Go Back   The Ford Barn > General Discussion > Early V8 (1932-53)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 11-18-2020, 07:06 PM   #21
DavidG
Senior Member
 
DavidG's Avatar
 
Join Date: May 2010
Location: southeastern Michigan
Posts: 10,069
Default Re: Cubic inch question

Some learned it as 2piR squared and others as Dpi squared; either way the answer comes out the same.
DavidG is offline   Reply With Quote
Old 11-18-2020, 08:34 PM   #22
V8COOPMAN
Senior Member
 
V8COOPMAN's Avatar
 
Join Date: May 2010
Location: East Shore of LAKE HOUSTON
Posts: 11,106
Default Re: Cubic inch question

Quote:
Originally Posted by DavidG View Post
Some learned it as 2piR squared and others as Dpi squared; either way the answer comes out the same.
David.....Believe me, I KNOW how smart you are. There's no disputing that fact..........PERIOD! But respectfully, "2piR squared" ain't gonna cut it. You've given me cause to take aspirin already trying to make YOUR formula work. So.....I believe you meant "pi(r)squared", or pi(r)(r). No?

And "D pi squared" doesn't seem to work, either. And Sir....I blow it every now and then, too! DD
__________________
Click Links Below __


'35-'36 W/8BA & MECHANICAL FAN


T5 W/TORQUE TUBE
V8COOPMAN is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 11-18-2020, 09:00 PM   #23
JayChicago
Senior Member
 
JayChicago's Avatar
 
Join Date: Jan 2019
Location: Chicago
Posts: 711
Default Re: Cubic inch question

I think David just made a mistake by including the words “squared”. Circumference of a circle is 2PiR or Dpi. But neither is squared.

Last edited by JayChicago; 11-18-2020 at 09:33 PM.
JayChicago is offline   Reply With Quote
Old 11-18-2020, 09:44 PM   #24
DavidG
Senior Member
 
DavidG's Avatar
 
Join Date: May 2010
Location: southeastern Michigan
Posts: 10,069
Default Re: Cubic inch question

Caught me guys! Man, getting old ain't no fun. Actually the two are equal, but you're right, not for the purpose at hand.
DavidG is offline   Reply With Quote
Old 11-18-2020, 11:48 PM   #25
tomcarman
Senior Member
 
tomcarman's Avatar
 
Join Date: Feb 2017
Location: Rochester Wa
Posts: 574
Default Re: Cubic inch question

At the risk of offending some. A hillbilly decided to go to college to study math. He comes home on holiday. Ma asks what he learned in math. He says; "Ma, I learned Pi r squared". Ma says; "No no son, Pie are round".
tomcarman is offline   Reply With Quote
Old 11-19-2020, 12:01 AM   #26
GB SISSON
Senior Member
 
GB SISSON's Avatar
 
Join Date: Jan 2014
Location: Orcas Island Washington
Posts: 4,846
Default Re: Cubic inch question

Sponsored Links (Register now to hide all advertisements)
Quote:
Originally Posted by tomcarman View Post
At the risk of offending some. A hillbilly decided to go to college to study math. He comes home on holiday. Ma asks what he learned in math. He says; "Ma, I learned Pi r squared". Ma says; "No no son, Pie are round".

... And cornbread r squared"
__________________
Owner/Operator of 'Jailbar Ranch' on the side of Mt. Pickett. Current stable consists of 1946 1/2 ton pickup turned woodie wagon with FH V8, 1947 Tonner Pickup (red) mostly stock with exception of a cummins 6at turbo diesel, 1946 Tonner Pickup (green) with 226 cu in 6 cyl flathead, 1979 Toyota landcruiser wagon, completely encased in 1947 Ford Jailbar sheet metal. Ok, cornbinder rear fenders..... 'Rusty ol' floorboards, hot on their feet' (Alan Jackson)
GB SISSON is offline   Reply With Quote
Old 11-19-2020, 12:18 AM   #27
tomcarman
Senior Member
 
tomcarman's Avatar
 
Join Date: Feb 2017
Location: Rochester Wa
Posts: 574
Default Re: Cubic inch question

Quote:
Originally Posted by GB SISSON View Post
... And cornbread r squared"
What if it were a cornbread muffin?
tomcarman is offline   Reply With Quote
Old 11-19-2020, 12:23 AM   #28
tomcarman
Senior Member
 
tomcarman's Avatar
 
Join Date: Feb 2017
Location: Rochester Wa
Posts: 574
Default Re: Cubic inch question

As long as we're on the subject of "corny".
Ma does a little studying of her own. She asks; Alright son, what is 2 Pi R? The son thinks a minute and replies; "Why Ma, 2 Pie are better than 1".
tomcarman is offline   Reply With Quote
Old 11-19-2020, 09:46 AM   #29
Frank Miller
Senior Member
 
