Tail Rotor Problems
I found one of the hardest aspects was keeping my feet on the floor instead of constantly trying to pedal a control that wasn’t there.
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Carebear and Aser,
Having helped build and qualify several training simulators, I can assure yu that they can teach you virtually nothing about extreme emergencies like tail rotor failure. I suggest that you do not be fooled by their seemingly perfect ability to mimic the real aircraft. Their behavioor for tail rotor failure, as well as all other flight beyond the normal envelope, has never been verified, and is based on assumptions that have no real flight data in them.
When you draw conclusions about the REAL helicopter's response to situations beyond the normal flight envelope based on flight in the simulator, you are probably wrong, but definately beyond the sim's ability to help.
Having helped build and qualify several training simulators, I can assure yu that they can teach you virtually nothing about extreme emergencies like tail rotor failure. I suggest that you do not be fooled by their seemingly perfect ability to mimic the real aircraft. Their behavioor for tail rotor failure, as well as all other flight beyond the normal envelope, has never been verified, and is based on assumptions that have no real flight data in them.
When you draw conclusions about the REAL helicopter's response to situations beyond the normal flight envelope based on flight in the simulator, you are probably wrong, but definately beyond the sim's ability to help.
Nick, you have beat me to it! I, too, was going to say don't believe the simulator when it comes to TR failures. If you compare the FSI 212 sim with the SAS one the behaviour is at opposite ends of the spectrum. The FSI one displays pretty benign characteristics and is not a big deal (I even autorotated onto the carrier at night) the SAS one will tumble instantly and freeze to prevent damage to the jacks. The truth is probably somewhere in between but closer to the SAS one.
Even a brand new level D sim for the 155 does not accurately replicate the TR drive failure and requires a run on landing about 40 kts higher than experience has shown true.
At the end of the day, the sim can only reproduce chracteristics derived from test flight data and checked against the QTG; anything outside of that is extrapolation and guess work.
Even a brand new level D sim for the 155 does not accurately replicate the TR drive failure and requires a run on landing about 40 kts higher than experience has shown true.
At the end of the day, the sim can only reproduce chracteristics derived from test flight data and checked against the QTG; anything outside of that is extrapolation and guess work.
My first and only experience with a level D sim was in SAS (the 412) and men... it was really AMAZING!
I'm just a guy that flew only r-22 and b-206 before, so I don't have much idea about the reality in the flight model, but after a complete t/r faiulure in hover , 2000' hover , final, etc. and being able to put down the chopper without a "red screen" I was feeling very confident to react for the unexpected.
Maybe it isn't very real , but I thought it was a wonderful tool to develop "instinctive reactions based on the procedures" isn't it?
Obviusly I'm not going to check if the rolls and fall back from hover maneouvers that I saw in the sim can be done with the real aircraft.
Regards.
Aser
I'm just a guy that flew only r-22 and b-206 before, so I don't have much idea about the reality in the flight model, but after a complete t/r faiulure in hover , 2000' hover , final, etc. and being able to put down the chopper without a "red screen" I was feeling very confident to react for the unexpected.
Maybe it isn't very real , but I thought it was a wonderful tool to develop "instinctive reactions based on the procedures" isn't it?
Obviusly I'm not going to check if the rolls and fall back from hover maneouvers that I saw in the sim can be done with the real aircraft.
Regards.
Aser
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John Eacott amaizing pictures!! glad you are with us to tell the tail and share the experience................ CARRE BEAR...... is right about his method for TRF and yes it works very well and easy in the 206, its your only option when a zero speed landing is needed, no need to roll the throttle off though any collective applied must be late / last sec and snatch to avoid early torque rotation, use then the pwr as long as you can ( even a second) to help prolong rpm, letting the nose rotate to match ground travel, if any, B4 using throttle to maintain it, done right and with practise you it is very effective and in the 206 very easy (dont try it in an r22)
... one point to make, the flare, apart from the obveouse is used to put the machine at best full right angle to ground travel if you do this then you got it won, also easier to get closer to the ground not worrying about the tail, anymore than a few Kts of wind and you will land it zero speed. And yes i show this to advanced students to show the "more ways to skin a cat"thoery and just to get them thinking, obveousley comes with practise and experience.
