Interpolation calculator

[Bailey's Dad]

Is any one aware of a simple interpolation calculator program ( possibly ran through an excel program ) that does all the hard work of interpolating numbers that are published in FCOM's ?
Ie: A QRH table.
Cheers

[Old Smokey]

Bailey's Dad,

If I provided one in BASIC, would you be able to adapt it to or mofify it to suit your application ?

Regards,

Old Smokey

[despegue]

Interpolation means just that: take something in between by your own mental calculations.
Interpolations are not meant to be 100% accurate.
Keep it simple .
It seems that we depend far to much on computers and calculators on the flightdeck nowadays.
I remember my time at Maritime academy where EVERYTHING had to be calculated with pencil, paper and tables (and lots of interpolating!)
It worked and kept you far more involved.

[cwatters]

Exel graph functions can fit a curve or line to a set of points. You can then read off intermediate values manually.

[mutt]

Just try inputting the values in Excel and calculate the interpolated values by formula. Apply the same logic that you would with a calculator.

Mutt

[N O Coolie]

Old Smokey,

Could you please provide such a program in BASIC? I use GW BASIC for all my work.

Best regards,

N O Coolie

[Old Smokey]

Consider it done N O Coolie, just give me a few days to satisfy the needs of the powers of darkness (otherwise known as Crew Scheduling) first, then thy will be done :ok:

I used to use Fortran, C+, C+++++'es et al because GW BASIC was just too slooooow, but with the newer generation high speed microprocessers, I find myself drifting back to BASIC for even quite complex routines, for all practical purposes it's now just as fast (and easy to edit, and so easy to hand onto other people).

Regards,

Old Smokey

[FearlessFreep]

In days past I wrote an Excel subroutine for a Weight & Balance / Performance spreadsheet I wrote for when I was flying a Metro III doing on call cargo. I had this installed on a Palm III that I could use to assist in calculating the performance stuff while loading the aircraft

Basically all you need to do is set up your charted data into the spreadsheet formatted so that you can do a VLOOKUP on the two values that envelope your desired value. Then all that is necessary is a ratio calculation. All that means is taking the "spread" between your known values and seeing what percentage of those values your desired value represents. Piece of cake.

Just remember that many times even with the tables that you are looking at values that are represented may not be linear, they could be logarithimic, and this could be representative of what I refer to as fractionally factorical (such as 10 to the .23 power versus a whole number - wrap your head around that one!) or it could be something else entirely. This is all well above my very basic mathematical understanding. Mathematics is something I wish I knew more about.

The interpolation routine I referred to should be sufficent to your needs. It all ties into the old saying "Measured With A Micrometer, Cut With An Ax!"

If pushed I could try to find the spreadsheet but I don't have a lot of free time right now.

Playing with Excel is fun and there is a lot that you can do with it. Give it a try!