Frank Miller's Avatar
 
Join Date: May 2010
Location: Auburn, MA
Posts: 2,106
Default Re: Cubic inch question

the .785 method is not so much a function of Pi but it is in lieu of Pi when plugging the diameter into a formula. For example if the diameter is 4 you readily know the radius is 2. But if the diameter is 3.187 you might not readily see that divided by 2. Because you are squaring the diameter you need to divide Pi by 4 or 2 squared.
__________________
“The technique of infamy is to start two lies at once and get people arguing heatedly over which is true.” ~ Ezra Pound
Frank Miller is offline   Reply With Quote
Old 11-19-2020, 05:35 PM   #30
V8COOPMAN
Senior Member
 
V8COOPMAN's Avatar
 
Join Date: May 2010
Location: East Shore of LAKE HOUSTON
Posts: 11,106
Default Re: Cubic inch question

Quote:
Originally Posted by Frank Miller View Post
the .785 method is not so much a function of Pi but it is in lieu of Pi when plugging the diameter into a formula. For example if the diameter is 4 you readily know the radius is 2. But if the diameter is 3.187 you might not readily see that divided by 2. Because you are squaring the diameter you need to divide Pi by 4 or 2 squared.
Hmmm...! Not so much a function of pi...? OK then, but ".7854" does just happen to be the quotient when performing the "function" of ascertaining what 1/4 of 3.1416 might be, or more simplistically....3.1416 divided by 4! I'm not sure that I understand what is in question here.

If I simply punch "3.187² X 4 X .7854 X 8 =" into the calculator (it took me about 6 seconds to perform), I don't have to worry about finding radii or any other details. That simple ".7854" becomes an integral part of THIS formula. This seems (to me) to be a lot simpler than having to first determine the figures necessary to extrapolate for the formula "πr²". And THAT only yields the area of the circle. Now, ya still have to figure-in the height for the volume, and then multiply by the number of cylinders. "My" way takes care of "pi", and ALL of that other superfluous BS....just to figure out how big your flattie (or your Chevy, etc.) is.

"Bore X bore X stroke X .7854 X 8 =" .....easy, peasy! DD
__________________
Click Links Below __


'35-'36 W/8BA & MECHANICAL FAN


T5 W/TORQUE TUBE
V8COOPMAN is offline   Reply With Quote
Old 11-19-2020, 07:16 PM   #31
Mart
Senior Member
 
Mart's Avatar
 
Join Date: May 2010
Location: Solihull, England.
Posts: 8,732
Default Re: Cubic inch question

Understanding how the .7854 was arrived at and knowing how it is calculated from first principles is the most important thing.
Mart is offline   Reply With Quote
Old 11-19-2020, 08:59 PM   #32
V8COOPMAN
Senior Member
 
V8COOPMAN's Avatar
 
Join Date: May 2010
Location: East Shore of LAKE HOUSTON
Posts: 11,106
Default Re: Cubic inch question

Quote:
Originally Posted by Mart View Post
Understanding how the .7854 was arrived at and knowing how it is calculated from first principles is the most important thing.
I UNDERSTAND where it came from. The best part is that it works oh so well, EVEN for those folks that MIGHT NOT understand the "whys". DD
__________________
Click Links Below __


'35-'36 W/8BA & MECHANICAL FAN


T5 W/TORQUE TUBE
V8COOPMAN is offline   Reply With Quote
Old 11-19-2020, 11:14 PM   #33
PeteVS
Senior Member
 
PeteVS's Avatar
 
Join Date: May 2010
Location: FP, NJ
Posts: 2,769
Default Re: Cubic inch question

Quote:
Originally Posted by adileo View Post
Who says one only remembers 5 minutes of what they learned in 5 years of college?
https://www.youtube.com/watch?v=kO8x8eoU3L4

Oh, and if you divide cubic inches by 61, you get liters so you can live in the modern world...
__________________
Don't never get rid of nuthin!
PeteVS is offline   Reply With Quote
Old 11-20-2020, 07:50 AM   #34
tubman
Senior Member
 
tubman's Avatar
 
Join Date: Dec 2013
Location: Minnesota, Florida Keys
Posts: 10,260
Default Re: Cubic inch question

I just usually divide by 60 to get litres; it's easier to do quickly in your head. Close counts in hand grenades, horseshoes, and now, engine displacement.
tubman is offline   Reply With Quote
Old 11-20-2020, 07:56 AM   #35
Frank Miller
Senior Member
 
Frank Miller's Avatar
 
Join Date: May 2010
Location: Auburn, MA
Posts: 2,106
Default Re: Cubic inch question

Quote:
Originally Posted by V8COOPMAN View Post
Hmmm...! Not so much a function of pi...? OK then, but ".7854" does just happen to be the quotient when performing the "function" of ascertaining what 1/4 of 3.1416 might be, or more simplistically....3.1416 divided by 4! I'm not sure that I understand what is in question here.

