Is a second or so enough?
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Is a second or so enough
How many people could make a life or death decision in just over a second, if that decision had to be made without prior warning, and at a time of great stress or concentration. If the answer is "only a few" then does one assume that pilots of light helicopters are superhumans or are they convinced that the training they have received is enough to cover such an emergency. How does one train for the unexpected happening at the worst possible moment. This thought occured to me today whilst up a ladder swinging a sledgehammer. If i miss the bricks should I hang onto the hammer or grab the ladders.? As it happens I managed neither. Lost the hammer and fell on my ass. I am normally competent with both hammers and ladders, but had not received training on this particular emergency. I blamed the high inertia hammer.
Sounds to me like you'd planned ahead - a nice comfortable landing on a handy donkey has to be preferable to landing on your arfe...
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It is a devilish question, one we make each time we develop and certify a helicopter, bugdevheli.
The training has to be automatic for power loss in a single engine helo, with an instinctive connection between the rotor rpm and the collective. There is no decision, no cogniton (thinking) involved if it is to be successful.
Back when I was very wet behind the ears, my instructor covered up the rotor tach and made me fly most of a training session, just to prove how the sound of the engine and the beat of the rotor become part of your subconscious control loop.
If you were to use the 1 second comparison when someone throws a rock at your head, you'd get pranged every time. Ditto with the flame of a hot stove. It not only can be learned, it is the entry point for allowing a solo flight, IMHO!
The training has to be automatic for power loss in a single engine helo, with an instinctive connection between the rotor rpm and the collective. There is no decision, no cogniton (thinking) involved if it is to be successful.
Back when I was very wet behind the ears, my instructor covered up the rotor tach and made me fly most of a training session, just to prove how the sound of the engine and the beat of the rotor become part of your subconscious control loop.
If you were to use the 1 second comparison when someone throws a rock at your head, you'd get pranged every time. Ditto with the flame of a hot stove. It not only can be learned, it is the entry point for allowing a solo flight, IMHO!
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Just a thought.
Perhaps for recreational helicopters, which the pilot flies infrequently, the craft should be equipped with a rotor governor. This type of governor is a RRPM - Pitch coupling. As the rotor looses speed, the pitch of the rotor decreases. Its operates differently than the common engine governor, which is a RRPM - Torque coupling.
A rotor governor requires action by the pilot to STOP the craft from going into autorotation.
Incidentally, a rotor governor was included in the world's first production helicopter, the Flettner FL-282. In fact, the FL-282 was the first recorded helicopter to enter and exit autorotation.
One of two remaining helicopters was taken to the US after the war, for evaluation.
The Prewitt Aircraft Co's. technical report ATI #20283 on the flight tests of the FL-282 states that the rotor governor was found to be very effective. It used a fly-ball rotor pitch governor. There was 10 % of RRPM adjustment. There is a specific report on it ~ Prewitt Aircraft Report N0. 5-130-2
A rotor governor requires action by the pilot to STOP the craft from going into autorotation.
Incidentally, a rotor governor was included in the world's first production helicopter, the Flettner FL-282. In fact, the FL-282 was the first recorded helicopter to enter and exit autorotation.
One of two remaining helicopters was taken to the US after the war, for evaluation.
The Prewitt Aircraft Co's. technical report ATI #20283 on the flight tests of the FL-282 states that the rotor governor was found to be very effective. It used a fly-ball rotor pitch governor. There was 10 % of RRPM adjustment. There is a specific report on it ~ Prewitt Aircraft Report N0. 5-130-2
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Nick is absolutely right. Until our students can properly enter autorotation when we unexpectely chop the throttle we don't send them solo. They also have to pull off a decent full touchdown auto. Of course, in the Bell 47 they have a reasonable amount of time to recognise and enter the auto.
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Yes, but....
An "unexpected" throttle chop in training is not actually unexpected. Students know it will happen, maybe not when, but sometime. It's very different from, say, flying along on a lovely sunny day, looking at the view, talking to a passenger, talking to ATC, and suddenly it all goes quiet, that horn goes off, and the helicopter yaws.
