I was quite proud with my progress detailed in the last post: Build Update 2 – Painting. With the motor/fin assembly now firmly bonded in place with copious amounts of epoxy, I shared a photo with a colleague of mine. He just so happens to have expert experience with high-powered model rocketry. Initially he seemed impressed. I then asked him about my plans to attach the cord for the parachute…
I started drafting this post in early April, straight after Build Update 1. Since then I have published the dilemma with the motor in “My motor choice went up in smoke”. Throughout the motor reselection process I was progressing the build, thus this post spans the build progress from April to now, mid-May.
At this point, in early April, I had applied my first coat of yellow paint (Humbrol 69). A single can of spray paint was wildly optimistic for a model of this size. I had quite crudely cut the slots in the phenolic body tube and fit-tested the motor and fin assembly. It looked as such:
I briefly covered my initial motor choice in the ‘Rocket Design’ blog post. For my rocket, GLYPO-001, I required a G-class motor that I could fly at my ‘local’ club FOG, and a more powerful H-class that I would fly elsewhere in the UK with a UKRA (UK Rocketry Association) certified RSO (Range Safety Officer).
I was not looking for altitude, I was looking for a nice dramatic slow launch. The Cesaroni AP (Ammonium Perchlorate) motors seemed ideal. They have some long-burn grains that I hoped would deliver the right stuff. By way of comparison, the Cesaroni Pro29 G-class motors (80–160 N·s) with three-grain refills have an average burn duration of 1.8 seconds across the range. They offer high-velocity grains that burn as quickly as 0.4 seconds, all the way to very slow-burn motors that last 4.4 seconds (Mellow).
This is a short, photo-heavy update showing the build progress so far.
OpenRocket produced some very helpful 1:1 scale PDF exports that made sizing the fins straightforward. The centring rings were also included in the export, but I opted to buy those pre-cut from Black Cat Rocketry.
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To mark the fin tab interface accurately but simply, I sketched the motor mount geometry in LibreCAD and printed it as a physical template.
Unsurprisingly, model rocketry is a niche hobby. That said, there are a number of shops across the UK, both bricks-and-mortar and online, that sell components for typical small black powder rockets (A–C class), which can be flown from a playing field.
The building and flying of large model rockets represents a much smaller subsection of this already limited market, which significantly restricts component availability.
Through internet searches and recommendations from colleagues, I identified a handful of UK suppliers and, thankfully, managed to procure almost everything domestically. As expected, the United States offers a much wider range of options.
I am hoping to attain my UKRA (UK Rocketry Association) Level 1 and Level 2 certifications, allowing me to launch high impulse (powerful) model rockets. I plan to start with an H-class rocket, the lowest motor impulse for a Level 1 rocket, and work my way up.
My local club, Fins over Gwent (FOG), billed as Wales’ premier rocketry club, is about 1.5 hours from my home in SW England. FOG issue a NOTAM (Notice to Airmen — a warning to pilots) that extends to 3,500 ft and is issued before each monthly club meet.