Laminar Flow Separation

[interested bystander]

Hey, Franklin, ANYBODY who has been around Land Speed Racing for a week knows all the this stuff- Don't clutter up this FANTASTIC website with your DRIVEL.

Let me suggest you RESPOND with your, at times, questionable, but sometimes informative, knowledge, to subjects, rather than initiate all of this stuff.

Your signing on reminds me of what I had to go thru before my recent colonoscopy, except you've just consumed four liters of Land Racing bowel cleaner!

Be careful, or I'll post photos of the PROPSTER on the construction portion!

Sorry, SSS!

[Ratliff]

Hey, Franklin, ANYBODY who has been around Land Speed Racing for a week knows all the this stuff- Don't clutter up this FANTASTIC website with your DRIVEL.

Let me suggest you RESPOND with your, at times, questionable, but sometimes informative, knowledge, to subjects, rather than initiate all of this stuff.

Your signing on reminds me of what I had to go thru before my recent colonoscopy, except you've just consumed four liters of Land Racing bowel cleaner!

Be careful, or I'll post photos of the PROPSTER on the construction portion!

Sorry, SSS!

If this is so easy to learn, why are there still cars at Speedweek and El Mirage with aerodynamics that are little advanced beyond the White Triplex?

[Harold Bettes]

Blue et al,

It is unfortunate that everything you said passed over the filter of the person's deluded ego. 

No, air hasn't changed, but the understanding of its actions and reactions have changed and thus the improvements in all sorts of technology applications.

I know a fair shade about fluids and engines and even with that knowledge I am positive that I really don't know very much at all. I was taught that is one mark of an educated person.

No, air hasn't changed since the first wind tunnel experiments of the Wrights in 1896 but a whole lot has changed in understanding how to measure and what to measure and what to apply and what to IGNORE. The Navier-Stokes equations haven't changed either, but we have a much better handle on the solutions than even 10 years ago. The process is called LEARNING.

Regards to All,
Resolute in Colorado
HB2

Yeah OK Slim I will smack myself with a wet noodle and will refrain from further outbursts. At least I will try.

[Stan Back]

They're call roadsters -- and they fit a whole different set of rules.

[Ratliff]

They're call roadsters -- and they fit a whole different set of rules.

No, they're called Top Fuel style lakesters.

[interested bystander]

That White-Triplex spin looks a lot like journeyman Fuel Altered pilot (The Rat Trap) Ron Hope's annual (to this day) spin on the Salt with the family roadster.

Sorry, Ron!

[Ratliff]

That White-Triplex spin looks a lot like journeyman Fuel Altered pilot (The Rat Trap) Ron Hope's annual (to this day) spin on the Salt with the family roadster.

Sorry, Ron!

Hey, somebody has got to maintain tradition.

[Blue]

Blue et al,

It is unfortunate that everything you said passed over the filter of the person's deluded ego. 

No, air hasn't changed, but the understanding of its actions and reactions have changed and thus the improvements in all sorts of technology applications.

I know a fair shade about fluids and engines and even with that knowledge I am positive that I really don't know very much at all. I was taught that is one mark of an educated person.

No, air hasn't changed since the first wind tunnel experiments of the Wrights in 1896 but a whole lot has changed in understanding how to measure and what to measure and what to apply and what to IGNORE. The Navier-Stokes equations haven't changed either, but we have a much better handle on the solutions than even 10 years ago. The process is called LEARNING.

Regards to All,
Resolute in Colorado
HB2

Yeah OK Slim I will smack myself with a wet noodle and will refrain from further outbursts. At least I will try.

Actually H, you and anyone else can take my comments for whatever you think they are worth or ignore them.  If you find them worthwhile, great.

[Ratliff]

Given a fixed volume of engine, drive system, fuel, and warhead, practical torpedoes were tested at less than 1/4th the drag of the long shape we are all familiar with.

Do you think the short and fat shapes, with higher frontal area but reduced skin surface area, could have practical application to LSR vehicles?

Having designed both Sir Malcolm Campbell's last Bluebird and John Cobb's streamliner, Reid Railton went from the first 300 mph car to the first 400 mph car in one shot. (However, it did take Railton two design iterations [1933 and 1935] to get Bluebird to go 300 mph. Bluebird used the Rolls-Royce R Type, the same engine used the Schneider trophy Supermarine seaplane that set a record of 407 mph in 1931.)

Cobb's car, built in the mid-thirties, was driven 403.10 mph one-way in 1947 while setting his 394 mph record (apparently, according to Cole Coonce's book "Infinity Over Zero", with help from a healthy dose of nitromethane).

Below are links to photos of Cobb's car.

http://www.motoringpicturelibrary.com/docs/2004-P-2558picc.jpg

http://www.edlhs.co.uk/Images/John%20Cobb's%20Railton%20at%2075dpi.jpg

http://historyforkids.utah.gov/fun_and_games/photos/images/beforecolorfilm/large/Railton_1.jpg

http://www.landspeed.com/images/History/railton.jpg

[Dynoroom]

Thank you for the links, much easier for my system to work with.

[Ratliff]

The article is an excellent example of why old references are limited.  Research from the early 60's showed that many minimum drag shapes were possible that achieved frontal area Cd's of less than half of what was quoted in this old book.  The research then shifted to volumetric drag coefficients, i.e. total drag vs. volume.  The work was funded by the Navy and started with towed mine detectors and later shifted to torpedoes. 

Given a fixed volume of engine, drive system, fuel, and warhead, practical torpedoes were tested at less than 1/4th the drag of the long shape we are all familiar with.  Speed and range surpassed the ability of the sonar to handle the flow noise, and the shapes required total redesign of the torpedo rooms and submarine architecture.  Therefore, these shapes were not adopted.

Since the 60's a great deal of R&D and testing has driven the minimum drag of some production air vehicles closer and closer to the theoretical minimum frontal area Cd of less than .02 vs. min drag Reynolds number.

While I have already been chastised for saying something mean about our over-zealous librarian, The difficulty I have with the last several posts is simply that they are nothing more than a huge volume of out-of-date reference material.  A HALF CENTURY of progress makes 100% of that article obsolete.  I appreciate that the poster is trying to be helpful, but he is not an aerodynamicist and the article creates nothing but misunderstanding of current knowledge and the perpetuation of 50-year old myths.

One might as well read about "the ether" that radio waves and light were supposed to propagate through.  We know better now, and accurate understanding takes no more than a high school physics understanding as long as the explanation is from our current knowledge base.

http://www.metro.co.uk/news/article.html?in_article_id=164536&in_page_id=34

(From www.steamcar.co.uk ) "Aerodynamic Drag increases as a square of the velocity. What this means is that any object traveling through the air at 100 MPH has four times as much drag as it does traveling at 50 MPH. Ultimately, the amount of power needed to drive a vehicle is determined by the rolling resistance of the vehicles tyres and the aerodynamic drag of the vehicle. The drag is a result of the shape of the car so a great deal of attention is given to the “appearance”.

Part of the result of the Masters thesis project that was conducted at Southampton University included creating an aerodynamically efficient shape to reduce the amount of energy lost to drag. That shape is known at the “Morelli” shape and it is extremely efficient for a traditional 4-wheeled automobile.

While the Morelli shape is the most aerodynamically desirable, it does not lend itself to some practical realities of the project.

When the team realized the size of the boilers that would produce the amount of steam required as well as some of the other operating parameters (driver size not withstanding) the overall shape had to change.

So, while the overall concept of the project has been retained with much of the overall shape intact, some substantial changes were necessary. However, the aerodynamic goal of a Coefficient of Drag (Cd) of 0.2 is still within the grasp of the project."