Or, I would think it is; I don't speak from experience. Because we no longer have throttle chops in R22s as part of the PPL course (although my gungho instructor did pull some on me). But I was given one on my FI course, with prior warning at the beginning of the lesson, but not close to it actually happening. I'd swear I got that lever down instantly, but the RRPM still went down to 90%. Now, 90% is recoverable, and I'm on the verge of being an old fart
and maybe my reactions aren't quite as fast as the wet-behind-the-ears daddy-paid-for-licence young PPLs, but...well, it makes you wonder. Or it makes me wonder. And I simply don't know the answer. 
An "unexpected" throttle chop in training is not actually unexpected. Students know it will happen, maybe not when, but sometime. It's very different from, say, flying along on a lovely sunny day, looking at the view, talking to a passenger, talking to ATC, and suddenly it all goes quiet, that horn goes off, and the helicopter yaws.
Or, I would think it is; I don't speak from experience. Because we no longer have throttle chops in R22s as part of the PPL course (although my gungho instructor did pull some on me). But I was given one on my FI course, with prior warning at the beginning of the lesson, but not close to it actually happening. I'd swear I got that lever down instantly, but the RRPM still went down to 90%. Now, 90% is recoverable, and I'm on the verge of being an old fart
and maybe my reactions aren't quite as fast as the wet-behind-the-ears daddy-paid-for-licence young PPLs, but...well, it makes you wonder. Or it makes me wonder. And I simply don't know the answer.
IMHO,
One second is nowhere near enough.
If low inertia rotors were a good idea then:
(a) People would not continue to die following engine stoppages
(b) The R-22 wouldn't have more loss of main rotor control incidents than other teetering types
(c) We wouldn't require SFAR-73
And something else...that one second people talk about for the R22 is NOT one second for the typical high pitch settings used, thats significantly less.
Please Note:
I am not a Robinson basher, I fly both the R22 and R44 and think they are mechanically reliable helicopters. I don't quite believe what Frank Robinson says about never foreseeing the market for training helicopter but do accept it. However, knowing how little weight would have to be added to the R22 rotor system to make it a high inertia system, I am very dissappointed that Frank hasn't spend a few months over the past 25 years sorting out this fundamental design fault with his most popular product.
One second is nowhere near enough.
If low inertia rotors were a good idea then:
(a) People would not continue to die following engine stoppages
(b) The R-22 wouldn't have more loss of main rotor control incidents than other teetering types
(c) We wouldn't require SFAR-73
And something else...that one second people talk about for the R22 is NOT one second for the typical high pitch settings used, thats significantly less.
Please Note:
I am not a Robinson basher, I fly both the R22 and R44 and think they are mechanically reliable helicopters. I don't quite believe what Frank Robinson says about never foreseeing the market for training helicopter but do accept it. However, knowing how little weight would have to be added to the R22 rotor system to make it a high inertia system, I am very dissappointed that Frank hasn't spend a few months over the past 25 years sorting out this fundamental design fault with his most popular product.
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The pre-conceived idea that a particular emergency is about to occur does alter a pilot's reaction. I've seen this many times whilst instructing in the simulator.
A couple of examples. Whilst giving students a series of double engine failures to teach entry to autorotation on a twin (Puma), I always gave them a SINGLE engine failure at some stage. Many pilots were surprised to be shown in the replay that they had shut down a perfectly serviceable turbine. The confusion occurs when autorotation is entered and the good engine backs off to idle. Made students think about checking T's and P's properly.
Similarly, recognition and successful recovery to autorotation from a tail rotor drive shaft failure was shown to be MUCH more difficult if the pilot didn't get a hint or a warning such as vibration. Once a student had the basic skills, I used to give them an unannounced one to deal with. It proved the point that the aircraft could be recovered from some "interesting" extreme situations. I think this is particularly important as diagnosis of this particular malfunction does take a short but finite time.
The video of a yellow Wessex that went into a Welsh reservoir a few years a go is a good example of how such an emergency might occur for real.
A couple of examples. Whilst giving students a series of double engine failures to teach entry to autorotation on a twin (Puma), I always gave them a SINGLE engine failure at some stage. Many pilots were surprised to be shown in the replay that they had shut down a perfectly serviceable turbine. The confusion occurs when autorotation is entered and the good engine backs off to idle. Made students think about checking T's and P's properly.
