R22 Corner
Iconoclast
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That ain't what it does.
To: Dave Jackson
The device I described was not a governor. Its’ purpose was to lower the collective when the powerplant went silent. The signaling input was the loss of engine oil pressure. The device that performed the lowering of the collective was a spring cylinder. In order to cock the spring hydraulic pressure was used to compress the spring within the cylinder.
The hydraulic pressure came from the same pump that supplied pressure to the servos. The pump was driven by the main transmission. With the clutch engaged and the engine turning the transmission the blades would start to rotate. As the pressure increased the collective stick was raised cocking the spring (with full collective). The pressure level increased to the operational point when the pump was turning 1200 RPM. Although the pump was turning at speed the blades were not. With the increase in pitch to maximum collective the blades were not generating sufficient lift and they would stall out and hit the tail cone or worse hit the canopy. Once the spring was fully cocked the collective could be lowered.
That’s why I said that the design was not fully thought out
The device I described was not a governor. Its’ purpose was to lower the collective when the powerplant went silent. The signaling input was the loss of engine oil pressure. The device that performed the lowering of the collective was a spring cylinder. In order to cock the spring hydraulic pressure was used to compress the spring within the cylinder.
The hydraulic pressure came from the same pump that supplied pressure to the servos. The pump was driven by the main transmission. With the clutch engaged and the engine turning the transmission the blades would start to rotate. As the pressure increased the collective stick was raised cocking the spring (with full collective). The pressure level increased to the operational point when the pump was turning 1200 RPM. Although the pump was turning at speed the blades were not. With the increase in pitch to maximum collective the blades were not generating sufficient lift and they would stall out and hit the tail cone or worse hit the canopy. Once the spring was fully cocked the collective could be lowered.
That’s why I said that the design was not fully thought out
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No doubt, all helicopter pilots derive great satisfaction from their talent. It is a profession of the few, and it is highly respected. The recreational gyrocopter pilot also enjoys the thrill and the skill of flight. Unfortunately, both entail a degree of risk, particularly for the low-time gyrocopter pilot.
Both situations raise the proverbial question; better training or better craft? Both come at a cost. At least, when you sell the helicopter, you get some of your initial investment back.
Shawn,
The intent would be to have a low speed rotor governor, which could be;
1/ Not activated for the flight, or
2/ Deactivated after the autorotation had been established, or
3/ Left on, but easily overridden by the pilot during descent, flare and touchdown.
It has been said that Low Nr is the second highest cause of fatalities in the R-22. It just seems to me that beginners should learn to ride the bicycle before attempting the unicycle.
Lu,
Thanks. It sounds like the intent was good but the method wasn't.
Both situations raise the proverbial question; better training or better craft? Both come at a cost. At least, when you sell the helicopter, you get some of your initial investment back.
Shawn,
The intent would be to have a low speed rotor governor, which could be;
1/ Not activated for the flight, or
2/ Deactivated after the autorotation had been established, or
3/ Left on, but easily overridden by the pilot during descent, flare and touchdown.
It has been said that Low Nr is the second highest cause of fatalities in the R-22. It just seems to me that beginners should learn to ride the bicycle before attempting the unicycle.
Lu,
Thanks. It sounds like the intent was good but the method wasn't.
Surely all you need is a parallel actuator in the collective system connected to the lever via a clutch with a breakout facility. Then have a manoeuvre button on the lever to temporarily disengage it when you need to. The height hold on lots of aircraft works like this but as Lu says it weighs a lot and therefore is unlikely to be considered for R22/44.
The R22 is very nice once it is in auto but it is tha rapidity of reaction required to get it there once the donk stops that catches people out and only regular practise will keep you up to speed.
The R22 is very nice once it is in auto but it is tha rapidity of reaction required to get it there once the donk stops that catches people out and only regular practise will keep you up to speed.
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Auto initiation device
If you cut the collective pushrod and inserted a spring loaded servo, and at one end feed engine oil pressure so that when the engine was running and the pressure in the servo would extend the collective pushrod to its "normal Lenght" and when engine oil pressure dropped the spring would "reduce the length of the collective pushrod (this reduction in lenght is determined by the stroke length of the servo) this would have a impact on the rate of rotor decay time as pitch was automatically reduced without pilot intevention, The slight drawback with this arrangement would be that the collective lever would feel a little higher than normal as the datum between rotor pitch and lever possition has now change slightly, but the advantages would out way this, and secondly it would be a totally passive system because as the engine was started the collective lever should be locked and held down whilst engine pressure increases and compresses the sprig in the servo.
