Hi all,
I want to pose some questions to the group that (obviously) I cant figure out on my own. I have a project under way that utilizes the Spitfire plan form (stolen directly from.) The plan form choice was rather easy as the lift distribution is perfect and of course the obvious sex-appeal. I have posted a plan view and a pic of the project to date in the "new member introductions" section https://www.homebuiltairplanes.com/forums/showthread.php?t=3532
Now the query: in my studies and number crunching I have not yet come across any info for (1) calculating reference or wetted area of an elliptical wing, nor the mention of (2) how to find MAC. I am not and engineer by education or profession and do not have a CAD to help me hear. (3) How should the wing wash be applied (I know... soap and water with a sponge!!!)? I planned to wash +2* at the root and 0* at the tip that will allow my 23012 airfoil both low lift and drag moments at the tip. But the question is how should the wash be applied, over the entire semispan in a linear way or in a manor relative the ellipse? The latest boggle in my mind is the sweep vs. CG, I have a drawing with the wing slightly swepped foreward so there is 0 sweep at 1/4 C. I like that idea because a strait spar would be slightly easier to build here! So the question is (4) what should the sweep be and is there any penalty particular to an elliptical wing for slight tweaking of sweep?
What I have done is assume a double tapered reference wing plan for all of my calculus and prior to finding this site was OK with that for final assumptions. But, I have decided that with the available expertise perhaps I can get the info that I’m lacking. I am close to the point where I must fix the wing spar position so as to be able to continue locating system parts and manipulating structures. So any input would really be welcome.
Thanks
_travis
I want to pose some questions to the group that (obviously) I cant figure out on my own. I have a project under way that utilizes the Spitfire plan form (stolen directly from.) The plan form choice was rather easy as the lift distribution is perfect and of course the obvious sex-appeal. I have posted a plan view and a pic of the project to date in the "new member introductions" section https://www.homebuiltairplanes.com/forums/showthread.php?t=3532
Now the query: in my studies and number crunching I have not yet come across any info for (1) calculating reference or wetted area of an elliptical wing, nor the mention of (2) how to find MAC. I am not and engineer by education or profession and do not have a CAD to help me hear. (3) How should the wing wash be applied (I know... soap and water with a sponge!!!)? I planned to wash +2* at the root and 0* at the tip that will allow my 23012 airfoil both low lift and drag moments at the tip. But the question is how should the wash be applied, over the entire semispan in a linear way or in a manor relative the ellipse? The latest boggle in my mind is the sweep vs. CG, I have a drawing with the wing slightly swepped foreward so there is 0 sweep at 1/4 C. I like that idea because a strait spar would be slightly easier to build here! So the question is (4) what should the sweep be and is there any penalty particular to an elliptical wing for slight tweaking of sweep?
What I have done is assume a double tapered reference wing plan for all of my calculus and prior to finding this site was OK with that for final assumptions. But, I have decided that with the available expertise perhaps I can get the info that I’m lacking. I am close to the point where I must fix the wing spar position so as to be able to continue locating system parts and manipulating structures. So any input would really be welcome.
Thanks
_travis
