Hello,
am drawing up a scale twin with 80.6 span and double tapered wing.trying to locate the cg.if the root is14.72 inches and the tip is 7.86 inches i hav a mac of 11.29.cg at 25-30 percent gives me 2.82 - 3.38.from leading at at station that has chord of 11.29.will start at 3.10 from leading edge.do these numbers sound right?been awhile since i have had to do this on a tapered wing.

Without knowing the amount of sweep for each panel, there's no way to verify your numbers.

le of tip rib is set back 5.21ninches from leading edge of root rib.any other numbers i forgot to include let me know.

Using your numbers, and a nominal panel span, it looks like this:
(panel span isn't all that important for this computation as long as the m.a.c. is in the main panel)

hello,
thanks for the input.what program do you use for this computation?looks like i could put it to good use?john

tall paul,
our numbers are within .20 inches.but the wing panel is just one panel 40.3 inches long.straight taper as in your diagram labeled panel 2.could you please run numbers again to verify no change in mac for me.better safe than sorry on the test flite.thanks.

Here's the URL for THE mean aerodynamic chord program everyone MUST have. It's downloable freeware, and will handle 5 panels:
.

http://perso.wanadoo.fr/scherrer/mat...glish/mce.html
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And here's the newer panel..

thank so much. have a nice weekend with no downwind landings

the center of gravity i calculated on the calculater was .20 inches in front of the cg calculated by this program.took me about 10 minutes with the calculator and getting the dimensions and angles and about 30 seconds with the program.big time saver.least with a bit nose heavy c.g for the test flight it is better than being tail heavy and i can relax a bit before the plane gets in the air.