2/25/08 "semi" update!

[Derwin]

Here is the "semi" update from Ian:

Don't fret guys -- I'm cool. Sorry for the radio silence, but there's been a lot happing here. Crazy busy, but it's all good. We're also in the middle of our aerodynamic analysis of the vehicle bodies:
http://www.flytheroadclub.com/forums/attachment.php?attachmentid=228&stc=1&d=1203959002
More on that later. We have our regular Monday department head meeting later this morning, and I'll report back here after that. Cheers,
-- Ian

Above was posted by Ian on 2/25/08

Derwin

[Miracleman89]

Dang it! Now, I have to read up on wind tunnel testing, so I can understand what all this means!:confused:

[WarpedOne]

Basics are not that hard. Those lines are pathways of air traveling along and behind the object = car. It is good when those lines are generaly parallel (laminar) and bad when they start twisting and behaving sporadic (turbulences). It is impossible to have no turbulences with useful body shapes but with different design solutions there are ways to decrease their magnitude and move them towards the end of the object - later they start, less drag they will create.

Colors show pressure buildups and dropoffs relative to normal air pressure. Here blue shows lower than normal (depression) and red shows higher then normal (compression) areas. Higher pressure differences cause more turbulences and drag and vice versa. To complicate matters some more, all this laminal and turbulent air paths are very dependant on speed so you have to decide for what speed range you are designing and optimizing.

The profile on this picture is very good. There are almost no turbulences along the car meaning very low wind noise levels and very low air drag. It would be possible to improve the flow at the back but gains would be minimal and costs high - much less useful space, strange looks ...

Airprofile of a classic motorcycle is much much worse.

AERODYNAMICS (http://www.tonyfoale.com/Articles/Aerodynamics/AERO.htm)
Wind Tunnel : Hayabusa vs. ZX-12R (http://www.qsl.net/n5mya/aero.html)
Motorscooter Aerodynamics (http://www.fluent.com/about/news/newsletters/02v11i2/a6.htm)