Just a thought
Proffessor Pat Pending
If you cut the collective pushrod and inserted a spring loaded servo, and at one end feed engine oil pressure so that when the engine was running and the pressure in the servo would extend the collective pushrod to its "normal Lenght" and when engine oil pressure dropped the spring would "reduce the length of the collective pushrod (this reduction in lenght is determined by the stroke length of the servo) this would have a impact on the rate of rotor decay time as pitch was automatically reduced without pilot intevention, The slight drawback with this arrangement would be that the collective lever would feel a little higher than normal as the datum between rotor pitch and lever possition has now change slightly, but the advantages would out way this, and secondly it would be a totally passive system because as the engine was started the collective lever should be locked and held down whilst engine pressure increases and compresses the sprig in the servo.
Just a thought
Proffessor Pat Pending
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imabell
Greetings.
Your post on the previous history of that R22 surprised me at it was contradictory to the information I received when I spoke to the former owner a few days ago who advised it was bought from a US operator with 1200 hours recorded and that maybe where the investigation may end up concentrating on.
I'm sure PF wouldn't mind me posting this as there seems to be a lot of illinformed speculation circulating and unfairly pointing the blame however good the intentions at the wrong people.
I'm sure though we all hope that the people responsible if this was deliberate are pursued caught and brought to justice as a deterrent to other unscrupulous operators.
Fly Safe
Greetings.
Your post on the previous history of that R22 surprised me at it was contradictory to the information I received when I spoke to the former owner a few days ago who advised it was bought from a US operator with 1200 hours recorded and that maybe where the investigation may end up concentrating on.
I'm sure PF wouldn't mind me posting this as there seems to be a lot of illinformed speculation circulating and unfairly pointing the blame however good the intentions at the wrong people.
I'm sure though we all hope that the people responsible if this was deliberate are pursued caught and brought to justice as a deterrent to other unscrupulous operators.
Fly Safe
Iconoclast
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Collective pushrod.
To: MaxNg
The collective pushrod on a Robbie is about 3-4" long. it would take a lot of engineering to squeeze your design into it.
The collective pushrod on a Robbie is about 3-4" long. it would take a lot of engineering to squeeze your design into it.
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MaxNg
IMO the physical relationship between the angle of the collective lever (amount of elbow bend) and the angle of the collective blade pitch should not vary. This allows student pilots to eventually acquire a subconscious association between the positions of the two.
Would there not be two situations?
One is where the pilot is flying 'hands-off ' the collective. In this situation, if the Nr dropped to a predetermined threshold, the collective lever, the linkage and the blades will slowly lower. This would assure that the Nr could not drop below this threshold. For boring in-transit flying, the pilot would occasionally tweak the throttle or an encoding altimeter, to maintain altitude.
The other situation is where the pilot is flying 'hands-on' the collective. As above, the collective will want to lower but there will be one or more warning devices (alarm etc.). At elevation, he has two choices; follow the collective lever down or perhaps better yet, leave the lever alone.
In other words, the initial corrective action to take at the onset of low Nr is DO NOTHING.
Just another thought.
IMO the physical relationship between the angle of the collective lever (amount of elbow bend) and the angle of the collective blade pitch should not vary. This allows student pilots to eventually acquire a subconscious association between the positions of the two.
Would there not be two situations?
One is where the pilot is flying 'hands-off ' the collective. In this situation, if the Nr dropped to a predetermined threshold, the collective lever, the linkage and the blades will slowly lower. This would assure that the Nr could not drop below this threshold. For boring in-transit flying, the pilot would occasionally tweak the throttle or an encoding altimeter, to maintain altitude.
The other situation is where the pilot is flying 'hands-on' the collective. As above, the collective will want to lower but there will be one or more warning devices (alarm etc.). At elevation, he has two choices; follow the collective lever down or perhaps better yet, leave the lever alone.
In other words, the initial corrective action to take at the onset of low Nr is DO NOTHING.
Just another thought.
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Robinson rotor decay autorotation governor
Might be a daft idea, replace the two pound tip weights with a couple of solid fuel rockets that are fired off by engine failure and give a ten second blast. anythings got to be better than 1.1 seconds
As the robinson swashplate mixing system requires all three pushrods to operate together in order to move the collective, i do not think it possible to construct any safety device using only what appears to be the collective pushrod. the proof is. disconnet the other two, raise the collective and see what happens.
