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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 09-09-2020, 06:19 AM   #41 (permalink)
Long time lurker
 
AeroMcAeroFace's Avatar
 
Join Date: May 2019
Location: Uk
Posts: 218
Thanks: 110
Thanked 153 Times in 119 Posts
Well it did say that the suspension was very soft, and if we assume that the car is actually a wing shape (which it isn't) and it only increases angle of attack a few degrees it isn't impossible to have an increase in lift with virtually no increase in drag.


CLARK Y AIRFOIL (clarky-il)

Click image for larger version

Name:	Clark Y2.JPG
Views:	12
Size:	26.3 KB
ID:	29110

Click image for larger version

Name:	Clark Y.JPG
Views:	14
Size:	24.9 KB
ID:	29109


Last edited by AeroMcAeroFace; 09-09-2020 at 06:25 AM.. Reason: Adding the other picture
  Reply With Quote
The Following 2 Users Say Thank You to AeroMcAeroFace For This Useful Post:
aerohead (09-09-2020), JulianEdgar (09-09-2020)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 09-09-2020, 02:00 PM   #42 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 15,861
Thanks: 23,922
Thanked 7,207 Times in 4,640 Posts
reply

I'll guess, all of the above.
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
Old 09-09-2020, 02:19 PM   #43 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 27,562
Thanks: 7,738
Thanked 8,554 Times in 7,041 Posts
Yay! Someone agrees with me. Sorta...
__________________
.
.
Without freedom of speech we wouldn't know who all the idiots are. -- anonymous poster

____________________
  Reply With Quote
Old 09-09-2020, 02:45 PM   #44 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 15,861
Thanks: 23,922
Thanked 7,207 Times in 4,640 Posts
pic

Quote:
Originally Posted by JulianEdgar View Post
I haven't been able to find a pic but I assume it's fairly flat.
Years ago I found an article online from Elsevier, which covered all the HONDA Dream solar cars,including some which never raced, with 3-views each I think.
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
Old 09-09-2020, 02:45 PM   #45 (permalink)
Master EcoModder
 
kach22i's Avatar
 
Join Date: Jul 2011
Location: Ann Arbor, Michigan
Posts: 4,158
Thanks: 120
Thanked 2,790 Times in 1,959 Posts
Late to the party, I would have guessed lift.

Question is, is too much lift what ever makes the driver white knuckle it and pray to God?

Or is too much lift an actual measurement with corresponding ratio to weight and speed?

I am not a professional sports car driver right at the edge of disaster every lap.

I just wanted my old truck to feel planted at speed leading to less stress, hence the anti-lift devices and treatments.

Good example this Honda solar car is, lift has been a taboo topic in this forum for too long.

Safety first was the motto of a company my father worked at, it was on all the pencils I used as a child. I think it sunk in.
__________________
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
  Reply With Quote
The Following User Says Thank You to kach22i For This Useful Post:
aerohead (09-09-2020)
Old 09-09-2020, 02:51 PM   #46 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 15,861
Thanks: 23,922
Thanked 7,207 Times in 4,640 Posts
'streamlined'

Quote:
Originally Posted by JulianEdgar View Post
Here is the second part of the answer:



So what happens when there is a yaw (crosswind) component to the airflow? Not good things!

The CLf (yellow diamonds) doesn't change much - in fact, it actually improves (gets lower).

But the CLr (black diamonds) increases massively, going positive (into lift) at only about 4-5 degrees of yaw, and then reaching a stunning 0.53 at 15 degrees of yaw. That's the highest CLr I've ever seen.

As a result of that, the overall CL (red squares) goes to well over 0.6(!!) at 15 degrees yaw.

Frontal area of the car was 0.999 square metres and mass was 330kg - I'll let someone else do the maths for the effective weight of the car at 60 km/h - let alone at 15 degrees of yaw and 140 km/h (obviously, in those conditions the car would have been impossible to drive).

