Here we go… AGAIN!
It all started with the Estes Mosquito. We’ve all flown them. These little gnats of the rocketry world that exist to suck your blood, empty your wallet of a few bucks, and then vanish into the tall grass the second the motor ignites.
A fellow member of The Rocketry Forum, PHX1212, asked a simple question: “What would happen if we up-scaled that "blink-and-you-miss-it" classic to a 4-inch monster?” Well…
The answer is The Ex-Wife: a giant, 4-inch diameter blood-sucker that’s loud, expensive, and demands your undivided attention. This will be a series of posts walking though the process of designing and building the Ex-Wife. Good Idea? No, but I'm the reason NAR has rules, so buckle up.
Off the Bubble
I’m David. I’ve been building and flying for nearly 40 years, but 3D printing changed the game for me. My brain is configured a little differently... I’m "off the bubble." That doesn't mean I'm broken; it just means I see the world from a different perspective. My super power.
This series isn't just about a rocket; it's about the mitosis of a design—how we take the DNA of a tiny kit and watch it divide, grow, and specialize into a High Power Kaiju.
One Airframe, Two Souls
I wanted this project to be accessible, so I’ve designed a universal 4-inch airframe with a 54mm motor mount that offers two distinct paths:
The Ex-Girlfriend (Class 1 Mode): Built with standard LOC tubing and lightweight printed fins. Perfect for G80 motors at the local park.
The Ex-Wife (Boss Mode): Built with rugged Blue Tube and carbon-fiber-reinforced fins. This version is designed to handle J250 power, hitting Mach 0.8 and screaming to 5,000 feet.
The abstract design is the same for both paths, but you get to choose your own adventure.
My Design Golden Rule: If it doesn't fit within a 256 mm³ build volume (Bambu Labs standard), it won’t be included in the kit. The tech shouldn't be the limit—only your experience.
What Does That Mean?
Rocketry is a fun and exciting pastime. However, it requires some understanding of basic rocketry concepts. If this is your first kit build... no, it is not. You need to have experience building rockets and work your way up to a builder’s kit. This is a big, heavy rocket that will leave one hell of a dent in someone’s car, or worse. You NEED to understand the potential that a rocket like this possesses. In the hands of an experienced builder, it’s going to turn heads, make all the guys want to be like you, and all the girls want to be with you (this is absolutely not true). If you don’t know what you are doing, please believe me, you will spend a lot of time building a heartbreak. The Ex-wife will quickly disabuse you of any notions that you are ‘The best to have ever done it’, take your hat and wallet, and leave you bleeding on the sidewalk.
“A man has got to know his limitations” - Dirty Harry
The Roadmap
Future - The CAD Bridge (Fusion 360) – Designing the "Skeleton" and the "Skin."
Future - Slicing & Materials – Why orientation is destiny and how to win the "Filament Holy Wars."
Future - The Build & The "Two is One" Rule – Assembly, epoxy gaps, and the "Bone Swap."
Next Week: We open the simulator and start breaking down the design with the "Philosophy of Intent."
(This article uses elements that were generated by AI)
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