Re: Simplex 'foil - was "dang it"

From: Fred or Judy Rash <frash_at_chartertn.net>
Date: Sat, 16 Jan 2010 12:01:55 -0500

The "Simplex" is a logarithmic spiral; the arc is a portion of the circumference of a circle. Both sometimes can be found in math (CRC Standard Mathematical Tables), chemistry, and engineering handbooks. The arc has max thickness at 50% but the Simplex has max thickness between 35 and 40%.

Fred Rash


From: Neil Dennis
Sent: Saturday, January 16, 2010 9:05 AM
To: Indoor_Construction_at_yahoogroups.com
Subject: [Indoor_Construction] Simplex 'foil - was "dang it"


  
Yeah, that "simplex" software calculates and prints any percent chord
you ask for about 10" long on a sheet of paper that you can make any
length rib outline out of. FWIW, I glue the print to a piece of "2 x 2"
and cut the outline with the band saw, then use that to make a lamina of
like 2 sheets of 1/32 balsa and strip the ribs from that. I've used
anything from a 3% to a 12% on my Dennydart MKIV's.

BTW, never did get an answer as to the comparison between an "arc" and a
"simplex" :-(

wombat





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