... one point to make, the flare, apart from the obveouse is used to put the machine at best full right angle to ground travel if you do this then you got it won, also easier to get closer to the ground not worrying about the tail, anymore than a few Kts of wind and you will land it zero speed. And yes i show this to advanced students to show the "more ways to skin a cat"thoery and just to get them thinking, obveousley comes with practise and experience.
Last edited by skitzs; 11th Mar 2005 at 17:30.
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T/R failure practice
Just to add a few notes regarding the R44 failure and as mentioned already, many FIs in the UK offer specific training so pilots have a sporting chance of coping with the condition ... albeit being outside the EASA/CAA approved PPL syllabus. Yes, it is a fact that too many T/R failure cases result in a major accident involving fatalities but I'd like to think that given a reasonably amount of dedicated instruction and subsequent practice, plus a slice of luck at the moment of failure and a fairly flat piece of ground, most pilots should be able to land the helicopter safely.
So to add my pennorth can I continue. When in practice exercises, I have my pilot place both feet on the cabin floor clear of the yaw pedals. I then make a 'best guess' at the yaw angles that would be experienced by observing the power settings in combination with the airspeed being used. I accept that these may not be exact, but the exercise does provide, as near as I am able, the changing yaw angles and attitudes required to maintain control.
For the exercise, the major items to be considered are ... power in use at the moment of failure ... then the next three being airspeed, height and aircraft weight. Helicopters having a large keel surface such as the Big Bells and the Enstroms generally allow a better level of control relative to airspeed selected. Taking a standard current production American aircraft as our example, a partial or total failure of the T/R system does, as we all know, produce an immediate loss of directional control as Newton's third law of motion takes over and engine torque drives the nose rapidly RIGHT (left in most European makes).
To remove any mystery of the condition, I teach my pilots that they don't actually have a problem! Pause to think! What they do have is an engine that they can no longer control. So initially we just carry out an exercise we have practiced many times ... ie to get rid of the source of the problem by lowering the collective lever and closing the throttle to enter autorotation. With a reasonable airspeed (say 70 knots) and lowish power (say under 50%) the RIGHT yaw might extend out to the 'two o clock' position but whatever, the pilot's immediate action of power reduction prevents further yaw, while the lowered lever drops the nose either increasing or at least maintaining speed. Using cyclic the pilot's first task is to level the 'wings' and maintain at least 60 knots. With the RIGHT yaw stopped, transmission friction take over causing the nose to slowly commence a yaw to the LEFT but again highly dependent on the speed being maintained.
With the nose rotating toward the LEFT 'ten o clock' position, the pilot can now use engine to control left rotation and by raising the collective lever increasing power to yaw the nose once again RIGHT ... the plan being to discover the maximum power setting that can be used at a given airspeed to allow a controlled yaw to the original 'two o clock' position. It should be borne in mind that the resultant 30 degree yaw involves large ASI errors. Opposite use of cyclic assists control, ie with right yaw use left cyclic, the plan being to achieve straight & level flight if possible, or at least a reduced rate of descent ... much depending on aircraft weight.
IF control can be achieved with steady height and airspeed at the 'two o clock' position, the world becomes your oyster! Or at least allows more time to select a suitable emergency landing area. If the former, you may even have time to return to your base airfield or at least reach a better landing site, alert the emergency services and carry out safety emergency drills.
Once over the selected landing site, the helicopter should be positioned so that a shallow rate of descent can be made to the landing site. Lowering the collective lever allows the nose to yaw LEFT back to the 'ten o clock' position while maintaining speed and directional control with a combination of lever position (power) and cyclic (speed). Ideally the approach needs to be made at progressively reduced speed bearing in mind the ASI errors.
So far, the procedure hasn't been that difficult but if a non-damaging landing is to be achieved, the handling co-ordination requirement to control the final rate of descent, the airspeed and yaw is now at its highest. At this point the pilot is aiming to bring the helicopter to within a few feet of the landing surface with as much power as can be used to achieve the lowest rate of descent and minimum forward speed.
