Berthimus Prime

Berthimus Prime
Diameter	4 inches (101mm)
Length	5 feet 9 inches (1.75 m)
Weight (no motor)	8 lbs. 2 oz. (3.7 kg)
Motor Size	38mm
Number of Flights	2
Highest Altitude	not recorded
Highest Speed	not recorded
Status	Ready to fly
Sim File	https://github.com/DanCrank/openrocket-sim-files/blob/master/berthimus-prime.ork

This is an upscaled Big Bertha built from an Animal Motor Works kit. According to AMW's website, a limited run of 101 was produced for National Sport Launch 2018 at the request of Vern Estes; AMW still had some left at Airfest 2019 and I picked one up there. It appears to be out of production now.

I painted the rocket in colors matching the photo in the 1979 Estes catalog and made the graphics on my vinyl cutter. On its first flight, the rocket zippered due to a late motor ejection, requiring the top 2 feet of the lower airframe to be replaced. I replaced that section with a fiberglass tube for its second flight just a few weeks later. I finally got around to repainting the repaired section and redoing the graphic, but have not flown it again since then.

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  Before, during and after the repair.

• The rocket lifting off on a smoky motor. The unpainted repair is seen in the middle of the rocket.

  Second launch with unpainted repair section.