Brief:
Another Semroc retro-repro kit, the Semroc Astrobee 350 is a modernized version of the Centuri 1965 kit that also is a quick, easy scale project.

Construction:
The kit includes:

• ST-1010 body tube
• Balsa nose cone
• 18mm x 2.75 motor tube pack
• 4 Laser-cut balsa fins
• 12" plastic chute
• Waterslide decal

Parts are excellent quality, and come in a sealed plastic bag complete with individual production number.

Semroc instructions are clear and easy to follow. This kit begins with basic motor mount assembly consisting of 2 centering rings, an 18mm tube, motor block, and metal retaining hook. A nice upgrade to the Centuri kit is the Kevlar® cord mounted to the motor mount with an elastic extension. The instructions call for tying a loop and placing the metal hook through the loop, which struck me as a potential weakness, so I wrapped mine around the tube instead and brought it out under the centering ring.

Fin prep is very easy with these kits as they're pre-cut using a laser. The fins are mounted on 90-degree angles around the tube. The instructions include a basic circle with hashmarks for a marking guide, which is quicker than cutting out a template but easier to goof up on. I tacked on my fins with a medium CA, then applied fillets using yellow glue.

This kit included a very nice balsa nose cone, which is secured via a good old-fashioned screw eye. My cone was a bit tight in the tube and took just a little bit of sanding for proper fit.

Construction wraps up with making the parachute, which is a basic plastic cutout with tape disks to attach the shroud lines.

I was in a bit of a hurry on this one (building a batch of 7 different Semroc kits at once), so skipped my usual spiral fill/grain fill application of Elmer's Fill 'n' Finish. This brought the total construction time down to about 30 minutes, at which point it was ready for paint.

Finishing:
I applied a couple of coats of primer, which did a reasonable job of filling the spirals once I sanded it back down a bit. After that, I followed up with two coats of Krylon gloss white. I then masked off the white (after allowing a couple of days to fully cure) and painted the fins red and the nose cone black per the standard paint scheme.

This kit comes with a very nice waterslide decal for a striped roll pattern at the top and a pair of thin stripes to trim the bottom. I found the decals very easy to work with and they add a nice accent.

Construction Rating: 4 ½ out of 5

Flight:
First flight was on a beautiful day of light winds. I went with a C6-7, which should have carried it to an estimated 1250 feet. Unfortunately, once it left the rod, it went into a bizarre loop then straightened out and took off at about a 40 degree angle. This clearly indicated that the rocket was unstable with the weight of the C6, and as the propelant burned down (and the CG moved forward), it became more stable. With this flight path, ejection was 3-4 seconds late, though the model landed gently, and I avoided any damage (not even a zipper).

Second flight was on a B6-6, which flew straight up without any problems, though I think it was only around 500 feet versus the estimated 650 on the kit header card.

Recovery:
The Kevlar®/elastic recovery is an excellent combination, and this is exactly the way modrocs should come. The plastic chute worked fine though this rocket needs plenty of wadding or dog barf to hold up over repeated flights.

Flight Rating: 3 ½ out of 5

Summary:
This is a fairly nice looking rocket that's very easy to build using excellent components. I would recommend a couple of washers for nose weight though, to take care of the stability problem using C motors.

Overall Rating: 4 out of 5

Brief:
A Semroc retro-repro version (KV-13)of Centuri's 1965 Astrobee 350 (KC-5)and incorporating updated technology like laser-cut fins and Kevlar®-mounted shock cord.

Construction:
The parts list is covered in Chan's review so I won't elaborate here.

This being my first Semroc build, I found the Astrobee 350 to be a nice and easy skill level one kit to put together with no "gotchas" and such. The components are top quality and the instructions come in the form of a detailed booklet in color. These instructions were very well written and easy enough for even the most inexperienced novice to understand well.

The motor assembly is constructed by inserting the motor hook into the pre-cut slot in the motor tube. After gluing in the thrust ring, the two cardstock centering rings are then glued into place. I then used white glue to add fillets around the edges of the centering rings where they slide over the motor tube. Once that is done, the completed motor assembly is glued into place in the body tube. Although I had my reservations about Semroc's recommendation to loop and tie off the Kevlar® cord to the motor hook, I nonetheless went ahead and did that anyway. Time will tell if the Kevlar® will hold up under such an arrangement.

Fin marking is provided by a fin guide in the instructions consisting of a circle with hash marks by which the end of the body tube is placed on the circle and the hash marks used as a guide for fin position markings. I had no problems using this although personally I would have preferred to use a wraparound fin marking guide. I then tacked the fins on with medium CA and followed this up with white glue for multiple fin fillets. Following on from this, the launch lug was added.

With the exception of using CA to tack on the fins, I used Selleys PVA (white glue) throughout the construction process.

Finishing:
This rocket was a cinch to finish. I filled in the balsa fin grain and the lovely balsa nose cone with two applications of Micro-Fill model sealer and after having initially slightly roughened up the body tube with 360 grit sandpaper, I gave the rocket two coats of Tamiya Fine White primer with light sanding in between and followed this up with two coats of Tamiya Pure White enamel gloss for the upper body tube, Black gloss for the nose cone and Italian Red gloss for the lower body tube and fins. I opted not to use a clear coat finishing paint to try keeping down the rocket's weight.

After having allowed the paint to cure for a full week, the striped roll waterslide decals were then carefully applied. I found these to be quite durable and easy to apply.

Construction Rating: 4 ½ out of 5

Flight:
Motor retention is by use of a short and springy motor hook which has shown itself to be quite durable.

The first flight was with an A8-5 motor with three squares of recovery wadding due to the small field that I was launching from. The rocket immediately went unstable upon launch and cartwheeled back down to the ground where ejection subsequently happened although there was no damage. Not to be deterred, I loaded up with another A8-5 and this time the flight was perfect with a lovely straight boost to around 270-280 feet.

Since then I have only used the A8-5 motor as the B6-6 and C6-7 motors could quite easily make for an out of sight flight!

Recovery:
The Kevlar®/elastic recovery system has proven to be very reliable and has held up to repeated flights without problems. The Semroc-supplied 12" plastic parachute is of excellent quality and has also proved to be very durable. I also applied thin CA to the top of the body tube before painting so as to lessen the chances of the Kevlar® causing any denting during recovery.

Flight Rating: 5 out of 5

Summary:
This is an excellent skill level one rocket for a rocketry novice. The excellent Semroc components ensure that a novice will be able to put together a nicely detailed scale rocket that should prove to very durable and robust with the potential for hours of fun.

Overall Rating: 5 out of 5