At around 20 to say 30 feet the helicopter is initially flared with aft cyclic to further reduce speed but then pushed forward to level the skids for the landing attitude. As the helicopter sinks collective lever is raised allowing the nose to yaw RIGHT back toward 'two o clock' but at around the 'one o clock' position the throttle is closed quite rapidly and as the nose yaws back toward the 'twelve o clock' position the cyclic is pushed forward to make rapid skid contact with the surface. With skids on the ground, collective lever and perhaps throttle is used to keep the helicopter straight allowing skid friction to stop forward movement.
It needs to be borne in mind that once the landing site is reached and descent commenced it will not usually be possible to make a 'go-around' and the pilot is committed to a landing.
I appreciate these suggested handling techniques are more applicable to a failure from a fairly benign configuration and may not apply to a worse-case take-off or landing or low height zero speed hovers where more advanced handling would be required.
I also hasten to add, that these notes are for guidance only and perhaps to promote discussion on such an important life-saving exercise, but I'd have to say, I've never been a supporter of the usual PFM recommendation to handle the T/R failure problem by ... "entering autorotation." For sure that technique will stop the rapid right yaw problem but will not allow the helicopter to be landed safely since the initial right yaw will, as outlined above, be followed immediately by a yaw to the left and in my view it matters not a lot whether the helicopter impacts the ground in a right or a left spin. And just to remind pilots that our European friends turn their rotors differently so where I say RIGHT .... use LEFT and vice-versa.
Just to close, much of the above has been learned from my four 'actual' T/R failures I've experienced in 14,000 plus hours over a forty-year career. Luck allowed me to survive the first in 1973 when a T/R shaft sheared on a sales demonstration, the second was a hover failure when a licenced engineer obligingly fitted the T/R blade assembly in a reversed 'trailing edge' first configuration which being an 'ace' pilot, I did't spot on the pre-flight inspection. With some experience under my belt, I completed a high speed run-on landing at Cranfield in 1986 and a later further occasion when I landed on a cricket field at one of Noel Edmonds 'Mr Blobby' events in Somerset. The final episode occurred at the 1999 Biggin Hill Air Fair when, with the hoped for 'slice of luck', I managed to get the Enstrom FX down without further damage. But Guys & Gals out there, I'm still waiting for my first engine failure!
Safe flying to all and I sincerely hope my words will help another pilot one day. DRK
So to add my pennorth can I continue. When in practice exercises, I have my pilot place both feet on the cabin floor clear of the yaw pedals. I then make a 'best guess' at the yaw angles that would be experienced by observing the power settings in combination with the airspeed being used. I accept that these may not be exact, but the exercise does provide, as near as I am able, the changing yaw angles and attitudes required to maintain control.
For the exercise, the major items to be considered are ... power in use at the moment of failure ... then the next three being airspeed, height and aircraft weight. Helicopters having a large keel surface such as the Big Bells and the Enstroms generally allow a better level of control relative to airspeed selected. Taking a standard current production American aircraft as our example, a partial or total failure of the T/R system does, as we all know, produce an immediate loss of directional control as Newton's third law of motion takes over and engine torque drives the nose rapidly RIGHT (left in most European makes).
To remove any mystery of the condition, I teach my pilots that they don't actually have a problem! Pause to think! What they do have is an engine that they can no longer control. So initially we just carry out an exercise we have practiced many times ... ie to get rid of the source of the problem by lowering the collective lever and closing the throttle to enter autorotation. With a reasonable airspeed (say 70 knots) and lowish power (say under 50%) the RIGHT yaw might extend out to the 'two o clock' position but whatever, the pilot's immediate action of power reduction prevents further yaw, while the lowered lever drops the nose either increasing or at least maintaining speed. Using cyclic the pilot's first task is to level the 'wings' and maintain at least 60 knots. With the RIGHT yaw stopped, transmission friction take over causing the nose to slowly commence a yaw to the LEFT but again highly dependent on the speed being maintained.
