W9YA's L3 Certification Article
Whooie in the High Plains of Colorado Springs
My L3 project demonstrated a method to achieve the goal of scaling-up the size and power of the flight motor AND increase the airframe size accordingly while the design can remain a simple "odd-roc" design using the same materials for the airframe as the smaller sized "odd-roc". No special items are required as all of the materials are common and available at your local home-supply, general hobby, or office supply store. And the final design can be easily duplicated without resorting to adding huge amounts of weight so often encountered when trying to avoid the exotic materials.
I cannot be sure this design is entirely novel, but I haven't seen such a motor mount used elsewhere in rocketry. It does not require or use completely circular rings or their equivalent and the circular parts deployment tubes connect to the airframe using less than 15-20% of the total 2 dimensional cross section of the the airframe inside surface. This is quite different mounting scheme than a conventional motor mount uses that uses ALL of the available cross-sectional surface area to enable motor retention in the plane of the thrust. The deployment tubes also connect to the motor mount with an equally limited amount of 2 dimensional surface area being connected to the triangular "hub" at truncated points. (These points are rotated 60 degrees from the triangle points of the airframe so the flats of the motor "hub" plate are located tangentially to where the airframe joins, but the only connection is another (fourth) sheet of 1/4 inch foamboard. It is also important to consider that the compression of the airframe below motor mount, which in this design is only located 1/2 the way down from the forward end of the motor casing and also only 1/2 the way down the airframe sides is bolstered ONLY by these deployment tubes. ALL of these details can be seen in the drawings and pictures located here.
The background story can be seen here.
Rocket Graphics courtesy of the Crystal Space Community. Pictures courtery of Nadine Kinney, Tom Beach, Greg Elder, and Grant Finch