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

Turn Radius Formula & Ascending/Descending Turns

Wikiposts
Search

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

Turn Radius Formula & Ascending/Descending Turns

Thread Tools
 
Search this Thread
 
Old 3rd October 2010 | 23:26
  #1 (permalink)  
Thread Starter
 
Joined: Jul 2008
Posts: 86
Likes: 0
From: Las Vegas, NV
Turn Radius Formula & Ascending/Descending Turns

When calculating the turn radius for an ascending or descending turn, does the gravitional constant value need to be adjusted accordingly?

Could the standard turn radius formula apply to ascending or descending turns and generate correct results?
Badmachine is offline  
Reply
Old 4th October 2010 | 07:28
  #2 (permalink)  
Per Ardua ad Astraeus
 
Joined: Mar 2000
Posts: 18,575
Likes: 4
From: UK
In practical terms, no. The other variations in performance, human, computer and nature far exceed the small variations due to what are normally small descent/
climb angles.

Why in particular the question? Are we theoretical or practical?
BOAC is offline  
Reply
Old 4th October 2010 | 09:43
  #3 (permalink)  
 
Joined: Oct 2010
Posts: 41
Likes: 0
From: Germany (North)
You want to calculate turn radius?
That is a pure function of turn acceleration and level flight speed (true). It is the acceleration you actually put in the turn.
It is no problem to separate vertical from lateral motion.
CabinMaster is offline  
Reply
Old 4th October 2010 | 10:20
  #4 (permalink)  
25 Anniversary
 
Joined: Feb 2000
Posts: 4,704
Likes: 589
From: 500 miles from Chaikhosi, Yogistan
Why stop there? What about the relativity issues?
compressor stall is offline  
Reply
Old 4th October 2010 | 10:53
  #5 (permalink)  
 
Joined: Jun 2002
Posts: 3
Likes: 5
From: Wor Yerm
Probably yes, but a close enough formula is TAS (Metres/Second) Squared/(Tangent of Angle of Bank * g). For g I'd use 1.

PM
Piltdown Man is offline  
Reply
Old 4th October 2010 | 11:26
  #6 (permalink)  
 
Joined: Oct 2010
Posts: 41
Likes: 0
From: Germany (North)
g still is approximately 9.81 m/s².
CabinMaster is offline  
Reply
Old 4th October 2010 | 12:49
  #7 (permalink)  
Per Ardua ad Astraeus
 
Joined: Mar 2000
Posts: 18,575
Likes: 4
From: UK
Maybe gravity in Piltdown is much less? Is it on the moon?
BOAC is offline  
Reply
Old 4th October 2010 | 12:53
  #8 (permalink)  
 
Joined: Mar 2006
Posts: 1,974
Likes: 0
From: Choroni, sometimes
Maybe gravity in Piltdown is much less? Is it on the moon?
Must be somewhere else, on the moon it's 1.63 m/s².
hetfield is offline  
Reply
Old 4th October 2010 | 13:14
  #9 (permalink)  
Per Ardua ad Astraeus
 
Joined: Mar 2000
Posts: 18,575
Likes: 4
From: UK
Now - this is a matter of some gravity. A weighty problem indeed.
BOAC is offline  
Reply
Old 4th October 2010 | 15:56
  #10 (permalink)  
 
Joined: Oct 2010
Posts: 41
Likes: 0
From: Germany (North)
Or he uses a different unit.
The answer is always "42".
Just the unit changes.
CabinMaster is offline  
Reply
Old 4th October 2010 | 16:35
  #11 (permalink)  
 
Joined: Jun 2004
Posts: 178
Likes: 8
From: UK
A very good point. I suspect he is using the TGM unit system, which is best for people with 12 fingers

TGM - a coherent dozenal metrology

Last edited by Rivet gun; 4th October 2010 at 17:54.
Rivet gun is offline  
Reply
Old 6th October 2010 | 00:57
  #12 (permalink)  
15 Anniversary
 
Joined: Dec 2006
Posts: 2,486
Likes: 8
From: The No Transgression Zone
no...the circumferential velocity vector, and the vertical velocity vector are kinematically independent; they are mutually exclusive axes

Last edited by Pugilistic Animus; 6th October 2010 at 01:10. Reason: stupid spell check
Pugilistic Animus is offline  
Reply
Old 16th January 2017 | 05:18
  #13 (permalink)  
 
Joined: Jan 2017
Posts: 1
Likes: 0
From: usa
How to calculate a turn radius for descending turns.

How to calculate a turn radius while aircraft is continuously descending(with some dive angle) and turning with specific bank angle.
shafqatgreat is offline  
Reply
Old 17th January 2017 | 10:51
  #14 (permalink)  
 
Joined: Jun 2000
Posts: 4,507
Likes: 4
From: last time I looked I was still here.
Don't forget to factor in the rotation of the earth as you descend, and the change in pressure.
RAT 5 is offline  
Reply
Old 17th January 2017 | 12:53
  #15 (permalink)  
15 Anniversary
 
Joined: May 2006
Aviation Qualifications: ATPL
Posts: 231
Likes: 5
From: Here, there and everywhere
I was about to mention Coriolis effect, but small cog beat me on that...
Broomstick Flier 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



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.