The Little Joe II was a NASA test vehicle used during the mid 1960’s to test the Apollo Launch Escape System. Estes produced the K-30, a 1/70th scale Little Joe II kit, from 1968 to 1971. It was another of my favorite rockets from my youth (I even became fairly adept at building that tricky wooden dowel escape tower). Due in part to its relatively short production run, original K-30 kits are now quite rare (and expensive). However when I found that Apogee Components was selling their beautiful 1/70th scale Apollo capsule kit separately, creating a ‘clone’ 1/70th scale Little Joe II became a viable option.
After downloading the original Estes plans from Jim Z’s site, the next step was to collect the necessary parts:
Note that I didn’t need the WD-2A wooden dowel — that was only necessary to offset the launch lug for use on a C-Rail launcher.
The embossed body wraps presented something of a problem. One option was to take some card stock and use something like a butter knife and a straight edge to create the embossed effect. However I’d tried that on a previous rocket and was not pleased with the result. Besides, after a couple coats of paint, the embossing all but disappears. Then I found Evergreen Scale Models Styrene Sheets — this is the stuff model railroaders use to build scale buildings and such. The “Car Siding, O Scale 3 1/4-inch Spacing, ..040” thick (part number 4067) was a nice match to the embossed pattern. It was tricky to work with (due to its thickness), but the effect was very good (details later). According to the Evergreen website, this car siding is also available in .020-inch thickness (p/n 2067), which would have been much easier to work with, but I was unable to find it locally.
For the most part, I built the rocket according to the original Estes instructions. On the engine mount, I added an engine hook, and made gussets out of 3/32-inch balsa to the approximate size show in the instructions. For the built-up fins, I first printed out the fin pattern sheet on card stock. I then used the pre-cut balsa templates on the pattern sheet to cut the balsa fin pieces from 3/32-inch balsa, and assembled the fins per the instructions. The hardest part of the built up fins is to get them symmetric, but they turned out OK. I used to think built up fins were neat, but they are something of a pain to get right. The next time I may just make the fins out of balsa stock. To strengthen the built-up fins, I ‘painted’ the paper fin skins with some 2-hour epoxy. I let the epoxy soak in for about 30 minutes before wiping off any excess.
After cutting the Evergreen Styrene to size for the body wraps, getting the relatively thick plastic to actually wrap around the body tube was something of a challenge. I started out by coiling the cut out wrap pieces as tight as practical, held there with several rubber bands, and let them sit like that for a few days so they’d start to hold the shape. I then attached them to the body tube using 3M Super 77 ® spray adhesive, again using rubber bands to hold them in place. I then used thin CA to seal around the edges of the wrap (using care not to glue the rubber bands in place). It actually worked well — it needed just a bit of green model putty on the wrap joint, but the overall effect is quite nice, giving a corrugated look very much like the original. I glued the fins directly to the plastic wrap with CA, and added a thin fillet of epoxy for extra strength.
The Apogee Apollo capsule is beautifully detailed, particularly the Boost Protect Shield (BPS) portion of the capsule. Unfortunately, the Little Joe II QTV (which the Estes K-30 modeled) and “boilerplate” flights did not use a real Apollo capsule. Instead, they carried simple “boilerplate” mock-ups of the Apollo capsule, which lacked all of that beautiful BPS detail. So I carefully and tediously scraped and sanded the BPS details until the Apogee capsule was smooth. Note that the very last Little Joe II flight — SC-002 — used an actual Apollo capsule and hence had all that BPS detail. However to properly model that configuration I would also have need to create the Reaction Control System details, and I elected not to do that (maybe next time J). The Estes K-30 instructions also add a “NCW-3” lead ballast weight to the escape tower tube, so I filled the Apogee escape tower tube with clay to get the same effect. This ended up being less than completely successful — as I discover ed when it came time to fly it (more on that later).
Finishing the rocket was reasonably straightforward. Although the original K-30 modeled the “QTV,” I prefer the “look” of the BP-12 (like the Estes 0892 Little Joe II kit), so that is what I modeled. I used a couple coats of primer to smooth out some minor imperfections in the built-up fins and fill the body tube spirals. The primer also helped ‘seal’ the surface of the Apollo capsule after all that sanding to remove the BPS details. I then painted everything gloss white, before masking off and painting the lower section silver. I finished it off with a set of appropriately scaled decals from Tango Papa.
Construction Rating: 4 out of 5
The recommended engines (from 1970) were A8-3, B4-2, B6-4, and C6-5 (plus the no longer produced A5-2), however I used a C6-3 for the first flight. The short delay turned out to be fortuitous — although the initial boost off the pad was OK, the Little Joe II went unstable and began chasing its tail about 100 feet up. However it did gain enough altitude that — combined with the short delay — it deployed the parachute and recovered safely. Apparently the Apogee Apollo capsule is light enough (compared to the Estes original) that filling the escape tower with clay was not sufficient to insure stability. So I stuffed some more clay into the base of the Apollo capsule, such that the CG of the Little Joe II, fully prepped with a C engine, was 4.75-inches aft of the tip of the Apollo capsule. The next flight (again with a C6-3) was perfectly stable, but this time the parachute became entangled with the Kevlar® heat shield I used and didn’t open. Fortunately the damage was not serious — one fin snapped off, and the escape tower tube split open along the spirals — and was easily fixed. However the damage to the escape tower tube did convince me that filling the tube with ballast clay was not such a good idea. Simply putting the ballast clay in the base of the capsule may be a better solution.
I give the Little Joe II a 4 1/2 rating (well, after I solved the stability issue). It is a nice flier, and it certainly isn’t the rockets fault the parachute didn’t open.
Flight Rating: 4 out of 5
The Apogee Apollo capsule kit makes it reasonably easy to create a 1/70th scale Little Joe II, although it is a shame to remove all those beautiful details from the Apollo boost protect shield. All the needed construction materials are readily available, and the construction itself is not overly challenging. This Little Joe II — once I got it stable — is a nice flier and a great ‘attention grabber.’
Overall Rating: 4 out of 5