Landracing Forum Home
December 15, 2017, 04:56:10 AM *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with username, password and session length
News:
BACK TO LANDRACING.COM HOMEPAGE
 
   Home   Help Search Calendar Login Register  


(Note: Donations are not tax deductible)







Live Audio Streaming and Archives of Past Events
Next Live Event: TBD
Pages: [1] 2   Go Down
  Print  
Author Topic: Article. Bloodhound Team measures flatness of S Africa Dry Lake Bed with lasers.  (Read 3058 times)
0 Members and 1 Guest are viewing this topic.
J79
New folks

Offline Offline

Location: San Francisco Bay Area
Posts: 29




Ignore
« on: May 06, 2016, 07:05:13 PM »

http://www.bbc.com/news/science-environment-34200629
« Last Edit: May 09, 2016, 08:42:58 PM by J79 » Logged

"My, people come and go so quickly here." Dorothy, from the movie Wizard of Oz.

"I have marveled often at the thin line that divides success from failure, and the sudden turn that leads from apparently certain disaster to comparative safety." Ernest Shackleton, Antarctic Explorer, 1874-1922.

From the movie Dr. Strangelove, General Jack D. Ripper:

"Mandrake, in the name of Her Majesty and the Continental Congress come here and feed me this belt boy... Mandrake, come over here, the Red Coats are coming!"

"He said war was too important to be left to the generals. When he said that, 50 years ago, he might have been right. But today, war is too important to be left to politicians. They have neither the time, the training, nor the inclination for strategic thought. I can no longer sit back and allow Communist infiltration, Communist indoctrination, Communist subversion and the international Communist conspiracy to sap and impurify all of our precious "automotive" bodily fluids."
tauruck
Hero Member
*****
Offline Offline

Age: N/A
Location: Johannesburg, South Africa
Posts: 4474





Ignore
« Reply #1 on: May 06, 2016, 09:17:21 PM »

I read the article. Thanks J79.
Questions, questions!!!!!!!
Do I now have to start building a suspension for my liner?. grin
Logged

J79
New folks

Offline Offline

Location: San Francisco Bay Area
Posts: 29




Ignore
« Reply #2 on: May 06, 2016, 10:11:59 PM »

I'd like to see the survey results of most likely to be used lake beds in the US as a comparison, ie Bonneville, Black Rock, Diamond Valley, Alvord. Keep in mind that since we live on a sphere, the earth curves at 8" every mile, so the surface is never perfectly flat.
Logged

"My, people come and go so quickly here." Dorothy, from the movie Wizard of Oz.

"I have marveled often at the thin line that divides success from failure, and the sudden turn that leads from apparently certain disaster to comparative safety." Ernest Shackleton, Antarctic Explorer, 1874-1922.

From the movie Dr. Strangelove, General Jack D. Ripper:

"Mandrake, in the name of Her Majesty and the Continental Congress come here and feed me this belt boy... Mandrake, come over here, the Red Coats are coming!"

"He said war was too important to be left to the generals. When he said that, 50 years ago, he might have been right. But today, war is too important to be left to politicians. They have neither the time, the training, nor the inclination for strategic thought. I can no longer sit back and allow Communist infiltration, Communist indoctrination, Communist subversion and the international Communist conspiracy to sap and impurify all of our precious "automotive" bodily fluids."
wobblywalrus
Hero Member
*****
Offline Offline

Age: 64
Location: backwoods Oregon
Posts: 4472





Ignore
« Reply #3 on: May 08, 2016, 06:25:31 PM »

The day before the accurate survey is needed, you walk the line with and put a 16 oz beer can down every 34 paces (this is 100 feet for most of us.)  Then, early in the morning before the heat waves, you lay on your belly and look down the row of cans.  Some cans will stick up more than others.  This tells the flatness of the route and where corrections need to be made.  All that laser stuff is for folks that have more money than talent.
Logged
WOODY@DDLLC
Hero Member
*****
Offline Offline

Age: 72
Location: Cincinnati
Posts: 1137


It's GONE ......... the Ohio Mile! :-(


WWW

Ignore
« Reply #4 on: May 08, 2016, 07:02:40 PM »

And YOU get to empty the beers the night before!  shocked grin
Logged

All models are wrong, but some are useful! G.E. Box (1967) www.designdreams.biz
will6er
Full Member
***
Offline Offline

Location: Lakewood, CO
Posts: 125





Ignore
« Reply #5 on: May 09, 2016, 03:46:47 PM »

Mickey Thompson addressed the problem of course smoothness.

