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Restricted takeoffs, VRS, and ground effect

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Restricted takeoffs, VRS, and ground effect

Old 12th Aug 2015, 11:18
  #81 (permalink)  

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This discussion is sounding like one of those pointless arguments in a pub about whose footaball team is best.

Irrespective of the reliability of modern turbine engines, the point about twin engined aircraft is that they have other duplicated systems, such as those which are required for flight in IFR e.g. generators, SAS/autopilot systems, hydraulics etc.

This rules out singles where continued flight is a safety and legal requirement. There is certainly no compelling evidence that a single engine is more reliable and therefore safer than two.

Having flown both singles and twins, I've always said that I'd rather have a well equipped, powerful single than an underpowered twin, some of which I've also flown.

But the latter came from "the dark ages" and modern twins do not generally fit into that category.

I'd say that both singles and twins each have their own "niche" and both will always exist. It's totally pointless trying to argue that singles should be exclusively manufactured and used because of a personal preference.
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Old 12th Aug 2015, 13:23
  #82 (permalink)  
 
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Completely agree Shy but you won't stop him doing it!
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Old 12th Aug 2015, 14:44
  #83 (permalink)  
 
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Crab
Your assumption that I haven't had my share of dark and stormy nights in inhospitable places is a little harsh. Been more than 500nm from land just for starters.

Yes Shy is right to some extent and Crab's examples are the emotional ones that make people kneejerk to believing that the twin is obvious. BUT the point I am trying to make is deeper than that. Extending to the 'lazy' redundancy concept. The most unreliable part of some helicopters are the duplicated parts and I would prefer to spend the weight/cost/complexity on making a very reliable SIMPLEX system with minimal to zero need for backup.

Safety systems in general really ought to be evaluated with the cost to payload etc taken into account. Otherwise you get the daft situation where 3 flights need to be made in an 'engine failure immune' helicopter against 1 flight in an engine 'exposed' helicopter. [not a complete arguement]. AND duplication can be the answer sometimes, just nothing like as often as people's emotion leads them to believe.

3000shp? do you need 3000hp? 3000x 10 lbs/hp = 30000lbs that's heavy.
How many hp was the Huey (did pretty well, payload and performance wise)

As with the chinook if you need both engines to obtain enough hp then it's not the same thing as redundancy.
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Old 12th Aug 2015, 17:55
  #84 (permalink)  
 
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As with the chinook if you need both engines to obtain enough hp then it's not the same thing as redundancy.
and that means if you need the payload then you need the power - that leads into your
Otherwise you get the daft situation where 3 flights need to be made in an 'engine failure immune' helicopter against 1 flight in an engine 'exposed' helicopter.
you have to make 3 flights to get the job done in a single when 1 flight in a twin would do it. What about exposure then???

Pie = sky...

Care to elaborate on your 500nm from land in a helicopter? Love to know what has that range.

3000shp? do you need 3000hp? 3000x 10 lbs/hp = 30000lbs that's heavy
the Sea King has 2 1400shp engines for a MAUM of 21400 lbs and they are old technology compared to something like the S92 which I think is 26,500 lbs AUM.

Any one got any Skycrane figures?
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Old 13th Aug 2015, 02:41
  #85 (permalink)  
 
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This discussion is sounding like one of those pointless arguments in a pub about whose footaball team is best.
So true... This used to be such a good thread one or two pages ago. Now round and round we go.
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Old 13th Aug 2015, 08:23
  #86 (permalink)  
 
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Care to elaborate on your 500nm from land in a helicopter? Love to know what has that range
A tuna boat?
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Old 13th Aug 2015, 09:21
  #87 (permalink)  
 
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Second class citizens???

We must all remember that whatever regulatory principles are handed down to us chopper pukes it will be the philosophies that apply in the fixed wing world that will dominate.

The old joke about the difficult journey - you know, the one that begins "well if I were you I wouldn't have started from here......"

Gentlemen, we are where we are, sad though that may be.

G.
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