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G2 down in Switzerland - 15 June 2022

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G2 down in Switzerland - 15 June 2022

Old 25th Jun 2022, 07:04
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Just for the record, I never said I had LTE. What I experienced in the R22 was a rather gentle affair. Nothing like the wild spinning of a Cabri. And it wasn't LTE. I suspect that it was just an interaction of the main blade tip vortex and the tail rotor.
Anyway, if you live in a legal system - the US legal system -, where admitting a mistake can bring a company down due to stupid lawsuits that make at least the lawyers rich, the culture is bound to move towards spin doctoring, creatively finding explanations that are natural causes that could not be seen because physics wasn't advanced enough.
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Old 25th Jun 2022, 07:16
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it has never been proven to exist on any other helo type
The UH-1H manual has a section on LTE with an diagram of the warning areas mapped out. That being the case you would expect to see the same warning/diagram in 212, 412 and AH-1 manuals, but don't
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Old 25th Jun 2022, 13:00
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Originally Posted by B2N2 View Post
Well, pilot was 65 and his passenger 70….that in itself requires it.
I believe you think you are funny. However, I am unsure whether your post is in-line with this network’s policy prohibiting discriminatory posts.
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Old 25th Jun 2022, 14:59
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Originally Posted by Rotorbee View Post
Anyway, if you live in a legal system - the US legal system -, where admitting a mistake can bring a company down due to stupid lawsuits that make at least the lawyers rich.
This immediately brought back Frank Robinson’s words when I was fortunate enough to attend a Factory Safety course quite some years ago. He asked for questions and I enquired about the doors off speed limit… oh… he said…pausing… thats’s the lawyers!
You see, if the door is off and you stick your arm out you might get injured.
So it was decided, to minimise claim risk, speed would be limited for door/s off.
(No aerodynamic or structural reasons)
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Old 25th Jun 2022, 15:13
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Originally Posted by joe_bloggs View Post
This immediately brought back Frank Robinson’s words when I was fortunate enough to attend a Factory Safety course quite some years ago. He asked for questions and I enquired about the doors off speed limit… oh… he said…pausing… thats’s the lawyers!
You see, if the door is off and you stick your arm out you might get injured.
So it was decided, to minimise claim risk, speed would be limited for door/s off.
(No aerodynamic or structural reasons)
,....but if you stick your arm out at 99 kts (or at 100 kts in the R22) you'll be just fine! ​​​​
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Old 25th Jun 2022, 16:23
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,....but if you stick your arm out at 99 kts (or at 100 kts in the R22) you'll be just fine! ​​​​
Perhaps not you, but Robinson. They told you so. It is always hard to admit one made a mistake, much easier to blame somebody else. Especially in a society that is fixated on success and always being the best. At least pilots should be familiar with situations where we mess up and hopefully catch our mistakes before anything happens. That is the idea of the regs we follow ... more or less, but there are many people out there, who never, ever make any mistakes. Therefore if something goes wrong, it must be the fault of somebody else and they find a lawyer that is only too happy to sue for ridiculous amounts of money on the basis of psychical distress because somebody got an outchy on their picky. Therefore companies must protect themselves from anything a stupid person might do, despite common sense. There is this saga that when Dornier certified the 228 in the US, they had to add, that the plane has to be turned in the direction of the runway for takeoff. I truly hope it isn't true, but it sounds like the loop hole a ambulance chaser would love to see.
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Old 25th Jun 2022, 16:59
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Originally Posted by Rotorbee View Post
Perhaps not you, but Robinson. They told you so. It is always hard to admit one made a mistake, much easier to blame somebody else. Especially in a society that is fixated on success and always being the best. At least pilots should be familiar with situations where we mess up and hopefully catch our mistakes before anything happens. That is the idea of the regs we follow ... more or less, but there are many people out there, who never, ever make any mistakes. Therefore if something goes wrong, it must be the fault of somebody else and they find a lawyer that is only too happy to sue for ridiculous amounts of money on the basis of psychical distress because somebody got an outchy on their picky. Therefore companies must protect themselves from anything a stupid person might do, despite common sense. There is this saga that when Dornier certified the 228 in the US, they had to add, that the plane has to be turned in the direction of the runway for takeoff. I truly hope it isn't true, but it sounds like the loop hole a ambulance chaser would love to see.
Well, Robby did eventually give us governors, hydraulic controls, and bladder tanks. Don't know if they admitted that not having these things was a mistake, but its still nice to have the improvements.

