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KIPS 5
- Thread starter darron
- Start date
![[bugeyed]](/data/assets/smilies/bugeyed.gif "[bugeyed] [bugeyed]")
EnglishMuffin
Mechanical
kenvlach:
If they know the Kg standard is changing, why don't they use whatever it is they are checking it with as the standard instead ? Why do they even need it ? Does anybody ever use it ?
p.s. - looks like you have to pay to read that article - typical NY Times.
If they know the Kg standard is changing, why don't they use whatever it is they are checking it with as the standard instead ? Why do they even need it ? Does anybody ever use it ?
p.s. - looks like you have to pay to read that article - typical NY Times.
SparWeb,
There are 1.5 Hogsheads in a Puncheon. Unfortunately, a Puncheon is either 84 gallons of wine, or 54 gallons of beer. At least, both gallons are four quarts!
My reference is The Mechanic's Calculator, Second Edition by William Grier Civil Engineer, MDCCCXXXV.
An instructor I had in college insisted that we do unit balances in our calculations. The obvious objective is that when you work out your weight as 150sq.in/sec, you know you have screwed up somewhere. This makes unit conversions easier too.
Any time I have seen calculations done by Europeans, they have been in the CGS system. Is the SI system (as opposed to the metric system) really that popular out there?
JHG
There are 1.5 Hogsheads in a Puncheon. Unfortunately, a Puncheon is either 84 gallons of wine, or 54 gallons of beer. At least, both gallons are four quarts!
My reference is The Mechanic's Calculator, Second Edition by William Grier Civil Engineer, MDCCCXXXV.
An instructor I had in college insisted that we do unit balances in our calculations. The obvious objective is that when you work out your weight as 150sq.in/sec, you know you have screwed up somewhere. This makes unit conversions easier too.
Any time I have seen calculations done by Europeans, they have been in the CGS system. Is the SI system (as opposed to the metric system) really that popular out there?
JHG
One more thought about units...
Check out literature that quotes the strength of a grade_12.9 screw (metric). According to the web site I just checked, the 12 is the strength of the bolt in units of 100MPa. I believe that this is what my Machinery's Handbook 26th edition claims too.
I have seen literature listing the strength of these bolts in psi, and the conversion is not exact. It becomes exact when I use my Machinery's Handbook 21st edition for a reference. The number 12 is the strength of the bolt in units of 10kgf/mm^2. One kilogram force equals approximately ten Newtons.
Ref:
JHG
Check out literature that quotes the strength of a grade_12.9 screw (metric). According to the web site I just checked, the 12 is the strength of the bolt in units of 100MPa. I believe that this is what my Machinery's Handbook 26th edition claims too.
I have seen literature listing the strength of these bolts in psi, and the conversion is not exact. It becomes exact when I use my Machinery's Handbook 21st edition for a reference. The number 12 is the strength of the bolt in units of 10kgf/mm^2. One kilogram force equals approximately ten Newtons.
Ref:
JHG
I work in the ft-lb system. Most any aircraft I deal with was designed and built to dimensions in inches, loads in pounds, speeds in knots. The Eurocopters and Fokkers are exceptions, being euro machines. It's strange to read a fuselage diagram in milimeters, when the aircraft is over 20 metres long! "At station 15673, we find the aft crew door..."
Could I switch? Of course. I grew up in a canadian school, and spent the first 20 years of my life in metric, until I came into contact with REAL machines. The dichotomy of canadian education vs. technology underpins my belief that theory and practice are two different things.
The choice between SI and CGS is also determined by industry. I would expect engineering to make more sense in Kg/meters, while chemistry would find grams much more useful.
I use MathCAD all the time for my analyses. It makes the units work effortlessly. It can switch between all three systems easily.
STF
Could I switch? Of course. I grew up in a canadian school, and spent the first 20 years of my life in metric, until I came into contact with REAL machines. The dichotomy of canadian education vs. technology underpins my belief that theory and practice are two different things.
The choice between SI and CGS is also determined by industry. I would expect engineering to make more sense in Kg/meters, while chemistry would find grams much more useful.
I use MathCAD all the time for my analyses. It makes the units work effortlessly. It can switch between all three systems easily.
STF
KIPS are extensively used on floating facilities and ships. Naval architects and people involved in Ballast Control. If you ask what a kip is in a Naval Engineering forum, they'll respond with a "WHERE HAVE YOU BEEN IDIOT? ARE YOU SURE YOU'RE AN ENGINEER?"
