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

Tubercles lower stalling airspeed?



 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
  #1  
Old May 15th 07, 07:08 PM posted to rec.aviation.soaring
Angus Mac Lir
external usenet poster
 
Posts: 1
Default Tubercles lower stalling airspeed?

Jokes aside, this is serious research:

'...The potential was enough for the Ontario Centres
of Excellence and the Ontario Power Authority to contribute
about $70,000 in early-stage research funding, and
to encourage collaboration with the wind-engineering
group at the University of Western Ontario. Independent
third-party verification of the new blade's performance
will be a crucial step toward commercial production.

snip...

It turns out the key to a humpback's agility lies in
its long flippers, which feature a unique row of bumps
or 'tubercles' along their leading edge that give the
wing-like appendages a serrated look. Researchers such
as Frank Fish, a professor of biology at West Chester
University in Pennsylvania, have found that the tubercles
dramatically increase the whale's aerodynamic efficiency.

In one particular study conducted inside a controlled
wind tunnel, Fish and research colleagues at Duke University
and the U.S. Naval Academy saw 32 per cent lower drag
and an 8 per cent improvement in lift from a flipper
with tubercles compared to a smooth flipper found on
other whales.

They also discovered that the angle of attack of the
bump-lined flipper could be 40 per cent steeper than
a smooth flipper before reaching stall – that is, before
seeing a dramatic loss in lift and increase in drag.
In an airplane scenario, that's typically when you
lose control and crash.

'That stall typically occurs on most wings at 11 or
12 degrees at the angle of attack,' says Fish, adding
that with the humpback design 'stall occurred much
later, at about 17 or 18 degrees of attack. So the
stall is being delayed.'

The implications are potentially enormous. Delayed
stall on airplane wings can improve safety and make
planes much more manoeuvrable and fuel-efficient. The
same benefits can also be found on ship and submarine
rudders, which explains the U.S. Navy's quiet involvement.'



 




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
Tubercles lower stalling airspeed? RichardFreytag Soaring 7 May 15th 07 07:02 PM
Stalling and spinning generally Ian Strachan Soaring 0 February 1st 04 08:40 PM
Spinning or the after effects of stalling. Dave Martin Soaring 0 January 29th 04 11:24 PM
Wingdrop while stalling drake Home Built 28 January 17th 04 12:43 PM
Tow plane airspeed vs. glider being towed airspeed? MHende6388 Soaring 2 September 28th 03 09:35 AM


All times are GMT +1. The time now is 11:22 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.