HWC small foam wings

22 December 2023

I have a short 6" bow cutter and cannot use it with rib templates.

6" is wider than most chords of small foam wings for wingspan of perhaps up to 20". So may be I can use it to cut triangular airfoil on expanded polystryene foam blocks.

• Block the wing planform, except that the leading edge is left straight for now and slightly oversized.
• Place trailing edge over table's edge and use root-tip span-wise LE template 1 at the straight leading edge to taper cut.
• Cut the leading edge sweepback on the wing planform, if any.
• Place leading edge template 2 over table's edge and use another root-tip span wise template 3 at the trailing edge to taper cut. 
• Trim to wing planform.
• Sand to trim the wing planform and airfoil.

The templates has to be stable and self supporting.

• LE template 1: Could be a taper if the thickness is to reduce at tip
• LE template 2: If there is no washout and no change in thickness, then it is a thin strip. Use a taper strip if there is washout, higher at the root. Use a more tapered strip if there is both washout and thickness change.
• TE template 3: The highest template. Not tapered if no thickness change and constant chord. Tapered strip to cater for tapered planform and change in thickness.

Washout is introduced at the leading edge; the trailing edge is left flat.

Elliptical planform led me to think of planform template.

Also, the high point is important. 

If the front and rear tapered slopes maintains throughout span, it means same airfoil throughout the span even though it looks thinner at the tip.