Big MAC?

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Jim Hardin
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Big MAC?

Postby Jim Hardin » Sat Jan 26, 2019 11:12 am

Teaching as well as using Weight and Balance to determine CG is always interesting...

I prefer using the Station and CG envelope in inches rather than Moment/1000. But Station can get interesting if the forward GC limit is not fixed. Then you have to interpolate the results to make sure you are still in there.

Only had to use % of MAC once. Student had a Stinson 108-3 and that was the first time since studying for my ATP that I ever used it. I couldn't see any practical advantage to using it.

Open end discussion, what do you guys think? :D

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drseti
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Re: Big MAC?

Postby drseti » Sun Jan 27, 2019 9:54 am

As an engineer, I find % MAC very useful. And I teach it. Very simple if you have a Hershey-bar wing, where chord us constant over the entire wingspan. Much more difficult with a swept, tapered, or semi-tapered wing requiring you to integrate the area under the curve and divide the integral by the span to establish the mean. :x
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
Prof H Paul Shuch
PhD CFII DPE LSRM-A/GL/WS/PPC iRMT
AvSport LLC, KLHV
fly@AvSport.org
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Atrosa
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Re: Big MAC?

Postby Atrosa » Sun Jan 27, 2019 6:45 pm

drseti wrote:As an engineer, I find % MAC very useful. And I teach it. Very simple if you have a Hershey-bar wing, where chord us constant over the entire wingspan. Much more difficult with a swept, tapered, or semi-tapered wing requiring you to integrate the area under the curve and divide the integral by the span to establish the mean. :x



WHAT!!! calculus. That's it I'm quitting becoming a pilot and joining the youth by being hypnotized by my phone.

TimTaylor
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Re: Big MAC?

Postby TimTaylor » Sun Jan 27, 2019 6:53 pm

Atrosa wrote:
drseti wrote:As an engineer, I find % MAC very useful. And I teach it. Very simple if you have a Hershey-bar wing, where chord us constant over the entire wingspan. Much more difficult with a swept, tapered, or semi-tapered wing requiring you to integrate the area under the curve and divide the integral by the span to establish the mean. :x



WHAT!!! calculus. That's it I'm quitting becoming a pilot and joining the youth by being hypnotized by my phone.


That's why I switched from Aeronautical Engineering to Industrial Engineering at NCSU. Two years of chemistry, calculus, and physics was enough. An MBA from Wisconsin was easy after all that.
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Jim Hardin
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Re: Big MAC?

Postby Jim Hardin » Tue Jan 29, 2019 1:34 pm

No pain, no gain :P

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foresterpoole
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Re: Big MAC?

Postby foresterpoole » Mon Feb 18, 2019 2:01 pm

TimTaylor wrote:
Atrosa wrote:
drseti wrote:As an engineer, I find % MAC very useful. And I teach it. Very simple if you have a Hershey-bar wing, where chord us constant over the entire wingspan. Much more difficult with a swept, tapered, or semi-tapered wing requiring you to integrate the area under the curve and divide the integral by the span to establish the mean. :x



WHAT!!! calculus. That's it I'm quitting becoming a pilot and joining the youth by being hypnotized by my phone.


That's why I switched from Aeronautical Engineering to Industrial Engineering at NCSU. Two years of chemistry, calculus, and physics was enough. An MBA from Wisconsin was easy after all that.


I thought I was getting into a mathematical dessert when I started in forestry, fast forward 2 decades: Between business planning on 600,000 acres of timberland, manufacturing quality control oversight at three of the largest wood products mills in the country, and a host of other pet projects like real estate finance, I live in an excel sheet, linear/conditional programming, and SAS (a stats program). My head hurts.... :D
Ed

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drseti
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Re: Big MAC?

Postby drseti » Mon Feb 18, 2019 2:33 pm

foresterpoole wrote: I live in an excel sheet, linear/conditional programming, and SAS


Ah, SAS - you're bringing me back to the 1970s!
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
Prof H Paul Shuch
PhD CFII DPE LSRM-A/GL/WS/PPC iRMT
AvSport LLC, KLHV
fly@AvSport.org
AvSport.org
facebook.com/SportFlying
SportPilotExaminer.US


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