Is a second or so enough?
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Interestingly, in recent times we've been putting some effort into stressing to R22 students the fact that autorotation should not be the automatic reaction to any suspected problem.
This is because we've had a number of fatal accidents in the UK involving pilots who entered autorotation because of a red light, or other perceived problem, and who then screwed up the auto one way or another - let the revs go to hell or ran into the side of a house. (This should also be taken into account when you consider why one in five R22 accidents is fatal. You're not dealing with high-time hotshots here).
The story now is - nose flicks left, engine failure, lever down. Nose flicks right, tail rotor failure, lever down. Anything else and you've got time to think about it before you commit.
As to R22 inertia, Tim Tucker waited an electronically-measured 2.4 seconds after throttle chop before beginning to lower the lever during one test, described to me as "in cruise flight." (Don't try this at home). The 1.1 seconds often quoted as the time you have available to rotor stall is if you seek to maintain height by raising the lever. The three main causes of low RPM rotor stalls are overpitching, rolling the throttle the wrong way (mostly in the pre-governor days) and gripping the throttle so hard that the governor was unable to turn it.
This is because we've had a number of fatal accidents in the UK involving pilots who entered autorotation because of a red light, or other perceived problem, and who then screwed up the auto one way or another - let the revs go to hell or ran into the side of a house. (This should also be taken into account when you consider why one in five R22 accidents is fatal. You're not dealing with high-time hotshots here).
The story now is - nose flicks left, engine failure, lever down. Nose flicks right, tail rotor failure, lever down. Anything else and you've got time to think about it before you commit.
As to R22 inertia, Tim Tucker waited an electronically-measured 2.4 seconds after throttle chop before beginning to lower the lever during one test, described to me as "in cruise flight." (Don't try this at home). The 1.1 seconds often quoted as the time you have available to rotor stall is if you seek to maintain height by raising the lever. The three main causes of low RPM rotor stalls are overpitching, rolling the throttle the wrong way (mostly in the pre-governor days) and gripping the throttle so hard that the governor was unable to turn it.
Iconoclast
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A person must have eyes in their mouth to see what they are saying.
To: NickLappos
On a typical Sikorsky, Bell, Aerospatiale and most other helicopters they have a rigged phase angle of 90-degrees. On most if not al of these helicopters the actual phase angle is less than 90-degrees (Phase angle shift). On a Robinson the rigged phase angle is 72-degrees with the assumption there is no if not a minimal shift in this phase angle.
No amount of modification of control input can compensate for a 90-degree pitch horn on a Robinson helicopter. The control input on the Robinson is identical to a two-blade system on a Bell. With forward cyclic the swashplate tips down over the nose and with left cyclic the swashplate will tip down over the left lateral axis. The opposite is true for opposite control inputs. On the Bell the pitch horn leads the blade by 90-degrees. When setting the forward pitch range on the Bell the blades are disposed over the lateral axis. In setting the lateral pitch ranges the blades are disposed over the longitudinal axis.
On the Robinson when setting the forward cyclic pitch settings the blade is disposed 18-degrees ahead of the lateral axis. In setting the lateral range the blades are disposed 18-degrees ahead of the longitudinal axis.
Now let’s discuss flapping on the Robinson. Flapping in this case is coning about the cone hinge.
On the R-22 with no pitch in the blades the pitch horn connect point with the pitch link is on or about coincident with the cone hinge so if a blade is raised from this static point there is no pitch flap coupling. However when collective pitch is increased the pitch horn will rise above the cone hinge so if the blade is moved about the cone hinge there will be pitch flap coupling with a decrease in pitch with up flap and an increase in pitch with down flap. This is normal.
However if you have a pitch horn that extends beyond the cone hinge you will have control problems. Using the above example with a 90-degree pitch horn if you raise the blade about the cone hinge with no pitch in the blades you will get an increase in pitch (on the R-22 there is no change in pitch. When collective is added and the blades cone there would be a significant increase in pitch over that which was input by the pilot. The kinematics of the blades in flight are beyond me but I do believe that with any flapping of the blades about the cone hinges the rotor would respond in a way that either increases the pilot input or acts in opposition to the pilot input.
The R-44 does not have a 90-degree pitch horn but it does extend beyond the cone hinge. Although the problems would not be as severe I believe that under certain conditions (autorotation) there could be a problem.
