Starlight Rockets Seieron 3

Starlight Rockets - Seieron 3 {Kit}

Contributed by John Lee

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstar_borderstar_border
Overall Rating: starstarstarstar_borderstar_border
Manufacturer: Starlight Rockets

starlight_seiron3Brief:
The Seieron 3 is the first kit I have attempted from Starlight Model Rocketry. It is a cluster and probably not too bad a choice for a first cluster. I had built the Semroc Defender before and considered the Seiron about the same level of difficulty. Some things were harder and some were easier but it averaged out.

Construction:
The packaging of Starlight rockets is nothing fancy but is certainly adequate. Within the package, everything was in good shape. The inventory consisted of the following:

  • BT-16 body tube 12" long
  • BT-10 body tube 8" long
  • BT-7 (x3) 6" long
  • Balsa nose cone
  • Balsa shoulder transition
  • 3 balsa fins, already cut out
  • pathetically small eye screw
  • 2 peel off "decal" sheets
  • 1/8" launch lugs (2)
  • 18" mylar parachute kit
  • round elastic shock cord
  • Shock cord mount
  • motor thrust rings (3)
  • motor spacer tube
  • 2 sheets of recovery wadding

Notice that the nomenclature for the body tubes is non-standard. The BT-16 is a large diameter, just right for a triangular cluster of 18mm motors. This BT is equivalent to an Estes BT-50 and the BT-7 matches the Estes BT 20.

The instruction consisted of 3 pages of 8 1/2 x 11 printed front and back. Simple, hand drawn illustrations were provided. The instructions contained a few spelling mistakes but were easy enough to understand. They followed a logical order and there was nothing unexpected to mess me up. The one possible problem is the non-standard nomenclature for the body tubes. Even so, the right part was easily figured out from the parts list and the illustrations.

Construction starts out with the motor assembly. 3 motor tubes are provided which are minimum diameter for 18mm motors. Each is 6 inches long. The instructions said to glue two of them together, parallel, and let the glue dry. Afterwards, the third was to be glued alongside the previous two. That is generally the procedure I followed but I added a step. I cut a 14" piece of Kevlar® from a spool I had available and put several overhand knots in one end. Before gluing on the third tube, I filled a portion of the central cavity that would be formed with yellow glue and laid the knotted end of the Kevlar® in it. I then glued on the third tube and set the assembly aside to dry.

When the motor tube cluster was dry, I dripped a little more yellow glue into the central cavity. Then, as instructed, I tore one sheet of the wadding in half, soaked it in glue and stuffed it down the cavity. This is intended to block the escape of ejection gasses. In my case, it also helped to strengthen my shock cord mounting system.

While waiting for that to dry, I had to make a decision about the payload bay. The rocket is designed so that the entire upper BT serves as a payload bay if you want it to. Since I never use payload bays, I did not.

I glued the NC to the upper BT and the upper BT to the shoulder. It was at this point I decided to scrap the miniature eye screw that came with the kit and use one of the leftovers I had from trying to clone the Centuri Vulcan. I believe it was 1/4" with a very aggressive thread.

The motor tube cluster was marked at 3", the halfway point. I then roughed up the top of the tubes a bit with some sandpaper so that the glue would hold better. After that, it was a simple matter to smear glued around the perimeter of the larger BT and insert the motor tube cluster up to the mark. It slid in easily, not too tight nor loose. The remaining recovery wadding was then soaked in glue and stuffed into the cavities around the perimeter. Again, this was to prevent the loss of ejection gasses.

When the stuffing was dry enough, I inserted the thrust rings. This was a simple matter of swabbing the inside of the motor tube with glue and using the provided, premarked dummy motor to shove the ring into place.

The fins did not come in a sheet and were already precut. They were also pretty good quality balsa and all the edges were very crisp. I usually round the leading and trailing edges but in this case decided to leave them square. The fins are mounted by the simple expedient of gluing the root edge in the gap between motor mount tubes. I used CA to make the connection. I had never done this before. If I ever have to do it again, I think I would sand the root edge into a wedge to make a tighter fit. After it had a chance to dry, I used yellow glue to fillet the fins. While that was setting up, I installed the launch lugs with CA.

