Takeoff Performance Spreadsheet instead of Graph

nauga said:
Performance charts should represent the performance of the airplane, not the pilot.
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That's why the are in the airplane book.

But building one's own based on them can be part of the establishment of personal minimums. And even thinking of doing it leads one to delve more deeply into them.
 
midlifeflyer said:
But building one's own based on them can be part of the establishment of personal minimums. And even thinking of doing it leads one to delve more deeply into them.
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I don't disagree with what I think it the sentiment of your post in that the more you know about how performance numbers were calculated the better you can assess whether or not you can attain them. Still, if it's a matter of differences in technique or skill or specific airplane performance I prefer increments or corrections to the charts rather than regenerating everything, especially for a one-off that might change as proficiency improved (or degraded, perhaps).

Nauga,
and his drag index
 
nauga said:
I don't disagree with what I think it the sentiment of your post in that the more you know about how performance numbers were calculated the better you can assess whether or not you can attain them. Still, if it's a matter of differences in technique or skill or specific airplane performance I prefer increments or corrections to the charts rather than regenerating everything, especially for a one-off that might change as proficiency improved (or degraded, perhaps).

Nauga,
and his drag index
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Can't speak for anyone else, but In my case I'm not regenerating anything. Nor do I want to. Just trying to simplify. In terms of a spreadsheet which performs calculations, it means some level of complexity to get the same (or at least conservatively close) numbers as the graph. A non-calculated alternative is to do a series of scenarios from the graph to create the type of simplified table Cessna used in some models rather than a graph for takeoff and landing performance.

What someone wants to do it up to them, if they want to do a series of test flights to determine the best numbers for their airplane with all its age, mods, dents, etc, I don't have an issue with it. Sometimes projects like this are more about the fun of intellectual curiosity rather than practical necessity.
 
midlifeflyer said:
I did a similar Excel flight planner years ago, including an airport and VOR database. Regularly do weight and balance ones. And I've been playing with this spreadsheet project for a while. Yes, the numbers are going to be different for each make and model. I've actually gotten as far as lookup tables using the ISA numbers taken from the graphs, some interpolation, and application of conservative rules of thumb for things like weight reduction. (I won't share; aside from being a work in progress, it's ok for me but my confidence level is too low to pass on to others.)
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That’s pretty nifty. I made an excel flight planner just for fun. I don’t use it but it was satisfying to see it kick out the same numbers as my E6B calculations and Foreflight. I think a W&B calculator would be useful. Maybe that will be my next project.
 
woodchucker said:
That’s pretty nifty. I made an excel flight planner just for fun. I don’t use it but it was satisfying to see it kick out the same numbers as my E6B calculations and Foreflight. I think a W&B calculator would be useful. Maybe that will be my next project.
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Wt & Balance is fun, useful, and can be surprisingly easy, even with a graph of the envelope and plots.
 
midlifeflyer said:
What someone wants to do it up to them, if they want to do a series of test flights to determine the best numbers for their airplane with all its age, mods, dents, etc, I don't have an issue with it. Sometimes projects like this are more about the fun of intellectual curiosity rather than practical necessity.
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Absolutely. I'm only posting what I am to dissuade the thinking that the charts are generated by going out and flying a bunch of test points and plotting the data. There are a lot of steps in between flight and plot to get all the data referred to the conditions/assumptions listed on the plot and you may be just as likely to underpredict as overpredict if you don't understand the process.

Nauga,
who strives for accuracy but lives with uncertainty
 
 
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NealRomeoGolf said:
Yep. I have mine in my Google docs so I can do one for my plane with my phone at any time.
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That's one issue I have. I created mine in Excel and the graph capabilities of Excel and Google docs don't translate. If I pull my Excel spreadsheet into G-Drive, I can get the calculations (which are enough) but don't get the graph.
 
midlifeflyer said:
That's one issue I have. I created mine in Excel and the graph capabilities of Excel and Google docs don't translate. If I pull my Excel spreadsheet into G-Drive, I can get the calculations (which are enough) but don't get the graph.
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I don't graph mine. I pasted a copy of my POH graph into the excel sheet and just have it do the math. Then I can see on the graph where I am.
 
NealRomeoGolf said:
I don't graph mine. I pasted a copy of my POH graph into the excel sheet and just have it do the math. Then I can see on the graph where I am.
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Yeah, but this is fun...
Once one is set up, it's pretty easy to do others. I think I have them for about 8 makes/models.

upload_2019-9-7_13-12-52.png
 
midlifeflyer said:
Yeah, but this is fun...
Once one is set up, it's pretty easy to do others. I think I have them for about 8 makes/models.

View attachment 77605
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Ok, you made me go graph in Sheets. That was painful. As a guy who makes a living in Excel, I wanted to jump off the roof. It works....but not really. I had to draw those lines manually since you can't do a combo graph with x,y in Sheets. Lame.

weight and bal.JPG
 
NealRomeoGolf said:
Ok, you made me go graph in Sheets. That was painful. As a guy who makes a living in Excel, I wanted to jump off the roof. It works....but not really. I had to draw those lines manually since you can't do a combo graph with x,y in Sheets. Lame.

View attachment 77608
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It's really too bad the graph formats don't translate.
 
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