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Big MAC?

Posted: Sat Jan 26, 2019 11:12 am
by Jim Hardin
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

Re: Big MAC?

Posted: Sun Jan 27, 2019 9:54 am
by drseti
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

Re: Big MAC?

Posted: Sun Jan 27, 2019 6:45 pm
by Atrosa
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.

Re: Big MAC?

Posted: Sun Jan 27, 2019 6:53 pm
by TimTaylor
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.

Re: Big MAC?

Posted: Tue Jan 29, 2019 1:34 pm
by Jim Hardin
No pain, no gain :P

Re: Big MAC?

Posted: Mon Feb 18, 2019 2:01 pm
by foresterpoole
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

Re: Big MAC?

Posted: Mon Feb 18, 2019 2:33 pm
by drseti
foresterpoole wrote: I live in an excel sheet, linear/conditional programming, and SAS
Ah, SAS - you're bringing me back to the 1970s!