Maybe one day Bruno will just decide to make a version of the Cabri with a more "traditional" tail rotor,...just for the hell of it.
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Old 26th Jun 2022, 03:31
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The UH-1H manual has a section on LTE with a diagram of the warning areas mapped out. That being the case you would expect to see the same warning/diagram in 212, 412 and AH-1 manuals, but don't
Never Proven to exist on other types, and anyway, the tail rotors on the newer birds rotate upwards into the flow and are on the flipside of the tail boom.
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Old 26th Jun 2022, 05:16
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Forgot about that AC, even our 205's had them on the opposite side to the Hotel. The Hotel data plate said "Manufacturers Model 205" and "Customer Model UH-1H", were civil 205's originally with the left mounted tail rotor?

Edit, found a thread

Bell 205 tail-rotor

Last edited by megan; 26th Jun 2022 at 05:43.
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Old 26th Jun 2022, 07:11
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And didn't the 205s have dual hydraulics?
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Old 26th Jun 2022, 13:06
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Originally Posted by Ascend Charlie View Post
And didn't the 205s have dual hydraulics?
205A single hyd. 205A-1 dual hyd. as I vaguely recall.
It was also advised that when flying with no collective hydraulics not lower the power below 35 PSI as raising it again would be difficult. …it was! ( I may be +- wrong about the 35 number.)
I luved flying the 205. Noisy, fun and forgiving…what more could a young boy want?
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Old 27th Jun 2022, 02:10
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Our 205A-1 were single hydraulic, one guy had a failure and being on fixed floats put it down in a sewerage farm pond/lake. Not a nice way to treat a lady. The 205A-1 maintenance manual says they may be single or dual systems.

Last edited by megan; 27th Jun 2022 at 02:24.
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Old 27th Jun 2022, 10:34
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Interesting to see where this thread is going...

So, back to the G2.
Structural wise I think the occupants were very lucky with the design!

Anyone with experience with regards to tail rotor authority?
A fenestron has it pros and cons I can imagine.
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Old 27th Jun 2022, 13:34
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Now there is a can of worms! We probably need a new subforum just for that topic. And another for Robinson vs the Rest
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Old 27th Jun 2022, 13:48
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Originally Posted by TimdeBoer View Post
Interesting to see where this thread is going...

So, back to the G2.
Structural wise I think the occupants were very lucky with the design!

Anyone with experience with regards to tail rotor authority?
A fenestron has it pros and cons I can imagine.
This is all hear/say, as the G2 is out of my price range, but I've heard that though the tail rotor produces plenty of thrust, it takes a lot more pedal input than one might expect to get it.

So, if you're not Fred Astaire you might run into some issues?
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Old 27th Jun 2022, 22:53
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I instructed on RAF Gazelles in 1984/5. The fenestron tail was quirky but worked well enough.

I went back to fly it three years later and by then I was surprised to find that they had invented fenestron stall. It still flew the same, but it was far more restricted in cross winds.
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Old 28th Jun 2022, 08:15
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I posted this on another thread
Like many fenstron equipped helicopters, the Cabri requires anticipation of the pedal requirement - in forward flight the fin is producing a lot of the anti-torque.

As you lose ETL, the fan has to work harder to replace that loss of fin-lift and so requires a great deal more power pedal.

Add in a crosswind where the aircraft wants to weathercock and it is quite easy to end up with undemanded yaw - not LTE - and often FULL right pedal is required to maintain or correct the heading.

So not much to do with the engine - until the very high rate of yaw has an effect - but mostly to do with lack of skill and possibly training.

Not saying this was the cause of the fatal accident in this thread - more a comment on the other accident linked above.
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Old 28th Jun 2022, 08:16
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I posted this on another thread
Like many fenstron equipped helicopters, the Cabri requires anticipation of the pedal requirement - in forward flight the fin is producing a lot of the anti-torque.

As you lose ETL, the fan has to work harder to replace that loss of fin-lift and so requires a great deal more power pedal.

