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 » Soaring
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

AoA keep it going!



 
 
Thread Tools Display Modes
  #1  
Old December 20th 07, 03:49 PM posted to rec.aviation.soaring
Ian
external usenet poster
 
Posts: 306
Default AoA keep it going!

On 20 Dec, 14:42, "kirk.stant" wrote:

Ian, we appear to be comparing apples and oranges - you are talking
about not stalling on final, while I am talking about being able to
accurately thermal, and incidentally have a better instrument for
flying accurate approaches.


I wonder how much "flying at Clmax" matters in good thermalling
compared with "being in the right bit of the thermal"?

Obviously, my opinion is colored by having actually flown airplanes
with excellent AOA systems, and by my wish to optimise my soaring for
XC and racing. I really think that within a few years someone will
come up with a simple, low drag, accurate AOA system that will be
adopted by the same group of pilots who eagerly adopted radios, TE,
audio varios, glide computers, GPS, PDA moving maps, transponders,
ELTs, traffic detection devices - all those "unecessary" gadgets that
clutter up our cockpits but, in my opinion, make soaring safer, more
efficient, and more fun.


If it does these things I'll be all for it. If it costs less than
twenty quid I may even buy one. As a matter of interest, how do you
define "efficient" here?

Ian
  #2  
Old December 21st 07, 05:39 PM posted to rec.aviation.soaring
Martin Gregorie[_1_]
external usenet poster
 
Posts: 276
Default AoA keep it going!

Ian wrote:
On 20 Dec, 14:42, "kirk.stant" wrote:

Ian, we appear to be comparing apples and oranges - you are talking
about not stalling on final, while I am talking about being able to
accurately thermal, and incidentally have a better instrument for
flying accurate approaches.


I wonder how much "flying at Clmax" matters in good thermalling
compared with "being in the right bit of the thermal"?

Minor correction: you should be thermaling at min.sink, which is the
point at which Cl^3/Cd^2 is maximized.

This is not in general the same as Cl max. Min.sink is usually at a
slightly lower AOA than CL max because Cd is rising steeply with
increasing AOA in the Cl max region. As a result, by the time you've
slowed to Cl max you've passed min.sink and your sinking speed has
started to increase.

Since the polar is usually flatter on the faster side of min.sink I
think you're better off thermaling somewhere between the min.sink and
best glide speeds, preferably nearer the former. Best glide is the speed
where Cl/Cd is a maximum.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |
 




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


All times are GMT +1. The time now is 07:22 PM.


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