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-   -   Police helicopter crashes onto Glasgow pub (https://www.pprune.org/rotorheads/528850-police-helicopter-crashes-onto-glasgow-pub.html)

jayteeto 22nd Jan 2014 14:45

Why has no-one made me aware?

Sorry if this sounds blunt, but why should we? The battery will last for up to 30 minutes, that is enough power for one hell of an autorotation......

Robin400 22nd Jan 2014 15:15

How long with the landing light and other services?
 
I understand it is only 13amp/hr. battery in service battery about 80% that.

jayteeto 22nd Jan 2014 15:20

No its a lot lot lot more than 13a/h. Its 40

Ainippe 22nd Jan 2014 15:44

me thinks Robin 400 is a mindless reporter OR a complete fool cannot work out which !!:ugh:

ShyTorque 22nd Jan 2014 15:50


Why has nobody made me aware the starter generator provides the electrical power and not a generator driven by the rotor accessory gearbox.

With both engines failed power is only available from the battery.
You should have read your own post #1924!!


I understand that the generators are driven from the gearbox of each engine.
You seemed to know it then... :ugh:

yellowbird135 22nd Jan 2014 15:59

I think Robin400 is in fact a very pretty 21 yr old girl with all the right sizes and I'm guessing blond......pretending to be a 70 year old guy....it would explain a lot

Q-SKI 22nd Jan 2014 17:08

What?
 
What a sad turn of events this thread has turned into, speculation of any sort not backed up by facts rather muddies the water and I think we forget about the human tragedy of this incident. :sad:

PieChaser 22nd Jan 2014 18:37

Talkpedlar,


With all due respect, comments from Piechaser, Falcon900 and Robin 400 show clear lack of knowledge, relevant experience and even intelligence.
That's a bit rich! "with all due respect" and "lacks intelligence" In the same sentence!

Talkpedlar, perhaps you could enlighten me as to the post or posts that I have made that show my lack of knowledge, experience and Intelligence.

talkpedlar 22nd Jan 2014 18:51

Piechaser?
 
Your comments in 1904 and 1907 for starters. I never wish to offend but where did you trawl that garbage from?

Sorry but your lack of appropriate knowledge, experience and intelligence just shine through.

Regards,

TP

ps If I get time tomorrow I will respond at length..and to Robin400 too who seems to have covered everything except tyre-pressures and paint-scheme.
:ugh:

Democritus 22nd Jan 2014 20:41

Please!! Enough!
 
Despite nearly 40 years of flying helicopters professionally I do not feel qualified to comment on this thread as I have been retired for the past 10 years and I am therefore out of touch and I also have no knowledge of the EC135 or its systems.

It is a great pity that somehow comments on this tragedy cannot be restricted to those who qualify under the heading of this forum ie "a haven for helicopter professionals to discuss the things that affect them". If you are not a helicopter professional then if you have genuine question I'm sure members will be willing to answer it but the unbelievable hypotheses from some posters who are not helicopter professionals contribute nothing to the thread and do disservice to those who have died in this disaster.

henra 22nd Jan 2014 21:09


Originally Posted by Robin400 (Post 8277789)
Why has nobody made me aware the starter generator provides the electrical power and not a generator driven by the rotor accessory gearbox.

Because it makes no difference whatssoever.

The rotor System of an EC135 in operating conditions will have a stored energy the order of Magnitude of 3-5 MJ.
That is 5 Million Watt Seconds. So a 1600 Watts Night Sun would run for about 1 hour with the energy stored in the rotor.

Would you be so kind and stop pursuing this totally pointless path?

Lemain 23rd Jan 2014 09:12


Would you be so kind and stop pursuing this totally pointless path?
It might not be as pointless as your numbers suggest. If the generator is also a starter (e.g. like a Dynastart) then the potential shaft power could be significant in the event of a fault current flowing. A shorted or low-ohms starter motor can be one hell of a brake. I'd bet that it'd take any pilot by surprise in the event of failure of the turbines to deliver power to the rotor over an urban area at night.

skadi 23rd Jan 2014 09:41


It might not be as pointless as your numbers suggest. If the generator is also a starter (e.g. like a Dynastart) then the potential shaft power could be significant in the event of a fault current flowing. A shorted or low-ohms starter motor can be one hell of a brake. I'd bet that it'd take any pilot by surprise in the event of failure of the turbines to deliver power to the rotor over an urban area at night.
Lemain, it doesnt matter wether the generator brakes like hell or not! There is a freewheeling unit on the engines output shaft ( like your bicycle!! ).

skadi

Lemain 23rd Jan 2014 10:53

skadi


Lemain, it doesnt matter wether the generator brakes like hell or not! There is a freewheeling unit on the engines output shaft ( like your bicycle!! ).
If the freewheeling mechanism is not damaged or faulty. We are looking for some thing(s) that went wrong. I'm not tabling this as the reason for the crash, it's perplexing, but if we are going to speculate we ought to consider multiple failures or maybe a single primary cause that causes other damage.

Incidentally, on the subject of the effect of a full load on the generator braking the rotor shaft, of the Night Sun at 1600W, that's over 2hp. We can all visualise 1.5 electric fire bars in the context of heat power, but in terms of motive power, most of us are more comfortable with hp when it comes to orientation of magnitude. I've never experimented with an aircraft but I used to have a sailing yacht of around 3 tonnes mass (much the same as a 135) and I sometimes had to turn off the fast-charge circuit when motoring entering or leaving a harbour against the tide. Made a huge difference and that was with a 23hp diesel running.

Anything that takes a skipper by surprise in an already dangerous and high workload situation can turn routine into disaster, as I am sure we all know first hand (those near misses that still give us the collywobbles when we think of them years later?) - not that any of us here would have been so stupid :\

SASless 23rd Jan 2014 13:47


me thinks Robin 400 is a mindless reporter OR a complete fool cannot work out which !!
Fools and Reporters.....is there a difference?

jayteeto 23rd Jan 2014 14:12

The starter/generator output shaft has a weak point that has been built in to the design to shear if it seizes. So if the weak point failed AND the freewheeling failed AFTER BOTH engines failed, then dahdaaahhhhh, you have solved it.

FFS. :ugh:

henra 23rd Jan 2014 17:59


Originally Posted by Lemain (Post 8279567)
Incidentally, on the subject of the effect of a full load on the generator braking the rotor shaft, of the Night Sun at 1600W, that's over 2hp.

Exactly.
2HP.
On a twin turbine helicopter with 1200+HP.
You don't want to tell me that you will notice a variation of +/- 1HP in an EC135???
Guys, seriously....

Senior Pilot 23rd Jan 2014 20:12

Piechaser and Lemain,

A reminder that this forum is "for helicopter professionals to discuss the things that affect them".

Neither of you are helicopter professionals yet you are abusing the courtesies being shown you by those who are. There are a number of non-professionals who have worn out their welcome and are restricted from posting here: it should be obvious to both of you that constant harping about trivialities with needless references to boating by Lemain are wearing very, very thin and you are on the verge of being similarly restricted.

Thomas coupling 23rd Jan 2014 20:38

Phew.......and take a deep breath........................:D

Lemain 23rd Jan 2014 21:18

SP and others. Sorry to have caused any offence.


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