulating the lift that would be created in a hover.
Now, if you were to climb into the helicopter, coning would increase, movement would occur at the
coning hinges but not the teetering hinge (ok, the cg change from you getting in would cause
movement at the teeter hinge, but you see my point, and if we added the weight right where the cg is
then it would not move the teeter hinge). Now lets think about cyclic inputs. Cyclic tilts the rotor
tip path plane. That means that when one blade goes up the other goes down. If we could then tilt
our contraption holding the tension on the cables we would simulate tilting the tip path plane. With
this picture in your mind, which hinges do you think will have the movement? I think it is obvious
that the teeter hinge will move and the coning hinges will not. Imagine how much force it would
take to misalign the hub from the tip path plane with all of the centrifugal force pulling on it. Just as
a rotor blade gains stiffness from centrifugal force, so do the coning hinges gain stiffness. If they
didn’t the blades would simply fold up as the helicopter tried to attain flight. Granted, there
probably is a VERY small amount of movement at the coning hinges. But not I think any more then
there would be on the bell from flexing.
HOWEVER, THE ROBINSON ROTORHEAD DOES NOT HAVE LAG HINGES SO THE
LEADING AND LAGGING TAKES PLACE VIA SPANWISE BENDING OF THE BLADES.
This is true, but also true for the bell and all teetering rotor systems. Underslinging reduces the coriolis effect but does not
eliminate it. And coriolis force is what causes lead lag forces.
THIS BENDING IS REACTED BY THE CONE HINGES AND THE TEETER HINGE WHICH
CAUSES THEM TO WEAR EGG SHAPE. ANOTHER REASON FOR THE CONE HINGE IS
TO RELEIVE BLADE BENDING AND MINIMIZE THE TRANSMISSION OF FLAPPING
LOADS INTO THE AIRFRAME.
True, the coning hinge is there to reduce blade bending from coning. But where did you come up
with them minimizing flapping loads into the airframe? As for the coning hinges wearing, can you
name a helicopter that does not have wearing parts?
SO, IF THIS IS TRUE THEN FRANK ROBINSON ADMITS TO THE BLADES FLAPPING
AND WE ALL KNOW THAT WHEN BLADES FLAP THEY LEAD AND LAG.
Of course the blades flap, but they flap on the teetering hinge. And yes they will lead and lag just
like they do on a bell or any other two-bladed teetering rotor system.
THE CONE ANGLE DOES NOT REMAIN CONSTANT. IT CHANGES DUE TO CYCLIC
INPUT AND BLADE LOADING AND WHEN THIS HAPPENS, THE BLADES WILL TRY
TO LEAD AND LAG.
Coning does not change from just a cyclic input, it’s only when the cyclic input causes rotor
thrust (loading) to change. And also, with CONING, both blades lead at the same time or lag at the
same time which translates into RPM changes not bending stress. And in fact the RPM doesn’t
change much because the governer compensates.
Final Note:
My purpose here is not to prove you wrong. I was trying to get you to stop making a fool of
yourself. You were presenting theories that were so blatantly flawed and with little evidence to back
them up and then so strongly defending them. Multiple people on this forum tried to straighten you
out. But you just kept getting yourself in deeper. Then you present your credentials as evidence
that what you say must be true. Now that really makes you look like the buffoon that someone
called you earlier. But the fact is I’ve let myself get drawn into this silliness, and I see now that it is
pretty pointless. So I’m not going to keep going on with you. Besides, I don’t know enough to really do justice to how complex helicopter dynamics are in reality.
I’m just a high school drop out without a college education trying to make a living flying these silly
contraptions (I say that with the utmost affection). So, what do I really know anyway. I know how
much credentials mean to you, so I doubt I could carry much weight in your mind in convincing you
of your errors. Dealing with your irrationality is too frustrating as you can tell by the tone of my
responses. Everyone else has figured this out already, that is why no one is posting on this thread
anymore, I’m just a late comer, but I finally get it.
Bye Lu.
