Semroc Micron

Semroc - Micron {Kit} (KV-8)

Contributed by Chan Stevens

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Diameter: 0.76 inches
Length: 9.20 inches
Manufacturer: Semroc
Skill Level: 1
Style: Sport
Semroc Micron

Brief:
Nice little minimum diameter rocket that zips off the pad in a hurry and at $4 retail, makes for a nice little kit for that Cub Scout or school group. This is also an appealing kit to the nostalgia buff that is based on the 1963 Centuri kit by the same name.

Construction:
As is the case with almost every Semroc kit, this one came in a professionally bagged package along with a certificate of authenticity/production number. Parts include:

  • ST-765 body tube
  • Balsa nose cone/screw eye
  • 4 laser cut balsa fins
  • Thrust ring
  • Streamer (crepe paper)
  • Kevlar®/elastic shock cord combo

With laser cut fins, this is definitely somewhere just below a skill level 2 kit. The only challenge is to mask a 2 or 3 color paint scheme.

The instructions were well written and clear; offering some decent construction tips along the way, such as how to fill grain on the balsa fins.

Being a minimum diameter kit, the body tube acts as a motor tube, so simply gluing a thrust ring into one end takes care of the motor mount assembly aspect of the build. Before doing this though, you tie one end of the Kevlar® shock cord to the ring, thereby anchoring it to the thrust ring inside the body tube. This is a very good and effective technique, one that I wish was more common in the lower skill level kit range.

Next, sanding the fins, which is easier to do this while still in the balsa sheet, and removing them from the laser-cut sheet. The instructions call for bonding them flush with the aft end of the tube, although I'd consider sliding them forward about 1/8". This won't throw the CP off that much and enables you to use a band of tape around the motor and body tube for improved motor retention.

Tack on the launch lug, glue the screw eye into the balsa nose cone, and you're ready for recovery and paint prep.

The streamer for this kit isn't too bad, it is a piece of bright orange crepe paper roughly 3" x 36", but it's attached using a fairly weak line and is secured by a single tape disk attached to the center. I don't think this is likely to hold up very well over repeat flights and would have preferred to see a chute instead.

Finishing:
I skipped the balsa sealing/filling routine on this one, jumping straight to primer. Two coats of primer and sanding in between with a 220 grit sponge did a reasonably good job on the balsa grain, so I moved on to two coats of Krylon gloss white. I finished up with a blue nose and red fins, matching the illustration on the package header. The header also depicts some blue accent stripes (roll pattern), which is possible to paint but would clearly be better (and easier) if a waterslide decal were supplied for this. I guess for $4 I shouldn't complain but I'd rather pay $6 and have a decent decal or two.

Construction Rating: 4 out of 5

Flight:
The maiden flight was on a beautiful fall day with low winds, though there was some cloud cover way up above our club's waiver ceiling. I went with a B6-4, as I did not have any B6-6s handy. Before I could even blink, this was pushed almost beyond my sight, well over 800 feet. Apogee might have been a little early, but not enough early to worry about.

The streamer deployed fine, but it didn't offer much drag for this rocket and it came down fairly fast. Fortunately, it landed in a large, soft grassy area undamaged. Still, given the descent rate and weak attachment point, I will be replacing the streamer with one of my spare chutes just to avoid any potential damage on the recovery.

Recovery:
PROs: Kevlar®/elastic combination is a solid, durable method.

CONs: undersized streamer, weak attachment disk/line.

Flight Rating: 4 out of 5

Summary:
This was a terrific value at $4 retail and I'd recommend buying this for a group build-fly session in the future.

Overall Rating: 4 out of 5

Other Reviews
  • Semroc Micron By Bill Eichelberger (April 24, 2014)

    The Semroc Micron was part of my first order from Semroc back in 2003.  I built it and the Skyhook side by side, and because of these two became enamored with the Semroc way.  The sleek Skyhook and the sturdy Micron combined the best that was available in the hobby at the time, reproductions of classic kits with updated recovery systems and laser cut fins.  Rocketry ...

  • Semroc Micron By Mike Mistele

    Brief: This is a very basic 4FNC, minimum-diameter, streamer-recovery rocket suitable for beginners. It's part of Semroc's RetroRepro line and, specifically, the Micron was originally a Centuri model (#KA-5) first released in 1963. The RetroRepro line updates these old models with more current technology--in this case, the upgrades include laser-cut fins and a Kevlar shock-cord. ...

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