Professional Pilot Training (includes ground studies) A forum for those on the steep path to that coveted professional licence. Whether studying for the written exams, training for the flight tests or building experience here's where you can hang out.

Center of Gravity

Old 29th Aug 2019, 07:35
  #1 (permalink)  
Thread Starter
 
Join Date: Aug 2019
Location: Oman
Posts: 3
Red face Center of Gravity

I would like to know for take off we calculate two CGs basically all speeds settings are decided on Take off CG . The zero Fuel CG is also calculated
What is the purpose of Calculating the Zero Fuel CG
Can any one can educate me
david15 is offline  
Old 4th Sep 2019, 00:13
  #2 (permalink)  
Moderator
 
Join Date: Oct 1999
Location: Chicago, IL
Posts: 787
What airplane type?
Some aircraft with swept wings can encounter an change in CG as fuel is burned. Obviously the ZFW CG is not helpful but there will be a forward most CG location encountered at ZFW + XXXlbs of fuel remaining. IOW you are determining that the CG remains inside the aircraft operating envelope while airborne.
weasil is offline  
Old 4th Sep 2019, 04:13
  #3 (permalink)  
 
Join Date: Dec 2005
Location: UK
Age: 41
Posts: 70
Because it has to be within CG limits for all possible situations. So in the worst case scenario where you blow through all your reserve fuel, at least it'll fly. Or glide.
rudestuff is offline  
Old 4th Sep 2019, 07:18
  #4 (permalink)  
Thread Starter
 
Join Date: Aug 2019
Location: Oman
Posts: 3
Dear SIr,
Thank you for your reply, but i need some more clarity. what is the importance of Zero fuel CG. Because TO CG is required for the take off, but ZF CG what is the importance
david15 is offline  
Old 4th Sep 2019, 14:03
  #5 (permalink)  
 
Join Date: Apr 2012
Location: Italy
Age: 30
Posts: 88
To be sure you'll be inside the envelope no matter how much fuel you use.
So even if you'll burn every single drop of fuel on board you'll be able to control the aircraft.
bulldog89 is offline  
Old 5th Sep 2019, 14:39
  #6 (permalink)  
JRK
 
Join Date: Feb 2017
Location: Europe
Posts: 6
Originally Posted by david15 View Post
Dear SIr,
Thank you for your reply, but i need some more clarity. what is the importance of Zero fuel CG. Because TO CG is required for the take off, but ZF CG what is the importance

If you are zero fuel you still need to be properly balanced to glide safely, recover from stall, etc.
So, this metric checks whether on zero fuel you are still within the CG envelope and not out of whack.
JRK is offline  
Old 5th Sep 2019, 15:57
  #7 (permalink)  
 
Join Date: Feb 2000
Location: UK
Posts: 13,621
In light aeroplanes, almost always there's a straight line of CG versus weight in any given configuration.

In airliners, and even more so with military aeroplanes, it's a lot more complex. I used to work with a military aircraft that had a 19 tank system, emptying on an automatic schedule - be thankful it's as simple as it is in light aircraft!

G
Genghis the Engineer is offline  
Old 7th Sep 2019, 12:27
  #8 (permalink)  
Thread Starter
 
Join Date: Aug 2019
Location: Oman
Posts: 3
Thank you for your reply
david15 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 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.