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Old 01-26-2007, 10:31 AM
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Default CG- Measuring in. to cm.

For those of you who think they are great at converting centimeters. to inches. um... think twice.

Me, a 41 Year old, with a math degree, Systems Analyst, pretty bright went ahead and converted the 10 cm. CG to 2.54 inches.

Well, ITS NOT 2.54" it's ~3.75 Inches...DOHH

Added so much lead the plane could have been a sinker if I was fishing. Luckily I was watching some threads on this board and it got me thinking, why was one person also having issues. So, before long I broke out a ruler and behold!

Thank the man upstairs I didn't attempt to have flown it since the weather has been freezing in the N.E. lately. Now I can go back and remove all that lead and start over.

Moral of this story... don't think you are too smart, measure twice and double check against a resource. If it seems out of whack, it probably is.

Old 01-26-2007, 11:16 AM
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Default RE: CG- Measuring in. to cm.

An online calculator on the Tower Hobbies web site shows 10 cm to be 3.937 inches

http://www.towerhobbies.com/help/convcalcs.html
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Old 01-26-2007, 11:21 AM
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Default RE: CG- Measuring in. to cm.

ORIGINAL: RealPilotAce

For those of you who think they are great at converting centimeters. to inches. um... think twice.

Me, a 41 Year old, with a math degree, Systems Analyst, pretty bright went ahead and converted the 10 cm. CG to 2.54 inches.

Well, ITS NOT 2.54" it's ~3.75 Inches...DOHH

Added so much lead the plane could have been a sinker if I was fishing. Luckily I was watching some threads on this board and it got me thinking, why was one person also having issues. So, before long I broke out a ruler and behold!

Thank the man upstairs I didn't attempt to have flown it since the weather has been freezing in the N.E. lately. Now I can go back and remove all that lead and start over.

Moral of this story... don't think you are too smart, measure twice and double check against a resource. If it seems out of whack, it probably is.

When I was at school I had to learn both systems and let me tell you now that 10 cm is a lot it is in fact 10% of a meter (about 3 ft 3). The conversion is 25.4 mm to 1 inch which when you put into 10 you get just under 4 (3.937007874 to be exact). So you are wrong on both counts CG a hair under 4. Another useful conversions are 2.2 pounds to 1 kg, 28.35 grams to 1 oz, 3.78 litres to 1 us gallon and 4.54 litres to 1 imperial gallon.

James
Old 01-26-2007, 11:39 AM
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Default RE: CG- Measuring in. to cm.

That was what the '~' was for about. But thanks for the exact measurement. I'm going to go a bit nose heavy, 1 cm. Which would work out to the 3.75 or so, Just to see how it will take to the air. Then make any changes afterwards.

I wish I could find my metal machinist ruler.
Old 01-26-2007, 11:56 PM
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Default RE: CG- Measuring in. to cm.

You got caught by the 2.54cms=1 inch
The best converter program I know of is the one from this site http://joshmadison.net/software/convert/ because it's free, it's not a big program and you can use it anytime.

It tells me your CG should be 1.057023e-017 light years back from the LE
Old 01-27-2007, 01:25 AM
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Default RE: CG- Measuring in. to cm.

Well, the real conversion is the distance from the earth's equator to the pole is 10,000 km, or 6,215.05 miles. Working out the conversion you end up with a meter to be bit over 39.37 inches in length.

I hope you are not the systems engineer that managed to plant the Mars Climate Orbiter back in 1999.

http://mars.jpl.nasa.gov/msp98/news/mco990930.html
Old 01-27-2007, 04:56 AM
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Default RE: CG- Measuring in. to cm.


ORIGINAL: downunder

You got caught by the 2.54cms=1 inch
The best converter program I know of is the one from this site http://joshmadison.net/software/convert/ because it's free, it's not a big program and you can use it anytime.

It tells me your CG should be 1.057023e-017 light years back from the LE
This is the greatest programme under the sun if you had to ask me, it is the first thing installed on any PC that I work on at work or at home. I do this mainly because I do all my calculations in metric, I can not understand those funny imperial units.