So, next time you read someone saying confidently that, well of course, streamlined cars have low lift, you can say: "You're dreaming!".
I'd just want to mention that the Dream is not a 'streamline half-body', something quite different.
The 2013, Cambridge University Eco Racer ,CUER , would be more of an example of a half-body.
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/

Last edited by aerohead; 09-09-2020 at 02:56 PM.. Reason: add data
  Reply With Quote
Old 09-09-2020, 03:38 PM   #47 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 27,562
Thanks: 7,738
Thanked 8,554 Times in 7,041 Posts
Quote:
Originally Posted by kach22i
Good example this Honda solar car is, lift has been a taboo topic in this forum for too long.
I tried. Not the hill I wanted to die on.



duckduckgo.com/?q=jocko%20johnson%20triple%20nickel
__________________
.
.
Without freedom of speech we wouldn't know who all the idiots are. -- anonymous poster

____________________
  Reply With Quote
The Following User Says Thank You to freebeard For This Useful Post:
aerohead (09-09-2020)
Old 09-09-2020, 03:58 PM   #48 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 15,861
Thanks: 23,922
Thanked 7,207 Times in 4,640 Posts
too much lift

Quote:
Originally Posted by kach22i View Post
Late to the party, I would have guessed lift.

Question is, is too much lift what ever makes the driver white knuckle it and pray to God?

Or is too much lift an actual measurement with corresponding ratio to weight and speed?

I am not a professional sports car driver right at the edge of disaster every lap.

I just wanted my old truck to feel planted at speed leading to less stress, hence the anti-lift devices and treatments.

Good example this Honda solar car is, lift has been a taboo topic in this forum for too long.

Safety first was the motto of a company my father worked at, it was on all the pencils I used as a child. I think it sunk in.
If memory serves me, a condition of competing in the World Solar Challenge, is that a vehicle remain safely stable in the presence of the Australian, triple-trailer land train's turbulence and wake, of which the racers will share the road during competition.
If a body doesn't produce lift, longitudinally, it may if it manages to get sideways ( center of pressure issues ).
GM deleted the wheel fairing package on Sunraycer in 1987, due to an associated yawing moment issue for this very reason. Drag went up, from Cd 0.125, to Cd 0.143 or so. They ended up winning anyway. They did a terrific rehearsal for the campaign, providing there own weather reports, knowing when to 'hold' or go balls to the wall.
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
Old 09-09-2020, 05:59 PM   #49 (permalink)
EcoModding Lurcher
 
mort's Avatar
 
Join Date: Dec 2010
Location: Los Angeles
Posts: 333
Thanks: 148
Thanked 109 Times in 80 Posts
Quote:
Originally Posted by AeroMcAeroFace View Post
Well it did say that the suspension was very soft, and if we assume that the car is actually a wing shape (which it isn't) and it only increases angle of attack a few degrees it isn't impossible to have an increase in lift with virtually no increase in drag.
You mean no increase in coefficient of drag,
-m
  Reply With Quote
The Following 2 Users Say Thank You to mort For This Useful Post:
aerohead (09-11-2020), AeroMcAeroFace (09-10-2020)
Old 09-10-2020, 05:55 AM   #50 (permalink)
Long time lurker
 
AeroMcAeroFace's Avatar
 
Join Date: May 2019
Location: Uk
Posts: 218
Thanks: 110
Thanked 153 Times in 119 Posts
"a sudden loss of dynamic stability"

Quote:
Originally Posted by aerohead View Post
I'd just want to mention that the Dream is not a 'streamline half-body', something quite different.
The 2013, Cambridge University Eco Racer ,CUER , would be more of an example of a half-body.
I am not sure if it is the same car but they did have a car crash due to "a sudden loss of dynamic stability" https://www.bbc.co.uk/news/uk-englan...shire-41486526

But seeing as their steering committee doesn't seem to understand aerodynamics at all “A bicycle has one human-horse power (300W), and Mirage has just four [sic] human-horsepowers" "However, my road car needs 1,500 human-horse [sic] powers to get me from A to B" https://www.cambridge-news.co.uk/new...-made-13549820

Yes, I do know that that a steering committee doesn't actually deal with car steering but what sort of road car needs 1500 horsepower?

  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com