On most helicopters blade pitch settings are made and then the adjustable stops are set to limit any movement beyond that point. On the Robinson they have fixed stops and the blades are set to that stop. All pitch settings are set with the cyclic in the neutral position and the collective full down. Since any movement from the neutral position to the forward stop would be equal to the same movement to the aft stop. From that you might assume that the pitch settings for forward and aft cyclic would be the same but, they are not.
Both blades are set with the cyclic against the forward stop. Then the cyclic is moved the aft stop and the blade pitch is set to the aft settings (which are different). In setting the aft pitch point it is necessary to adjust the pitch links which destroys the setting for forward cyclic. The mechanic is then told to recheck the forward pitch setting which are now changed. At or from this point the mechanic is left to ponder what he must do as the maintenance manual is moot from this point onward. The lateral settings are the same.
In some cases it is necessary to make adjustments on the pitch-input rods to the swashplate (after having neutralized the swashplate). These adjustments can cause a binding on the swashplate monoball. The tail rotor settings are just as confusing.
Nick, I have a question. Put yourself in Frank Robinson’s place. You design a rotorhead and then construct a helicopter around it. The rotorhead is different in that it can flap about a teeter bearing and it an also flap about cone hinges. Good design says that the pitch horn can't extend beyond the cone hinge so that the helicopter has a rig angle of 72-degrees. Now design a blade that will respond in 72-degrees where all other helicopters have a rigged phase angle of 90-degrees and their blades respond accordingly.
On a typical Sikorsky, Bell, Aerospatiale and most other helicopters they have a rigged phase angle of 90-degrees. On most if not al of these helicopters the actual phase angle is less than 90-degrees (Phase angle shift). On a Robinson the rigged phase angle is 72-degrees with the assumption there is no if not a minimal shift in this phase angle.
No amount of modification of control input can compensate for a 90-degree pitch horn on a Robinson helicopter. The control input on the Robinson is identical to a two-blade system on a Bell. With forward cyclic the swashplate tips down over the nose and with left cyclic the swashplate will tip down over the left lateral axis. The opposite is true for opposite control inputs. On the Bell the pitch horn leads the blade by 90-degrees. When setting the forward pitch range on the Bell the blades are disposed over the lateral axis. In setting the lateral pitch ranges the blades are disposed over the longitudinal axis.
On the Robinson when setting the forward cyclic pitch settings the blade is disposed 18-degrees ahead of the lateral axis. In setting the lateral range the blades are disposed 18-degrees ahead of the longitudinal axis.
Now let’s discuss flapping on the Robinson. Flapping in this case is coning about the cone hinge.
On the R-22 with no pitch in the blades the pitch horn connect point with the pitch link is on or about coincident with the cone hinge so if a blade is raised from this static point there is no pitch flap coupling. However when collective pitch is increased the pitch horn will rise above the cone hinge so if the blade is moved about the cone hinge there will be pitch flap coupling with a decrease in pitch with up flap and an increase in pitch with down flap. This is normal.
However if you have a pitch horn that extends beyond the cone hinge you will have control problems. Using the above example with a 90-degree pitch horn if you raise the blade about the cone hinge with no pitch in the blades you will get an increase in pitch (on the R-22 there is no change in pitch. When collective is added and the blades cone there would be a significant increase in pitch over that which was input by the pilot. The kinematics of the blades in flight are beyond me but I do believe that with any flapping of the blades about the cone hinges the rotor would respond in a way that either increases the pilot input or acts in opposition to the pilot input.
The R-44 does not have a 90-degree pitch horn but it does extend beyond the cone hinge. Although the problems would not be as severe I believe that under certain conditions (autorotation) there could be a problem.
On most helicopters blade pitch settings are made and then the adjustable stops are set to limit any movement beyond that point. On the Robinson they have fixed stops and the blades are set to that stop. All pitch settings are set with the cyclic in the neutral position and the collective full down. Since any movement from the neutral position to the forward stop would be equal to the same movement to the aft stop. From that you might assume that the pitch settings for forward and aft cyclic would be the same but, they are not.
Both blades are set with the cyclic against the forward stop. Then the cyclic is moved the aft stop and the blade pitch is set to the aft settings (which are different). In setting the aft pitch point it is necessary to adjust the pitch links which destroys the setting for forward cyclic. The mechanic is then told to recheck the forward pitch setting which are now changed. At or from this point the mechanic is left to ponder what he must do as the maintenance manual is moot from this point onward. The lateral settings are the same.
