Tuesday, January 17, 2012

Scavenger! Build Part 9 Fin Plan

Here's the fin plan for the Scavenger rocket.
These are based on the Estes Optima, a fin style I have always liked.

I start with full-size pencil drawings on copy paper.
After one drawing, another new piece of paper is taped on top of the first.
I make corrections by tracing over the first drawing.
These are usually subtle changes to the angles of the leading edge or fin span until I feel there is a good balance.

While not the same size, there are a lot of similarities in the two fins.
Both root edges are the same length.
The pencil extensions of the leading and trailing edges (going out to the right) are the same in both front and rear fins. In other words, the "triangle" pencil line extensions out are the same size.
On the upper fin, the angle of the outside edge is the same on the lower fin. Except that angle is flipped on the lower fin's outside edge.

The lower fin will the through-the-wall, the upper fin will be surface mounted.
All fins will be cut from scrap 1/8" basswood.

In the picture, the body tube edge on the upper left is actually straight. There was some distortion when I held up the drawing for a photograph.

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