REFLECTOR: interference drag

[Ken C. Baker]

Doug,
 
Looks good! A word of caution though - most of the pour foams available on
the market, even the very good ones, do not make good structural cores. They
have very low pcf ratings, and during crystallization they form irregular
cell structures. As well, they are prone to soft spots. They're great for
shaping things that you will ultimately glass over - but it's important to
remove the pour foam, and replace it with a structural core like 3/8"
divinycell, then glass the other side. In other words, it's important to get
that sandwich structure back in there - especially at a critical structural
union like the strake/fuselage junction.
 
Happy Building,
 
-Ken Baker
kenb at velocityaircraft.com
XL-RG Hybrid-5 in Progress

  _____  

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Douglas Holub
Sent: Tuesday, November 20, 2007 12:00 PM
To: reflector at tvbf.org
Subject: REFLECTOR: interference drag


I used pour foam to fill in the intersection between the strake and the
fuselage, then shaped it with some 40 grit sand paper glued around a Clorox
bottle. Here's what the fillet looks like with a Clorox bottle radius. By
doing the top and bottom of the wings, strakes, and winglet intersections
this way, I'm hoping to pick up a few extra mph.
 
Doug Holub
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.tvbf.org/mailman/private/reflector/attachments/20071120/7ec7d9fa/attachment.htm