Similarly, recognition and successful recovery to autorotation from a tail rotor drive shaft failure was shown to be MUCH more difficult if the pilot didn't get a hint or a warning such as vibration. Once a student had the basic skills, I used to give them an unannounced one to deal with. It proved the point that the aircraft could be recovered from some "interesting" extreme situations. I think this is particularly important as diagnosis of this particular malfunction does take a short but finite time.
The video of a yellow Wessex that went into a Welsh reservoir a few years a go is a good example of how such an emergency might occur for real.
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Effective training appears to be the key.
If you don't know how your helicopter will react to an engine failure at any stage of flight, and what and how you are going to react, perhaps you should think about changing jobs.
I realize this can breed a bit of paranoia, but it's better to be paranoid than surprised the wrong way.
In one accident I looked into, I could visualize how surprised an Alouette pilot was when the engine sputtered and stopped - he had 7,000 hours on a type with an incredibly reliable engine, yet the engine quit and from all accounts he wasn't prepared for it in terms of the route of flight, etc.
I'm very surprised that there isn't some way to demonstrate effectively to R-22 students how they have to be ready for an engine failure at any time.
One second is enough if you're ready for it, but for the three engine failures I've had, I wasn't prepared for it - fortunately the cost so far has been only minimal airframe damage and wounded pride.
If you don't know how your helicopter will react to an engine failure at any stage of flight, and what and how you are going to react, perhaps you should think about changing jobs.
I realize this can breed a bit of paranoia, but it's better to be paranoid than surprised the wrong way.
In one accident I looked into, I could visualize how surprised an Alouette pilot was when the engine sputtered and stopped - he had 7,000 hours on a type with an incredibly reliable engine, yet the engine quit and from all accounts he wasn't prepared for it in terms of the route of flight, etc.
I'm very surprised that there isn't some way to demonstrate effectively to R-22 students how they have to be ready for an engine failure at any time.
One second is enough if you're ready for it, but for the three engine failures I've had, I wasn't prepared for it - fortunately the cost so far has been only minimal airframe damage and wounded pride.
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One second is enough if you're ready for it, but for the three engine failures I've had, I wasn't prepared for it - fortunately the cost so far has been only minimal airframe damage and wounded pride.
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s76Heavy
It would be nice to be able to increase the reaction times. I don't see how it could be done unless you come up with some warning system that says - your engine is not healthy and is about to fail. Vibration sensors? Maybe. Carb icing happening? Bad ju-ju sensor? Hmmm.
Something should be possible - perhaps a rate of decay of engine RPM vs. collective position or throttle position or something. Someone somewhere has some engineering data on what the pre-cursors to engine failure in piston engines are - perhaps they can help.
It would be nice to be able to increase the reaction times. I don't see how it could be done unless you come up with some warning system that says - your engine is not healthy and is about to fail. Vibration sensors? Maybe. Carb icing happening? Bad ju-ju sensor? Hmmm.
Something should be possible - perhaps a rate of decay of engine RPM vs. collective position or throttle position or something. Someone somewhere has some engineering data on what the pre-cursors to engine failure in piston engines are - perhaps they can help.
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Shawn: don't stop now!
Clearly the BadJuJu sensor would be paramount.
But even better: do there not exist in the test-pilot caverns some inexpensive forms of vibration monitors? Hi-medium-low frequency sensors for same? A scale precision calibrated in sophisticated units of "acceptable-normal" and "panic-bailout"?
After all, we do equivalent accuracy with G-meters on aerobatic airplanes . . . why not a helicopter shaking-apart measure?
Crowded for panel space? Usurp the IAS meter real estate below 50 knots, the 0-40 k range is useless anyway, as witness your own Bell 206 mast-top spinning sensor!
But even better: do there not exist in the test-pilot caverns some inexpensive forms of vibration monitors? Hi-medium-low frequency sensors for same? A scale precision calibrated in sophisticated units of "acceptable-normal" and "panic-bailout"?
After all, we do equivalent accuracy with G-meters on aerobatic airplanes . . . why not a helicopter shaking-apart measure?
Crowded for panel space? Usurp the IAS meter real estate below 50 knots, the 0-40 k range is useless anyway, as witness your own Bell 206 mast-top spinning sensor!
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Aerodynamics? What's that?