In some cases it is necessary to make adjustments on the pitch-input rods to the swashplate (after having neutralized the swashplate). These adjustments can cause a binding on the swashplate monoball. The tail rotor settings are just as confusing.
Nick, I have a question. Put yourself in Frank Robinson’s place. You design a rotorhead and then construct a helicopter around it. The rotorhead is different in that it can flap about a teeter bearing and it an also flap about cone hinges. Good design says that the pitch horn can't extend beyond the cone hinge so that the helicopter has a rig angle of 72-degrees. Now design a blade that will respond in 72-degrees where all other helicopters have a rigged phase angle of 90-degrees and their blades respond accordingly.
Last edited by Lu Zuckerman; 16th Nov 2004 at 18:36.
Hands up all those who saw that coming? One, 2, 3 - er, lots...
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Eyesout
Hi all
If one was to experiance engine failure in the R22 whilst flying at sensible speeds ( >60knts), would immediately flaring the aircraft help to reduce the rate of RRPM decay or even stop the decay untill the lever was down? I only ask because your hand may not be on the collective the moment the engine quits.
I'm about to take my PPL flight test, I'm a little worried about R22 safety in the event of power failure.
Regards Eyesout.
If one was to experiance engine failure in the R22 whilst flying at sensible speeds ( >60knts), would immediately flaring the aircraft help to reduce the rate of RRPM decay or even stop the decay untill the lever was down? I only ask because your hand may not be on the collective the moment the engine quits.
I'm about to take my PPL flight test, I'm a little worried about R22 safety in the event of power failure.
Regards Eyesout.
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Whoops!
Nick, what you say is informative and makes sense. Unfortunately, we have a problem.
Lu said, "You got it wrong. If the pitch horn extends beyond the cone hinge when the blades cone pitch will be added to the blades not removed.
"Lu, You got it right. I assumed (naughty, naughty) that your " It has been brought to my attention that on the R-44 the pitch horn extends beyond the cone hinge by approximately 28mm.". meant that the pitch link was outboard of the coning hinge. Burkhard Domke's picture confirms that the pitch link is actually inboard.
This means that on the R-44, upward coning adds pitch and upward teetering removes pitch. Therefore, much of what Lu says makes sense. In addition, Steve76's comment " They better rethink the Delta 3 application for the R44 if they think that it helps to make it more stable in turbulence..." also appears to support this position
Frank R. must have had his reasons for moving the pitch link inboard of the coning hinge but it appears to be counterintuitive to the thinking of those on this forum, and Chuck Beaty. This sure make Lu's concerns a lot more interesting.
Nick, what you say is informative and makes sense. Unfortunately, we have a problem.
Lu said, "You got it wrong. If the pitch horn extends beyond the cone hinge when the blades cone pitch will be added to the blades not removed.
"Lu, You got it right. I assumed (naughty, naughty) that your " It has been brought to my attention that on the R-44 the pitch horn extends beyond the cone hinge by approximately 28mm.". meant that the pitch link was outboard of the coning hinge. Burkhard Domke's picture confirms that the pitch link is actually inboard.
This means that on the R-44, upward coning adds pitch and upward teetering removes pitch. Therefore, much of what Lu says makes sense. In addition, Steve76's comment " They better rethink the Delta 3 application for the R44 if they think that it helps to make it more stable in turbulence..." also appears to support this position
Frank R. must have had his reasons for moving the pitch link inboard of the coning hinge but it appears to be counterintuitive to the thinking of those on this forum, and Chuck Beaty. This sure make Lu's concerns a lot more interesting.
Eyesout: Flaring would conserve the rate of decay of Nr it might even increase the Nr if you're fast enough.
I never let go of the cyclic, mainly because my FLM tells me that if I have a SAS runaway and the cyclic is 'unattended' I could lose 400'+ within a couple of seconds!
I rarely let go of the collective - possibly because of my background as a mil instructor and protecting myself from a clumsy student pilot. Mainly though - there is a big fat steel rod attaching the Nr gauge/rotors and collective. Ask the engineers to point it out. You really should be ultra close to that collective most of the time.
What response time do they give R22 drivers for rotor recovery: 1.3 seconds, is it?
I never let go of the cyclic, mainly because my FLM tells me that if I have a SAS runaway and the cyclic is 'unattended' I could lose 400'+ within a couple of seconds!
