Old cars tested in modern wind tunnels

[Piotrsko]

Firstly, mechanical gauges with associated frictions and calibration points centered around expected norms. When you measure stuff you want to use centered gauges, but sometimes !SURPRISE! The measurement equipment is in the lower or upper third where it is suspect.

A close analogy is the computer sim data used today where it accurately predicts what something will do based on on observed mathematical algorithms which may or may not be correct or accurate

[Cd]

FINALLY!! Production 1969 Dodge Charger Daytona in a wind tunnel

1969 Charger Daytona STOCK tested at .37 Cd

[Cd]

Has anyone retested a Panhard LM64 ?
Even if several counts off, that car has to be one of the sleekest cars I have seen.
Point twelve Cd ???

[JulianEdgar]

Originally Posted by Cd

Has anyone retested a Panhard LM64 ?
Even if several counts off, that car has to be one of the sleekest cars I have seen.
Point twelve Cd ???

Yes, it's a gorgeous looking car. I don't think it's been tested in a modern wind tunnel.

[freebeard]

I see some commonality with the Volkhart-Sagitta and this Ford Special:


https://www.uniquecarsandparts.com.a...ks_steamlining


Pontooned front fenders and a 'templatey' cabin, with special care in the A-pillar area.

[orange4boy]

Probably obvious to everyone here but just a reminder of what a huge influence wheels and their wheel wells have on drag. Everyone looks at the profile but the wheels represent a huge portion of drag. You can have a great profile but if the wheels are badly dealt with, a crap CD.

[JulianEdgar]

Originally Posted by orange4boy

Probably obvious to everyone here but just a reminder of what a huge influence wheels and their wheel wells have on drag. Everyone looks at the profile but the wheels represent a huge portion of drag. You can have a great profile but if the wheels are badly dealt with, a crap CD.

Yes, absolutely.

But don't forget to ask Aerohead about his opinion that rotating wheels and moving floors in wind tunnels make no difference to measured drag values...

Another of his theories in conflict with all current aero tech literature.

[freebeard]

You can have a great profile but if the wheels are badly dealt with, a crap CD.

Cd is one aspect of any use case.



See also Tropfenwagen.

[aerohead]

Originally Posted by JulianEdgar

Yes, absolutely.

But don't forget to ask Aerohead about his opinion that rotating wheels and moving floors in wind tunnels make no difference to measured drag values...

Another of his theories in conflict with all current aero tech literature.

At the moment, my opinion is that, since research on rotating wheels has demonstrated one phenomena in one wind tunnel, and the opposite in another, that , NO ' all current aero tech' consensus exists within the aerodynamic community, with respect to predicting what one might experience given any specific vehicle.
The burden of proof to prove otherwise falls on Julian Edgar.
Which brings us back to MetroMPG's admonition about limiting any claim with respect to a case-specific basis.

[JulianEdgar]

Originally Posted by aerohead

At the moment, my opinion is that, since research on rotating wheels has demonstrated one phenomena in one wind tunnel, and the opposite in another, that , NO ' all current aero tech' consensus exists within the aerodynamic community, with respect to predicting what one might experience given any specific vehicle.
The burden of proof to prove otherwise falls on Julian Edgar.
Which brings us back to MetroMPG's admonition about limiting any claim with respect to a case-specific basis.

Aerodynamics of Road Vehicles 5th edition shows different drag and lift figures, as measured in wind tunnels, with/without wheel rotation. Interestingly, when I looked closely, the results weren't always worse with wheel rotation - but they certainly were different.