Brief:
Very affordably priced single stage, 13mm minimum diameter kit. Very high performance--it will zip up to incredible altitudes almost instantly. This is actually a Semroc original, not one of their retro/repro Centuri designs.

Construction:
The kit came sealed in a plastic bag with a header card and included a serial number identifying its production number. Components were all very good quality and included:

• ST-5120 body tube (basically a BT-5)
• Balsa nose cone/screw eye
• Laser-cut balsa fins
• 1/8" launch lug
• Kevlar/elastic shock cord combo
• Crepe paper streamer
• Motor block
• Waterslide decals
• Motor casing, Q-tip glue applicator

Yes, this kit includes a motor casing (actually just a plain cardboard tube) and a Q-tip for applying glue up inside the body tube. Not bad for a $5 kit and that makes this a very good project for Cub Scouts and school groups. Cheap, easy, and includes the little gadgets to simplify construction that most of us experienced builders take for granted. This kit is definitely something that can be built in under an hour, plus paint/finish time. The instructions were clear, have plenty of good illustrations, and everything fit fine.

Being a minimum diameter kit, there's no motor mount assembly to work on. Instead, you just glue a motor block inside the body tube. Even though I usually use scrap balsa for this, I though it was neat that they included a Q-tip for this application. Keep in mind though that before gluing in the motor block, you must first tie the Kevlar shock cord to the block. I really like the Kevlar but this looked a bit light (maybe 90#) and I'm curious how it will stand up to repeated flights.

Fin preparation is pretty easy, since the fins for this (and all Semroc kits) are laser cut. After a light sanding, they're ready to bond to the body tube. There are 3 fins attached at the standard 120-degree rotation. Be sure to apply a good fillet on these, as the fins are tiny and there is a lot of stress when flying this on an A10.

The nose cone is a standard balsa nose with screw eye anchor. No additional nose weight is needed on this. This was a very nice balsa cone. Semroc really packs quality and value into their kits.

Construction wraps up with the attachment of the crepe paper streamer. It's a nice orange 1" wide streamer, although I think the small tape disk/dot for attachment is pretty flimsy so I upgraded mine to heavy masking tape at the base.

Finishing:
The instructions do a nice job of detailing out how to properly seal balsa; suggesting up to 3 coats of sanding sealer. I cheated and went with a single diluted coat of Elmer's Fill 'n' Finish, which I sanded down with 240 grit sandpaper.

After sanding down a coat of gray primer (used mainly to fill spirals), I followed up with a white primer base, then two coats of gloss white. The illustration on the header card shows a yellow base. I've never really had much luck with Krylon yellow and unless it's over pure white I wind up needing a lot of coats to cover up basic pencil marks or base coats. I found a can of safety/dayglo yellow though and decided to give it a shot. It looked GREAT and only needed a couple of coats. The bright yellow really stands out.

The kit also includes a set of water slide decals, which I think are an excellent addition to this kit. It would look fairly boring otherwise, but with the decals it almost looks like a bee.

Construction Rating: 4 out of 5

Flight:
First flight was on a fairly windy day, approaching 8-10 mph. I went with a 1/2A3-4. Despite the wind, this raced absolutely straight up and cooked to easily 400 feet. The streamer rolled out right over apogee and everything came back in great shape.

I have since flown it in calmer winds on A3s and A10s, both of which take it out of sight. For full As, I recommend using tracking powder to make sure you can spot it. Tempera paint powder makes great tracking powder as does crushed chalk (from a home supply store).

Recovery:
Perfect flights, no problems whatsoever.

Flight Rating: 5 out of 5

Summary:
I've built a bunch of Semroc kits now and this one is one of my favorites. It's a great value, easy to build, and flies out of sight on a $0.75 motor. It doesn't get much better than that.

Overall Rating: 5 out of 5