The launch lug comes in two parts. I took a short length of 1/8" rod and put the lugs on it in the approximate spacing I wanted. I then applied CA to the lugs and set them in place on the rocket, using the rod to keep things straight. After a few seconds, I removed the rod and went back to touching up the fillets.

Pros: easy, should be rated at no more than level 2
Cons: eye screw too small, silly shock cord mount

Finishing:
Finishing started off with mixing up a batch of Elmer's Fill 'n Seal and applying it to the fins and NC. I also applied it to some of the gaps left behind by the wadding/glue mess in the tail. This was not to fill them in, it was just to even them out.

I learned, again the hard way, that it is better to smooth things out before they are assembled than after you have all the tight little corners. I guess I hate doing it so much that I keep putting it off hoping I will learn of a miracle method I don't mind so much. In any event, most of the rocket sanded down just fine but getting at the tight crevices was a chore. Once the chore was completed, I primed with white.

After a light sanding, I gave the rocket several coats of gloss white. Then I had to make a decision. I normally go with the default scheme of the manufacturer. This was no exception but there are two similar schemes. The photos on the website show a white rocket with red nosecone, red transition and one red fin. The photo on the face card was almost the same but sported 2 black fins in opposition to the red one instead of white fins. I liked the look of the black but that means that some of the decals, intended for the fins, would be useless. I decided to go with the second scheme.

I masked for red, sprayed 2 coats and was pleasantly surprised to see that I had little leaking around the fins and motor tubes. When it was try, I brushed the other 2 fins black. I brushed them because I discovered to my horror that I was out of black spray, the local Walmarts are no longer 24 hour operations and I wanted to finish! In this case, the brushing was easier than the masking and there are almost no brush strokes showing.

The decals were peel off stickers. They were very simple in design, consisting of the name of the rocket, an experimental warning, the numbers "1, 2, and 3" and a small stylized logo. They were no less effective for their simplicity and turned the humdrum into something with a little more impact. My complaints are against peel off stickers in general and against the tackiness of these in particular. The plastic is thick and the adhesion is not too good. A few would probably not survive a single flight. For that reason, I applied some Future floor polish and hoped for the best.

Pros: simple but effective paint scheme, looks good
Cons: stickers instead of decals, sticker ink for fins is lost on red or black

Construction Rating: 4 out of 5

Flight:
The recommended motors are A6-4x3, A8-3x3, B6-6x3 or C6-7x3. I only got to launch this one once because it was at a club launch and I wound up serving as RSO. It was also the busiest launch my club has ever had. That's great but hard on my flying!

I used a cluster of A8-5s for the maiden flight. It left the pad and boosted well but became unstable during coast. The chute deployed about 100 feet up and it recovered safely. An inspection revealed that one motor failed to ignite.

I believe that with steady thrust, this rocket will perform satisfactorily. I will post a notice to that effect when I get to fly it again.

Pros: Looks nice in the air in boost
Cons: looks lousy when bebopping about the sky, unstable without even thrust.

Flight Rating: 3 out of 5

Summary:
Despite my problems, I like this rocket. It looks good and makes for a good first cluster.

Overall Rating: 3 out of 5

Flights

Comments:

avatar
J.A.L. (March 8, 2008)
I finally had a chance to try and fly this one again and I must say I am IMPRESSED. I used a cluster of 3 A8-3s this time. They all ignited and the rocket took off straight as an arrow. It went MUCH higher than I expected, not quite out of site, and deployed perfectly at apogee. The rocket then came down well until landing hard. Part of the upper BT was deformed but it is a minor affair. This rocket would be awesome on larger motors!
avatar
Philip Nubel (April 29, 2018)

I flew my Seiron-3 with three B6-4s and the ascent was perfectly straight up to about 600 ft, ejection was near apogee, and it floated down on a 15" thin-mill chute to a nice landing without any damage.  I used Estes sonic igniters.

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