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Chop tail off in the hover??

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Chop tail off in the hover??

Old 16th Mar 2021, 20:28
  #41 (permalink)  
 
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Actually the landing power check, if you even need one (you did plan it, right?),
Planning it and having it are two different things - if you pull to the take-off limit before you commit to a high hover, you know you have what you planned for - inherently safer than flying somewhere between 6 and 8 inches (not exactly precise) below 5 Min Max and approximating that you might have enough power before discovering you haven't as the RoD builds up from your attempt at OGE hover. How difficult is it to take 5 seconds to PROVE you have the performance available?

What you do as a commercial pilot doesn't concern me, you should be old and ugly enough to deal with limited power - my concern is the PPLH like the guy in the accident who has neither the skills or experience - he doesn't have to work with razor thin margins and if he does he is likely to come unstuck. Strangely enough I am trying to help.

As for checking the performance added by each inch of MAP - just establish an OGE hover, check the MAP and add an inch to see what rate of vertical climb it gives you. You can then try 2 inches - at least then you have an idea of what sort of RoD you might be able to recover from if your OGE hover is a bit wobbly.

But I've only been flying and teaching confined area ops for 38 years day, night and NVD in singles and twins so I probably don't know what I'm talking about.
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Old 16th Mar 2021, 22:34
  #42 (permalink)  
 
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Originally Posted by [email protected] View Post
But I've only been flying and teaching confined area ops for 38 years day, night and NVD in singles and twins so I probably don't know what I'm talking about.
And a few people who fly Robinsons are telling you what the industry teaches about flying Robinsons. The whole industry, pretty much. They can't all be wrong. Or even substantially incomplete. Or not know what they are talking about. There might even be more than one way to skin a cat. It might be safer to look at MP margins at Vy than try to come to an OGE hover if conditions don't allow it.

These differences in methodology may be a mil vs civ thing, or even a UK mil vs USA civ thing. Or an R44 vs. big turbine thing. Or some combination of the above.

I've never had an ex. mil. instructor. Only 200-500 hour civilian-only CFIs, one 2000 hour civilian-only CFI, and one 10,000+ hour civilian-only CFI. All of whom evolved in the Robinson-based training ecosystem. They can't all be wrong.

It's not going to happen, but it would be very, very interesting to know what your feedback would be if you jumped into an R44 for 10 hours or so to observe the performance of the design first-hand, and also to observe the performance of the instruction available to you first hand.


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Old 16th Mar 2021, 23:43
  #43 (permalink)  
 
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Again, what am I thinking? How could I possibly question such an experienced God of the air who flys pleasure trips for a living?

I must have a word with myself and point out to the rest of the helicopter world, mil and civ that the Robinson way is the way to do it!

I had the R22 on my licence (ATPLH) in 1992 and re-taught a private owner with 120 hours how to fly because he was scared of the aircraft and what would happen if the engine failed - I am quite aware of the power and performance issues with a single-engined piston helicopter thank you.

It might be safer to look at MP margins at Vy than try to come to an OGE hover if conditions don't allow it.
You are not listening - it is safer to confirm that you have take-off power available before committing to the hover rather than relying on a hand-me down approximation which seems to vary - is it 6 or 8? very scientific and professional.
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Old 17th Mar 2021, 00:48
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Originally Posted by [email protected] View Post
Again, what am I thinking? How could I possibly question such an experienced God of the air who flys pleasure trips for a living?
Crab, once again aa777888 and his delinquent sidekick want to pick a fight, quite frankly I can’t understand why they aren’t prepared to enter into a sensible discussion that might be beneficial to all parties and indeed many others. Instead they just resort to the same BS on every thread... getting boring.

I must have a word with myself and point out to the rest of the helicopter world, mil and civ that the Robinson way is the way to do it!

Lol Please don’t do that, I only have a 100 hours as a pax ... and have never accepted a Robinson as an option for my personal travel, yes may sound like a snob... and guess what if I couldn’t afford the alternative would happily take a ship, train or taxi.. just saying

Last edited by Senior Pilot; 17th Mar 2021 at 00:50. Reason: fix quote
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Old 17th Mar 2021, 01:05
  #45 (permalink)  
 
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I'm no sky god. I am only as good as my training, which is what I report on here. I don't pretend to be a test pilot or any other sort of authority. But I can accurately report on my training and its efficacy, which has so far been adequate to keep things in one piece.