With the nose rotating toward the LEFT 'ten o clock' position, the pilot can now use engine to control left rotation and by raising the collective lever increasing power to yaw the nose once again RIGHT ... the plan being to discover the maximum power setting that can be used at a given airspeed to allow a controlled yaw to the original 'two o clock' position. It should be borne in mind that the resultant 30 degree yaw involves large ASI errors. Opposite use of cyclic assists control, ie with right yaw use left cyclic, the plan being to achieve straight & level flight if possible, or at least a reduced rate of descent ... much depending on aircraft weight.
IF control can be achieved with steady height and airspeed at the 'two o clock' position, the world becomes your oyster! Or at least allows more time to select a suitable emergency landing area. If the former, you may even have time to return to your base airfield or at least reach a better landing site, alert the emergency services and carry out safety emergency drills.
Once over the selected landing site, the helicopter should be positioned so that a shallow rate of descent can be made to the landing site. Lowering the collective lever allows the nose to yaw LEFT back to the 'ten o clock' position while maintaining speed and directional control with a combination of lever position (power) and cyclic (speed). Ideally the approach needs to be made at progressively reduced speed bearing in mind the ASI errors.
So far, the procedure hasn't been that difficult but if a non-damaging landing is to be achieved, the handling co-ordination requirement to control the final rate of descent, the airspeed and yaw is now at its highest. At this point the pilot is aiming to bring the helicopter to within a few feet of the landing surface with as much power as can be used to achieve the lowest rate of descent and minimum forward speed.
At around 20 to say 30 feet the helicopter is initially flared with aft cyclic to further reduce speed but then pushed forward to level the skids for the landing attitude. As the helicopter sinks collective lever is raised allowing the nose to yaw RIGHT back toward 'two o clock' but at around the 'one o clock' position the throttle is closed quite rapidly and as the nose yaws back toward the 'twelve o clock' position the cyclic is pushed forward to make rapid skid contact with the surface. With skids on the ground, collective lever and perhaps throttle is used to keep the helicopter straight allowing skid friction to stop forward movement.
It needs to be borne in mind that once the landing site is reached and descent commenced it will not usually be possible to make a 'go-around' and the pilot is committed to a landing.
I appreciate these suggested handling techniques are more applicable to a failure from a fairly benign configuration and may not apply to a worse-case take-off or landing or low height zero speed hovers where more advanced handling would be required.
I also hasten to add, that these notes are for guidance only and perhaps to promote discussion on such an important life-saving exercise, but I'd have to say, I've never been a supporter of the usual PFM recommendation to handle the T/R failure problem by ... "entering autorotation." For sure that technique will stop the rapid right yaw problem but will not allow the helicopter to be landed safely since the initial right yaw will, as outlined above, be followed immediately by a yaw to the left and in my view it matters not a lot whether the helicopter impacts the ground in a right or a left spin. And just to remind pilots that our European friends turn their rotors differently so where I say RIGHT .... use LEFT and vice-versa.
Just to close, much of the above has been learned from my four 'actual' T/R failures I've experienced in 14,000 plus hours over a forty-year career. Luck allowed me to survive the first in 1973 when a T/R shaft sheared on a sales demonstration, the second was a hover failure when a licenced engineer obligingly fitted the T/R blade assembly in a reversed 'trailing edge' first configuration which being an 'ace' pilot, I did't spot on the pre-flight inspection. With some experience under my belt, I completed a high speed run-on landing at Cranfield in 1986 and a later further occasion when I landed on a cricket field at one of Noel Edmonds 'Mr Blobby' events in Somerset. The final episode occurred at the 1999 Biggin Hill Air Fair when, with the hoped for 'slice of luck', I managed to get the Enstrom FX down without further damage. But Guys & Gals out there, I'm still waiting for my first engine failure!
