This rocket is meant to be kind of a "Rocket Scrap Yard" build.  It has some Mercury, Gemini and Apollo influences.  It's also a modular build.  It has a removable Cargo Bay that can be installed or removed.

The upper three motor canted cluster utilizes a 24mm motor.  There's a 24mm motor mount in the fin can, and the cargo bay too.

Link to Build Thread: Lakeroadster's Lifting Rocket | The Rocketry Forum