​​​​​​Discourse on this website has been a valuable adjunct to that training, but you don't do much to make the process at all pleasant.

Instead of the last two posts you just offered why don't you explain why testing an OGE hover is better and safer than maintaining LTE at Vy and looking for a given margin?
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Old 17th Mar 2021, 02:42
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Well, I AM a sky God! So bow down and kiss my skids!
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Old 17th Mar 2021, 08:21
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Instead of the last two posts you just offered why don't you explain why testing an OGE hover is better and safer than maintaining LTE at Vy and looking for a given margin?
You still aren't listening.

You pull to your max power BEFORE you get anywhere near the OGE hover ie at the same speed you would be assessing your inaccurate Vy MAP somewhere between 6 and 8 inch power margin.

Instead of relying on an approximate assessment of power available, you have proved that what your charts require and what you have planned is in fact available in the conditions of the day - all while flying quite safely above ETL.

Your way isn't backed up by any empirical evidence or accurate power assessment - my way confirms the POH figures, provided by Robinson, are available - which do you think is more accurate and therefore safer?

Discourse on this website has been a valuable adjunct to that training, but you don't do much to make the process at all pleasant.
Right back at you with that one.

Just understand that the Robinson training system is not the be all and end all of helicopter training - it does what it was designed for, getting people into Robinson helicopters. Plenty of people on this forum have been trained to far higher standards in many disciplines.

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Old 17th Mar 2021, 08:22
  #48 (permalink)  
 
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nomorehelosforme - I try to offer advice where I can - their noise won't distract me from that.
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Old 17th Mar 2021, 14:18
  #49 (permalink)  
 
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Originally Posted by [email protected] View Post
You still aren't listening.
Actually I am listening, or reading, very carefully and precisely. As a result I have identified a number of factual errors throughout this topic.

You pull to your max power BEFORE you get anywhere near the OGE hover ie at the same speed you would be assessing your inaccurate Vy MAP somewhere between 6 and 8 inch power margin.
This is the first time you've written that this max power test occurs at Vy. Since that was not explicitly stated I had erroneously understood that it was part of an OGE hover test.

Instead of relying on an approximate assessment of power available, you have proved that what your charts require and what you have planned is in fact available in the conditions of the day - all while flying quite safely above ETL.
If I understand this correctly, this can be broken down into two concerns:

1. That the engine is capable of obtaining a given, indicated MP.
2. That the helicopter climbs at some vertical speed.

Your way isn't backed up by any empirical evidence or accurate power assessment - my way confirms the POH figures, provided by Robinson, are available - which do you think is more accurate and therefore safer?
With respect to (1) above, that is true. However if an engine has a problem producing power under those conditions it will be known long before then due to the way the engine is derated and the way that derating is respected by means of the MAP chart.

With respect to (2), there are no numbers in the POH that say if you can obtain a given vertical speed at max power and Vy then you can safely attain OGE hover performance at that density altitude. Thus a given vertical speed reading becomes the same sort of rule of thumb that the 6-8" of MP margin is. Both methods are empirical by definition.

Absolutely willing to be wrong here...
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Old 17th Mar 2021, 15:27
  #50 (permalink)  
 
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This is the first time you've written that this max power test occurs at Vy.
i didn't think I had to explicitly state it since I was talking about doing the power check before committing to a hover - it doesn't have to be done at Vy, it can be done at pretty much any speed, you are simply proving the engine.

With respect to (1) above, that is true. However if an engine has a problem producing power under those conditions it will be known long before then due to the way the engine is derated and the way that derating is respected by means of the MAP chart.
If you didn't pull to full take off power at any stage previously in the flight, how do you know it will produce it? Coming to the OGE hover short of power because your engine is starting to show its age or has a niggly fault is not clever, especially into a confined area.

It's just a power check - plain and simple - but you have proven the engine so you know it will perform as advertised. You are going to put yourself in a hazardous position, possibly well inside the HV curve if you are using OGE hover to get into a deep confined area - why wouldn't you want the confidence that the engine will perform as it should?

With respect to (2), there are no numbers in the POH that say if you can obtain a given vertical speed at max power and Vy then you can safely attain OGE hover performance at that density altitude. Thus a given vertical speed reading becomes the same sort of rule of thumb that the 6-8" of MP margin is. Both methods are empirical by definition.
I didn't say that at all - I was trying to point out that since you do have a lack of performance figures in the POH, you can give youself an idea of what the difference of one or 2 inches MAP makes in an OGE hover by trying it for yourself.