He wrote, "...the fastest that a shock absorber can work on a two-inch bound and rebound is a very fat fraction of a second. ...If I'm going several hundred feet per second, what earthly difference does it make what the springs and shocks did a thousand feet back? They're just starting to react to a condition that existed long ago and far away. What's the good of suspension if it doesn't know what hit it until it's maybe a quarter mile down the course?" (Challenger: Mickey Thompson's own story of his life of speed.)

Multiply this by a factor of 2 1/2 and it raises more questions about suspension and the course.

Will Willis
#6302
Logged
Dynoroom
Global Moderator
Hero Member
***
Offline Offline

Age: 60
Location: Chino Hills, Ca.
Posts: 1981




« Reply #6 on: May 09, 2016, 06:59:17 PM »

Mickey Thompson addressed the problem of course smoothness.

He wrote, "...the fastest that a shock absorber can work on a two-inch bound and rebound is a very fat fraction of a second. ...If I'm going several hundred feet per second, what earthly difference does it make what the springs and shocks did a thousand feet back? They're just starting to react to a condition that existed long ago and far away. What's the good of suspension if it doesn't know what hit it until it's maybe a quarter mile down the course?" (Challenger: Mickey Thompson's own story of his life of speed.)

Multiply this by a factor of 2 1/2 and it raises more questions about suspension and the course.

Will Willis
#6302

I always love when folks use this quote to validate not using suspension.

The very next land speed record car Mickey Thompson built, Challenger II (the car his son Danny is currently going to try to set the LSR with) has suspension both front & rear. I wonder why?
It must be because his original statement was in error. 

 cheers      smiley


*  (249.53 KB, 1200x737 - viewed 133 times.)
Logged

Michael LeFevers
Kugel and LeFevers Pontiac Firebird

Without Data You're Just Another Guy With An Opinion!

Racing is just a series of "Problem Solving" events that allow you to spend money & make noise...
Seldom Seen Slim
Administrator
Hero Member
***
Offline Offline

Age: 69
Location: Skandia, Michigan
Posts: 11824


Nancy -- 201.913 mph record on a production ZX15!


WWW
« Reply #7 on: May 09, 2016, 08:05:34 PM »

Man-o-man that's a sight for sore eyes.  So was hearing Danny's 406 run a couple of years ago - a sound for starved ears.   grin grin
Logged

Jon E. Wennerberg
 a/k/a Seldom Seen Slim
 Skandia, Michigan
 (that's way up north)
2 Club member x2
Owner of landracing.com
Peter Jack
Hero Member
*****
Offline Offline

Age: 74
Location: Calgary, Alberta
Posts: 3450





Ignore
« Reply #8 on: May 10, 2016, 09:06:09 AM »

I think you're bang on Mark.  cheers cheers cheers

Pete
Logged
manta22
Hero Member
*****
Offline Offline

Age: 79
Location: Tucson, AZ
Posts: 3025


What, me worry?




Ignore
« Reply #9 on: May 10, 2016, 10:34:45 AM »

Mark;

"Could it possibly be because a car without suspension has a "wheel rate" of nearly infinity?   Component and chassis flex "reduce" the rate somewhat.    (Suspension guys, please point out my error if I am wrong here.)"

You need to add in the tire spring rate; the result is not really infinite but it is very high. The whole car will bounce around instead of just the wheels and suspension- tough to control and a very uncomfortable ride!

Regards, Neil  Tucson, AZ
Logged

Regards, Neil  Tucson, AZ
John Burk
Sr. Member
****
Offline Offline

Age: 77
Location: Hainesport , New Jersey
Posts: 624




Ignore
« Reply #10 on: May 10, 2016, 01:25:53 PM »

Tom Burkland's 294 mph Datsun logged rear suspension travel and found .050" travel at high speed . Without light weight wheels and irs suspension seems futile for fast lsr cars .
Logged
manta22
Hero Member
*****
Offline Offline

Age: 79
Location: Tucson, AZ
Posts: 3025


What, me worry?




