Go Back   EcoModder Forum > EcoModding > Aerodynamics
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 03-25-2016, 06:03 AM   #1911 (permalink)
Master EcoModder
 
sendler's Avatar
 
Join Date: May 2011
Location: Syracuse, NY USA
Posts: 2,935

Honda CBR250R FI Single - '11 Honda CBR250R
90 day: 105.14 mpg (US)

2001 Honda Insight stick - '01 Honda Insight manual
90 day: 60.68 mpg (US)

2009 Honda Fit auto - '09 Honda Fit Auto
90 day: 38.51 mpg (US)

PCX153 - '13 Honda PCX150
90 day: 104.48 mpg (US)

2015 Yamaha R3 - '15 Yamaha R3
90 day: 80.94 mpg (US)

Ninja650 - '19 Kawasaki Ninja 650
90 day: 72.57 mpg (US)
Thanks: 326
Thanked 1,312 Times in 966 Posts
Quote:
Originally Posted by jjackstone View Post
photo of the Eta
Is the pointy nose really faster than an air foil nose in 90 mph air? Because there is a big draw back in handling side winds when there is that much overhang ahead of the front wheel. And it looks like the shape at the back narrows into a J form too quickly to maintain attachment. Is there a rule as to why the body had to be so short behind the rear wheel?
.
Speed-bikes
.
It looks like it would actually have lower drag in reverse.
.
Aerovelo
.

  Reply With Quote
The Following User Says Thank You to sendler For This Useful Post:
aerohead (03-26-2016)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 03-25-2016, 09:34 AM   #1912 (permalink)
Master EcoModder
 
kach22i's Avatar
 
Join Date: Jul 2011
Location: Ann Arbor, Michigan
Posts: 3,555
Thanks: 19
Thanked 2,321 Times in 1,620 Posts
Quote:
Originally Posted by jjackstone View Post
Here's a link to their site. Aerovelo
Cool, thanks.

I can now see the flat screen inside which must allow for a view ahead.

Kind of miss the fin and maple leaf though.

EDIT: Found this............
http://www.bloomberg.com/news/articl...highway-speeds


EDIT-2: Various competitors......................differing approaches.

https://jnyyz.wordpress.com/2015/09/page/4/
__________________
George
Architect, Artist and Designer of Objects

1977 Porsche 911s Targa
1998 Chevy S-10 Pick-Up truck
1989 Scat II HP Hovercraft

Chin Spoiler:
http://forums.pelicanparts.com/off-t...effective.html

Rear Spoiler Pick Up Truck
http://forums.pelicanparts.com/off-t...xperiment.html

Roof Wing
http://ecomodder.com/forum/showthrea...1-a-19525.html

Last edited by kach22i; 03-25-2016 at 09:44 AM..
  Reply With Quote
Old 03-25-2016, 11:57 AM   #1913 (permalink)
Master EcoModder
 
Join Date: Jan 2008
Location: Sacramento, CA
Posts: 396
Thanks: 31
Thanked 135 Times in 99 Posts
Quote:
Originally Posted by sendler View Post
Is the pointy nose really faster than an air foil nose in 90 mph air? Because there is a big draw back in handling side winds when there is that much overhang ahead of the front wheel. And it looks like the shape at the back narrows into a J form too quickly to maintain attachment. Is there a rule as to why the body had to be so short behind the rear wheel?
.
Speed-bikes
.
It looks like it would actually have lower drag in reverse.
.
Aerovelo
.
In these bikes, the widest spot is usually where the rider's shoulders are which is normally near the rear of the bike. So as I understand it, the front end of the bike is designed to provide laminar airflow as far back as possible and the short rear end is to minimize skin friction and help with pressure recovery. As you noticed the shape doesn't match the standard teardrop shape template so often used on this site. All I know is the results. These guys added over 3 mph to a record that had been increasing by maybe a half mile per hour every couple years for about a decade. The speeds are attained on less than 1 horsepower for the most part. There are a few very strong riders that can put out more power than that for a short time period.

The bikes aren't particularly stable and a good wind can easily send someone off into a ditch. But they are made for one thing... that's going fast in a straight line. Normally no one will ride if the wind is much more than 8 to 10 miles per hour. Too dangerous.

JJ
  Reply With Quote
The Following User Says Thank You to jjackstone For This Useful Post:
aerohead (03-26-2016)
Old 03-25-2016, 12:06 PM   #1914 (permalink)
Master EcoModder
 
Join Date: Jan 2008
Location: Sacramento, CA
Posts: 396
Thanks: 31
Thanked 135 Times in 99 Posts
This is one of my favorite bikes and rider. Damjan actually rides the thing backwards lying on his back. He uses a mirror looking out a small hatch in the top of the bike to see to steer. His top speed is "only" 80 mph.