Safe flying to all and I sincerely hope my words will help another pilot one day. DRK
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T/R Failure
Hi Nigel ... interesting you should raise that point. For my Biggin Hill recovery, I made a point of landing in a 'Three o Clock' cross-wind making an initial touch down on the right skid so once I'd achieved ground contact the right side wind and right skid friction held the nose straight in the 'twelve o clock' position until the last few yards. With both skids down M/R friction took over and the machine completed a 100 degree left spin as it stopped, fortunately I was on a hard grass surface. IF I had been able to make more accurate use of collective lever/throttle, no doubt I could even have avoided that! Regards. DRK
Nigel
Very interesting, personally I think it is better to be straight into the wind so you keep precious airflow over your stabiliser to help keep it straight as one runs on. Remember it is accleration that kills us, so touching down at the slowest possible speed must be the best, thus landing into wind. An example in a 500, stick about 1.5 inches of right pedal forward you can do a zero zero landing without moving the pedals and keeping straight in 15 ish knots of wind ( 2 up half fuel) drop the wind to less than 10 kts and you cant do it without closing the throttle to remove the tq reaction as you slow down
Very interesting, personally I think it is better to be straight into the wind so you keep precious airflow over your stabiliser to help keep it straight as one runs on. Remember it is accleration that kills us, so touching down at the slowest possible speed must be the best, thus landing into wind. An example in a 500, stick about 1.5 inches of right pedal forward you can do a zero zero landing without moving the pedals and keeping straight in 15 ish knots of wind ( 2 up half fuel) drop the wind to less than 10 kts and you cant do it without closing the throttle to remove the tq reaction as you slow down
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The word benign was used which is easier to understand that what I usually say as - arrive at nothing with nothing - instead land in the most benign manner.Skating along close to the ground washing off even a little airspeed, you will end up pulling too much power and thus yaw, or too steep an approach the same applies.
With practice with wind from either the quarter or nose a zero zero touchdown can be achieved and allow the last little rotation to wear itself off as you hold off with the toe of right side skid down. That is with T/R fail simulated with 2/3 pedal in the '47 or R22.
As it finally falls you will see the cyclic all the way over toward the skid toe with lever fully up.
A good pre exercise is to fly along at slow airspeed and wind the throttle on-off-on-off a few times to learn the torque /rotation control and heading effect of the throttle.
With practice with wind from either the quarter or nose a zero zero touchdown can be achieved and allow the last little rotation to wear itself off as you hold off with the toe of right side skid down. That is with T/R fail simulated with 2/3 pedal in the '47 or R22.
As it finally falls you will see the cyclic all the way over toward the skid toe with lever fully up.
A good pre exercise is to fly along at slow airspeed and wind the throttle on-off-on-off a few times to learn the torque /rotation control and heading effect of the throttle.
Hughes500 - be very careful who you give advice to here...Dennis wrote the book and you are advising him on how it should be done
Tail rotor failure - my pet subject. A VERY complicated phenomena, made much much more difficult to understand when the main aerodynamicists the world over, aren't fully comfortable with what happens and how best to handle it. We teach this malfunction on a daily basis to the best pilots in the world and the data we get from Westlands / AW / Sikorsky is a little scant, to say the least.
Very few helicopter pilots fully understand what to do when the tail rotor stops. 99% think they know and a tiny proportion prepare as best they can for the time it may happen to them. BUT like most aviation related skills it is a perishable skill and needs constant rehearsal.
Mosy military pilots allow for this in their training repetoire, but I suspect once a civvy qualifies and gets their ticket, they rarely if ever train in anger with this phenomenon.
There is a world of difference between tail rotor control failure and tail rotor failure. The former will allow most helicopters to arrive safey on terra firma in most instances (except with gross mis handling) The latter relies heavily on luck more than on judgement.
I won't drag on with more detailed explanations but what I will say is anyone who successfully lands a helo after a tail rotor Failure deserves atleast a Distinguished Warfare Medal , to say the least.
(Actually a DWM would be an insult - but I couldn't resist it after reading in the nes today that the yanks are awarding these for Drone operators
)
What Dennis and TopendTq did / said is as close to copy book as one can get.