If I simply punch "3.187² X 4 X .7854 X 8 =" into the calculator (it took me about 6 seconds to perform), I don't have to worry about finding radii or any other details. That simple ".7854" becomes an integral part of THIS formula. This seems (to me) to be a lot simpler than having to first determine the figures necessary to extrapolate for the formula "πr²". And THAT only yields the area of the circle. Now, ya still have to figure-in the height for the volume, and then multiply by the number of cylinders. "My" way takes care of "pi", and ALL of that other superfluous BS....just to figure out how big your flattie (or your Chevy, etc.) is.

"Bore X bore X stroke X .7854 X 8 =" .....easy, peasy! DD
You're still using Pi. You've just simplified the formula. Pi is the function as it relates to the circle.
__________________
“The technique of infamy is to start two lies at once and get people arguing heatedly over which is true.” ~ Ezra Pound
Frank Miller is offline   Reply With Quote
Old 11-20-2020, 11:21 AM   #36
glennpm
Senior Member
 
glennpm's Avatar
 
Join Date: Sep 2014
Location: Wiscasset, Maine
Posts: 1,965
Default Re: Cubic inch question

"The number π (/paɪ/) is a mathematical constant. It is defined as the ratio of a circle's circumference to its diameter, and it also has various equivalent definitions. It appears in many formulas in all areas of mathematics and physics. It is approximately equal to 3.14159. It has been represented by the Greek letter "π" since the mid-18th century, and is spelled out as "pi". It is also referred to as Archimedes' constant.[1][2][3]"


From https://en.wikipedia.org/wiki/Pi which also has a neat graphic.
glennpm is offline   Reply With Quote
Old 11-20-2020, 06:37 PM   #37
V8COOPMAN
Senior Member
 
V8COOPMAN's Avatar
 
Join Date: May 2010
Location: East Shore of LAKE HOUSTON
Posts: 11,106
Default Re: Cubic inch question

Quote:
Originally Posted by Frank Miller View Post
You're still using Pi. You've just simplified the formula. Pi is the function as it relates to the circle.
No kidding?

Did I not mention something about "pi" back in post #11? I'm not understanding the overall point that you're trying to make here! DD
__________________
Click Links Below __


'35-'36 W/8BA & MECHANICAL FAN


T5 W/TORQUE TUBE
V8COOPMAN is offline   Reply With Quote
Old 11-20-2020, 06:50 PM   #38
Phil Gillespie
Senior Member
 
Phil Gillespie's Avatar
 
Join Date: Sep 2011
Location: Christchurch New Zealand
Posts: 1,603
Default Re: Cubic inch question

i am enjoying the Maths update lessons it sure takes me back.
Was there also a recent movie out called " The Life if PI".
I still enjoy doing mental numbers in the head to keep brain active.
Phil NZ
Phil Gillespie is offline   Reply With Quote
Old 11-20-2020, 07:56 PM   #39
GB SISSON
Senior Member
 
GB SISSON's Avatar
 
Join Date: Jan 2014
Location: Orcas Island Washington
Posts: 4,846
Default Re: Cubic inch question

I am in awe of the math skills shown here. I once trimmed out the interior of a house that had two round turrets. Watching my progress , our high school's math teacher, who had taken a painting job for the summer, asked me if I would be willing to come to the high school on career day in the fall and talk to the students about how I use math in my job. Well about mid September he called me and outlined what I'd need to discuss in my 45 minutes. Yikes! all I could think of was the strings and nails and routers bolted to long plywood strips that I used instead of math. I ended up declining his offer, as I had spent a career teaching myself how to do my work without using math. Sometimes we can work around our shortfalls on a relatively simple task and get by. Just don't ask me to offset grind your merc crank to 4 1/8". I could not begin to understand the math involved!
__________________
Owner/Operator of 'Jailbar Ranch' on the side of Mt. Pickett. Current stable consists of 1946 1/2 ton pickup turned woodie wagon with FH V8, 1947 Tonner Pickup (red) mostly stock with exception of a cummins 6at turbo diesel, 1946 Tonner Pickup (green) with 226 cu in 6 cyl flathead, 1979 Toyota landcruiser wagon, completely encased in 1947 Ford Jailbar sheet metal. Ok, cornbinder rear fenders..... 'Rusty ol' floorboards, hot on their feet' (Alan Jackson)

Last edited by GB SISSON; 11-21-2020 at 07:20 AM.
GB SISSON is offline   Reply With Quote
Old 11-21-2020, 05:25 AM   #40
Mart
Senior Member
 
Mart's Avatar
 
Join Date: May 2010
Location: Solihull, England.
Posts: 8,732
Default Re: Cubic inch question

"Just don't ask me to offset grind your merc crank to 4 1/8"

If you can do that with a router and string I'd like to see it.
Mart is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 01:59 PM.