(Contributed - by Chan Stevens - 01/01/07)
This is another excellent addition to Semroc's "Retro-Repro" line of reintroduced classics from the early
years of model rocketry. The LJ-II was issued in 1968 as a companion to the 1/70 Saturn 1B, making it almost as old as
I am. As with the original Estes kit, this one shares the same command module, which is also available as a very nice
separate kit. At $21, it's a bit pricier than the original K-30 at $2.75, but for the detail included in this kit, it
does represent pretty good value today.
It's typical Semroc excellent quality parts throughout, including some of the finest balsa parts I've ever seen. When
you open the baggie, you'll find:
- BT-70 body tube
- 18mm motor tube/block/metal hook
- 18/70 centering rings
- Laser cut balsa fin braces (see construction notes)
- Cardstock fin skins
- Embossed/glossy wraps (2)
- 1/8" launch lug
- 12" plastic chute
- Waterslide decals
You'll also receive an Apollo capsule kit (available separately for $10) which includes:
- 2 Balsa nose cones
- Balsa tail cone
- BT-3 body tube
- Cardstock shroud pattern and construction/alignment guide
- Cardboard jig for building tower
- Wood dowels
- TC-70 coupler
- 24/70 centering rings (which is actually tapered for the shroud)
- 12" plastic chute pack
On the surface, this hardly looks like it deserves the skill level 5 assessment on the package, but as you get
into the tower, you'll find that's a very accurate rating. The rocket itself is not overly challenging (maybe a skill
level 3), but the capsule is best left to experienced modelers with keen eyesight, attention to detail, and plenty of
The instructions are well written and illustrated with nice check boxes along the way so you can make sure you
haven't overlooked a step as you stop/start work on this.
Construction begins with the motor tube assembly, which is fairly straightforward. It consists of a motor tube,
coupler used as a block, a metal hook held in place with masking tape, and a pair of centering rings. Additionally, you
need to anchor the Kevlar
line to the motor hook. This is a very much appreciated improvement over the original tri-fold paper and rubber cord
system used back in the day.
Next up is applying the wraps. If you're into craftsmanship and intend to fill the tube spirals, it would be a
good idea to do that first. For one thing, it's a pain to fill and sand up to a tube/wrap seam. For another, the
sanding down of the glossy surface of the tube makes for an excellent bonding surface for the wraps. Apply an extremely
thin layer of white glue (do NOT use yellow glue or CA) to the edges of the wraps then press carefully in place around
the tube. I found the lower wrap fit perfectly without any trimming, and the upper was long by about 1/32", which
I shaved slightly. The wraps have a glossy surface to them, which offers one other nice feature--if you get any
splotches of glue on your fingers and then on the wraps, it wipes away very quickly and easily with a damp cloth,
leaving a pristine finish.
For the fins, this kit uses what is called the "built up method". What this means is that you
cut out and bond tiny balsa frame pieces to the inside of a skin pattern. You then fold the skin pattern over and bond
to the other side of the braces. The result is a very cool tapered fin, very much like a scale rendering. This process
is a little tricky as you need sharp fold lines and there will be tiny gaps where braces join together, but it's worth
the trouble. The completed fins are then attached to the body tube, and CA will work just fine here.
Note to Carl at Semroc: you might want to consider a slight improvement to the wraps, pre-printing fin locations
to make the alignment go a little more smoothly. Alignment of tapered fins can be a little nuisance.
Stick a launch lug on the body tube and you're ready for the real construction adventure...
The Apollo capsule starts of simply enough. You assemble a tube, nose cone, and tail cone. These parts are fairly
small and filling the grain on the tail cone was quite challenging. Next, cut out the shroud pattern and form it. The
shroud is pre-printed with nice graphics on one side and plain on the other (per scale), so you have your choice on
appearance. The shroud then slides over the lower nose cone and is reinforced on the aft end by a centering ring.
The tower assembly is the major pain and biggest challenge. You start with 4 plain wood dowels, and need to sand
them down to 0.058 and 0.041 in diameter. The good news is that a gauge is supplied so you can tell when you're to
spec, but sanding down these dowels is very time consuming. I have to admit, after building two of these (the other
went to my Saturn 1B), I very much prefer the quick/simple plastic capsule of the Apogee kits and would have gladly
paid a little extra for this kit if the dowels had been to size or at least closer.
Once you've sanded down the dowels, you need to start cutting out tiny little braces and tacking them together.
There are 40 total pieces, all having some degree of angled cuts. There's a little bit of extra dowel, but not much so
cut carefully. In fact, I found that after sanding down 2 dowels to 0.041 and 2 to 0.058 per the instructions, I had to
later sand down my leftover 0.058 material to 0.041 in order to have enough to cover the smaller braces.
Alignment and construction of the tower is greatly aided by templates/patterns on a cardstock sheet plus a
fiberboard jig. This same jig can also be used to poke holes in the lower balsa nose cone to serve as a base.
The finishing touches on the tower assembly come in the form of the four RCS nozzles, which are formed out of
very small paper shroud wraps--so small that forming around a pencil tip is barely sufficient.
Overall, I think I spent somewhere around 2 hours on the model and 15 hours on the tower, but the finished
product is worth it. I just wish I hadn't had to spend so much time sanding down dowels...
Finishing is very simple on this kit. The body tube/wraps/fins are all silver (I used automotive aluminum, which
looks less shiny than most silvers), and the tower is solid white. There's a single waterslide decal for the block
out of 5
For the first flight, I decided to jump all the way up to a C6-5 since the winds were practically non-existent. I
must have canted my fins slightly, as it spun a bit on the way up but was otherwise straight. Deployment was perfectly
timed, right at apogee.
With a second chute in the capsule kit, you have options with regards to deployment. Since my finished model weighed
in at 1.9 ounces, I figured a single 12" chute would suffice. Unfortunately, it came down a bit rough, landing on
the access road in an otherwise grassy square mile park and broke one of the fins off on impact.
I'd recommend going with two chutes and separate recovery of the tower and lower tube. In particular wrap a yok
around the tower so it does not come down tip first.
½ out of 5
PROs: Excellent kit, a challenge to build, great scale features.
CON: Tower is much more difficult construction than necessary
out of 5