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Helicopter down outside Leicester City Football Club

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Helicopter down outside Leicester City Football Club

Old 28th Nov 2018, 13:06
  #861 (permalink)  
 
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Originally Posted by ShyTorque View Post
Chopjock,

As always you think you know better than those who actually do the job. However, most of us tend to operate the aircraft in accordance with the manufacturer's certificated performance procedures, even those of us not operating for public transport (where it is usually mandatory). It is sometimes a condition of the aircraft insurer (and therefore a requirement / condition of maintaining one's employment status with the operator) and it is always a condition of a CAA congested area written permission.
Just like what I said earlier...
And they were put in that position by the regulations in the name of safety...
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Old 28th Nov 2018, 13:08
  #862 (permalink)  
 
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Chopjock, you are the ultimate laxative.

You continue to put forward your ridiculous views in the face of logic and weight of informed opinion against you. It would not surprise me if you were the twin (or alter ego) of the other fool on this board.

Jim
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Old 28th Nov 2018, 13:11
  #863 (permalink)  
 
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Now there is a thought......ONLY two Fools in this Forum!
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Old 28th Nov 2018, 13:13
  #864 (permalink)  
 
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Originally Posted by SASless View Post
Now there is a thought......ONLY two Fools in this Forum!
Don't forget me!
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Old 28th Nov 2018, 13:24
  #865 (permalink)  
 
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Originally Posted by DOUBLE BOGEY View Post
Chopjock, the profile you propose would require reject distance available if the helicopter is above the OEI-IGE Hover Mass. You would also need to prove you could clear the stadium OEI after TDP on the remaining engine. Its really difficult to make this work when the distance available are so short. That's why the Rearwards Profile (VTOL Helipad) was conceived. To overcome these issues.
Except no consideration at all about longer exposure time and total dependance on the tail rotor...
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Old 28th Nov 2018, 13:47
  #866 (permalink)  
 
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Originally Posted by TeeS View Post
Hi 212man, it is a long time since I flew retractable undercarriage aircraft but I always thought/assumed that the gear was retracted as soon as possible after TDP in order to minimise drag during the acceleration to Vtoss/Vy, I do wonder whether this was another hang over from fixed wing A/C where the target speeds are higher and so the drag had a bigger influence. Obviously those operating single pilot might feel there would be more important considerations during a busy stage of flight!

Cheers TeeS
TeeS, no the certification and so hence RFM profiles assume that the gear is left down until Vy and 200 ft agl. for a conventional accelerating departure as it is assumed that the pilot/crew are too busy concentrating on achieving the first segment climb at Vtoss to be operating any other controls. For a procedure where the TDP is already above 200 ft I would assume that retraction would take place at Vy.

and less stress to the tail rotor
Chopjock - what stress are you talking about? This is a tail rotor on a Part 29/CS29 certified modern machine, not something on a balsa wood aeroplane with a wind up propeller. Do you seriously think that a gentle climbing imanoeuvre is somehow placing any components in jeopardy?
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Old 28th Nov 2018, 13:53
  #867 (permalink)  
 
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Hi Chopjock, so you have backed your helicopter into the corner, accelerated as fast as possible towards the opposite corner (135m away according to Google Earth and that might just allow you to get to 25-30kts before you hit the far stands) and then 'zoom climbed' at a moment when you guess that your angle of climb will just avoid the stadium roof. Thankfully your one engine (one of my two engines) hasn't stopped because the engines are rather reliable, the climb continues until you get to the top of the stadium roof whereupon you continue an acceleration/climb to a suitable height. If at any time an engine stops (except in the first few seconds of acceleration or on reaching a safe height), the tail rotor quits its job, the rotor head lets go or you just overestimate your guess at what climb angle you were going to achieve, you stand a good chance of killing your passengers. How on earth can you argue that you have reduced any exposure times!!
Cheers
TeeS
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Old 28th Nov 2018, 14:00
  #868 (permalink)  
 
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Chopjock, don't think that the exposure to TR failure poor outcomes is restricted to zero speed hovering. TR Malfunction risks are present throughout the envelope and decrease significantly with speeds above Vy, However, in a twin, TR drive failure anywhere in the envelope turns you effectively into a SEH as an autorotation is generally required. Unless you have a Fenestron behind you whereby your options are significantly increased.

To illustrate my rather awkward point. If we all agreed to depart in accordance with your suggestion (Lets call it the "Corner" profile), losing the TR control or drive anytime in the first 70 knots would see you in a smoking heap. Up to 100 kts in the climb out your arse would be eating the seat cushion and the prospects of survival still 50/50. There are no easy alternatives.