JJ
  Reply With Quote
The Following 2 Users Say Thank You to jjackstone For This Useful Post:
aerohead (03-26-2016), Bicycle Bob (06-06-2019)
Old 03-25-2016, 02:42 PM   #1915 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 17,182
Thanks: 4,599
Thanked 5,749 Times in 4,586 Posts
Interesting aerodynamic bikes...


https://4.bp.blogspot.com/-6Xj8LA1RA...0/monster9.jpg
  Reply With Quote
The Following User Says Thank You to freebeard For This Useful Post:
aerohead (03-26-2016)
Old 03-25-2016, 04:56 PM   #1916 (permalink)
(:
 
Frank Lee's Avatar
 
Join Date: Jan 2008
Location: up north
Posts: 12,738

Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 1,572
Thanked 3,508 Times in 2,195 Posts
The idea behind having max width more rearward than "our teardrops" is to achieve more true laminar flow over a greater percentage of the form.
__________________


  Reply With Quote
The Following User Says Thank You to Frank Lee For This Useful Post:
aerohead (03-26-2016)
Old 03-26-2016, 06:20 AM   #1917 (permalink)
Master EcoModder
 
sendler's Avatar
 
Join Date: May 2011
Location: Syracuse, NY USA
Posts: 2,935

Honda CBR250R FI Single - '11 Honda CBR250R
90 day: 105.14 mpg (US)

2001 Honda Insight stick - '01 Honda Insight manual
90 day: 60.68 mpg (US)

2009 Honda Fit auto - '09 Honda Fit Auto
90 day: 38.51 mpg (US)

PCX153 - '13 Honda PCX150
90 day: 104.48 mpg (US)

2015 Yamaha R3 - '15 Yamaha R3
90 day: 80.94 mpg (US)

Ninja650 - '19 Kawasaki Ninja 650
90 day: 72.57 mpg (US)
Thanks: 326
Thanked 1,312 Times in 966 Posts
Quote:
Originally Posted by jjackstone View Post
This is one of my favorite bikes
The EiviE is way more aero but needed a bigger rider.
.
I'm surprised that none of these human powered machine teams ever seem to hire a pro level sprinter or track racer which are able put out more than 2hp for 30 seconds at the end of a grueling 150 mile race.
.
  Reply With Quote
Old 03-26-2016, 09:02 AM   #1918 (permalink)
EcoModding Lurker
 
Join Date: Mar 2015
Location: -
Posts: 30
Thanks: 3
Thanked 12 Times in 11 Posts
Quote:
Originally Posted by sendler View Post
The EiviE is way more aero but needed a bigger rider.
.
I'm surprised that none of these human powered machine teams ever seem to hire a pro level sprinter or track racer which are able put out more than 2hp for 30 seconds at the end of a grueling 150 mile race.
.
Graeme Obree and Jason Queally had tried and failed badly.
Obree had quite amateurish bike. He wanted to win by using prone position which failed.
Queally insisted on spacious interior, so he could produce all his power which killed his drag area.
And Todd is actually better for the task than most pros - because he's a pro trained for top power for 30 seconds w/out a 150 mile race before.

Added:
http://www.recumbents.com/wisil/fastest_list.asp
Queally is a 3 hp engine, yet made 103 km/h. That's 26 below the record at the time.
Obree made 91.

Last edited by gafhj; 03-26-2016 at 01:07 PM..
  Reply With Quote
The Following User Says Thank You to gafhj For This Useful Post:
aerohead (03-26-2016)
Old 03-26-2016, 09:10 AM   #1919 (permalink)
Master EcoModder
 
Join Date: Feb 2010
Location: Elmira, NY
Posts: 1,709
Thanks: 302
Thanked 320 Times in 267 Posts
The shape is similar to the fuselage of high performance sailplanes.
  Reply With Quote
The Following User Says Thank You to Grant-53 For This Useful Post:
aerohead (03-26-2016)
Old 03-26-2016, 01:32 PM   #1920 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 11,674
Thanks: 18,767
Thanked 6,075 Times in 3,720 Posts
pointy nose

Quote:
Originally Posted by sendler View Post
Is the pointy nose really faster than an air foil nose in 90 mph air? Because there is a big draw back in handling side winds when there is that much overhang ahead of the front wheel. And it looks like the shape at the back narrows into a J form too quickly to maintain attachment. Is there a rule as to why the body had to be so short behind the rear wheel?
.
Speed-bikes
.
It looks like it would actually have lower drag in reverse.
.
Aerovelo
.
I agree with all the members who've already mentioned laminar boundary layer bodies.
The Delft team told me that this was the premise for their designs.
Keeping the max cross-section aft held the forebody in a favorable pressure gradient for laminar boundary layer (low skin friction),The turbulent boundary layer transition was held far back on the body,and so much kinetic energy was available in the TBL due to the forebody,that more aggressive curvature in the rear (reduced wetted area ) could maintain attached flow.
This is all predicated upon 'calm' conditions.Once the wind comes up,the body in immersed within Earth's turbulent boundary layer,and the ambient air turbulence kills the laminar boundary layer,especially in a crosswind which contaminates it,forcing an immediate TBL transition.
Keeping the envelope as small as possible (length) helps because it directly affects Reynolds number,of which LBL is directly related.

__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
The Following User Says Thank You to aerohead For This Useful Post:
gafhj (03-27-2016)
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Electric Cars Push Japan Engine Parts Makers to Crisis Mode tjts1 The Lounge 14 12-23-2012 12:47 PM
Name that Eco Car! Quiz: identify these aerodynamic production cars MetroMPG Aerodynamics 16 08-30-2009 05:24 AM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com