To: S76Heavy
Many years ago the Hydraulics design group at Sikorsky undertook the design of a device that would provide that one-second reaction time without any input from the pilot.
The device was connected to the collective stick. It was cylindrical in shape and inside of the cylinder was a piston. One side of the piston was connected to the servo hydraulic system and the other side of the piston had a spring. The operating concept had the hydraulic system pressurize the piston compressing the spring. The spring was then in the cocked position and the trigger mechanism that released the spring was connected to the engine oil pressure system. The instant the oil pressure dropped the spring would be released forcing the collective stick down establishing autorotation.
There was one minor problem. In order to cock the piston (compressed spring) the hydraulic pressure had to raise the collective stick. The pressure would increase from zero to about 300 to 400 PSI raising the piston but the servo pump was driven from the transmission and at the same time the pressure rose to the point of cocking the cylinder the blades were rotating about 100 RPM. This significant increase in pitch would result in blade sailing and eventual stall out causing the blades to impact the tail cone.
And, another hare brained scheme bit the dust.
Doesn't this support the case for a technical solution to increase reaction times? We're all human and after years of flying without engine failures, we're no longer really ready for it (although we still think we are). Inevitably, some form of complacency will set in, I suppose.
The device was connected to the collective stick. It was cylindrical in shape and inside of the cylinder was a piston. One side of the piston was connected to the servo hydraulic system and the other side of the piston had a spring. The operating concept had the hydraulic system pressurize the piston compressing the spring. The spring was then in the cocked position and the trigger mechanism that released the spring was connected to the engine oil pressure system. The instant the oil pressure dropped the spring would be released forcing the collective stick down establishing autorotation.
There was one minor problem. In order to cock the piston (compressed spring) the hydraulic pressure had to raise the collective stick. The pressure would increase from zero to about 300 to 400 PSI raising the piston but the servo pump was driven from the transmission and at the same time the pressure rose to the point of cocking the cylinder the blades were rotating about 100 RPM. This significant increase in pitch would result in blade sailing and eventual stall out causing the blades to impact the tail cone.
And, another hare brained scheme bit the dust.
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Practice and currency is a real must. I used to work as a training captain at a Jetbox outfit and at the same time also doing PPL training on the R22.
The AOC operator used a variety of freelance pilots. Most of the guys had oodles of experience : offshore and/or military. Most were current somewhere else : often on airliners or twin engine IFR big helos.
It wasn't my practice to do throttle chops, but "voice actuated" practice engine failures, with my hand following to deal with the twist grip. The difference between the two groups was ofetn noticeable. It was common for the experienced guys on the B206 to be slow to respond to the command and hesitant in execution. PPL students during training (who say had gone solo and were flying regularly) were fairly prompt. I guess I would not have sent them solo, if they were not.
[I should also say that everyone improved by the end of the practice which is what it is for].
The worst people were a group of PPL aircraft owners. This was before JAR-FCL, so once a PPL had his licence he never needed to fly with an instructor ever again - not possible now, and IMHO one of the (few) benefits of JAR FCL. Essentially some of this group could even be scared of doing a slow-time autorotation.
If my memory serves me, the AAIB did a study many years ago when an offshore hele crashed due to engine failure and subsequent low RRPM. They got a set of sim sessions to add an unannounced double engne failure and time the reaction time. I recall the times were pretty slow and most would not have responded in time.
These days I fly solely twin engine heles, and I can't instruct (sadly). I always used to feel sorry for line pilots struggling to keep REALLY current with just a 6 month base check and not much other oportunity to practice - now I am he!
I am contemplating doing some single engine flying in the near future, and I will be making sure that I get a very thorough workout before I am finished.
A bit of risk management is surely the practical solution (pending the arrival of the doom sensometer). In a single (and especially one with a low interia system) currency is key. At certain places I flew from, when I was hours building, autos were banned without an instructor. Clearly, this reduced the risk of problems during solo practice autos! However, I wasn't happy in that situation at all and avoided it. If any single engine pilot gets to the point where they are reluctant to do an auto, they need to get out there and in practce again with an instructor. A little game I was taught was to fly along and enter auto at the start of the next radio transmission.
When flying a single never ever let yourself be distracted (hand off the lever etc.) while in the climb or anywhere where MR pitch would give you a more rapid decline in RRPM if the donk stops. You then do the best that you can to manage the risk.
