10-20-2020, 07:17 AM
|
#3591 (permalink)
|
Long time lurker
Join Date: May 2019
Location: Uk
Posts: 218
Thanks: 110
Thanked 153 Times in 119 Posts
|
Why does the mass location not make any difference? Would the car be as likely to tip in cross winds if the mass was concentrated 100 feet in the air? Maybe resistance to sliding, turning or being a weather vane is related to total mass but I don't understand how the mass being lower wouldn't improve crosswind tipping resistance.
If the mass was infinitely high it would be an inverted pendulum and any breeze would topple it over.
|
|
|
Today
|
|
|
Other popular topics in this forum...
|
|
|
10-20-2020, 07:25 AM
|
#3592 (permalink)
|
EcoModding Apprentice
Join Date: May 2008
Location: N. Saskatchewan, CA
Posts: 1,805
Thanks: 91
Thanked 459 Times in 327 Posts
|
Quote:
Originally Posted by AeroMcAeroFace
Why does the mass location not make any difference? Would the car be as likely to tip in cross winds if the mass was concentrated 100 feet in the air? Maybe resistance to sliding, turning or being a weather vane is related to total mass but I don't understand how the mass being lower wouldn't improve crosswind tipping resistance.
If the mass was infinitely high it would be an inverted pendulum and any breeze would topple it over.
|
If the mass were very high, it would take the centre of pressure up with it in any realistic visualization. However, the mass itself will always be acting straight down, and as long as the road is level and straight, will have the same effect.
__________________
There is no excuse for a land vehicle to weigh more than its average payload.
|
|
|
10-20-2020, 12:32 PM
|
#3593 (permalink)
|
Master EcoModder
Join Date: Aug 2012
Location: northwest of normal
Posts: 27,659
Thanks: 7,765
Thanked 8,575 Times in 7,061 Posts
|
Quote:
That VW has a gurney flap on the diffuser, is that for diffuser function or air flowing over the top of the diffuser? Has anyone seen any evidence for this or heard of it before?
|
At 4:00 — "It extends the effective length, apparently."
The postal truck has a central peak. How does that affect crosswind performance?
__________________
.
.Without freedom of speech we wouldn't know who all the idiots are. -- anonymous poster
____________________
.
."We're deeply sorry." -- Pfizer
|
|
|
The Following User Says Thank You to freebeard For This Useful Post:
|
|
10-21-2020, 10:07 AM
|
#3594 (permalink)
|
Master EcoModder
Join Date: Jul 2011
Location: Ann Arbor, Michigan
Posts: 4,158
Thanks: 120
Thanked 2,790 Times in 1,959 Posts
|
|
|
|
The Following User Says Thank You to kach22i For This Useful Post:
|
|
10-21-2020, 12:57 PM
|
#3595 (permalink)
|
Master EcoModder
Join Date: Jul 2011
Location: Ann Arbor, Michigan
Posts: 4,158
Thanks: 120
Thanked 2,790 Times in 1,959 Posts
|
Cool scale model.
AutoCult 1/43 Audi Front UW8/40PS Jayray 04026
https://houseofhobbies.com/products/...s-jayray-04026
|
|
|
The Following User Says Thank You to kach22i For This Useful Post:
|
|
10-21-2020, 01:08 PM
|
#3596 (permalink)
|
Master EcoModder
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 15,883
Thanks: 23,957
Thanked 7,219 Times in 4,646 Posts
|
Gurney flap
Quote:
Originally Posted by AeroMcAeroFace
I wouldn't fancy driving that delivery vehicle over a windy bridge, you would hope it has a low centre of mass so it doesn't tip over.
That VW has a gurney flap on the diffuser, is that for diffuser function or air flowing over the top of the diffuser? Has anyone seen any evidence for this or heard of it before?
|
I'd like the guy to expand on his thesis.
The original 1971 Gurney flap was intended for undisturbed, upper body flow.
Embedded within the wake, as it's shown, perhaps it's isolating the diffuser effect from the wake turbulence enough to marginally amplify the downforce. A direct explanation is always better than a guess. Especially mine.
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
|
|
|
10-21-2020, 02:39 PM
|
#3597 (permalink)
|
Master EcoModder
Join Date: Aug 2012
Location: northwest of normal
Posts: 27,659
Thanks: 7,765
Thanked 8,575 Times in 7,061 Posts
|
Quote:
A direct explanation is always better than a guess. Especially mine.
|
I think we're all bozos on this bus.
I see it as a localized feature at the interface between the (more or less stagnant) wake and fast-moving air. In this case the fast moving air is in the diffuser. I wonder why it isn't inverted. It would be easy enough to test both orientations.
__________________
.
.Without freedom of speech we wouldn't know who all the idiots are. -- anonymous poster
____________________
.
."We're deeply sorry." -- Pfizer
|
|
|
The Following User Says Thank You to freebeard For This Useful Post:
|
|
10-22-2020, 10:22 AM
|
#3598 (permalink)
|
Master EcoModder
Join Date: Jul 2011
Location: Ann Arbor, Michigan
Posts: 4,158
Thanks: 120
Thanked 2,790 Times in 1,959 Posts
|
https://myautoworld.com/gm/history/c...tte1-57ss.html
Quote:
The science of aerodynamics has progressed since the days when GM engineers conducted airflow tests with tufts of yarn taped to Zora Arkus-Duntov's 1957 Corvette SS.
|
|
|
|
10-22-2020, 11:10 AM
|
#3599 (permalink)
|
Master EcoModder
Join Date: Jun 2011
Location: Earth
Posts: 604
Thanks: 27
Thanked 145 Times in 113 Posts
|
Eco-Runner X:
|
|
|
The Following User Says Thank You to sgtlethargic For This Useful Post:
|
|
10-22-2020, 12:25 PM
|
#3600 (permalink)
|
EcoModding Apprentice
Join Date: May 2008
Location: N. Saskatchewan, CA
Posts: 1,805
Thanks: 91
Thanked 459 Times in 327 Posts
|
Quote:
Originally Posted by sgtlethargic
Eco-Runner X:
|
It is amazing how many sponsors don't mind looking 70 years out of date.
__________________
There is no excuse for a land vehicle to weigh more than its average payload.
|
|
|
|