Tail rotor failure - my pet subject. A VERY complicated phenomena, made much much more difficult to understand when the main aerodynamicists the world over, aren't fully comfortable with what happens and how best to handle it. We teach this malfunction on a daily basis to the best pilots in the world and the data we get from Westlands / AW / Sikorsky is a little scant, to say the least.
Very few helicopter pilots fully understand what to do when the tail rotor stops. 99% think they know and a tiny proportion prepare as best they can for the time it may happen to them. BUT like most aviation related skills it is a perishable skill and needs constant rehearsal.
Mosy military pilots allow for this in their training repetoire, but I suspect once a civvy qualifies and gets their ticket, they rarely if ever train in anger with this phenomenon.
There is a world of difference between tail rotor control failure and tail rotor failure. The former will allow most helicopters to arrive safey on terra firma in most instances (except with gross mis handling) The latter relies heavily on luck more than on judgement.
I won't drag on with more detailed explanations but what I will say is anyone who successfully lands a helo after a tail rotor Failure deserves atleast a Distinguished Warfare Medal , to say the least.
(Actually a DWM would be an insult - but I couldn't resist it after reading in the nes today that the yanks are awarding these for Drone operators
)What Dennis and TopendTq did / said is as close to copy book as one can get.
Ok TC ...we will keep this one civil
With all due respect to you superior training and experience ( actually not being sarcastic ) ...I would have thought that t/r malfunction , as in stuck , controls could be far worse . If we take it that a t/r with no drive produces little to no thrust , other than a small weather vain pull or push , you then have the ability to change heading by use of collective and throttle either way ...yes ?
In the event of the t/r sticking on a high power setting , say max take off ....ie fullish left pedal ( in yank machine ) then your options are vastly reduced . You can pull full power to get straight ....but then how do you lose height and make a landing .....if you reduce power you are going to spin . The only way I thought you could cope would be to do very tight turns using a lot of power but still managing to sink until close to ground . I would be interested to hear how full left pedal would be easier to cope with .
Ps. For these purposes we are not including c of g issues which you would have with the departure of blades , xmsn etc
With all due respect to you superior training and experience ( actually not being sarcastic ) ...I would have thought that t/r malfunction , as in stuck , controls could be far worse . If we take it that a t/r with no drive produces little to no thrust , other than a small weather vain pull or push , you then have the ability to change heading by use of collective and throttle either way ...yes ?
In the event of the t/r sticking on a high power setting , say max take off ....ie fullish left pedal ( in yank machine ) then your options are vastly reduced . You can pull full power to get straight ....but then how do you lose height and make a landing .....if you reduce power you are going to spin . The only way I thought you could cope would be to do very tight turns using a lot of power but still managing to sink until close to ground . I would be interested to hear how full left pedal would be easier to cope with .
Ps. For these purposes we are not including c of g issues which you would have with the departure of blades , xmsn etc
Last edited by nigelh; 15th Feb 2013 at 14:07.
Nigel - TC beasts us with these complex TR malfunctions on a regular basis and a stuck pedal in the manner you describe is a regular exercise - the answer is to reduce the Nr if you can because that will reduce the amount of TR thrust and make things easier to handle.
You still end up in a slow, high power approach but it is manageable, even with very high TR pitch settings.
If you mend your fences with TC he might even let you have a go
You still end up in a slow, high power approach but it is manageable, even with very high TR pitch settings.
If you mend your fences with TC he might even let you have a go
Ok ...but can he supply the helicopter ??!! I recall I have done that exercise with drooping NR but I don't think with max left rudder . I shall do it with someone like JJ next LPC for sure . Certainly a good exercise to keep up to speed on ( we all spend so much time practicing engine failures when they are probably the very least likely bad scenario to happen . Hence DK with none .... Touch wood )
)
NigeH, We have an opportunity here to publicly discuss, probably the helicopter pilot's worse nightmare - Tail rotor failure. Excepting of course all those who fly tandem or contra rotating helicopters.
If you're happy let's start a separate thread on Tail rotor malfunctions and see what comes of it.
I suspect this has been discussed time and time again on Pprune but my search didn't throw much up
It would actually bring together some of the best and worst views and opinions, experiences and suggestions. People like Dennis et al could tell us what actually happens.......