Ignore
« Reply #11 on: May 10, 2016, 02:51:53 PM »

John;

Effective bump performance in a suspension depends on the sprung/unsprung weight ratio. You're right about needing lightweight wheels- the rest of the unsprung mass (tires, uprights, brake rotors & calipers, part of the suspension control arms, etc) needs to be lightweight, too. Practical considerations usually dictate how light you can go. Of course, a heavy car can get away with heavier sprung components.

Regards, Neil  Tucson, AZ
Logged

Regards, Neil  Tucson, AZ
hotrod
Hero Member
*****
Offline Offline

Posts: 1231


WWW

Ignore
« Reply #12 on: May 10, 2016, 07:55:42 PM »

I suspect a good fraction of the "effective" suspension travel occurs in the tires only, since the wheel inertia, shock absorbers and spring rates does not allow it to accelerate fast enough to follow the surface.

It would be very interesting to see a very fast frame rate video of the tire contact patch of a 200+ mph car at speed with suitable visual markers present to see how much suspension compliance actually is confined to the tires.
Logged

tallguy
Full Member
***
Offline Offline

Location: Northern California
Posts: 157




Ignore
« Reply #13 on: May 11, 2016, 03:10:52 AM »

Craig Breedlove and others have said that when you're going extremely fast,
that little general elevation changes in the ground result in an airborne vehicle
much of the time during the high-speed part of the run -- which, of course,
makes steering pretty iffy.  I think this is one reason that cars will have to
rely on aerodynamics acting on the steered wheel(s), and possibly also on the
fuselage as well.

People who generally aren't car buffs will look at something like the Blue Flame
and say "That's not a car - it's a rocket with wheels."  Well, yeah -- it is a rocket
with wheels.  But it's self-propelled, and carries a driver, and can be steered, and
is not restricted to running on rails like a train.  So the Blue Flame is a car.  Many
folks have trouble thinking outside their ho-hum daily lives.  And it's a rare (but
admired!) breed of person who designs something new and improved, but technically
within the rules.

As speeds increase and it therefore becomes increasingly difficult for the wheels
to stay in contact with the ground, should/can we expect to see these vehicles
designed to purposefully lift the wheels from the ground at speed, and use wings
to support the vehicle, with only some "token wheels" rolling along, and touching
the ground much of the time?  If so, what should the rules be, and how would
they be enforceable?  I'm just extrapolating, folks.  I think we can all agree that
the current (recognized) and recent (recognized) absolute land speed records
were set -- and recognized and accepted, perhaps without much thought given
to the fact that at times, the entire vehicle may have been briefly airborne during
the record-setting runs! 

It may be that there should be a rule that limits the use of hardware or design
intended to intentionally (I know that this is a mushy, hard-to-prove word) lift
the vehicle at high speed.  Or not.  Actually, it may be very nearly impossible
for any land speed car (or bike) to keep any part in continuous contact with
the ground at (say) 600+ mph.  An extreme example would be something that
looks like a jet fighter aircraft flying with the main fuselage just a couple feet
above the ground, and a tiny little wheel (say about 2 inches in diameter?) on
a relatively stiff trailing link, with the wheel touching the ground most of the
time.  Seems silly, don'cha think?  But how can the existing (or future) rules
specifically prohibit this?  Should they?

I suppose that technically we may be able to have enforceable rules that would
allow an official "judge" to measure the marks left on the ground by the wheel(s),
and conclude with reasonable certainty that the wheel(s) were in contact with
the ground for a majority of the measured mile.  But I also don't believe that I
will live long enough to see the day when land speed racing is like this.

I do, however, like to encourage out-of-the-box thinking.  I admire designers,
builders, and racers who are good at it.  This is what keeps progress alive,
thus resulting in new land speed records.  And as we should all know, "records
are made to be broken".

Logged
Peter Jack
Hero Member
*****
Offline Offline

Age: 74
Location: Calgary, Alberta
Posts: 3450





Ignore
« Reply #14 on: May 11, 2016, 05:38:36 AM »

There's always the old "not within the spirit of the rules" which can usually be invoked. That's why it's wise to check with the tech director for the sanctioning body before you try something totally off the wall.

Pete
Logged
Pages: [1] 2   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!


Google visited last this page October 02, 2017, 09:43:49 AM