EDA Calculation

[CloudyIFR]

Hello,

When calculating EDA do you use the ASIN or ATAN function?

Let's say I have a wing with 10 degrees dihedral, vertical distance from horizontal of 4.25" and 24" 1/2 span and the outer panel of 20 degrees, vertical distance from horizontal 10.4" and 18" span and use the ASIN function I'll get 12.42 EDA.

If I use the same method above and use ATAN I'll get 11.98 EDA. However, I believe when using the ASIN function I can measure the wing as on the model but when using ATAN I'll need to find the horizontal projected span which is difficult to do.

My question is, is there a formula that I can use in MS Excel to find the projected horizontal span from the angle or dihedral distance from horizontal and actual panel length?

Also, which method holds the true aerodynamic conventions for the EDA calculations, ASIN or ATAN?
Thanks
Curtis
Montana

[Ricardo RW]

bah! I were to recommend you use a spreadsheet and not bothering about the calculations... and that Spreadsheet is... yours. :p

There's another SS that's only for EDA, maybe it has the answer, don't have it in my work PC, I'll look for it tonight at home.

[CloudyIFR]

Thanks and I have it figured out, perfectly!!!!

Curtis
Spreadsheets are available in MS Excel here: http://h1.ripway.com/cloudyifr/files.htm