The AOC operator used a variety of freelance pilots. Most of the guys had oodles of experience : offshore and/or military. Most were current somewhere else : often on airliners or twin engine IFR big helos.
It wasn't my practice to do throttle chops, but "voice actuated" practice engine failures, with my hand following to deal with the twist grip. The difference between the two groups was ofetn noticeable. It was common for the experienced guys on the B206 to be slow to respond to the command and hesitant in execution. PPL students during training (who say had gone solo and were flying regularly) were fairly prompt. I guess I would not have sent them solo, if they were not.
[I should also say that everyone improved by the end of the practice which is what it is for].
The worst people were a group of PPL aircraft owners. This was before JAR-FCL, so once a PPL had his licence he never needed to fly with an instructor ever again - not possible now, and IMHO one of the (few) benefits of JAR FCL. Essentially some of this group could even be scared of doing a slow-time autorotation.
If my memory serves me, the AAIB did a study many years ago when an offshore hele crashed due to engine failure and subsequent low RRPM. They got a set of sim sessions to add an unannounced double engne failure and time the reaction time. I recall the times were pretty slow and most would not have responded in time.
These days I fly solely twin engine heles, and I can't instruct (sadly). I always used to feel sorry for line pilots struggling to keep REALLY current with just a 6 month base check and not much other oportunity to practice - now I am he!
I am contemplating doing some single engine flying in the near future, and I will be making sure that I get a very thorough workout before I am finished.
A bit of risk management is surely the practical solution (pending the arrival of the doom sensometer). In a single (and especially one with a low interia system) currency is key. At certain places I flew from, when I was hours building, autos were banned without an instructor. Clearly, this reduced the risk of problems during solo practice autos! However, I wasn't happy in that situation at all and avoided it. If any single engine pilot gets to the point where they are reluctant to do an auto, they need to get out there and in practce again with an instructor. A little game I was taught was to fly along and enter auto at the start of the next radio transmission.
When flying a single never ever let yourself be distracted (hand off the lever etc.) while in the climb or anywhere where MR pitch would give you a more rapid decline in RRPM if the donk stops. You then do the best that you can to manage the risk.
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In threads about entry into autorotation and the time available for the pilot to react, the subjects of low rotor inertia and the Robinson R-22 inevitably come up
Lu mentioned on an earlier thread; " It has been brought to my attention that on the R-44 the pitch horn extends beyond the cone hinge by approximately 28mm.". I believe that the design of the R-44 hub and the R-22 are basically the same. An exception to this similarity is that the pitch horn on the R-22 is inline with the cone hinge. This raises an interesting subject for consideration.
When the pitch horn is on the leading edge of the blade and it is beyond the coning hinge, the rotor has a Pitch-Cone coupling. This coupling causes the pitch angle to reduce as the coning angle increases. One cause for an increase in the coning angle is a reduction in rotor speed. This Pitch-Cone coupling characteristic serves as a type of rotor speed governor, since by removing pitch it reduces the rate at which the rotor looses speed.
The implication is that, all things being equal, the pilot should have more time to react in an R-44 than in a R-22. Might this be true?
Related info on the Groen gyroplane for anyone interested
[Groen added]
Lu mentioned on an earlier thread; " It has been brought to my attention that on the R-44 the pitch horn extends beyond the cone hinge by approximately 28mm.". I believe that the design of the R-44 hub and the R-22 are basically the same. An exception to this similarity is that the pitch horn on the R-22 is inline with the cone hinge. This raises an interesting subject for consideration.
When the pitch horn is on the leading edge of the blade and it is beyond the coning hinge, the rotor has a Pitch-Cone coupling. This coupling causes the pitch angle to reduce as the coning angle increases. One cause for an increase in the coning angle is a reduction in rotor speed. This Pitch-Cone coupling characteristic serves as a type of rotor speed governor, since by removing pitch it reduces the rate at which the rotor looses speed.
The implication is that, all things being equal, the pilot should have more time to react in an R-44 than in a R-22. Might this be true?
Related info on the Groen gyroplane for anyone interested
[Groen added]
Last edited by Dave_Jackson; 16th Nov 2004 at 02:38.