I rarely let go of the collective - possibly because of my background as a mil instructor and protecting myself from a clumsy student pilot. Mainly though - there is a big fat steel rod attaching the Nr gauge/rotors and collective. Ask the engineers to point it out. You really should be ultra close to that collective most of the time.
What response time do they give R22 drivers for rotor recovery: 1.3 seconds, is it?
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YES at eng fail down collective AND flare!
Eyesout: widespread standard doctrine, so far as I've heard, simultaneous dump-and-flare. Cheap insurance against being too slow with dumping collective.
This was the subject of a recent safety article in one of the mainline helicopter magazines, I'll look for the reference but probably somebody else will beat me to posting it.
This was the subject of a recent safety article in one of the mainline helicopter magazines, I'll look for the reference but probably somebody else will beat me to posting it.
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Eyesout:
Flare is absolutely vital.
I've had demonstrated in an R22 a throttle roll-off at 90kt followed by a steadily increasing flare which kept the RRPM from decaying for seven seconds before the lever had to be lowered.
Flare is absolutely vital.
I've had demonstrated in an R22 a throttle roll-off at 90kt followed by a steadily increasing flare which kept the RRPM from decaying for seven seconds before the lever had to be lowered.
Pat
Flaring for 7 seconds is all very well but you will be slowing down ! In my experience of students and low houred pilots they tend to over control, which means too harsh a flare and you could easily go below best auto speed and then you have an equaly big problem. Namely to recover speed you have to push the disc forward ( off load ) this will futher slow down the blades, until speed of ac will slowly pick rrpm back up. If you do not have enough height here you and mother earth will meet up. You seem to want to give the impression that the R22 is very good at this because Tim Tucker can do X Y and Z, he bloody well should be able to, the average 50 hour pilot cannot. Of all helicopters the R22 should be treated with the upmost caution by novice pilots, it never ceases to amaze me the number of pilots who pay scant disregard of keeping your hand on the lever.
Please do not give the impression that the R22 is very good in novice hands - it ain't !
Flaring for 7 seconds is all very well but you will be slowing down ! In my experience of students and low houred pilots they tend to over control, which means too harsh a flare and you could easily go below best auto speed and then you have an equaly big problem. Namely to recover speed you have to push the disc forward ( off load ) this will futher slow down the blades, until speed of ac will slowly pick rrpm back up. If you do not have enough height here you and mother earth will meet up. You seem to want to give the impression that the R22 is very good at this because Tim Tucker can do X Y and Z, he bloody well should be able to, the average 50 hour pilot cannot. Of all helicopters the R22 should be treated with the upmost caution by novice pilots, it never ceases to amaze me the number of pilots who pay scant disregard of keeping your hand on the lever.
Please do not give the impression that the R22 is very good in novice hands - it ain't !
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There is no problem going below best auto airspeed, especially if it means keeping the rotor RPM in the green range. Autorotations can be done at a great variety of airspeeds, including if necessary zero airspeed (not recommended, but far better to be at zero airspeed with lots of rotor RPM than to be at airspeed with no or low rotor RPM).
Pushing forward on the cyclic automatically following an engine failure was the subject of a superb article in one of the newer magazines recently - basically - don't do it.
There are people who do autorotations to holes in the jungle and then drop at zero airspeed into the hole and survive the landing at the bottom (they even train for this). So there are lots of ways to do this, but the key is that you have to have rotor RPM - not necessarily airspeed.
Pushing forward on the cyclic automatically following an engine failure was the subject of a superb article in one of the newer magazines recently - basically - don't do it.
There are people who do autorotations to holes in the jungle and then drop at zero airspeed into the hole and survive the landing at the bottom (they even train for this). So there are lots of ways to do this, but the key is that you have to have rotor RPM - not necessarily airspeed.
Shawn
I agree wholeheartly about rrpm, but in any helicopter you need airspeed so you have something to flare with at the bottom, espically an R22
A question to you if you owned a brand new helicopter would you sit at the duals and ask a low time pilot to do an engine off landing with 20 kt airspeed or 60 kts airspeed. If the answer is the former you are very brave and risk bending the ac and yourself if there is the slightest missjudgement.
My point is that yes rrpm is life down to close to the ground, but airspeed so you can flare will probably mean a less experienced pilot will walk away !
I agree wholeheartly about rrpm, but in any helicopter you need airspeed so you have something to flare with at the bottom, espically an R22
A question to you if you owned a brand new helicopter would you sit at the duals and ask a low time pilot to do an engine off landing with 20 kt airspeed or 60 kts airspeed. If the answer is the former you are very brave and risk bending the ac and yourself if there is the slightest missjudgement.
