[TheForge] the solid forged aluminum wheels for the supersonic car.

[jerry Frost]

No, you can't have something mud flaps on a super sonic vehicle. Things as
minimal as smudges on the skin or windscreen of super sonic aircraft can
cost them surprisingly significant speed. Then you have the problem of
keeping something so UN aerodynamic attached. I used to think the force from
wind was geometric but it's (DARN I lost the term!) it's NOT the square of
the velocity it's the cube of the velocity. So doubling the speed multiplies
the force by the by the power of 3. 

Yeah, I talk experts to and read about wind generation for a number of
ideas, been thinking about it for decades. One of the guys who takes
competitive dog sport classes where Deb teaches holds a pHD. in physics and
designs wind turbines. We've had some interesting conversations. He's who
clued me to the "cube of the velocity," reality of wind power.

I skimmed the site and they didn't say where they were making the attempt
but the one photo of it looks a lot like Bonneville Salt flats. If so the
tires/wheels will be kicking up salt grains so as an average estimate figure
1gm. x 1,000mph. impacts x Oh I don't know a few hundred to maybe a couple
thousand per second.

You can damage steel with walnut shell blast media if you hit it in one spot
too long and that's moving at maybe 300-350mph.

Were I designing the project I'd wind tunnel testing two main anti salt
blasting my car to pieces at stupid fast velocities.: First would be a
redirected air flow around the front tires that air blasted the grit off and
away from the tires and car's under body. Second would be super slippery
Rhino liner type plastic grit shield behind the front wheels, probably the
full length of the car to take into account ricocheted off the under body
and salt flats. Any debris will be bouncing between the two maybe a couple
times before the car is past.

I also used to talk to land speed guys, one lived three housed up the street
from us when I was a kid. He used to let us hand him tools when he was
working on his Laker a speed racer intended for dry lake racing. We used to
go to all the MTA (Mojave, Timing Association) events on El Mirage dry lake.
That's a few miles from Edwards Airforce base on Groom Lake. I never made a
speed trial at Bonneville though. <sigh> Been to the salt flats, it's gritty
but flat as a fritter.

The aerodynamics on a streamliner at 500 mph. is significant. A racer that
gets airborne at that speed usually disintegrates, literally gets pealed
like an orange by the wind. A tire blowing at speed is just like a bomb
going off the one time that happened when we were there was a fatal wreck. I
don't think there was anything but pieces of the guy left, the car was blown
to small pieces. He was doing a tune up run on his Bonneville car and lost
it at near 600 mph.

Wow, that turned into a long ramble didn't it. Short answer is no mud flaps
won't work.

Frosty

-----Original Message-----
From: TheForge [mailto:theforge-bounces at mailman.qth.net] On Behalf Of Bruce
.
Sent: Wednesday, May 20, 2015 6:26 AM
To: terry l. ridder; Blacksmithing List Sponsored by ABANA
Subject: Re: [TheForge] the solid forged aluminium wheels for the supersonic
car.

I wonder whether these designer dudes ever heard of mud flaps.  Seems to me
that's only the simplest way to keep grit kicked up by front wheels from
hitting the back.  Other ideas come to mind as well.

Bruce
NJ