Guest
Posts: n/a
To: Helisphere
Are you trying to resurrect the dead horse you were beating on a previous post when you tried to prove me wrong using mathematical formulae? Look at the response from Frank Robinson and you will find his reference regarding the consideration of a 90-degree pitch horn. That is where I came up with my statement. I was referencing his claim to have given consideration of the 90-degree pitch horn. Regarding my use of the term rigging it is true that it references the adjustment of the control system. However your use of the term as applied to the control system, as rigging is totally wrong.
You are trying to prove that by redesigning the control system you can compensate for a 90-degree pitch horn. This is a ludicrous assumption. Get it through your head that because of the massive pitch coupling related to a 90-degree pitch horn on a Robinson rotorhead the FAA would tell Frank Robinson to piss off and go back to the drawing board. The fact that you fly some pretty complex helicopters does not give you the background to discuss the certification of those helicopters. It is the requirements of (AC 27-1) that set the standards for certification and those standards would not allow the use of a 90-degree pitch horn on the Robinson rotorhead. How many times do I have to repeat this fact? It relates to controllability and that the use of a 90-degree pitch horn on a Robinson helicopter would render it uncontrollable.
The fact that AC-27-1 sets the standards for certification does not guarantee that the pilots that fly those helicopters get a properly designed and thoroughly tested helicopter. Read the NTSB report on the Robinson R22 and R44 and also read the posts on Just Helicopters about the Bell 407.
I have one question. Are you related to RW-1?
------------------
The Cat
Are you trying to resurrect the dead horse you were beating on a previous post when you tried to prove me wrong using mathematical formulae? Look at the response from Frank Robinson and you will find his reference regarding the consideration of a 90-degree pitch horn. That is where I came up with my statement. I was referencing his claim to have given consideration of the 90-degree pitch horn. Regarding my use of the term rigging it is true that it references the adjustment of the control system. However your use of the term as applied to the control system, as rigging is totally wrong.
You are trying to prove that by redesigning the control system you can compensate for a 90-degree pitch horn. This is a ludicrous assumption. Get it through your head that because of the massive pitch coupling related to a 90-degree pitch horn on a Robinson rotorhead the FAA would tell Frank Robinson to piss off and go back to the drawing board. The fact that you fly some pretty complex helicopters does not give you the background to discuss the certification of those helicopters. It is the requirements of (AC 27-1) that set the standards for certification and those standards would not allow the use of a 90-degree pitch horn on the Robinson rotorhead. How many times do I have to repeat this fact? It relates to controllability and that the use of a 90-degree pitch horn on a Robinson helicopter would render it uncontrollable.
The fact that AC-27-1 sets the standards for certification does not guarantee that the pilots that fly those helicopters get a properly designed and thoroughly tested helicopter. Read the NTSB report on the Robinson R22 and R44 and also read the posts on Just Helicopters about the Bell 407.
I have one question. Are you related to RW-1?
------------------
The Cat
Guest
Posts: n/a
Jeez guys give it a rest already !!!.This thread is going the same way as many of the other ones involving the R22.......'You said' and ' No I did not'.
It's becomming a bit overbearing now.....Why cant you just respect each others point of view instead of slagging each other off at the drop of a hat.
Jeez.....
------------------
..AD ASTRA PER NOSTRUM..
(Dont pick your nose on finals)
It's becomming a bit overbearing now.....Why cant you just respect each others point of view instead of slagging each other off at the drop of a hat.
Jeez.....
------------------
..AD ASTRA PER NOSTRUM..
(Dont pick your nose on finals)
Guest
Posts: n/a
And on that note I am going to exercise one of my prerogatives and close this topic.
On to bigger and better things.
My heartfelt thanks and warmest regards to all of you for contributing to this discussion.
Cheers
------------------
feel free to visitHelidrvr here
On to bigger and better things.
My heartfelt thanks and warmest regards to all of you for contributing to this discussion.
Cheers
------------------
feel free to visitHelidrvr here