Let me know what you think?
If you're happy let's start a separate thread on Tail rotor malfunctions and see what comes of it.
I suspect this has been discussed time and time again on Pprune but my search didn't throw much up
It would actually bring together some of the best and worst views and opinions, experiences and suggestions. People like Dennis et al could tell us what actually happens.......
Let me know what you think?
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the answer is to reduce the Nr if you can because that will reduce the amount of TR thrust and make things easier to handle.
However may I register a small divergence.
I always aim to enter with 100% RRPM as i look at the critical surviving factor as the highest remaining RRPM to retain flying control after throttle is wound off for heading control.
Torque variation gives heading control, therefore maximum torque is required under the prevailing benign power required condition
If RRPM is decayed then so too is torque and if you wind throttle off to straighten up starting from low RRPM it gets spooky real quick.
A separate thread could be a good idea.
Yeah I'll stick my mitt up for one those dang DWMs too although i got one of those company star and bar turnouts for surviving with no damage a T/R drive shaft pop out at thirty feet with zero airspeed.
Because of that we initiated T/R failure at the hover OGE (1500 feet min please for lighties) as well as the usual in the hover IGE.
Last edited by topendtorque; 15th Feb 2013 at 22:20.
TET, your point regarding Nr is certainly valid for horrid low inertia rotors like the R22 and R44 - I would want as much Nr as possible in one of those - read the R22 accident report from the latest UK AAIB, it makes for sobering reading about low inertia heads and how quickly low Nr can turn into NO Nr!
Ref torque though, as you slow the rotor down the torque goes up so your max Tq will be as you try to accelerate the low Nr back up to normal setting.
In the high TR pitch scenario we are talking about, you can use lower Nr to help manoeuvre and get a rate of descent - then, once you are near the ground at low speed (with a higher power demand) you can wind on the throttle a bit to help directional control.
Nigel, what TC can supply is a top-drawer simulator where such things can be practised over and over again.
Ref torque though, as you slow the rotor down the torque goes up so your max Tq will be as you try to accelerate the low Nr back up to normal setting.
In the high TR pitch scenario we are talking about, you can use lower Nr to help manoeuvre and get a rate of descent - then, once you are near the ground at low speed (with a higher power demand) you can wind on the throttle a bit to help directional control.
Nigel, what TC can supply is a top-drawer simulator where such things can be practised over and over again.
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Tail rotor issues and the FFS
Just before you get carried away just remember that unless your simulator has been programmed with actual flight data then it would have been programmed using a mathematical model and given the evidence I have seen thus far I would be a touch sceptical.
The major instinct you want the trainee to grasp is an instantaneous (or as near as) recognition of a TR malfunction and if it is one that involves total loss of directional control to then lower the collective fully whatever the phase of flight.
A few seconds later then you may have a chance to reassess the collective position according to your circumstances but I believe we can say with some confidence that the longer you delay your reaction the more problematic the outcome.
G.
The major instinct you want the trainee to grasp is an instantaneous (or as near as) recognition of a TR malfunction and if it is one that involves total loss of directional control to then lower the collective fully whatever the phase of flight.
A few seconds later then you may have a chance to reassess the collective position according to your circumstances but I believe we can say with some confidence that the longer you delay your reaction the more problematic the outcome.
G.
Selamat ,diraf, all helicopters have a measure of directional stability;that is,they are like a weathervane,pointing into the relative wind,in the normal flight case,going forwards,and or sideways; that is a generalisation,as some,those withe long streamlined fuselages,are better than those with `skinny` tails.However, hovering tail to wind/downwind alters the airflow pattern around the fuselage,tailcone,tail-rotor,horizontal stabiliser,and you are now in the regime of the weathervane,with a larger `side-area` being affected,and any slight yaw will attempt to make the aircraft want to turn back into the natural wind. So,it requires a lot more `work` on the pedals to keep the helo pointing `downwind`.Anyway, most helicopter pilots are very `light on their toes`,and the really good ones wear `dancing shoes` anyway...!!!!.
