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

two basic questions .

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

two basic questions .

Old 30th Sep 2010, 03:57
  #1 (permalink)  
Thread Starter
 
Join Date: Aug 2009
Location: CHINA
Posts: 15
Likes: 0
Received 0 Likes on 0 Posts
two basic questions .

question one :
on FCOM,i see this a lot ."this speed give you FULL MANEUVER ABILITY or AT LEAST 45 DEGREE BANK,25 BANK AND 20 OVERSHOOT.'"

can any body tell me what this full maneuver ability is ?i am pretty sure i have ever learned this definition from my private pilot ground school,but could not remember it now .

question two:what is a foward slip?as long as i can remember now ,i did the foward slip approach on a cessna with right rudder and left york.but it was ten years ago.and as a student pilot i just follow the instructions and didnt think too much....and this morning i was reading this FCTM of 737NG,a chap about rudder trim technic.it says for the correct trimming ,there might be a bit FOWARD SLIP.and a slight bank angle.and also a deflection of the skid indicator.
can the bank angle to either side ?which side should it be ?
b744FPEK is offline  
Old 30th Sep 2010, 09:11
  #2 (permalink)  
 
Join Date: Oct 2009
Location: UK
Posts: 1,270
Likes: 0
Received 0 Likes on 0 Posts
Hi b744FPEK,

Full maneuver capability is the speed for a particular configuration which gives you a stall margin which allows normal bank of 30 degs (+ an overshoot margin). If your speed is less than that figure, then you're restricted to a maximum of 15 degs bank.

Forward slip is a cross wind landing technique, where you fly with some bank into wind and with some "opposite" rudder to align your heading with the runway track.
rudderrudderrat is offline  
Old 30th Sep 2010, 11:02
  #3 (permalink)  
Thread Starter
 
Join Date: Aug 2009
Location: CHINA
Posts: 15
Likes: 0
Received 0 Likes on 0 Posts
thank you .rudderrudderat.
b744FPEK is offline  
Old 30th Sep 2010, 11:56
  #4 (permalink)  
 
Join Date: Jun 2004
Location: UK
Posts: 172
Likes: 0
Received 0 Likes on 0 Posts
Full maneuver margin is a speed which allows you to pull a certain amount of G without stalling. In the case of the 737 NG the amber "hockey stick" on the speed tape represents a 0.3 g maneuver margin (i.e. 1.3 g load factor) which is what you would experience in a 40 deg bank level turn. Since you won't deliberatly exceed 30 deg bank in a transport aircraft this provides some allowance for error.

The second part of your question refers to the primary rudder trim technique in the B737 NG FCTM. In general you would trim the rudder in order to eliminate slip and thus minimise drag. However this is a simple trimming technique which may not be perfectly accurate. It could leave you with a slight slip condition, (either way)

If you want greater accuracy of trimming, read the next paragraph about the alternate rudder trim technique.
Rivet gun is offline  
Old 30th Sep 2010, 12:35
  #5 (permalink)  
Thread Starter
 
Join Date: Aug 2009
Location: CHINA
Posts: 15
Likes: 0
Received 0 Likes on 0 Posts
rivet gun .
thank you .totally understand now .
b744FPEK is offline  
Old 30th Sep 2010, 17:08
  #6 (permalink)  
 
Join Date: Nov 2000
Location: Netherlands
Posts: 254
Likes: 0
Received 0 Likes on 0 Posts
Actually, forward slip is a descent steepening maneuver. Sideslip is a Xwind landing maneuver.

In the words of your FCOM it is correct, the correct rudder trim technique may induce a small FORWARD slip, where the nose of the airplane may not be alligned with the heading.

Slip (aerodynamic) - Wikipedia, the free encyclopedia

Some reading material!
flyburg is offline  
Old 30th Sep 2010, 18:47
  #7 (permalink)  
 
Join Date: Jan 2008
Location: Herts, UK
Posts: 748
Likes: 0
Received 0 Likes on 0 Posts
Sideslip is a Xwind landing maneuve
Sideslip is also (and has been since flight immemorial) a descent steepening maneouvre.. i.e. some degree of crossed controls

Typically (or classically) and maybe most commnly seen and used by stringbags (Tiger Moths etc) to slip into tight fields, uncrossing the controls over the fence
HarryMann is offline  
Old 1st Oct 2010, 01:56
  #8 (permalink)  
Moderator
 
Join Date: Apr 2001
Location: various places .....
Posts: 7,178
Received 92 Likes on 61 Posts
Actually, forward slip is a descent steepening maneuver. Sideslip is a Xwind landing maneuver

They're both the same other than for the desire, in one case, to track a desired path over the ground (for landing)
john_tullamarine is offline  
Old 7th Oct 2010, 21:14
  #9 (permalink)  
 
Join Date: Jan 2008
Location: Herts, UK
Posts: 748
Likes: 0
Received 0 Likes on 0 Posts
Seems like someone's playing with words rather than actions...
HarryMann is offline  
Old 8th Oct 2010, 15:34
  #10 (permalink)  
 
Join Date: Nov 2005
Location: Troposphere
Age: 53
Posts: 17
Likes: 0
Received 0 Likes on 0 Posts
there is a lot of misunderstanding among the pilots with regards the two types of slips.

A Side Slip is used to correct a crab condition and to line up the aircraft with the runway centerline during a X-wind landing.
You bank into the wind and apply rudder to keep the longitudinal axis of the airplane aligned with the runway centerline.

A forward Slip is to loose altitude if you are high on final. slight bank not more than 5 degrees and apply full rudder in the opposite direction. a perfect forward slip would have the aircraft longitudinal axis NOT aligned with runway extended centerline (or the relative flight path). This will cause the side of the fuselage to meet the relative airflow and cause high parasite drag and hence the loss of altitude.

They both serve a different purpose.
SURGEBLEEDVALVE 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


Thread Tools
Search this Thread

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.