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Old 01-18-2019, 11:11 AM   #8 (permalink)
kach22i
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Quote:
Originally Posted by oldtamiyaphile View Post
Putting them further back is a concession to practicality, they won't scrape as much on driveways etc.
Exactly, and the main point is - not much of a difference from the CFD images I posted.

Don't look for the small differences just yet fastflyer, look for the overall similarities to understand the concepts involved.

EDIT:
Another way to place value/importance to the forces on the chin spoiler with and without splitter relative to it's inboard or outbard distance from the center of vehicle gravity is to reflect upon "moment arms".

https://www.physics.uoguelph.ca/tuto...que.intro.html

Quote:
Imagine pushing a door to open it. The force of your push (F) causes the door to rotate about its hinges (the pivot point, O). How hard you need to push depends on the distance you are from the hinges (r) (and several other things, but let's ignore them now). The closer you are to the hinges (i.e. the smaller r is), the harder it is to push. This is what happens when you try to push open a door on the wrong side. The torque you created on the door is smaller than it would have been had you pushed the correct side (away from its hinges).
I'm just saying that the further out from the center of gravity (C of G) the more the resultant effect.

That is to say, move the same force a little more inboard, and it will not have the same effect, it will be less.

To put your mind at ease, the chin spoiler and or splitter tucked further under the car is going to exert less force because of it's shorter moment arm.

Below is an example of using moment arms to maximize down-force on front and rear axles.

https://www.f1technical.net/forum/vi...16453&start=30


The idea location for down-force on a well balanced car would be at it's center of gravity, but the wing must be much larger because like the door and door hinge example there is a very short moment arm (so more force is needed to get the same net results - work done).

https://www.f1technical.net/forum/vi...16453&start=30


By studying these extreme examples of moment arms in practice you can put in context and properly evaluate the effects of tucking inboard a chin spoiler 6-inches or so.
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1977 Porsche 911s Targa
1998 Chevy S-10 Pick-Up truck
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Chin Spoiler:
http://forums.pelicanparts.com/off-t...effective.html

Rear Spoiler Pick Up Truck
http://forums.pelicanparts.com/off-t...xperiment.html

Roof Wing
http://ecomodder.com/forum/showthrea...1-a-19525.html

Last edited by kach22i; 01-19-2019 at 12:08 PM..
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