BobDaly
WellKnown Member
attached is a spreadsheet that calculates wing loads for the Minimax airplane.
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It appears to be similar. The final numbers are very close.Bob.....I don't have the appropriate program on my computer to open the attachment you posted. I have a copy of the October 1991 Structural Analysis that was done by an engineer, W. J. Collie, for TEAM. Is the analysis you posted similar, or ??
attached is a spreadsheet that calculates wing loads for the Minimax airplane.
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is there any ebook, pdf of this book
Design of Light Aircraft, 1995, Richard D. Hiscocks
?
Thank you and sorry for not replying sooner. The angle of attack is one of the inputs to the calculations. The Minimax airfoil is supposed to have a maximum lift coefficient of 1.5 unflapped and 2.0 with the flaps fully deployed. If the lift curve slope is 0.1/° then the 2 dimensional alphas would be 15° and 20°. But the calculation includes 3d effects so the angle of attack is somewhat higher. So, the 24° angle of attack is the fullflap angle of attack.Nice job, BobDaly! There are two things that called my attention, though: 1) Angle of attack: you used 24 degrees. Unless I am not foreseeing something, it seems a little excessive  but I suspect that you have an explanation for that; 2) Load factor of 4.4: Is that the maximum operational load factor? I would suggest, as you are very good at setting up a spreadsheet calculation, that you set up a spreadsheet to build the Vn diagram, to verify what is more critical, maneuvering or gust load factors. Once you do it, there are two strengths one has to check: permanent deformations (comparing stresses with the material yeld stress) and failure (comparing stresses with the material ultimate stress). To check for failure, one has to add 50% to the Vn diagram load factors.
What are you trying to accomplish? You would probably be better served finding a beam calculator. This spreadsheet is specific to the Minimax. That's not to say it couldn't be used for most twospar, fabric covered, strut braced monoplanes with some modification but one cannot simply change a couple parameters and expect useable results.Thanks for posting the spreadsheet. My computer has a "read only" program for Excel spreadsheets, Is it possible someone could change a couple of parameters and provide the resulting change to one loading?
If so here is what I need.
Line21 change from +4.4 to3.0
Line 34 change H from 47 to 84
Line 34 change V from 29 to 46
Interested in change to line 27 and 28 THANKS
So are you saying that if the airfoils are identical on both the MiniMax and Legal Eagle (they are, also identical in chord) that the spreadsheet values are valid? I have decided to do a test to destruction (compression) of a couple of struts using a strain gauge, faster and easier (also has more validity) than refreshing 60 yr old math skills that I most likely got a "C" in anyway. JohnBThis file has an error in it..
at L=WP and L=nWp (this formula has circular references error means L is calculated by P and P is calculated by L)
the designer took airfoil's value directly like maximum camber and location of it also some coefficients, you have to change all the airfoil parameters as per your airfoil in all the necessary formulas.
i will change it to workable manner, if anyone share (Design of Light Aircraft, 1995, Richard D. Hiscocks ) pdf ..
searching for this book to read necessary but dint get yet...
Computers allow overindulgences in many ways.and the number of iterative calculations is specified, a hundred is plenty.
Really I retired from the Army after twenty years in 1990! I think I've got you beaten!I got mine from Murphy Aircraft but this was in the nineties (Wow I am old)