As the robinson swashplate mixing system requires all three pushrods to operate together in order to move the collective, i do not think it possible to construct any safety device using only what appears to be the collective pushrod. the proof is. disconnet the other two, raise the collective and see what happens.
Iconoclast
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What's not natural?
To: Tain'tNatural or is it t'aint natural With all the bouncing on my hobby horse I get confused.
I made several posts. Which post and which two preceding posts are you referring to?
I feel a slagging match coming on.
I made several posts. Which post and which two preceding posts are you referring to?
I feel a slagging match coming on.
t'aint natural & Lu
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Dave-jackson
It wouldn't be that difficult to design a servo that once pressure had dropped (engine not running) and the collective lever lowered fully (pilot now fully aware that engine has failed and is recovering Rrpm) would re-datum itself and become a nomal lenght pushrod. the pilot would then have the normal blade pitch to collective relationship. the aim of such a system is only to increase the time of before critical rotor decay, the equivalent if you like of increaseing the mass of the blades but without the weight/cost penalty.
Budgveheli
There is only one collective
Lu
Your a glass half full man arn't you, most engineers are.
It wouldn't be that difficult to design a servo that once pressure had dropped (engine not running) and the collective lever lowered fully (pilot now fully aware that engine has failed and is recovering Rrpm) would re-datum itself and become a nomal lenght pushrod. the pilot would then have the normal blade pitch to collective relationship. the aim of such a system is only to increase the time of before critical rotor decay, the equivalent if you like of increaseing the mass of the blades but without the weight/cost penalty.
Budgveheli
There is only one collective
Lu
Your a glass half full man arn't you, most engineers are.
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Slightly off topic, but I've always thought it would be better to have a warning horn that was activated by the rate of decrease of RRPM as well as at a certain RRPM value.
Governor-on, the R22 operates at a fairly precise 104%, and in most machines the low rpm warning horn activates at 98%. An extra six percent of early warning would be welcome. Wouldn't have to be expensive or complicated either.
Governor-on, the R22 operates at a fairly precise 104%, and in most machines the low rpm warning horn activates at 98%. An extra six percent of early warning would be welcome. Wouldn't have to be expensive or complicated either.
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Hi all,
Dave, with all respect to your goal of making the ultimate foolproof helicopter, it will always stay a theoretical discussion.
Anything you propose will cost R&D, certification, etc.
So it will raise the price of a supposed economic article. It is safe now, so why bother.
I did not fly any new R-22 lately, but if R-44 are an indication:
The Robinson engine governor is better than any Turbine governor I had the pleasure to fly! You really have to rip hard on the collective to have the engine notch away even 1% from the nominal 104%.
bugdevheli:
The 1.1 sec is NOT the time to loose your live. It is the calculated time to rotorstall IF you want to maintain speed AND altitude. Engine out in a R-22 means you will start to sink immediately.
IF (and this one has nothing to do with the machine...) the pilot is decently trained he can maintain altitude AND rpm for several seconds in the R-22 (...by holding the nose up in a flare attidude and let speed bleed of. In a real case you would let the speed bleed of less rapid and allow the helicopter to settle into the auto decent). IF you do not believe it, pass by and I demo it to you (..no stunts just straight forward basic training. I don´t believe in stunts...)
The secret is good training and energy management.
I always read this statements of "Getting the collective down in a split second" in a R-22 - not true, get it down quickly but smooth, no extra hurry needed, just like in every other helicopter....
Why would you want to be able to hang on for ever buzzled until you react?
Imagine you are in your car. How long does it take for you to react if some one pulls out in front of you?
Splitsecond - you jump on the brakes, turn the wheel immediately, whatever..
If you where not speeding beyond a sane level you mostly avoid damage. Why? Because of everyday driving making certain reactions automatic.
A well trained heli pilot will react with the same automatic response.
A WELL TRAINED PILOT...........then there shouldn´t be any badly trained ones, should there!!
If there are, this is where improvment has to come from, not the machine.
The best accident protected cars will not help to avoid them if their drivers are bad!
More warning lights and buzzers:
What more do you want? It lights up and starts to scream at 98% (the old ones were at 95%) telling you "watch me and do something!"
You are still WAY in the green area (remember max glide distance is at 90%....it still just tells you keep watching me closely before you go too low) The R-22 will not fall out of the sky before you go well below 80%.
I learned on a Bell-47, no warning horns or lights for low rpm at all....