My point is that yes rrpm is life down to close to the ground, but airspeed so you can flare will probably mean a less experienced pilot will walk away !
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I am becoming more and more convinced that one of the easiest autorotations to do is the 'constant attitude, no flare' autorotation.
This presupposes that you really don't care where it is you land - all you want to do is walk away from the crash, so we'll leave out the "have to get to a particular spot" aspect for this discussion.
The airspeed for this type of autorotation will depend on the helicopter - probably a slower speed than will be used here would be appropriate for a Bell 47 and a higher speed than used here for a Bell 407. For the Bell 206 series, I use 40 Knots plus half the windspeed.
After turning into the wind and setting the airspeed / attitude there is nothing to do until the ground starts to rush up, which is a pretty strong cue from below about 75' AGL in wide open territory. At this point, application of collective has to wait until about 20-25' above ground when it is applied smoothly and positively.
The helicopter is in a slightly nose-up attitude so applying collective will both slow / stop the rate of descent and slow the forward speed to something that would be survivable.
A couple of demonstrations and even very low time fixed wing pilots can fly it.
But the point is, you don't need to have airspeed to survive the landing - just a way to get the rate of descent and forward speed to something survivable.
I think there is a strong case to be made to teach this technique first and when the pilot has slightly more experience to teach the use airspeed and rotor RPM to get you to a desired spot and learn how to flare, etc.
This presupposes that you really don't care where it is you land - all you want to do is walk away from the crash, so we'll leave out the "have to get to a particular spot" aspect for this discussion.
The airspeed for this type of autorotation will depend on the helicopter - probably a slower speed than will be used here would be appropriate for a Bell 47 and a higher speed than used here for a Bell 407. For the Bell 206 series, I use 40 Knots plus half the windspeed.
After turning into the wind and setting the airspeed / attitude there is nothing to do until the ground starts to rush up, which is a pretty strong cue from below about 75' AGL in wide open territory. At this point, application of collective has to wait until about 20-25' above ground when it is applied smoothly and positively.
The helicopter is in a slightly nose-up attitude so applying collective will both slow / stop the rate of descent and slow the forward speed to something that would be survivable.
A couple of demonstrations and even very low time fixed wing pilots can fly it.
But the point is, you don't need to have airspeed to survive the landing - just a way to get the rate of descent and forward speed to something survivable.
I think there is a strong case to be made to teach this technique first and when the pilot has slightly more experience to teach the use airspeed and rotor RPM to get you to a desired spot and learn how to flare, etc.
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Hughes 500:
Preserving RRPM at the moment of failure is the primary concern, and unless you're down among the bushes you can flare until she's standing on her tail, and to hell with the airspeed. Usually you can get that back, but there's no way home from a rotor stall. And of course, you've got no problem with zero-G pushovers if there's no torque.
We teach students zero-speed autorotations in a 22, and as long as you start gaining airspeed around 500 feet you'll have plenty of time and inertia for the landing flare.
As to the seven seconds, as I say, it was a demonstration. I've had a number of impressive demonstrations in the 22, some of them very silly - like backwards autorotation in actual IMC. I wouldn't do it myself, or tell a student that it's work for a novice.
Preserving RRPM at the moment of failure is the primary concern, and unless you're down among the bushes you can flare until she's standing on her tail, and to hell with the airspeed. Usually you can get that back, but there's no way home from a rotor stall. And of course, you've got no problem with zero-G pushovers if there's no torque.
We teach students zero-speed autorotations in a 22, and as long as you start gaining airspeed around 500 feet you'll have plenty of time and inertia for the landing flare.
As to the seven seconds, as I say, it was a demonstration. I've had a number of impressive demonstrations in the 22, some of them very silly - like backwards autorotation in actual IMC. I wouldn't do it myself, or tell a student that it's work for a novice.
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Shawn,
Those constant attitude autos are great in helos with a ton of rotor inertia, but not conducive to longevity in low inertia helos, and in high disk loading ones, too. I used to teach them in Cobras, and they work well, but I wouldn't try one in an S-76 or an H-60! I'd bet a Robbie wouldn't do so well either!
Those constant attitude autos are great in helos with a ton of rotor inertia, but not conducive to longevity in low inertia helos, and in high disk loading ones, too. I used to teach them in Cobras, and they work well, but I wouldn't try one in an S-76 or an H-60! I'd bet a Robbie wouldn't do so well either!