Go out at a weight that you know won't need take off power in an OGE hover, stabilise and check the actual MAP. Then see what rate of climb an extra inch of MAP - or 2 - gives you, it just allows you to calibrate your brain to how much or little performance you have left when you are pushing the limits of the aircraft. If you know you are only just below the max gross for an OGE hover then you will know you have to be super-careful if you have to go into a tricky confined area.

It's no different to checking the MAP in a low hover to see what your margin is before committing to a high vertical climb out of a confined area - you will effectively be doing the power check in the climb in that case if you hadn't done one before going into it.

In essence - 1. Make sure you have sufficient power available according to the POH ie you are inside the lines according to the graph at your intended gross weight, PA and temperature.

2. Confirm that the aircraft will actually produce take-off power at some stage of the flight before you put yourself in a condition where you are going to rely on it doing so.
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Old 17th Mar 2021, 15:58
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Originally Posted by [email protected] View Post
Go out at a weight that you know won't need take off power in an OGE hover, stabilise and check the actual MAP. Then see what rate of climb an extra inch of MAP - or 2 - gives you, it just allows you to calibrate your brain to how much or little performance you have left when you are pushing the limits of the aircraft. If you know you are only just below the max gross for an OGE hover then you will know you have to be super-careful if you have to go into a tricky confined area.
Done and past done, demonstrated and in every day use. I.e. the aforementioned 2" MP margin for max. performance and 6-8" for OGE hover. Rules of thumb, or brain calibrations if you prefer. Those guidelines work. No need to reinvent the wheel. Assuming a healthy engine, of course, which was the other major point you are making, I think.
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Old 17th Mar 2021, 16:47
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Assuming a healthy engine, of course, which was the other major point you are making, I think
Yes, exactly. Just combine the 'rules of thumb' with the confirmation of engine performance using a power check and you shouldn't go far wrong.
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Old 17th Mar 2021, 16:52
  #53 (permalink)  
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The accident event was initiated by an uncommanded yaw that the pilot could not stop, yes?
AFTER the accident aircraft had descended into the confined area, aborted and was in the vertical climb to exit, yes?
The theory is that this was an LTE event.
First, I have to say the theory of LTE is generally accepted, but in 48 years of flying, I never had one even though I landed up, down and both crosswinds thousands of times; in confined areas, natural and man-made, elevated (as in roof-top pads), with all knids of turbulence and none at all- I would guess that LTE is probably pretty rare and type specific- OH58 and 206B in particular... although thousands of my landings were in all wind conditions in 206s, Bs and Ls. They do have weakish tail rotors, is the R44 in that class?
The Aerospatiales I flew, the AS350 and 355 could turn tail into just about anything up to about 40 knots. Not that it is a good idea, the tail does get busy, especially in the it's near the upwind edge an blocky ledge, rooftop. I didn't want the pax exposed to the tail rotor.

The accident aircraft was in a vertical climb, exiting the confined area- it had sufficient power. As the accident aircraft ckimbed above, exited the terrain that was obstructing the wind, it became a 15-20 knot breeze from the left front. Yes, it fits the LTE pie chart.... But that is enough air that the aircraft should have experienced effective translational lift, and could have reduced power and continued a climb or accelerated into the wind, minimizing the demand on the tail rotor. But that's not what happened, apparently full pedal didn't stop the yaw, so the pedals were reversed (????) and the yaw developed into a spin.

The nose goes up and the nose goes down as the world goes round and round, you become disoriented. I know pilots who advance the idea of following the nose and accelerating out of it in a spiral- highly skilled professionals. I doubt the accident pilot had been trained in that and certainly did not consider it- or reducing power demand. I have had the technique demonstrated (never used it) and I don't think I could have done it after at least two revolutions in the spin, up and down, position over the ground is what I remember being aware of when the student botched the hovering auto- reducing power and the rotation rate, get the aircraft under control (well really, a chop and hovering auto, the student was locked in all other axis).

I was appalled at how little is actually required for a commercial much less a private when I was teaching. Maintaining the aircraft upright and intact, some theory and limited emergency training- success! Now go challenge the world without any limitations.
You teach them plan, fly the aircraft as slowly as possible into hazard and move slowly, abort at any point at which success is not assured. A slow climb into changing winds, even pausing and evaluating in the process, perhaps letting the tail streamline a little as you move into and as close as possible to the upwind barrier and when effective translation is achieved fly out and make a new plan.