Just as MaxNg said:
Training is the key!! IF there are people that cannot come up to a level where they can safely handle a today´s training helicopter, they really should not fly a helicopter. Period.
No sense to push people into a helicopter if they cannot handle it when all the safety gadgets let go!....and that´s just a matter of time.
So it would serve more to make helicopters more affordable and simple (I believe you cannot do a whole lot more than the R-22) and stress good training and examination.
To start with a green instructor is not that bad, but at some point the new student has to be taken over by an experienced hightimer to get him in the correct direction efficiently and safely.
No gadget will do that.
Though I do agree to do everything possible to make helicopters as safe as possible. The multi-engine, multimillion $ monsters are as safe as possible, .....for a couple of million a piece.
And they still fall out of the sky occasionally. I don´t think that their pilots don´t know what they are doing.......
3top
Dave, with all respect to your goal of making the ultimate foolproof helicopter, it will always stay a theoretical discussion.
Anything you propose will cost R&D, certification, etc.
So it will raise the price of a supposed economic article. It is safe now, so why bother.
I did not fly any new R-22 lately, but if R-44 are an indication:
The Robinson engine governor is better than any Turbine governor I had the pleasure to fly! You really have to rip hard on the collective to have the engine notch away even 1% from the nominal 104%.
bugdevheli:
The 1.1 sec is NOT the time to loose your live. It is the calculated time to rotorstall IF you want to maintain speed AND altitude. Engine out in a R-22 means you will start to sink immediately.
IF (and this one has nothing to do with the machine...) the pilot is decently trained he can maintain altitude AND rpm for several seconds in the R-22 (...by holding the nose up in a flare attidude and let speed bleed of. In a real case you would let the speed bleed of less rapid and allow the helicopter to settle into the auto decent). IF you do not believe it, pass by and I demo it to you (..no stunts just straight forward basic training. I don´t believe in stunts...)
The secret is good training and energy management.
I always read this statements of "Getting the collective down in a split second" in a R-22 - not true, get it down quickly but smooth, no extra hurry needed, just like in every other helicopter....
Why would you want to be able to hang on for ever buzzled until you react?
Imagine you are in your car. How long does it take for you to react if some one pulls out in front of you?
Splitsecond - you jump on the brakes, turn the wheel immediately, whatever..
If you where not speeding beyond a sane level you mostly avoid damage. Why? Because of everyday driving making certain reactions automatic.
A well trained heli pilot will react with the same automatic response.
A WELL TRAINED PILOT...........then there shouldn´t be any badly trained ones, should there!!
If there are, this is where improvment has to come from, not the machine.
The best accident protected cars will not help to avoid them if their drivers are bad!
More warning lights and buzzers:
What more do you want? It lights up and starts to scream at 98% (the old ones were at 95%) telling you "watch me and do something!"
You are still WAY in the green area (remember max glide distance is at 90%....it still just tells you keep watching me closely before you go too low) The R-22 will not fall out of the sky before you go well below 80%.
I learned on a Bell-47, no warning horns or lights for low rpm at all....
Just as MaxNg said:
Training is the key!! IF there are people that cannot come up to a level where they can safely handle a today´s training helicopter, they really should not fly a helicopter. Period.
No sense to push people into a helicopter if they cannot handle it when all the safety gadgets let go!....and that´s just a matter of time.
So it would serve more to make helicopters more affordable and simple (I believe you cannot do a whole lot more than the R-22) and stress good training and examination.
To start with a green instructor is not that bad, but at some point the new student has to be taken over by an experienced hightimer to get him in the correct direction efficiently and safely.
No gadget will do that.
Though I do agree to do everything possible to make helicopters as safe as possible. The multi-engine, multimillion $ monsters are as safe as possible, .....for a couple of million a piece.
And they still fall out of the sky occasionally. I don´t think that their pilots don´t know what they are doing.......
3top
Last edited by 3top; 24th Jul 2003 at 09:46.
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3top
You present very good arguments, but I would politely disagree on one major point.
A person is the product of their experiences and therefore my working in engineering and production for GM, on through to having a manufacturing company, has resulted in a strong affinity with 'mass production'. I therefore believe that the cost of any product can be significantly reduced if the volume can be significantly increased.
R&D and certification will become relatively insignificant portions of the craft's cost, when a 'Henry Ford' comes along and produces an easy-to-fly (idiot proof) rotorcraft. The simplicity and popularity of its pilot's license will lead to the rental, then the purchase, and subsequently the popularity of the craft.
