Quote:
Originally Posted by Christ
Uh-Uh.
It's literally better for the air to form it's own bubble in front of the flat nose of the CoE truck, because there is more skin friction and shape induced drag for the same surface area on the extended nose trucks.
When the airflow "hits" the cab nose at highway speed, there becomes a bubble effect on the CoE trucks that displaces air further ahead of the cab due to air spoiling at the nose, creating it's own "teardrop-ish" shape.
The extended nose design could have something in it's favor if it were actually shaped to divert airflow from the smaller nose up over the cab and around the widest points without having to make contact with them, though.
Watching the teardrop shape, we understand that nose extensions are only necessary to an extent ahead of the primary body, and the angles at which they direct flow can be very steep compared to tail angles.
I'm trying to find a virtual image of the bubble that forms in front of a CoE in a wind tunnel, but I'm not having any luck.
Also, I found this post here:
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When neither gets aerodynamic treatment like radiused edges, I think it makes sense that the conventional would be more aerodynamic than the cabover. The flat front COE might have a bubble, but the conventional has a smaller bubble, then another bubble forming a ramp between the hood and the windshield.