Wedge Ribs

21 June 2024

As an example for a top covered airfoiled wing using the described wedge ribs, balsa sheet wood can be cut efficiently with minimal waste as per the following photo. 

I have sketched six upper wedges with a base and eight lower wedges without the base. 

The challenge with the wedges without a base is the difficulty in accurately cutting the acute angle, which complicates the positioning of the wedge ribs to the trailing edge line, and the sharpened ends may not provide adequate support.

The base won't detract too much aesthetically because the exposed corners can be sanded off. 

20 June 2024

Simple wedge ribs for small light models. Photo shows concept. All ribs share the same wedge shape and only need to slice off to the desired chord. Whatever the chord length, the high point of camber is at 30% and the thickness to chord ratio does not change, i.e. conventionally, it's called a 10% thick airfoil. Sand down a bit more and the thickness reduced. 

Structurally, glue on the leading sheet, trailing sheet, groove to insert spar (if double skin) or another spar sheet at the bottom if you think the wing will clap in the air. 

You want a more rounded leading edge for double skinned? You can always glue on a glue on a square balsa and sand away.

Sand the structurally constructed wing and sand away the pyramid top if that offends you too much.

I don't think the air at low reynolds will be too picky.

This method offers a great balance between simplicity, weight, and performance for small, lightweight models. It's a perfect way to get your models flying quickly and efficiently!