Semroc Swift

Semroc - Swift {Kit} (KB-2) [1968-1971]

Contributed by Chan Stevens

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar_border
Diameter: 0.76 inches
Length: 11.90 inches
Manufacturer: Semroc
Skill Level: 1
Style: Sport
SemRoc Swift

Brief:
Single stage, basic 3-fin/nose cone style that really cooks on B and C motors. If flying on a C, be sure to switch out the chute for a basic streamer or you'll be faced with a really long recovery walk.

This is another Semroc Retro-Repro, which is a slight modernization of a Centuri classic. In this case, this is based on the 1968 Semroc kit, which was modeled after the Estes Mark II and the Centuri Micron. The Semroc kit originally sold for $1.29 and now retails for $6. I got mine as a free kit when ordering several others from the Semroc website.

Construction:
Components were all very good quality, and included:

  • Balsa nose cone with screw eye
  • ST-790 body tube
  • Laser cut balsa fins
  • Centering ring (motor block)
  • Kevlar®/elastic shock cord
  • 12" plastic chute
  • 1/8" launch lug

The instructions for this were typical Semroc: well written, good illustrations, and easy to follow. This would probably be considered a skill level 1 kit as it's fairly easy to build in a single afternoon.

This is a minimum diameter kit, so there's no motor mount. Instead, you simply insert a centering ring into the body tube to serve as a motor block and that's it after tying the Kevlar® cord to the centering ring to anchor the recovery system.

The fins are laser cut, so you can spend some of the time saved in cutting them by applying a little sanding sealer to fill the grains instead. The instructions offer some nice tips on sealing balsa, which is a nice old-fashioned touch in an otherwise modern kit.

Fin placement on the tube is supported by a template printed in the instructions. I think a wrap would work a bit better and be much easier for novice builders. Also, the fins are to be placed flush with the aft end of the tube. I think moving them forward 1/4" would be a good idea as this makes motor retention a bit easier allowing you to tape the motor to the tube rather than only friction fit.

Tack the launch lug to the tube and glue the screw eye into the base of the nose cone and construction is done.

Finishing:
There are no decals for this kit, so you can get creative with the paint scheme if you like. I went with the stock scheme illustrated on the header card: green fins and cone over a white body. I wasn't that impressed with the overall look and would recommend a darker base or possibly metallic paints.

I had applied my typical two primer coats, sanded it down, wiped it clean, and then 2 finish coats.

For $6, I can't complain, but I'd at least like to see a basic decal or two with this, especially one that has the rocket's name on it. When you stick an unidentified 3FNC style rocket in the box, good luck remembering what it is you're flying...

Construction Rating: 4 out of 5

Flight:
Scrambling for a potential entry in a set duration/45-second contest, I decided to press this into service using a B6-4 by substituting a long mylar streamer (2" x 100") rather than the 12" chute as it was a fairly breezy day and I was flying on a small field.

The Swift name probably refers to its flight profile. This really zipped up to at least 800 feet on the B6. The 4 second delay was a bit early (the recommended delay was a 6 and I hadn't checked before heading out). Deployment was fine and the streamer brought it safely back for a fairly short walk. My duration was only 35 seconds though, so I'll probably go with a slightly larger streamer.

If using the 12" chute, be prepared for long walks. The estimated altitudes for a B are 950 feet and 1500 feet for a C. I think those are reasonably accurate and I will probably stick to A and B motors.

Recovery:
PROs: Kevlar® upgrade is excellent, especially in a $6 kit.

CONs: nice chute but this would come back just fine (and sooner) with a streamer.

Flight Rating: 4 out of 5

Summary:
This is a decent rocket, very good flyer, although a bit ordinary in terms of design. At $6, it represents a very good value and is an appealing skill level 1 rocket for the beginner.

Overall Rating: 4 out of 5

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