Rex;
Underbody air flow is one of those subjects that seem to be lacking much
published data. I've never seen anything quantitive on the subject but
if anyone has run across such data; perhaps they will share it with this
list.
Your comment "Downforce on the sloped nose pushes the CG and car weight
balance forward the faster it goes." is a very important point.
Regards, Neil Tucson, AZ
-----Original Message-----
From: owner-land-speed@autox.team.net
[mailto:owner-land-speed@autox.team.net] On Behalf Of Rex Svoboda
Sent: Thursday, April 21, 2005 10:03 PM
Cc: land-speed-digest@autox.team.net
Subject: Re: land-speed-digest V1 #1879
>Reference: CP CG discussion. To determine a crude center of pressure
for yaw stability on the Mclaren I took a side photo of the car, printed
and scaled it, put it on a drawing board and assigned the side view a
series of geometric shapes. Then I figured the area in each shape and
tried to make sure I had more surface area behind the known CG than in
front of it. Balancing a paper cutout of the sideview is a heck of a lot
easier and more accurate than the way I did it. The top and underbody
fins were added to push the CP rearward from the original design which I
imagine relied on tire traction to assist in keeping the car aimed at
high speed. Downforce on the sloped nose pushes the CG and car weight
balance forward the faster it goes. The car has yawed pretty seriously
in high cross winds under 100 mph (August 2002-the hurricane) but on the
same run it became very stable once it got up to 150 and above. Can
someone continue the conversation with some basics on how un!
derbody air under flat bottomed cars affects CP, especially in yaw?
thanks
>
>
Rex
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