Koch Chart Formula

Google found several "aviation Koch chart" links including
this one
http://wind-drifter.com/technical/technical.htm scroll
down the page. They have some calculators listed, but the
Koch Chart is just the graph. But any high school math
teacher should be able to walk you through the solution of
the algebra problem to find the system of equations.





"Peter Duniho" wrote in
message ...
| "abripl" wrote in message
|
ups.com...
| Does anybody have the Koch Chart formula (equation)? Or
know where to
| find it?
|
| I don't think there is an actual equation that works
generally. As an
| obvious counter-proof to the idea that there is one,
consider that density
| altitude affects airplanes with normally aspirated engines
differently from
| those with turbocharged engines. The same Koch chart
would not work for
| both types of airplanes.
|
| I haven't done a lot of research on the origin of the Koch
chart, but I
| believe that it's to be used as a general guideline, not
as a precise
| determination of how airplane performance is affected by
density altitude.
|
| If you do want to implement the Koch chart mathematically
somehow, I'd
| suggest that your best bet (in terms of ease of
implementation) would be to
| manually read off a range of pressure altitude and
temperature combinations
| to create tables giving the performance adjustment, and
then interpolate
| between the values for specific input of pressure altitude
and temperature.
|
| You could more accurately describe a Koch chart
mathematically by actually
| reverse engineering it (the scales on the middle portion
of the chart appear
| to be logarithmic and exponential for the takeoff distance
and climb rate
| reduction, respectively, so you simply need to measure the
scales and
| determine the base and power for those functions, and the
pressure altitude
| and temperature graphs appear to be linear), but that may
be more trouble
| than it's worth. Given that the chart isn't a precise way
to determine the
| performance change anyway, you may find it's overkill to
analyze the chart
| that way.
|
| Pete
|
|

"Jim Macklin" wrote in message
news:CGYGg.5789$SZ3.2892@dukeread04...
Google found several "aviation Koch chart" links including
this one
http://wind-drifter.com/technical/technical.htm scroll
down the page.

So what? No one was asking what a Koch chart is, and hopefully everyone
here knows how to use Google by now.

They have some calculators listed, but the
Koch Chart is just the graph.

There are no calculators to provide the information that the Koch chart
provides.

But any high school math
teacher should be able to walk you through the solution of
the algebra problem to find the system of equations.

Doubtful. There is no single "system of equations" that provides the
general answer that a Koch chart attempts to provide. The best you can do
is to show what the Koch chart itself shows, and that chart is based on
general rules of thumb, not actual mathematically derived functions based on
actual density altitude effects.

Pete

On Wed, 23 Aug 2006 09:37:50 -0700, "Peter Duniho"
wrote in
:

There are no calculators to provide the information that the Koch chart
provides.

Although not what you were talking about, there is this:

http://www.mountainflying.com/apr_denalt.htm
The APR DENALT (DENsity ALTitude) Performance Computer
To solve the takeoff distance and rate of climb at any particular
density altitude, dial in the outside air temperature (degrees
Fahrenheit) and read the "takeoff factor" and "rate-of-climb
factor" to apply to the normal sea level values obtained from the
Pilot's Operating Handbook.

For those who care, you can save the Koch Chart as a picture
file to your computer. Then open it with PAINT or some
other photo editing program. Locate the x,y coordinates for
each part of the graphs and then use those numbers to solve
the algebra problem to get the formula for the system of
equations. Or just use the chart and add a cushion for
safety.



"Larry Dighera" wrote in message
...
| On Wed, 23 Aug 2006 09:37:50 -0700, "Peter Duniho"
| wrote in
| :
|
| There are no calculators to provide the information that
the Koch chart
| provides.
|
| Although not what you were talking about, there is this:
|
| http://www.mountainflying.com/apr_denalt.htm
| The APR DENALT (DENsity ALTitude) Performance Computer
| To solve the takeoff distance and rate of climb at any
particular
| density altitude, dial in the outside air temperature
(degrees
| Fahrenheit) and read the "takeoff factor" and
"rate-of-climb
| factor" to apply to the normal sea level values
obtained from the
| Pilot's Operating Handbook.