Go Back  PPRuNe Forums > Aircrew Forums > Rotorheads
Reload this Page >

Restricted takeoffs, VRS, and ground effect

Wikiposts
Search
Rotorheads A haven for helicopter professionals to discuss the things that affect them

Restricted takeoffs, VRS, and ground effect

Thread Tools
 
Search this Thread
 
Old 12th Aug 2015, 11:18
  #81 (permalink)  

Avoid imitations
 
Join Date: Nov 2000
Location: Wandering the FIR and cyberspace often at highly unsociable times
Posts: 14,574
Received 422 Likes on 222 Posts
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.
ShyTorque is offline  
Old 12th Aug 2015, 13:23
  #82 (permalink)  
 
Join Date: Apr 2000
Location: EGDC
Posts: 10,332
Received 623 Likes on 271 Posts
Completely agree Shy but you won't stop him doing it!
crab@SAAvn.co.uk is offline  
Old 12th Aug 2015, 14:44
  #83 (permalink)  
 
Join Date: Dec 2008
Location: N/A
Posts: 845
Likes: 0
Received 0 Likes on 0 Posts
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.
AnFI is offline  
Old 12th Aug 2015, 17:55
  #84 (permalink)  
 
Join Date: Apr 2000
Location: EGDC
Posts: 10,332
Received 623 Likes on 271 Posts
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?
crab@SAAvn.co.uk is offline  
Old 13th Aug 2015, 02:41
  #85 (permalink)  
 
Join Date: Mar 2012
Location: steady
Posts: 382
Received 3 Likes on 3 Posts
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.
whoknows idont is offline  
Old 13th Aug 2015, 08:23
  #86 (permalink)  
 
Join Date: Oct 1999
Location: Den Haag
Age: 57
Posts: 6,263
Received 336 Likes on 188 Posts
Care to elaborate on your 500nm from land in a helicopter? Love to know what has that range
A tuna boat?
212man is online now  
Old 13th Aug 2015, 09:21
  #87 (permalink)  
 
Join Date: Aug 2001
Location: Cornwall
Age: 75
Posts: 1,307
Likes: 0
Received 0 Likes on 0 Posts
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.
Geoffersincornwall is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.