If an object is 24 inches wide and the taper is 6 degrees per side I come up
with it being a little over 114 inches long or 9.5 feet. 6 to 7 degrees is
generally accepted as the optimum angle for a land based vehicle for lowest
drag. That is if it is going to end in a point, but generally there is a
chute can and push bar to deal with in the rear so it will come out shorter.
So where is the revelation? I can not figure out how you came up with your
lengths at 8 and 16 degrees either. I think the calculator may need a new
battery. I was doubting my calcs for a minute so I fired up he cad system
and drew the part you described.
For 2 ft wide and an included angle or 16 degrees= 7.12 ft long (rounded)
For 2 ft wide and an included angle or 8 degrees= 14.3 ft long (rounded)
Is there something I am missing here?
I drew the part as a box 12 inches high and 200 inches long.
Rotated one side 1/2 the included angle.
Trimmed where they intersect.
measured the length.
Unfortunately to build a car with the widest section at 24 inches I think
you either need a jockey or a talented 9 year old to drive.
Assuming 1.5 inch roll bar and 0.0625 aluminum body touching the roll
bar..with 1 inch padding on cage..and 0.125 thick seat touching cage
24-3-2-0.125-0.25=18.625 driver area. that is pretty tight when you have to
wear a firesuit and you end up needing someone that is under 18 inches wide
at the shoulders. I would think a minimum shoulder width would end up around
20 inches only because I am not that big a guy and my office chair is 19
inches wide and my shoulders touch at both sides without a firesuit on.
Can't test that don't own one or need one for that matter.
Dave
> -----Original Message-----
> From: owner-land-speed@Autox.Team.Net
> [mailto:owner-land-speed@Autox.Team.Net]On Behalf Of John Burk
> Sent: Friday, January 07, 2005 11:38 PM
> To: land-speed@Autox.Team.Net
> Subject: Aero Revelations
>
>
> While reading my "Theory of Wing Sections" today I found a couple
> of things I
> didn't realize - (1) A streamlined shape that's widest in the
> middle has the
> least drag (always thought the best was fatest at 30% with a more gradual
> taper in the back) - (2) A streamlined shape that's 2 ft wide has
> less drag if
> it's 10 ft long than if it's 20 ft long - Less surface with 16
> deg. taper is
> better than more area and 8 deg. taper - Anybody disagree with
> these things -
> John
|