Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

why does the Antonov wait 4 minutes with engines at 50% before take off?

Wikiposts
Search
Tech Log The very best in practical technical discussion on the web

why does the Antonov wait 4 minutes with engines at 50% before take off?

Thread Tools
 
Search this Thread
 
Old 5th Nov 2008, 21:18
  #1 (permalink)  
Thread Starter
 
Join Date: Oct 2007
Location: UK
Posts: 121
Likes: 0
Received 0 Likes on 0 Posts
why does the Antonov wait 4 minutes with engines at 50% before take off?

evening,

just as the title asks - can anyone explain why the Antonov (ruslan) wait 4 minutes on the runway with engines at 50% prior to dept?

surely this must be a pain for guys in ATC?
Vulcan607 is offline  
Old 5th Nov 2008, 21:22
  #2 (permalink)  
 
Join Date: Oct 1999
Location: Anywhere
Posts: 2,212
Likes: 0
Received 0 Likes on 0 Posts
Don't know but would like to.

However - from an ATC point of view it's not that much of a problem. As we're expecting it then it can be planned around.
Chilli Monster is offline  
Old 5th Nov 2008, 21:37
  #3 (permalink)  
 
Join Date: May 2000
Location: Scotland
Posts: 262
Likes: 0
Received 0 Likes on 0 Posts
I believe that they have had problems in the past with certain engines like those fitted to the An124, when the engine has run up to full power and then kept going (ie spinning faster and faster until it disintegrates), as whatever was supposed to stop it "overspeeding", didn't. The theory now is that if all engines stabilise at high power for several minutes before departure, all is well. If not, better to be sitting on the runway when it goes wrong!
That is the story I've heard, anyway, so I'd like to hear confirmation from someone who knows.

Like Chilli says, it's not a problem if you can plan for it (and not line an An124/225 up in a 6-mile gap and expect to get away with it!)
NudgingSteel is offline  
Old 5th Nov 2008, 21:46
  #4 (permalink)  
 
Join Date: Dec 2006
Location: The No Transgression Zone
Posts: 2,483
Received 5 Likes on 3 Posts
Off Topic a bit:

but how many donks can the 225 lose
1. on TO?
2. Enroute---3 out on same side? four out???

same query in regards to the B52?

these questions have bothered me a long while now

PA
Pugilistic Animus is offline  
Old 6th Nov 2008, 08:15
  #5 (permalink)  
Registered User **
 
Join Date: Nov 2007
Location: -
Posts: 15
Likes: 0
Received 0 Likes on 0 Posts
Maybe the folk up the pointy end, are having a few 'shots of the white thingy' before takeoff.. hence the 4 mins
1 min to open bottle
1 min to pour and serve
1 min to down it, and
1 min to burp
yes, just about right, I would assume
Dash7Ace is offline  
Old 6th Nov 2008, 08:21
  #6 (permalink)  
 
Join Date: May 2002
Location: dubai
Posts: 942
Likes: 0
Received 0 Likes on 0 Posts
The AN 124 being of advanced design, needs 2 F/E's to "trim" the engines for 5 minutes before t/o.
doubleu-anker is offline  
Old 6th Nov 2008, 08:44
  #7 (permalink)  
 
Join Date: Mar 2000
Location: Arizona USA
Posts: 8,571
Likes: 0
Received 0 Likes on 0 Posts
...needs 2 F/E's to "trim" the engines for 5 minutes before t/o.
Sort of like a big RR Dart...
411A is offline  
Old 6th Nov 2008, 08:49
  #8 (permalink)  

Bottums Up
 
Join Date: Feb 2000
Location: dunnunda
Age: 66
Posts: 3,440
Likes: 0
Received 1 Like on 1 Post
It's my understanding that some of the Russian turbines need a slow run to power to allow internal seals to seal properly. I guess Russian seals aren't as capable as US/European seals.
Capt Claret is offline  
Old 6th Nov 2008, 09:14
  #9 (permalink)  
 
Join Date: Jul 1999
Location: 58-33N. 00-18W. Peterborough UK
Posts: 3,040
Likes: 0
Received 0 Likes on 0 Posts
I guess Russian seals aren't as capable as US/European seals.
So you don't need any seals in Space?
forget is offline  
Old 6th Nov 2008, 09:29
  #10 (permalink)  
 
Join Date: Aug 2002
Location: London (Babylon-on-Thames)
Age: 42
Posts: 6,168
Likes: 0
Received 0 Likes on 0 Posts
No the fish to feed them screws the payload..... now Pigs in Space is a different matter entirely
Skipness One Echo is offline  
Old 6th Nov 2008, 09:42
  #11 (permalink)  
 
Join Date: Jul 2008
Location: CET
Posts: 19
Likes: 0
Received 0 Likes on 0 Posts
This is mostly to let engines' thermal variations to even out, before going full thrust on take-off.

Due to East's less sophisticated engine materials, this enhances engine durability. The same goes with thrust reductions in flight as well, ref "shock cooling" of big piston engines of the same era.

ss
sengasengana is offline  
Old 6th Nov 2008, 10:04
  #12 (permalink)  
 
Join Date: Nov 2000
Location: Home
Posts: 903
Likes: 0
Received 0 Likes on 0 Posts
concur what sengasengana states if you were to advance the throttles to takeoff power like a GE or P&W chances are that the runway would be littered with engine parts.

Remember at Kuwait on the AN124 sitting at the end of the runway waiting the prescribed time period for the engines to stabilise and an Air France aircraft on finals. After take off heard the AF crew complaining that the sand storm created had almost reduced the visibility to below CATI standard
Engineer is offline  
Old 6th Nov 2008, 11:45
  #13 (permalink)  
 
Join Date: Dec 2002
Location: Where the Quaboag River flows, USA
Age: 71
Posts: 3,414
Received 3 Likes on 3 Posts
Early C5 era did something like it for 2 minutes for the same reason, thermal stability. We stopped it before I got there in 88. The old FEs called it 'cooking the engines'.

GF
galaxy flyer is offline  
Old 6th Nov 2008, 16:52
  #14 (permalink)  
Spitoon
Guest
 
Posts: n/a
I believe it is also something to do with ensuring good oil temps and flow but maybe this is only in low temps.
 
Old 7th Nov 2008, 06:06
  #15 (permalink)  
 
Join Date: Feb 2005
Location: NZ
Age: 72
Posts: 205
Likes: 0
Received 0 Likes on 0 Posts
now Pigs in Space is a different matter entirely
Nice one Skip(or should I say Miss Piggy)
Fark'n'ell is offline  
Old 7th Nov 2008, 11:41
  #16 (permalink)  
 
Join Date: Oct 2004
Location: Near sheep!
Posts: 915
Likes: 0
Received 0 Likes on 0 Posts
Doing a crew headcount maybe..?
Skipper.....'here'.........fo.....'here.......fe1....'here'. .......
WindSheer 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.