RCU Forums - View Single Post - My first foamie... a SPAD Foamie
View Single Post
Old 03-13-2005, 09:56 AM
  #11  
-pkh-
Senior Member
My Feedback: (2)
 
-pkh-'s Avatar
 
Join Date: May 2004
Location: Emmaus, PA
Posts: 3,354
Likes: 0
Received 0 Likes on 0 Posts
Default RE: My first foamie... a SPAD Foamie

Imopar69...

Airfoil shape is not critical... you'd be surprised what can actually fly pretty well! For planes with wing spars, you just place the spar where the plans indicate (usually spec'd a certain distance from the leading edge), and just fold the wing material (foam, in this case) over the spar and glue the trailing edge of the wing. Depending on how hard you pull back on the top when you fold it over the spar, you can end up with a flat-bottomed airfoil (not pulling hard) or a semi-symmetric airfoil (pulling harder, and actually curving the bottom leading edge upward). This was a spar-less wing design, and the plans didn't spec the exact location of the airfoil peak, so I just looked at the plan photos and eyeballed it. I actually put in a yardstick as a temporary spar when I folded this wing and glued it. This gave me a little thicker airfoil than the plans spec'd, which I believe will produce more lift, and hence a little more drag. I'm sure there are some optimal shapes for airfoils, but after building a few SPADs (with Corplast, or corrugated plastic folded wings) I've come to realize that you can screw up several details of the wing's shape, and not really notice anything in flight.

The foam is Dupont Bluecor Fan-Fold foam, used for insulation in houses, not sure exactly where though. It is used because it is relatively cheap (although you have to buy a large bundle of it) and readily available at home improvement stores like Lowes. Here's a link to the stuff on Lowes' website...

[link=http://www.lowes.com/lkn?action=productDetail&productId=15346-46086-CP-14-LOW]Dupont Bluecor Foam at Lowes[/link]