A 'cheap' pilot's license, with only a drivers license for the medical, is not ridiculous. The US Sport Pilot/Plane is excluding helicopters because of the owner's inability to do maintenance on a complex craft. The mechanically simpler gyrocopter is to be included.
________________________
And
~ exponentially deviating from the thread;
This century, a person will get into a car, tell it where to go, then sit back and play computer games. This century, a person will get into a VTOL, and do the same. The only significant difference between the two will be the addition of the third dimension ~ vertical travel.
The next century will see the addition of the forth dimension ~ time travel.
The following century will see the addition of the fifth dimension ~ instances (parallel universes).
The century following the following will see ... [sorry ~ classified information]
You present very good arguments, but I would politely disagree on one major point.
A person is the product of their experiences and therefore my working in engineering and production for GM, on through to having a manufacturing company, has resulted in a strong affinity with 'mass production'. I therefore believe that the cost of any product can be significantly reduced if the volume can be significantly increased.
R&D and certification will become relatively insignificant portions of the craft's cost, when a 'Henry Ford' comes along and produces an easy-to-fly (idiot proof) rotorcraft. The simplicity and popularity of its pilot's license will lead to the rental, then the purchase, and subsequently the popularity of the craft.
A 'cheap' pilot's license, with only a drivers license for the medical, is not ridiculous. The US Sport Pilot/Plane is excluding helicopters because of the owner's inability to do maintenance on a complex craft. The mechanically simpler gyrocopter is to be included.
________________________
And
~ exponentially deviating from the thread; This century, a person will get into a car, tell it where to go, then sit back and play computer games. This century, a person will get into a VTOL, and do the same. The only significant difference between the two will be the addition of the third dimension ~ vertical travel.
The next century will see the addition of the forth dimension ~ time travel.
The following century will see the addition of the fifth dimension ~ instances (parallel universes).
The century following the following will see ... [sorry ~ classified information]
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Robinson Nr decay, autorotation&governor
The collective mechanism on a Robinson is controlled by not one, but by all three pushrods. When you raise the collective lever, the linkage is arranged so that both the mixer controlling fore, aft, and lateral and the rear (or collective)pushrod are moved up or down as required. This provides an equal push on the plasic bearing on which the swashplate moves, and helps reduce any free play. If there was "only one collective" it would be possible, to disconnect the front two pushrods and move the swashplate up and down. If you carry out this test you will find that the swashplate simply rocks backwards and forewards and the two disconnected shafts move up and down in line with the rear pushrod. Whilst it may appear that the rear pushrod is the "collective".this is not so. all three pushrods actuate the collective system bugdevheli "alias Glass half full"
Iconoclast
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Which is it?
To: bugdevheli
Make up your mind. You can't have it both ways. The two pushrods attaching to the swashplate at its' front are for lateral control. The aft push rod is fore and aft control. As you had indicated when the collective is raised all three move up to increase pitch collectively.
The collective pushrod attaches the collective stick to the "Mixing Unit". When the collective is raised it raises the mixing unit and effects the three pushrods attached to the swashplate.
A similar system is used on the Agusta 109 and the Agusta 129
and by a slight stretch the Sikorsky S-55.
I completely forgot. The P-51 although it has no collective the pitch and roll are just like the A-109 and the A-129. Most likely that's where Agusta got the idea.
Edited for the red comment.
Make up your mind. You can't have it both ways. The two pushrods attaching to the swashplate at its' front are for lateral control. The aft push rod is fore and aft control. As you had indicated when the collective is raised all three move up to increase pitch collectively.
The collective pushrod attaches the collective stick to the "Mixing Unit". When the collective is raised it raises the mixing unit and effects the three pushrods attached to the swashplate.
A similar system is used on the Agusta 109 and the Agusta 129
and by a slight stretch the Sikorsky S-55.
I completely forgot. The P-51 although it has no collective the pitch and roll are just like the A-109 and the A-129. Most likely that's where Agusta got the idea.
Edited for the red comment.
Last edited by Lu Zuckerman; 15th Jul 2003 at 00:28.
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Robinson Nr decay, autorotation,&governor
Lu zuckerman, you are correct i stand head bowed, my discriptive powers had for a moment left me in the haste to reply to a previous comment which i thought said i was a half pint or something, turns out he was addressing someone else. apologies to that person. but from your reply it would appear you agree with my statement about all three pushrods etc. thanks Bug
Any word??
