Random Aerodynamic Oddity of the Day Thread

[Logic]

Originally Posted by Piwoslaw

Supercars and race cars don't prioritise access to the rear hatch, so their exhaust can be anywhere.
It is all about trade-offs: Efficiency for user-friendliness, or whatever...

Trade offs: Quite so!

The S bend required to get the exhaust halfway up the trunk without impinging on trunk space would stifle flow.
Then there's water buildup when the steam/vapour in the exhaust condenses before exiting in cold climates.
All making it more suitable to / used by fast race and rally cars.

Or would it?
This 'Vortex Creation' is an interesting way of doing a very sharp S bend!
And spreading/slowing the flow out over a larger area.

https://www.youtube.com/watch?v=5BXyD_spzRw

"...air flows up into two horizontal cylindrical ducts, inducing a vortex in each. This creates a negative pressure gradient that actually helps suck more air into the duct (one of the secrets of the Dyson vacuum). The shape of the duct also helps keep airflow attached to the sides as the round duct transitions to meet the rectangular radiator. This ensures that every square millimeter of the heat exchanger gets blasted with cooling air..."
https://www.motortrend.com/news/2022...gn-aero-tricks

This would take a better look at that duct and AeroShaper or similar software and someone good at using it!
We do have augers that might 'insure' spiral flow.

I don't know how well it will work on an exhaust, but worth considering, just for the joy of it..

[freebeard]

This 'Vortex Creation' is an interesting way of doing a very sharp S bend!

Did you know that gray's garage is an inactive Ecomodderer? But the mods had disappeared him by 2024: .com/forum/showthread.php/interesting-video-lucid-air-aerodynamics-efficiency-41580.html

He was doing really interesting experiments in a water tunnel using hydrogen bubbles instead of smoke.

Even slowmover, who was banned, has posts still available. When Old Mech exited his posts were renamed to User Removed and his posts are available.

[cRiPpLe_rOoStEr]

Originally Posted by freebeard

Both. A rear mounted turbocharger has an exhaust system running to the back and an air duct back to the front. The exhaust energy would substitute for the driveshaft in the example.

Ducting in a way which could generate some actual thrust might be somewhat challenging. But not a bad idea at all.

[freebeard]

Those lowriders with their flamethrower exhaust would totally lose it.

If anyone could do it -- Integza

[freebeard]

A survey of un-produced prototypes, centered on the MAZ-2000

MAZ-2000 Perestroika — The Soviet Truck from the Future

The modular configutation is at ?t=510

The Faegol is at ?t=975

[Logic]

1938 Killinger & Freund: The Motorcycle That Hid Its Engine in the Front Wheel

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

[freebeard]

Did they ever make a two wheel drive version?

Better yet a reverse tadpole with the front wheels on leading arms like the Spinners in Blade Runner.

[freebeard]

Speaking of annoying narrators, he did this one on the Majestic:

1929 Majestic: The Motorcycle That Thought It Was a Car From the Future

Art Deco logo at ?t=167
Spherical ball joint on a sliding pillar at ?t=186
Alligator crackle finish at ?t=213

He assert about ten in existence. I scrubbed the time-line and it appears to include all of them, my favorite at ?t=397 in green and cream two tone with the braced luggage rack and mesh engine cover.

[cRiPpLe_rOoStEr]

Makes me wonder how much more different it would be switching from RWD to FWD on motorcycles. When it comes to cars, sure there is a noticeable difference under certain circumstances, but it doesn't seem so extreme under normal driving conditions.

[freebeard]

That's an interesting question. The answer is 'precession'

Physics Stack Exchange
What determines the direction of precession of a gyroscope?
The right hand rule is OK only for decelerating gyros. Say a horizontal disc spins clockwise as seen from above & observer viewing west edge pushes it down: For first 180 degrees average precession lowers north edge of disc but raises it for the next half turn. At constant rotation rate, north edge is back

Hold a spinning bicycle wheel and try to turn it left and right. It will respond by precessing the force 90 degrees and trying to overturn.

And it depends on whether your speeding up or slowing down which way you fall, apparently.