adding feet and inches on a regular calculator 5

[dvd]

I have been using this method of adding feet and inches on a regular calculator for several years. I just recently stumbled on a write-up of the method. If you work in feet and inches, this is a very helpful method.

 

[zeusfaber]

JTE,

If an aviator says he's at FL3000, something has gone horribly wrong - that puts hima about five times higher than concorde ever flew.

Flight levels isn't really a height measure anyway - it's all about flying at a constant ambient pressure (so on a day when the barometer is reading a bit high, all the jets flying airways are that bit further away from the ground too). Once you get into the business of genuinely wanting to know how close the ground is (perhaps so you can bomb, avoid, or land on it), everyone turns back to feet or, if the numbers are getting big, thousands of feet.

A.

 

[KenA]

@David : "80F feels warmer than 17C."
Well that's because it is! 80F = 26.7C

 

[SomptingGuy]

Returning to the original post.

I agree with the comments that this looks like a simple problem turned into a complicated process. People carry out complicated processes with zero idea as to what they are really doing and why (e.g. school kids using log tables).


- Steve

 

[rob768]

by the way: kgf/m^2 is not a metric unit. It is and old unit and it should be Pascal (which in term is N/m^2).

Personally, living in Hollang I favor metric because it is easier (and more logical) to use steps of ten than twelve.
And over here in Europe, we have the idea that the US stopped promoting the use if SI units after the blew a satellite because of a unit mistake. Don't know if that is the real reason of course..

 

[MintJulep]

I say use nautical miles for distance. They make all sorts of aviation type calculations easy to do you in your head.

A nautical mile is darn near 6000 feet. So a Knot is 6000 feet/hr, which is easily converted in your head to 100 feet/min, and as rate of climb is usually in ft/min your L/D is also easy to do in your head.

 

[eromlignod]

This is what I'm talking about. Every time someone tries to tout the Metric System, or their own personal favorite, they give an asinine example of an "engineering problem" that involves simple, round integers that are nonchalantly converted in one's head. This is ridiculous in the real world, since we almost always deal with crazy real numbers that have to be dealt with using a calculator anyway.

Don
Kansas City

 

[rb1957]

let's not forget the US "imperial" units ... the US gallon (=3.8lt instead of 4.54 for the "full" imp. gallon), the short ton (= 2000 lbs, maybe 'cause they couldn't work with 2240 lbs ?) ...

byw zeusfaber, 1 mile = 1760yds = 5280ft

napoleon (ok, maybe republican france) tried "metric" time ... we're fixed to 365.25 days per year (but can have 10 months) and a day is a fixed length (but we can fudge with the hours/minutes/seconds, maybe 10 hours,100 minutes, 100 seconds).

 

[JStephen]

kgf/cm^2 is a "metric" unit, it just isn't a standard SI unit. Similar to dynes, bars, poises, and whatever other dimensional oddities are floating around out there in the real world.

 

[rob768]

I stand corrected..

 

[zeusfaber]

As do I.

A.

 

[SomptingGuy]

kgf/cm^2 may be thought of as a metric unit, but it's a bad one, with an arbitrary nasty constant thrown in (based on Earth's gravitation field).

- Steve