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No, I wouldn't want to do a constant attitude airspeed in a Robbie. On the other hand, when I was learning, I think too much was made of this keeping your airspeed up. Unless your low hours pilot is flying a lot lower than he/she should, get that lever down and flare, and never mind the airspeed. You then have time. And if you then use altering the airspeed rather than making turns to aim for your field/spot/flat bit, you have less need to make precise height/distance judgements. So long as you get back to 60 kts before the flare, you should be OK.
Now, how much difference does landing into wind make, is what I'm still wondering? Unless the wind is really strong, could your novice fairly safely forget about it?
Now, how much difference does landing into wind make, is what I'm still wondering? Unless the wind is really strong, could your novice fairly safely forget about it?
Avoid imitations
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A few rambling thoughts.....
If a reasonable landing area is available, one of the two prime concerns is to reduce the ROD at touchdown to a safe, survivable level. If a low airspeed is recovered too late, it can only be done by lowering the nose, which will increase the ROD and decrease the Nr.... decreasing the chances of a good landing.
A minimum height for attempting to recover airspeed should be considered. My (military) training taught me that constant attitude autorotations were a good thing to consider at night, offering the pilot a better view ahead. Flaring the aircraft sends the landing light beam skywards of course, leaving the pilot with an unlit area ahead. We were taught minimum speed autorotations (IAS off the clock) as a manoeuvre to make a field almost directly below but to recover the IAS at 600' due to effects of lowering the nose to recover airspeed / Nr. In any event, we were taught to aim for wings level and a "recovered" airspeed by a minimum of 300' agl if possible.
Whirly asked:
Unless the wind is really strong, could your novice fairly safely forget about it?
In the real case of engine failure, the second prime concern is the likelihood of a gatepost between the legs . A 5 knot tailwind is 10 knots worse than a 5 kt headwind when it comes to considering the possibility of impending forward impact......
I think a mental picture of the wind direction is vital at all times when flying a single.
If a reasonable landing area is available, one of the two prime concerns is to reduce the ROD at touchdown to a safe, survivable level. If a low airspeed is recovered too late, it can only be done by lowering the nose, which will increase the ROD and decrease the Nr.... decreasing the chances of a good landing.
A minimum height for attempting to recover airspeed should be considered. My (military) training taught me that constant attitude autorotations were a good thing to consider at night, offering the pilot a better view ahead. Flaring the aircraft sends the landing light beam skywards of course, leaving the pilot with an unlit area ahead. We were taught minimum speed autorotations (IAS off the clock) as a manoeuvre to make a field almost directly below but to recover the IAS at 600' due to effects of lowering the nose to recover airspeed / Nr. In any event, we were taught to aim for wings level and a "recovered" airspeed by a minimum of 300' agl if possible.
Whirly asked:
Unless the wind is really strong, could your novice fairly safely forget about it?
In the real case of engine failure, the second prime concern is the likelihood of a gatepost between the legs
. A 5 knot tailwind is 10 knots worse than a 5 kt headwind when it comes to considering the possibility of impending forward impact......I think a mental picture of the wind direction is vital at all times when flying a single.
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Whirlybird asked:
I guess the answer to that depends on two things: what kind of surface you have underneath you; and whether you don't care about damaging the aircraft.
Check this out: http://www.ntsb.gov/ntsb/brief.asp?e...05X00168&key=1
The pilot was delivering a brand-new EC-120 from Grand Prairie to Alaska. He had just left the factory and was cruising along at 500 feet agl with the wind at his back (probably enjoying the high groundspeed) when he developed a power problem. I guess Eurocopter didn't focus much on 180 autos. He put the lever down and set up for a field right in front of him (it was Texas, after all). He got it down okay, but evidently during the ground run, a skid dug in and the ship rolled onto it's side. Ouch.
Some would say, "Good job!" and leave it at that. But somewhere there was a commercial helicopter operator without the use of a (needed?) aircraft until a replacement could be procured. Somewhere there was an insurance company executive writing a check for the repair costs (minus deductable) of a brand-new EC-120. And somewhere there was a pilot with a very red face who will always wonder, "What if I had flown at 700 agl so I would have had a chance to turn into the wind?" (Let us hope that the unspoken question which will forever run through his mind is not, "What if I had known which way the wind was coming from that day?")