You can demonstrate this once or twice, and maybe even talk the process in landings, takeoff. It's really not in any syllabus I was given. (I do talk the whole process constantly even when nobody's aboard- some habits are forever.) And then they get the ticket and learn that they can do all the hot dog yank and bank, see it modelled in real life and media...
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Old 17th Mar 2021, 17:31
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Someone suggested earlier in the thread that the pilot could have been too tense on the controls and prevented the governor from doing its job - that could have caused reducing Nr and subsequent reduction in TR thrust.

Combine that with a little weather-cocking - I'm not convinced by the LTE pie chart - and he mis-diagnosed a TR malfunction, over controlled and crashed. Had he just used full left pedal and waited, he would probably not have ended up in the spin.

Interference between the MR vortex and the TR isn't a new piece of knowledge, we used to teach it specifically in a Max All Up Mass sortie on the Wessex 30 plus years ago - it certainly doesn't cause a spin, just a bit of twitching in yaw which goes when you change the heading in relation to the wind direction - the arc really isn't that big.
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Old 17th Mar 2021, 21:38
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Once while hovering in an S300 I was practically standing on the left pedal, yet the nose just would not turn,...then I looked down and noticed the rpm was at the botton of the green. So, I rolled it up and the nose began to turn.

So, yeah, its possible this guy just had the death grip and overrode the governor? Its not like it hasn't happened before, as there is another video of a guy descending in a 44 due to low-rpm, because he had the death grip while flying through turbulence.

Still, we don't know for certain that this guy had full left pedal applied, so who knows?
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Old 17th Mar 2021, 23:24
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With that type of wind in that direction, the R44 will not run out of pedal. The type does not suffer from LTE, the tail rotor is extremely efficient. The aircraft can oscillate in the yaw axis as the tail rotor catches the vortices from the main rotor, but itís controllable.

I would have thought the aircraft would want to weather cock into wind (nose to the left in this case) coupled with the increased power to climb out of the CA, was there a left yaw, which happened quicker than anticipated, which surprised the pilot?

However, if youíre heavy on the pedal inputs, you can droop the rrpm as the governor can lag.
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Old 18th Mar 2021, 02:27
  #57 (permalink)  
 
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Originally Posted by aa777888 View Post
Assuming a healthy engine, of course, which was the other major point you are making, I think.
And that you have read the right altitude/temperature figures on the MAP chart, and appreciated that there is the section on the MAP chart labelled Ďfull throttleí when you are no longer gearbox/drivetrain/torque limited, but limited by the fact the engine wonít give anymore... i.e. instead of having a theoretical max, you will have an actual maximum engine power available with no specified figure (you wonít get the extra 2.8Ē take-off power), and you need to establish what that actual maximum power available is. Admittedly this is only an issue at higher altitude if you have a healthy engine/mags/gauge*, but that is precisely where it is really going to matter. Itís a wake up call when you start getting droop at 21Ē and you are used to being able to pull 25.5Ē, particularly if you are not prepared and expecting it!

Last edited by Aucky; 18th Mar 2021 at 02:37.
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Old 18th Mar 2021, 07:03
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You make it all look so difficult. I suppose there are one or two things one need to know on any given helicopter type.

There is a simple rule: The first 100 hours *after* you got your PPL-H donít fly to go fishing, fly for practice. And donít take pax, fly alone.
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Old 18th Mar 2021, 16:35
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Originally Posted by Hot and Hi View Post
You make it all look so difficult. I suppose there are one or two things one need to know on any given helicopter type.

There is a simple rule: The first 100 hours *after* you got your PPL-H donít fly to go fishing, fly for practice. And donít take pax, fly alone.
As a former self-fly- hire just for fun Robby pilot I have to say, that the dumbest "simple rule" I've ever heard!

"Congrats kid, you're now a private pilot!,...now remember, only fly circles around the airport alone for the next 100 hours.".
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Old 18th Mar 2021, 17:46
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The solution I chose was to immediately press on and obtain a commercial cert. I felt pretty comfortable with a fixed wing private in my hot little hands, but the helicopter private certificate felt more like a "license to get killed"

Of course everyone's mileage will vary quite a bit on this one. But that's how I felt, FWIW.
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