The biggest opponents of conversion to the SI was the “Oil Patch” and the aircraft industry.
Like many I’ve work with both and seen many of the aforementioned conversion mistakes. Leaving off the suffix or changing units in midstream are quite common.
A problem that I’ve seen locally is the convention of using of SI units in dimensioning. I worked on two large scale chemical plants that were designed and had some components constructed in Europe. All dimensions on the drawings were in millimeters (6000,9000,etc.). They are teaching in schools to change to cm’s, etc. Print in hand I tried to show the instructors at a technical school and Jr college this and got a response of, What are you trying to do confuse the issue.
A very good conversion program is "Conversion Buddy" by Jim Presley. He also has a another program Expression Buddy.
You can dictate the accuracy in Conversion Buddy.
They are available as a free download at:
Like many I’ve work with both and seen many of the aforementioned conversion mistakes. Leaving off the suffix or changing units in midstream are quite common.
A problem that I’ve seen locally is the convention of using of SI units in dimensioning. I worked on two large scale chemical plants that were designed and had some components constructed in Europe. All dimensions on the drawings were in millimeters (6000,9000,etc.). They are teaching in schools to change to cm’s, etc. Print in hand I tried to show the instructors at a technical school and Jr college this and got a response of, What are you trying to do confuse the issue.
A very good conversion program is "Conversion Buddy" by Jim Presley. He also has a another program Expression Buddy.
You can dictate the accuracy in Conversion Buddy.
They are available as a free download at:
structuresguy
Structural
I use a program called, oddly enough, CONVERT, to do all my conversions.
Pretty handy, most things are already built in, plus you can add custom conversions.
And its FREE!
Pretty handy, most things are already built in, plus you can add custom conversions.
And its FREE!
My huge objection to the metric system is exactly what DaveViking stated. The use of 'artificial' units like pascals. All that does is make it difficult to check your answer by analyzing units. The only such really dumb example I know of in the English (Imperial not emperical) system is in the calculation of shear flow the use of VQ/Ib where Q is actually Ay. I hate to think how many thousands of hours have been wasted over the years by engineers searching through books mumbling "What the Hell is Q?".
I remember being confused and amazed learning the imperial units for a surveying unit at uni:
25 links = 1 rod
4 rods = 1 chain
10 chains = 1 furlong
8 furlongs = 1 mile
3 miles = 1 league
1 furlong x 1 chain = 1 acre
640 acres = 1 square mile
Thanks goodness for metres and hectares!
25 links = 1 rod
4 rods = 1 chain
10 chains = 1 furlong
8 furlongs = 1 mile
3 miles = 1 league
1 furlong x 1 chain = 1 acre
640 acres = 1 square mile
Thanks goodness for metres and hectares!
Unclesyd,
I hope that engineering schools are NOT teaching people to use centimeters for dimensions!
In an environment where people use both english and metric dimensions, they have to look different. Millimeter and inch dimensions are hard to confuse. I am not so sure about centimeters and inches.
The nice thing about millimeters is that for a lot of stuff, you lose fractions and decimals.
JHG
I hope that engineering schools are NOT teaching people to use centimeters for dimensions!
In an environment where people use both english and metric dimensions, they have to look different. Millimeter and inch dimensions are hard to confuse. I am not so sure about centimeters and inches.
The nice thing about millimeters is that for a lot of stuff, you lose fractions and decimals.
JHG
I don't have any problem working with either the SI or the English system of units because we were taught to use both in the elementary grades at school. I would, however, like to see everybody agree on using one set of units for the reasons cited above. By the way, remember when those road signs that were posted in the US showing both metric and english units were riddled with bullet holes? Gives you an idea of the attitude the general public here has about converting over...
Maui
Maui
Here's an obscure unit,
1 poundal = the force that accelerates a pound mass one foot per second per second. (1 poundal= 1 lbm*ft/sec/sec)
The only legitimate argument for converting to SI is that everyone else is doing it. The guy that posted the thread couldn't convert from kips to newtons--hopefully he's not designing anything important.
Viva la difference!
1 poundal = the force that accelerates a pound mass one foot per second per second. (1 poundal= 1 lbm*ft/sec/sec)
The only legitimate argument for converting to SI is that everyone else is doing it. The guy that posted the thread couldn't convert from kips to newtons--hopefully he's not designing anything important.
Viva la difference!
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