That's why others on this thread (and you have managed to stimulate JimL into a frenzy), think you somewhat lacking in the old common sense department. However, try not to get defensive and think carefully about what I have written. This is nothing new. TR Malfunctions and Drive Failures present limited prospects of success wherever they occur.
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Old 28th Nov 2018, 14:15
  #869 (permalink)  
 
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TeeS
How on earth can you argue that you have reduced any exposure times!!
How long does it take to VTOSS using CatA profile V a "Corner" profile?
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Old 28th Nov 2018, 14:17
  #870 (permalink)  
 
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Originally Posted by 212man View Post
TeeS, no the certification and so hence RFM profiles assume that the gear is left down until Vy and 200 ft agl. for a conventional accelerating departure as it is assumed that the pilot/crew are too busy concentrating on achieving the first segment climb at Vtoss to be operating any other controls. For a procedure where the TDP is already above 200 ft I would assume that retraction would take place at Vy.
Thanks for that 212man, I hadn't come across that as a certification spec - every day is a learning day :-)
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Old 28th Nov 2018, 14:40
  #871 (permalink)  
 
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Originally Posted by chopjock View Post
TeeS


How long does it take to VTOSS using CatA profile V a "Corner" profile?
Well I would be able to calculate that pretty accurately for the VTOL profile as the test pilots have produced the graphs but I can't compare it to your 'Corner' profile as that would depend on your gut feeling about when to stop your acceleration in order to miss the stadium roof and hence what speed you would reach and therefore what your rate of climb would be.

Cheers
TeeS
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Old 28th Nov 2018, 18:49
  #872 (permalink)  
 
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Chopjock is a drone operator.
{and has flown as a passenger in an R22 once}.
So be gentle.
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Old 28th Nov 2018, 19:03
  #873 (permalink)  

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Originally Posted by chopjock View Post
TeeS


How long does it take to VTOSS using CatA profile V a "Corner" profile?
Surely you don't think that Vtoss is in any way related to the tail rotor?

Here's an example of a pilot trying to fly your proposed technique:
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Old 28th Nov 2018, 19:35
  #874 (permalink)  
 
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Originally Posted by ShyTorque View Post
Surely you don't think that Vtoss is in any way related to the tail rotor?
I was giving a time period in which to answer a question.


Here's an example of a pilot trying to fly your proposed technique:
https://www.youtube.com/watch?v=N6vWraEkVkY
That was all too slow, nothing like "my technique". No back up, no firm acceleration and no zoom climb...
I wonder how in that video it would have turned out if that Bell had attempted a Cat A departure profile?
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Old 28th Nov 2018, 19:43
  #875 (permalink)  

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If he had attempted a Cat A departure profile and had insufficient power to fly away, which is exactly what happened, he would have been able to fly safely back down to the departure point.
Maybe the point that Cat A departure profiles are designed for exactly this reason has so far escaped your understanding.
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Old 28th Nov 2018, 20:12
  #876 (permalink)  
 
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Like this...
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Old 28th Nov 2018, 20:37
  #877 (permalink)  
 
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You've got it at last Chopjock, that is a perfect demonstration of a class 1 profile (it wasn't called that then). From the hover the pilot flying accelerates the aircraft and the pilot monitoring calls 'groundspeed' when he sees the ground moving past the window and then 'airspeed' when the ASI just begins to fluctuate. At that point, the pilot flying adjusts the attitude and power to climb almost vertically whereupon the pilot monitoring calls '20 feet', '40 feet' and 'rotate' as the radalt shows 50'. At that point, the pilot flying initiates a further acceleration and is committed to fly away - before this point, in the event of an engine failure (or other emergency) the take off is rejected.

This profile allows the S61 to depart from a very short runway providing class 1 performance in the same way that the vertical profile provides. It does not allow a departure with obstructions that would be found in a stadium environment!

Cheers

TeeS
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Old 28th Nov 2018, 20:47
  #878 (permalink)  
 
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Ok a Class 1 profile takes about 12 to 15 seconds of "exposure" time to Vtoss. A Cat A profile takes about 30 seconds or more. If neither can survive a tail rotor failure during this time, then which is the lesser of the two evils? I would suggest a shorter exposure time...
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Old 28th Nov 2018, 20:51
  #879 (permalink)  
 
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Laddy....if you think 15 seconds means squat considering the rarity of a Tail Rotor failure.....you ought to stay home in bed all day and pray a Police Helicopter doesn't join you.
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Old 28th Nov 2018, 20:57
  #880 (permalink)  
 
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Originally Posted by SASless View Post
Laddy....if you think 15 seconds means squat considering the rarity of a Tail Rotor failure.....you ought to stay home in bed all day and pray a Police Helicopter doesn't join you.
Multiply by how often did they do this and was it after 15 seconds when this tail rotor failed?
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