Random Aerodynamic Oddity of the Day Thread

[freebeard]

Front fender cove, like the 1956 Corvette.

I like the roof line, the black windshield frame and the magnesium panel at the header. The black over red two tone reminds me of the old Karmann Ghias.

[kach22i]

https://forums.pelicanparts.com/off-...l#post12639997

[kach22i]

https://www.topgear.com.ph/features/...ncy-experiment


To be fair, the bilao was used as a template for sheet rubber.

Aerodynamic buffs often refer to the idealized teardrop-shaped template as one that provides the least drag. The template above comes from a 1930s aerodynamics study, and is shared online by noted aerodynamics enthusiast Phil Knox. Some of his work can be seen here.

[kach22i]

https://forums.pelicanparts.com/off-...l#post12649315

[kach22i]

https://forums.pelicanparts.com/off-...l#post12649315

[Logic]

https://scientificgems.wordpress.com...ins-and-stuff/

https://delftsolarteam.com/legacy/nuna-13

NB the Dorsal Fins!
Those turn into the wind, with a bit of 'attack angle', creating forward thrust.


What AI has to say about a fin 2m high (well below max legal height), with a chord that decreases from 1m to 0.5m at the top:

Rough Force Estimates (Physics-Based)
Using standard airfoil equations (½ ρ V² × Area × Coefficient), with a decent airfoil (Cl ≈ 1.0 at moderate AoA, Cd ≈ 0.08–0.12 → L/D around 10:1).

At stationary car, 25 km/h pure crosswind (typical breezy day in windy areas):
Forward thrust (from lift component): ~35–50 N (~3.5–5 kg force)
Sideways force: ~80–120 N (~8–12 kg force) — still higher due to vector geometry, but not overwhelmingly so with a good wing.

At 40 km/h car speed + 25 km/h crosswind (common mixed condition):
Apparent wind improves → forward thrust rises to ~80–130 N (8 to 13 kg) range, with better forward/side ratio.

At 80 km/h car speed + 25 km/h crosswind:
Forward thrust can reach 200–350+ N (20 to 35+ kg) in good angles — that's genuinely useful (several percent of total drag on a small hatchback).