A aviation & planes forum. AviationBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AviationBanter forum » rec.aviation newsgroups » Piloting
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Question to Mxmanic



 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
  #11  
Old April 16th 07, 09:12 PM posted to rec.aviation.piloting,rec.aviation.student
Kev
external usenet poster
 
Posts: 368
Default Question to Mxmanic

On Apr 16, 11:15 am, "Maxwell" wrote:
"Kev" wrote in message
It's going to take about 30 seconds to fly a 360 steep turn at
100kts. My wake _should_ descend about 150' during that time (300
fpm). I can't imagine a C172 wake being tall enough to stay in my
way unless something else is ocurring (me descending, or the wake
staying up).


I am certainly no expert on the subject, but I think most of the data on
wake turbulence comes from studies held at or very near the ground.


My searches on the web show the opposite... or at least that there's
studies both at altitude and near the ground. For examples:

http://www.nasa.gov/centers/dryden/a...4-14-DFRC.html

"NASA research has shown that as large aircraft move through the air,
trailing vortices tend to remain spaced less than a wingspan apart
while sinking at a rate of several hundred feet per minute. Over time,
the sink rate will slow and their strength will taper off. Research
has shown, however, that vortices can also rise during conditions of
ambient thermal lifting."

"Aircraft Accident Reconstruction and Litigation" By M. P. Papadakis,
Barnes Warnock MacCormick, states that vortices descend 5-10 fps
(30-600 fpm).

Based on the numbers I recall, they did indeed teach that the wake from a
landing heavy would NORMALLY travel both down and away from the aircraft a 5
kts or so. But they were also quick to mention that a simple 5 kt or so
crosswind componet could leave the vortex in the middle of the runway for
quite some time.


Yes, we were all taught that part.

The problem with trying to use this information at altitude is that you
don't have the ground to help stablize the vertical movement of the vortex.


Here is information taken at altitude: Vortices are 14-36 feet in
diameter, approx the wingspan apart, and sink 160 - 1100 fpm.

http://www.airpower.maxwell.af.mil/a...ug/carten.html

I just think it's an interesting question, because we've all had it
happen, but no one here can give a definitive reason for it (beyond
"yo stupid of course it does" which is pretty lame even for the usual
Mx bashers ;-)

I think I've convinced myself that since I don't always hit my wake on
a perfect steep turn, and because it mostly seems to happen over areas
of rising air, that the explanation is simple. Unless someone can
post better research.

Thanks, Kev

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
I want to ask you the most important question of your life. The question is: Are you saved? It is no gasman Soaring 0 August 26th 05 06:39 PM
Good morning or good evening depending upon your location. I want to ask you the most important question of your life. Your joy or sorrow for all eternity depends upon your answer. The question is: Are you saved? It is not a question of how good Excelsior Home Built 0 April 22nd 05 01:11 AM
Question about Question 4488 [email protected] Instrument Flight Rules 3 October 27th 03 01:26 AM


All times are GMT +1. The time now is 11:11 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 AviationBanter.
The comments are property of their posters.