Landracing Forum Home
October 23, 2017, 03:54:39 PM *
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 [3]   Go Down
  Print  
Author Topic: Hp needed for % of Speed Increase  (Read 16898 times)
0 Members and 2 Guests are viewing this topic.
SHughes
New folks

Offline Offline

Age: 40
Location: Bellevue, NE
Posts: 14




Ignore
« Reply #30 on: April 09, 2010, 10:05:35 AM »

Not to high-jack the thread, but this is a great topic and I LOVE the formulas.  IF they are accurate, I need far less power to meet my goals than I previously thought.

And power is certainly not the problem I have...it's money to make the truck safe to drive that's the problem.
Logged

agrassfidf
Jr. Member
**
Offline Offline

Posts: 33




Ignore
« Reply #31 on: May 12, 2010, 10:28:00 PM »

Is there a formula that involves weight, or does that not matter when you already have hp and top speed? Is there a reasonably accurate formula for motorcycle?
Logged
LSR Mike
Sr. Member
****
Offline Offline

Age: 61
Location: Dublin, Ohio USA
Posts: 527


First Pass-June 25, 2000; Muroc Dry Lake


WWW

Ignore
« Reply #32 on: May 13, 2010, 11:49:32 AM »

Dr Mayfield,
Mayf, for all the Listers, has a site with many specifics including the Cd, frontal area etc... of many production cars and trucks,
along with simple explanations...

http://www.mayfco.com/dragcoef.htm
« Last Edit: May 13, 2010, 11:51:48 AM by LSR Mike » Logged

Mike M.
BNI/ECTA
ECTA Record Holder/Former Bonneville Record Holder
1212FBGS
Hero Member
*****
Offline Offline

Age: 57
Location: Vista, Ca
Posts: 2532


WWW

Ignore
« Reply #33 on: May 13, 2010, 02:55:59 PM »

theoretical vehicles set theoretical records every theoretical time.....
Kent
Logged
Seldom Seen Slim
Administrator
Hero Member
***
Offline Offline

Age: 69
Location: Skandia, Michigan
Posts: 11791


Nancy -- 201.913 mph record on a production ZX15!


WWW
« Reply #34 on: May 13, 2010, 03:04:09 PM »

Kent, you should add that you're speaking theoretically, I theorize.
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: 3441





Ignore
« Reply #35 on: May 13, 2010, 04:24:21 PM »

But it's so true! grin grin grin

Pete
Logged
desotoman
Hero Member
*****
Offline Offline

Location: So Cal.
Posts: 2404


Modified Roadster




Ignore
« Reply #36 on: May 13, 2010, 09:30:55 PM »

Dr Mayfield,
Mayf, for all the Listers, has a site with many specifics including the Cd, f :evil:rontal area etc... of many production cars and trucks,
along with simple explanations...

http://www.mayfco.com/dragcoef.htm

Mike,

He forgot Roadsters!!!!!!!!!!!!   evil shocked grin

Tom G.
Logged

Asking questions is one's only way of getting answers. As a young boy I was always taught that there is no such thing as a stupid question. It suggests that the quest for knowledge includes failure, and that just because one person may know less than others they should not be afraid to ask rather than pretend they already know. In many cases multiple people may not know but are too afraid to ask the "stupid question"; the one who asks the question may in fact be doing a service to those around them.
Peter Jack
Hero Member
*****
Offline Offline

Age: 74
Location: Calgary, Alberta
Posts: 3441





Ignore
« Reply #37 on: May 13, 2010, 09:59:31 PM »

And he runs one ------------ just a little newer than the rules allow!!! huh huh grin grin

Pete
Logged
LSR Mike
Sr. Member
****
Offline Offline

Age: 61
Location: Dublin, Ohio USA
Posts: 527


First Pass-June 25, 2000; Muroc Dry Lake


WWW

Ignore
« Reply #38 on: May 24, 2010, 06:15:54 PM »

Interestingly enough Tom, I stole an old method from my high school Photography instructor to calculate the frontal area for #300. He was a Air Force Photo Intelligence Interpreter.

Shoot a pix of the of the intended vehicle with a known value object in the frame. From there you can calculate the frontal area of the vehicle. In Vietnam they knew what the bore of rifle the VC was carrying, therefore he could tell you what size shoe he (the VC) was wearing.

I have since lost the excel file I was working with to approximate the HP necessary to put that brick over the record, and we really never knew how much HP we were producing because the LSR tires would never hod traction on a chassis dyno. but alas, we know what happened to that engine...I still have some (very broken) parts of it in the "offering to the gods of speed" section of my LSR chapel.
Logged

Mike M.
BNI/ECTA
ECTA Record Holder/Former Bonneville Record Holder
thecarfarmer
New folks

Offline Offline

Location: a little north of Seattle
Posts: 11





Ignore
« Reply #39 on: August 18, 2012, 11:26:19 AM »

DRAG goes up as Square of velocity. HORSEPOWER goes up as CUBE.

Really?

Maybe someone can explain how this works...

If most of the drag on a car at speed (like >100 MPH) is aero, and aero drag goes up as a second power function of the increased velocity, how come HP needed would go up as a third power function?

In other words, if air resistance is the largest single factor in drag, and if it goes up 4X when I double the speed... where's the other "horsepower vampire" hiding here? 

Just tryin' to understand...

-Bill
Logged

We all enter this world in the same way: naked; screaming; soaked in blood. But if you live your life right, that kind of thing doesn't have to stop there.

-Dana Gould
hotrod
Hero Member
*****
Offline Offline

Posts: 1231


WWW

Ignore
« Reply #40 on: August 18, 2012, 11:59:17 AM »

Quote
In other words, if air resistance is the largest single factor in drag, and if it goes up 4X when I double the speed... where's the other "horsepower vampire" hiding here?

Just tryin' to understand...

The speed itself is the 3rd factor.

If you could drive in a vacuum the power required to go faster would go up directly in proportion to the speed. With air resistance you also increase drag at the square of the speed. speed squared x speed = speed cubed

Larry
Logged

panic
Sr. Member
****
Offline Offline

Age: 72
Location: Lynbrook, New York
Posts: 754



WWW

Ignore
« Reply #41 on: August 18, 2012, 05:44:39 PM »

In Vietnam they knew what the bore of rifle the VC was carrying, therefore he could tell you what size shoe he (the VC) was wearing.

Plus or minus 100%...
Logged
Jack Gifford
Hero Member
*****
Offline Offline

Age: 77
Location: Phelps, NY
Posts: 1031





Ignore
« Reply #42 on: August 18, 2012, 11:43:42 PM »

Bill- what you were missing is that power is force times velocity.
Logged

M/T Pontiac hemi guru
Pages: 1 2 [3]   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 September 10, 2017, 10:40:32 AM