Cheers
Pups
Old 01-27-2007, 07:50 AM
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Default RE: CG- Measuring in. to cm.


ORIGINAL: pupmeister


ORIGINAL: downunder

You got caught by the 2.54cms=1 inch
The best converter program I know of is the one from this site http://joshmadison.net/software/convert/ because it's free, it's not a big program and you can use it anytime.

It tells me your CG should be 1.057023e-017 light years back from the LE
This is the greatest programme under the sun if you had to ask me, it is the first thing installed on any PC that I work on at work or at home. I do this mainly because I do all my calculations in metric, I can not understand those funny imperial units.

Cheers
Pups
I use this program too, but I've found another converter that works just as well. And so far I haven't found anything that can't be converted. It's google. Go to the google search engine and type in "covert 10 cm to inches". It returns the answer of "10 centimeters = 3.93700787 inches".

Ken
Old 01-27-2007, 10:12 AM
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Default RE: CG- Measuring in. to cm.

I love Ken's solution! Heck, Google even does the light years conversion as well.

Old 01-27-2007, 12:21 PM
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Default RE: CG- Measuring in. to cm.

Wasn't a miscalculation between metric and imperial the cause of a probe to Mars running out of fuel and being lost. And those were Nasa Engineers, supposed to be the smartest in the country!!! [X(]
Old 01-27-2007, 02:07 PM
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Default RE: CG- Measuring in. to cm.

A very easy way to do it that includes no calculations is to get a ruler with both cm and inches on it, and then line up the values with a straight edge or carpenters square. Using this method, I get 10 cm = 3 and 15/16" Which calculates to 3.9375. That is exactly the same as the google calculator. Sorry for the fuzzy pics, but you get the point.

LT-40
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Old 01-27-2007, 02:24 PM
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Default RE: CG- Measuring in. to cm.

LT-40--You the man! Hooray for the 20th century![8D]
Old 01-27-2007, 03:38 PM
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Default RE: CG- Measuring in. to cm.

Thats right! Big difference in mile vs kilometers in distance. JPL tried for a hole in one.

quote]Mars Climate Orbiter was lost on arrival September 23, 1999. Engineers concluded that the spacecraft entered the planet's atmosphere too low and probably burned up.[[/quote]
Old 01-27-2007, 06:12 PM
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Default RE: CG- Measuring in. to cm.

The absolute best way I've found to use the metric measurements you find in so many manuals is...............

my metric ruler and when that's not long enough, the yardstick that has metric along one edge with inches on the other
Old 01-28-2007, 02:00 AM
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Default RE: CG- Measuring in. to cm.

ORIGINAL: LT-40

A very easy way to do it that includes no calculations is to get a ruler with both cm and inches on it, and then line up the values with a straight edge or carpenters square. Using this method, I get 10 cm = 3 and 15/16" Which calculates to 3.9375. That is exactly the same as the google calculator. Sorry for the fuzzy pics, but you get the point.

LT-40
Just a note but this type of ruler is almost the only type you can buy in England, so if you know anyone over there or going over there then that could be a viable little present for you.

Good idea, I used to use it alot in England.

James
Old 01-28-2007, 08:55 AM
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Default RE: CG- Measuring in. to cm.

Almost every hardware or home improvement store around here sells rulers and yardsticks with metric along one side and inches along the other.

And most are even more useful in that they have the rules on both sides and originating from the same end. I use one to line up horizontal stabilizers because it's metric AND can simply be rolled in the hand (instead of turned end to end) when I compare the other side (wing to stab measurement).
Old 01-28-2007, 09:00 AM
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Default RE: CG- Measuring in. to cm.

And in fact, the last place I was in that had very good metal rulers and yardsticks with both metric and inches was an office supply. All the office supply places carry good quality, decently priced rulers.

BTW, they also have useful stuff like the circle template I bought a couple of days ago. I'm always looking around the shop for a jar top or roll of tape the right diameter to draw a circle. Now I've got that template with graduated holes in it. And it wasn't but a couple of bucks. Now where is that sucker????

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