Re: Is there a simple way to lay out different camber arcs?

From: <Warthodson_at_aol.com>
Date: Sun, 3 Apr 2016 14:40:04 -0400

"Simplexor Logarithmic Spiral Airfoil curves have the interesting property that onetemplate can be used for a wing of any chord and still give the same percentagethickness. The Leading Edge (LE) pointis always fixed at the left edge, and the Trailing Edge is cut to match thedesired chord." This quote is from Fred Rash's ReadMe File in the Files section of this Group.
There is also a program you can download to print an airfoil based on the % airfoil you want. I.E. 4%, 5%, 6%, etc. As I recall, the printed airfoil will have a cord of about 10" (it fits on an 8.5" X 11" piece of paper) & the % you specify. If you want a shorter cord, No problem. Just draw a line whose length is the cord you wish, starting at the leading edge of the printed curve and cross the curve at the cord you wish. It will always be the % you specified.
This is particularly useful on tapered wings. No scaling required. Just draw a straight line.
I can do it & I do not know what a "sagitta" is. It sounds like a delicious cheese.
Gary Hodson
 

-----Original Message-----
From: dweigt47_at_gmail.com [Indoor_Construction] <Indoor_Construction_at_yahoogroups.com>
To: Indoor_Construction Indoor_Construction_at_yahoogroups.com
Sent: Sun, Apr 3, 2016 11:29 am
Subject: Re: [Indoor_Construction] Is there a simple way to lay out different camber arcs?



  
    
                  
I understand how to calculate the airfoil height. What I need is how to calculate the radius, so I can subtract height to get the sagitta. I hope I'm using that correctly, as I don't recall ever seeing "sagitta" before! I just tried using the spreadsheet you posted, and see that it does calculate both. Thanks!

I don't know what a Simplex airfoil is, or where they are used. Also, it seems a bother to have to scale up an airfoil to its final size. Errors creep in taking measurements and plotting larger versions, and copiers distort, too.

Thanks, Wombat and Ole Bill for your replies! Educational, and useful!

Don Weigt
    
             

  
Received on Sun Apr 03 2016 - 11:40:06 CEST