Interesting Aerodynamic Cars (Mike Vetter's ETV, also Avion)

[bandit86]

This thing is interesting...
https://www.facebook.com/share/1ExDssWJ6Z/

[kach22i]

Originally Posted by bandit86

This thing is interesting...
https://www.facebook.com/share/1ExDssWJ6Z/

Freebeard don't do Facebook, so I'll post this for him.

Class A RV, '69 Dodge Travco 210
https://www.facebook.com/marketplace...F1ExDssWJ6Z%2F

Class A RV, '69 Dodge Travco 210
I had a vision in my head... and I made it real.
It's one of a kind. A head-turner, a neck-breaker. Do you want to own one of the most beautiful and unique motorhomes in the world?
This is a fully restored 1969 Dodge Travco 210 (21 feet) inside and out.
Almost the entire exterior is new.
Almost the entire living area is modern and new.
Outside:
-Beautiful new painjob, black over orange to give this motorhome a hotrod and muscle car look.
-All LED lighting (most tinted black)
-New cargo doors all around
-New outdoor shower
I'm limited on text, so I'll send you the rest by writing. I'm inundated with messages, very, very serious people only. No suckers, no congratulations, no exchanges please, it's too much to handle, thank you!

[kach22i]

Optimizing a Tail for Low Drag: Part 4
June 17, 2024
https://www.amateuraerodynamics.com/...ag-part-4.html

[kach22i]

https://forums.pelicanparts.com/off-...ures-2805.html


1983 Rondeau M482
https://rmsothebys.com/auctions/lm23...-rondeau-m482/

Designed jointly by chassis expert Don Foster and aerodynamicist Max Sardou, the M482 was the first Rondeau to have been conceived specifically as a Group C car. It represented the company’s first foray into both monocoque design and ground effect technology. Its twin-Venturi tunnels—incorporating lessons learned from Sardou’s earlier Lola T600 design—necessitated an outlandish “triple sponson” rear bodywork section. A long-stroke 3.9-litre Ford DFV engine operated as a stressed unit in conjunction with a five-speed Hewland VG5 gearbox, while double-wishbone suspension was employed conventionally at the front and via rocker arms at the rear.

https://www.lastdodo.com/en/items/23...-ford-cosworth

[freebeard]

kach22i --Thanx. I was curious but didn't rant about it.


Imagine this with boxer four cylinder heads sticking out of the central sponson.

[aerohead]

Dr. Hermann Burst might have recommended that you respect the tearing edge of the Prius' rear spoiler, and do the elongation off that location, leaving a subtle 'notch' in the contour.
The 'streamlined-looking' roof contour of the 2011 Audi A7 suffered premature flow separation and rear lift on account of the super-deceleration of it's backlight architecture, forcing VW to add a rear spoiler, as with their Audi TT, Porsche 911, others.
Tufting often will often not reveal attached longitudinal trailing vortices, inducing a downwash, mistaken for 'attached flow.'

[Vman455]

Originally Posted by aerohead

Dr. Hermann Burst might have recommended that you respect the tearing edge of the Prius' rear spoiler, and do the elongation off that location, leaving a subtle 'notch' in the contour.
The 'streamlined-looking' roof contour of the 2011 Audi A7 suffered premature flow separation and rear lift on account of the super-deceleration of it's backlight architecture, forcing VW to add a rear spoiler, as with their Audi TT, Porsche 911, others.
Tufting often will often not reveal attached longitudinal trailing vortices, inducing a downwash, mistaken for 'attached flow.'

*sigh* It really is true what they say: When your only tool is a hammer, every problem is a nail.

For everyone else, what aerohead is referring to here (and brings up seemingly every time someone posts an image of attached tufts over a sloped rear) is the well-known phenomenon, first identified at VW in the 1970s and later characterized by slant-angle studies on the Ahmed body, of high drag resulting from trailing edge vortex downwash similar to the effect of wingtip vortices. You can read Hucho's excellent summary of the phenomenon here (use Google translate if your German isn't up to speed, it gets it mostly correct).

The way to avoid this is to use multiple measurement techniques to ensure you aren't getting the strongly negative pressure and increase in drag that indicates vortex downwash is a problem. If you click through and read my series of posts, you will see that I did not just tape tufts to the extension; I measured pressures on it and the base of the car under it, both with and without the small flat spoiler:





Additionally, I coast down tested the car with and without the extension:



The change in acceleration--which is the slope of each line--indicates a reduction in drag of 6-7% with the extension in place (note that this calculation includes the modeled rolling resistance so it is not simply the difference in acceleration. You can find the derivation here).

[freebeard]

...high drag resulting from trailing edge vortex downwash similar to the effect of wingtip vortices.

A phenomenon exploited by two of my favorite car designs, the VW Beetle (in the 1930s), and the Cybertruck (in the 2010s).

So in Aerospace Engineering if the line goes down and to the right that's not deceleration?

What do you think half the extension length would obtain?

A two piece boxed cavity with a hinge line at the roof of a diffuser, so that the upper portion could swing back to let the hatch open?

[RedDevil]

One unique car with features well ahead of its time:
https://en.wikipedia.org/wiki/Leichtbau_Maier

The car had a full metal unibody construction, a headlamp that pointed with the wheels, fenders flush with the body and some other novelties, all patented by the inventor Friedrich Eugen Maier in 1934.





Sadly, instead of getting rich as everyone was using his patented inventions he got nothing. He could barely keep the remains of the car he built (it was destroyed in the 2nd world war).

When he died in 1976 the car was sold to a film production company, then passed hands several times until it was bought by its current owner who restored it, but kept the VW beetle engine which the film company put in it as its original DKW ewgine was defunct.

https://www.youtube.com/watch?v=BEsXOCta_hw

[freebeard]

What's that hanging down between the front wheels and does it still work when it's been bent backwards?

New term of art: "cat ladder".

Weren't DKW front-wheel drive?