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

a reverse thrust q...


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

a reverse thrust q...

Old 19th November 2015 | 10:45
  #1 (permalink)  
Thread Starter
 
Joined: Sep 2015
Posts: 48
Likes: 0
From: with my parents
a reverse thrust q...

Once the blocker doors are fully deployed, with an increase in RPM, which of the following statements would be incorrect?
a. Forward thrust from the hot gases would increase.
b. Forward thrust from the hot gases would decrease.
c. Reverse thrust from the blocked air would increase.
d. TGT will increase.
marked answer B . I believe it should be a.
D driver is offline  
Reply
Old 19th November 2015 | 11:01
  #2 (permalink)  
 
Joined: Sep 1998
Posts: 1,615
Likes: 1
From: wherever
b is the correct answer in most cases. Blocker doors in the question implies it is not a clam shell system so it's the bypass air that's reversed not the core air.
FE Hoppy is offline  
Reply
Old 19th November 2015 | 11:25
  #3 (permalink)  
20 Anniversary
 
Joined: May 2005
Posts: 1,198
Likes: 32
From: France
As Hoppy says:

With blocker doors, only the cold by-pass air is reversed. The hot gases continue to exit rearwards through the central exhaust as they do in 'forward thrust'.

So, once the blocker doors are fully deployed and RPM increases, hot gases exhaust (forward thrust) increases, TGT increases and reverse thrust from the blocked air increases.

So the only incorrect statement is b).
a), c) and d) are correct statements.
eckhard is offline  
Reply
Old 19th November 2015 | 12:28
  #4 (permalink)  
 
Joined: Jan 2006
Posts: 434
Likes: 0
From: Ijatta
Bad question.

It depends on the type of reverser or how you define "blocker doors".

https://en.wikipedia.org/wiki/Thrust_reversal
wanabee777 is offline  
Reply
Old 20th November 2015 | 17:44
  #5 (permalink)  
 
Joined: Nov 2002
Posts: 69
Likes: 0
From: Europe
They are looking for the incorrect statement, that's B assuming core air is not reversed.
Gryphon is offline  
Reply
Old 20th November 2015 | 18:36
  #6 (permalink)  
 
Joined: Jan 2006
Posts: 434
Likes: 0
From: Ijatta
They are looking for the incorrect statement, that's B assuming core air is not reversed.
It's still a poorly phrased question.
wanabee777 is offline  
Reply
Old 22nd November 2015 | 03:56
  #7 (permalink)  
Thread Starter
 
Joined: Sep 2015
Posts: 48
Likes: 0
From: with my parents
thankyou averyone i see how b is correct.
D driver is offline  
Reply
Old 22nd November 2015 | 07:52
  #8 (permalink)  
 
Joined: Jun 2013
Posts: 326
Likes: 1
From: Or-E-Gun, USA
FE Hoppy+++

IMO, several nailed it very well, but FE Hoppy was first and sort of said it best. And please do not be mislead as the question asks for the incorrect response. You're doing just fine!
No Fly Zone is offline  
Reply

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


Thread Tools
Search this Thread

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

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.