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Dave,
That coupling (also called delta 3) is very much a ride quality and rotor thrust stability improvement. It basically flattens out the rotor's thrust changes as affected by gusts. This also makes the aircraft seem more dynamically stable in turbulence. It does cause rotor speed increases when the plot commands thrust changes with cyclic, as well. It would have a secondary effect of reducing collective as the rotor coned, but to cone the rpm would have to decay first. I'll bet the effect is secondary.
At the bottom of an auto, the delta 3 is a bit harmful, because it slightly reduces the thrust in the flare, making the pilot need to flare more quickly and to a higher nose angle to extract the energy to stop the descent. This effect is fairly small, however, so it should not dominate.
The rotor decay rate at auto entry is almost all due to the rotor inertia (stored energy) as compared to the power being drawn at the engine cut. The allowable rotor droop is almost entirely due to the stall margin of the rotor at the cut point (the aerodynamic blade loading margin). With low inertia the rotor rpm decays rapidly, because of low stored energy. It could be however that the rotor retains effective control at low rpm though, so that large rotor rpm droops are acceptable.
What is the min rotor rpm in the R-22 and R-44? What are the normal rpm's? What s the weight of the rotor blade? With this, I can try to estimate the residual energy (I am sure you can, too, Dave!)
That coupling (also called delta 3) is very much a ride quality and rotor thrust stability improvement. It basically flattens out the rotor's thrust changes as affected by gusts. This also makes the aircraft seem more dynamically stable in turbulence. It does cause rotor speed increases when the plot commands thrust changes with cyclic, as well. It would have a secondary effect of reducing collective as the rotor coned, but to cone the rpm would have to decay first. I'll bet the effect is secondary.
At the bottom of an auto, the delta 3 is a bit harmful, because it slightly reduces the thrust in the flare, making the pilot need to flare more quickly and to a higher nose angle to extract the energy to stop the descent. This effect is fairly small, however, so it should not dominate.
The rotor decay rate at auto entry is almost all due to the rotor inertia (stored energy) as compared to the power being drawn at the engine cut. The allowable rotor droop is almost entirely due to the stall margin of the rotor at the cut point (the aerodynamic blade loading margin). With low inertia the rotor rpm decays rapidly, because of low stored energy. It could be however that the rotor retains effective control at low rpm though, so that large rotor rpm droops are acceptable.
What is the min rotor rpm in the R-22 and R-44? What are the normal rpm's? What s the weight of the rotor blade? With this, I can try to estimate the residual energy (I am sure you can, too, Dave!)
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You got it wrong.
To: Dave Jackson
If the pitch horn extends beyond the cone hinge when the blades cone pitch will be added to the blades not removed. This is not such a bad thing. However when the pilot enters into autorotation and he moves the collective to the full down position the blades are still coned and the pitch can not return to the full down basic pitch setting and this will effect the autorotation characteristics.
If the effect is great enough the pilot will report this to the mechanic and he in turn will adjust the pitch links taking the blades below the basic rigged neutral pitch setting.
This is my basic argument when Frank Robinson stated that he had considered incorporating a 90-degree pitch horn. If he had done so the helicopter would be uncontrollable. Extending the pitch horn 1” or so beyond the cone hinge will not make the helicopter uncontrollable but it will effect the autorotation characteristics.
The entire rigging procedure on the Robinson helicopters is contrary to the rigging procedure on every other helicopter and can lead to some very interesting problems for the mechanics.
This coupling causes the pitch angle to reduce as the coning angle increases.
If the effect is great enough the pilot will report this to the mechanic and he in turn will adjust the pitch links taking the blades below the basic rigged neutral pitch setting.
This is my basic argument when Frank Robinson stated that he had considered incorporating a 90-degree pitch horn. If he had done so the helicopter would be uncontrollable. Extending the pitch horn 1” or so beyond the cone hinge will not make the helicopter uncontrollable but it will effect the autorotation characteristics.
The entire rigging procedure on the Robinson helicopters is contrary to the rigging procedure on every other helicopter and can lead to some very interesting problems for the mechanics.
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Lu,
Any delta 3 effects can be easily worked out when the engineers perform the rigging that then goes into the maintenance manual. Bottom pitch stop on most helos is determined by the auto rpm, in any case.
In other words, no problemo.