Add in a crosswind where the aircraft wants to weathercock and it is quite easy to end up with undemanded yaw - not LTE - and often FULL right pedal is required to maintain or correct the heading.
fenestrons have a different thrust to pedal position curve - a conventional TR is almost linear in its thrust, a fenestron is more S shaped. Training and anticipation are required but the fenestron still works fine.
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Old 28th Jun 2022, 08:24
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SHY - Fenestron Stall was much misunderstood even though it didn't exist. Hover taxiing sideways at 10' in and out of dispersal put us in the avoid curve, just as well the Astazou was such a reliable engine.
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Old 28th Jun 2022, 13:45
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I give you that from 2001. PPRuNe Rotorheads. Interesting read.
eden
19th Feb 2001, 02:22
Having flown the Gazelle in a wide variety of flight regimes ..... and during a time where many pilots were coming unstuck with Fenestron related problems .......and during a time when some very telling tests were done with Aersospatiale using some Fleet Air Arm instructors. I have a few views and observations which would suggest that FENESTRON STALL is infact an excuse used to describe MISHANDLING,rather than a Stall of the blades. Mighty Gem – makes a point with regard to this and I’m sorry that it happened to you …. As long as you only dented the pride as opposed to yourself …. Do we know each other???

1. The term FENESTRON stall became obselete within the RN when - as a result of careful examination of circumstances surrounding the departure from controlled flight of a number of aircraft being flown by student pilots and some very expereienced instructors at low speed or in the hover.

The Navy severely damaged several airframes as a result and felt compelled to look deeper into the problem …….. they visited Aerospatiale and carried out some extreme flight tests in the hover …….all captured on video and all VERY ALARMING to watch. The aircraft was put in a spot turn to the left and then allowed to continue to turn …… the rotation was allowed to accelerate and at a point where the rotation was becoming almost disorientating the opposite (RH) pedal was applied using FULL deflection. It caused a massive sustained overtorque but the aircraft rotation stopped (as I recall) pretty much as described by Mighty Gem(within about 270 – 360 deg). These test were carried out at differing rates of rotation and different amounts of opposite pedal were used. The final outcome – illustrated that the aircraft is able to recover from a high rotational left turn but needed FULL APPLICATION of the opposite pedal. It would also cause a massive overtorque and was obviously a flight regime to be avoided.

2. The RN then decided that the term FENESTRON STALL – was no longer valid and the term YAW DIVERGENCE was born – which actually described the problem fairly well. The recovery action required from any apparent loss of control in a LH spot turn was to apply – FULL Right pedal. If FULL RH pedal was not applied – there was a risk that the aircraft might not recover and continue to suffer the YAW DIVERGENCE – which manifested itself as an increasing acceleration to the left. By way of demonstration – I used to show student pilots an incipient level of the problem:

I used to sit in the hover into wind and I would apply……1-2 inches of RH pedal, the aircraft would Yaw right and settle reasonably quickly within 20 – 40 deg of I/W heading (approx). I would then return the aircraft to the I/ w position and repeat the process with 1-2 inches of left pedal ….the aircraft would continue past the 40 deg point and begin to accelerate, if left uncontained, the rotation would continue to accelerate in a dynamic and unstable way. I used to start recovery after 360 deg before any excessive yaw rate had developed. The demonstration was effective and illustrated the caution required in handling low speed left hand yaw applications.

3. YAW DIVERGENCE – incidents were significantly reduced as a result of the increased awareness and if encountered were prevented by using the FULL application of the RH pedal. It is believed that many of the occurrences and incidents involving alleged F/STALL were infact errors or misinterpretation in handling; and whilst many pilots believed they had applied FULL RH pedal it is considered likely that they never achieved FULL DEFLECTION in order to counter the problem. Many of the incidents were dealt with as if they had experienced a TR FAILURE – ie shutting the engine down . The subsequent high rotation – perceived as a TR FAIL’ and the ensuing EOL combined to make a mess of several airframes.
Sorry that I have taken so much time to explain what MIGHTY GEM said in a few lines – but it perhaps puts some background into the thinking behind the MYTH. It would be good to get the views of the Light Blue and Green – if possible?
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