Cozy spar and wings status


Here’s a short posting to show some of the progress on the Cozy. The Cozy was derived from the LongEZ and uses identical construction techniques. The main difference is that it is a 4-place airplane whereas the LongEZ is a 2-place.

This is the jig in which the main spar is built. The main spar is a box beam that is very strong. The wings attach to the spar and it is a major structural component of the airframe.

The part that makes up the shape of the spar is just foam, but it’s covered with many layers of fiberglass and epoxy which give it tremendous strength.

The wings are made of foam, fiberglass and epoxy. The shape of the wing is cut using airfoil templates with a ‘hot wire’ saw to give it an airfoil shape. This is probably the most fun part of building a composite airplane. In just a few minutes you go from a block of foam to something that looks like it belongs on an airplane.

The wing needs to be assembled in a jig to maintain proper dimensions. The jig also helps to set the sweep and twist of the airfoil.

The spar and wings attached to the rest of the fuselage.

2 thoughts on “Cozy spar and wings status

  1. Hello, Can you give me some advise on how you cut the foam wing, I am trying to cut a similar wing and can not get the hot wire to work correctly.
    Ric R

    • I learned this technique from the book and video called “Building the Rutan Composites” available from Aircraft Spruce. They also sell all the materials to make the hot wire tool and wing foam. Not all foams can be cut with a hot wire and some give off poisonous fumes so please refer to that book/video if you want to do it right.

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