Regarding 90 degree pitch horns, the controls are mixed to account for the phase lag, if the horn geometry is changed, all you have to do is re-mix the mechanical controls to make the helo fly right. We have been thru this perhaps 50 times, the way the aircraft handles is NOT affected by the head geometry, as long as the controls are properly mixed. And the Robbie has properly mixed controls.
That 18 degree horse died a long time ago, Lu.
Any delta 3 effects can be easily worked out when the engineers perform the rigging that then goes into the maintenance manual. Bottom pitch stop on most helos is determined by the auto rpm, in any case.
In other words, no problemo.
Regarding 90 degree pitch horns, the controls are mixed to account for the phase lag, if the horn geometry is changed, all you have to do is re-mix the mechanical controls to make the helo fly right. We have been thru this perhaps 50 times, the way the aircraft handles is NOT affected by the head geometry, as long as the controls are properly mixed. And the Robbie has properly mixed controls.
That 18 degree horse died a long time ago, Lu.
They better rethink the Delta 3 application for the R44 if they think that it helps to make it more stable in turbulence...
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So, if we had a "automatic autorotation entry device" coupled to the RRPM, that would mean increased exposure to damage when the RRPM decays in a hovering auto. Generally you don't want to drop the collective too much when you are in a 6ft hover and the engine quits.
I would rather bleed off all the RRPM rolling to the right and fall down the hill, than settle into my passangers as they perform a hover exit from the left of the aircraft. RRPM use is the discretion of the pilot.
Surely there are other good reasons that manufacturers have not installed these. Myself, I was trained to respond to all problems by heading for the ground. Auto was the quickest and generally it puts you into a place where you can quickly access what is happening. I once met a small whirlwind in a B47 and the resultant was ...ummm.... interesting. Needless to say, when we were upright again, I had to roll on the throttle and recover from an induced autorotation. Instinct....
Happened much faster than 1 second and the training to drop pitch and then access the problem (height specific of course) was done without cognitive thought. Just one of a few occurances where the reactions are faster than the thinking.
Many would say that is not uncommon for me thou....hahaha
Still I am amazed, as Shawn was, with the experienced pilots that you go for a training flight with who have no preconcieved idea about what they are going to do in an emergency.
Every rig departure, of which there were 35 a day, required you to think about each stage of the next 20secs and what you would do if the engine quit here, there and down there. It took a lot of discipline to focus because the engine very rarely quit. But we did have a lot of other interesting caution lights which encouraged forethought about your immediate actions.
When your life span can be measured in seconds, you better have a plan.
...and having seen the number of wheelchair bound people who have fallen off ladders and got a free helo ride....
Budgie, take my advice and stay off the ladder.
Daewoo of the sky
So, if we had a "automatic autorotation entry device" coupled to the RRPM, that would mean increased exposure to damage when the RRPM decays in a hovering auto. Generally you don't want to drop the collective too much when you are in a 6ft hover and the engine quits.
I would rather bleed off all the RRPM rolling to the right and fall down the hill, than settle into my passangers as they perform a hover exit from the left of the aircraft. RRPM use is the discretion of the pilot.
Surely there are other good reasons that manufacturers have not installed these. Myself, I was trained to respond to all problems by heading for the ground. Auto was the quickest and generally it puts you into a place where you can quickly access what is happening. I once met a small whirlwind in a B47 and the resultant was ...ummm.... interesting. Needless to say, when we were upright again, I had to roll on the throttle and recover from an induced autorotation. Instinct....
Happened much faster than 1 second and the training to drop pitch and then access the problem (height specific of course) was done without cognitive thought. Just one of a few occurances where the reactions are faster than the thinking.
Many would say that is not uncommon for me thou....hahaha
Still I am amazed, as Shawn was, with the experienced pilots that you go for a training flight with who have no preconcieved idea about what they are going to do in an emergency.
Every rig departure, of which there were 35 a day, required you to think about each stage of the next 20secs and what you would do if the engine quit here, there and down there. It took a lot of discipline to focus because the engine very rarely quit. But we did have a lot of other interesting caution lights which encouraged forethought about your immediate actions.
When your life span can be measured in seconds, you better have a plan.
...and having seen the number of wheelchair bound people who have fallen off ladders and got a free helo ride....
Budgie, take my advice and stay off the ladder.