Is landing into the wind important? Obviously. To get back to the original question of this thread: Is a second or so enough?
It's not good enough to be an "average" or an "okay" or "so-so" helicopter pilot. That might work in fixed-wing, which tolerate such foolishness. Sometimes helicopters do not abide anything but perfect technique. And if you find yourself in one of those situations where you have 1.1 second to do something, you better hope to God that you're not only as good as you think you are, but as good as the situatioin demands.
Now, how much difference does landing into wind make, is what I'm still wondering? Unless the wind is really strong, could your novice fairly safely forget about it?
Check this out: http://www.ntsb.gov/ntsb/brief.asp?e...05X00168&key=1
The pilot was delivering a brand-new EC-120 from Grand Prairie to Alaska. He had just left the factory and was cruising along at 500 feet agl with the wind at his back (probably enjoying the high groundspeed) when he developed a power problem. I guess Eurocopter didn't focus much on 180 autos. He put the lever down and set up for a field right in front of him (it was Texas, after all). He got it down okay, but evidently during the ground run, a skid dug in and the ship rolled onto it's side. Ouch.
Some would say, "Good job!" and leave it at that. But somewhere there was a commercial helicopter operator without the use of a (needed?) aircraft until a replacement could be procured. Somewhere there was an insurance company executive writing a check for the repair costs (minus deductable) of a brand-new EC-120. And somewhere there was a pilot with a very red face who will always wonder, "What if I had flown at 700 agl so I would have had a chance to turn into the wind?" (Let us hope that the unspoken question which will forever run through his mind is not, "What if I had known which way the wind was coming from that day?")
Is landing into the wind important? Obviously. To get back to the original question of this thread: Is a second or so enough?
It's not good enough to be an "average" or an "okay" or "so-so" helicopter pilot. That might work in fixed-wing, which tolerate such foolishness. Sometimes helicopters do not abide anything but perfect technique. And if you find yourself in one of those situations where you have 1.1 second to do something, you better hope to God that you're not only as good as you think you are, but as good as the situatioin demands.
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We were taught that a constant-attitude auto in an R22 should be done at 40kt, and you'd only do it at night, but it was an academic exercise - I never knew anyone who took one to the ground.
A word about forward speed versus rate of descent in the flare/landing phase. A 22 will autorotate in the 1800fpm area. That's less than 20kt, vertically. It you spear in bum-first without even trying to flare, you've got the skids to absorb energy, then the seat structure.
But you're going forwards at 60kt or so, and all you've got between you and the tree/pylon/house etc is a quarter inch of perspex. Yet people seem to consider the vertical before the horizontal, and prefer to accept some run-on even in a tight area.
A word about forward speed versus rate of descent in the flare/landing phase. A 22 will autorotate in the 1800fpm area. That's less than 20kt, vertically. It you spear in bum-first without even trying to flare, you've got the skids to absorb energy, then the seat structure.
But you're going forwards at 60kt or so, and all you've got between you and the tree/pylon/house etc is a quarter inch of perspex. Yet people seem to consider the vertical before the horizontal, and prefer to accept some run-on even in a tight area.
Pat
What is the problem with 60 kts airspeed, you flare it off about 35 ft from the ground. This does 2 things, increases Nr - therefore more stored inertia, reduces ROD to near zero. leaving you alot of energy in the blades to cushion your touchdown. In reality if you stand the helicopter on its end in no wind at 30 ft you will hardly run on at all. An anology for you for your 20 mph rod, would you prefer to come off a motorcycle at 60 mph and slide along road, or come off at 20 mph and hit a brickwall. It is accleration / decleration that kills. How many GP 500 riders do you see killed when they take a slide at 100 mph plus - nil.
Shawn, you havent answered my question - if you owned a brand new R22 ! Or are you a secret politician ?
What is the problem with 60 kts airspeed, you flare it off about 35 ft from the ground. This does 2 things, increases Nr - therefore more stored inertia, reduces ROD to near zero. leaving you alot of energy in the blades to cushion your touchdown. In reality if you stand the helicopter on its end in no wind at 30 ft you will hardly run on at all. An anology for you for your 20 mph rod, would you prefer to come off a motorcycle at 60 mph and slide along road, or come off at 20 mph and hit a brickwall. It is accleration / decleration that kills. How many GP 500 riders do you see killed when they take a slide at 100 mph plus - nil.
Shawn, you havent answered my question - if you owned a brand new R22 ! Or are you a secret politician ?