Centuri Lil' Hercules

The Centuri Lil' Hercules (also called Lil' Herc) first appeared in the 1965 catalog and remained in there lineup until the Centuri product line was phased out in 1984. This was supposed to be a quick fill-in build while I was waiting for Little Joe II replacement parts. Well, it turned out to be less trivial than I thought...

The build started out straight forward, filling in the balsa grain on the wood nose cones and fins...

For marking the body tube, I decided to purchase Estes new model rocket construction tool and fin marking guides. I have a feeling I'll be mostly using the fin marking guides although the tool is handy for drawing straight fin alignment lines on the body tube.

... but for this build, I just used my aluminum angle.

Then while reading through the instructions I saw that the supplied washers were not for nose weight as I had assumed but for tail weight to allow the rocket to tumble correctly. The instructions called for just glueing them to both sides of each fin near the bottom.

I wanted to make my model resemble the kit panel which had no such visible washers so I decided I would have to embed them into the wood.

I used a little thicker than normal Elmers wood filler to help "bury" the washers into the face of each fin and the results were fairly successful.

Here is what the embedded washers looked like after an initial coat of primer. They were now ready to attach to the body tube.

Due to the extra weight, attaching the fins was a bit more challenging. Basically I had to hold each fin in place manually until the epoxy set up.

I was originally planning to use the Estes tool for attaching the fins but it proved to be a less than ideal design for this size rocket.

All fins attached...

Primered and ready for paint...

The completed model...

Painting Woes

I can no longer recommend Rustoleum Ultracoat spraypaint. The first can I bought was for the Atlantis project and it worked fine. However the last 3 cans I've tried have been absolute garbage!

This was the results I got on the original Little Joe II body tube painted with the first can. Everything was fine. Paint went on smooth with no issues. When that can ran out, I bought another 2 at Ace Hardware. However the results from the 2nd can were horrible. Gritty gunk everywhere. I took it back and exchanged it and got better results, but still not as good as the first can. The surface wasn't gritty but certainly wasn't glass smooth like the first can produced. So I tried the 3rd can...

Here is the result from the 3rd can. By far the worst yet. All these cans were used in similar environmental conditions (about 68 degrees and dry) and I used the exact same technique in all cases.

I will now be returning all of the Rustoleum I have purchased and exchanging it for good ol' Krylon.

Little Joe II - Rebuilding the body tube (Part 1)

Due to our painting mishap on the original body tube assembly (refer to last Little Joe II post for details) I have to re-build the main body of the rocket from scratch. This includes scatch building the corrugated body wraps. In the original kit, the body wrap was made out of embossed cardstock. The new wraps I'm makeing will be from styrene which will actually be an improvement in the overall appearance of the rocket.

The new body tube I ordered from SEMROC is of a very nice quality. The tube spiral lines are barely noticable and will likely only need a coat of primer to fill. The problem is that the SEMROC tube is about 1/16th of an inch longer than the Estes tube. Since I'm trying to replicate the Estes kit, I'm going to cut the SEMROC tube to match.

I fabricated a tube cutting jig out of 2"x 2" aluminum angle, and a single edge razor blade. And proceded to cut a 1/16th inch sliver off the end of the new tube.

The jig worked surprisingly well. It made a very smooth even cut and I'm sure it will come in handy for future cloneing projects.

Now the new tube is the correct size and we can begin reconstruction.

Estes Alpha Build

The second model I started while waiting on Little Joe II parts was my Estes Alpha. I had one of the newer kits which contained the decals, plastic nose and modified fins but I wanted to do an original "K-25" version of the Alpha that I first built in the 70s. The Alpha was actually the first rocket I ever successfully built. The Centuri Micron was the first rocket I ever bought but I never actually built it.

The balsa nose cone and original fins are available from SEMROC, so I ordered those and tossed the ones that came with the kit into the spare parts bin along with the decal sheet.



The very first Alpha's from the 60s and very early 70s had a couple of different paint schemes. Some had military decals, one was just a white body with red nose cone. I always liked the iconic version (pictured above) that made it's debut in the 1973 catalog and lasted until 1982 when Estes started providing a decal in the kit.

As with all "fbt" kits (that's fins & body tube) the first step I do is to fill the balsa parts starting with the fins. I've been using Elmers wood filler for this and am getting used to it so that now I can usually get it done in 1 thickly applied coat. Getting the consistency right seems to be the key and just takes some practice.

I filled the nose in the same way as the fins. One thing I've noticed with balsa nose cones is that they often stick out at the top of shoulder and in order to have a smooth joint between body tube and nose, I have to sand down the nose ever so slightly.

Body tube spirals filled. This step is probably not that necessary given that I'm using a thick high build primer, but I do it anyway. I hate tube spiral lines!

Fins get attached. I use 5 min epoxy to tack on the fins because I get that adjustment time I like to get them lined up perfectly straight.

I also used 5 min epoxy for the fillets here but this may be the last rocket I do this for as I've discovered I really like doing fillets with an epoxy clay such as "Fix It" available from Apogee Components.

A couple of thick coats of high build, sandable, automotive primer gets rid of the last traces of tube spiral lines and any wood grain that may have survived the filling process.

I painted the nose cone kind of an "Apple Red" and gave the body and fins the base color of gloss white.

Here is the completed model after the black trim has been added. The black trim took two attempts. On the first attempt, I failed to rough up the gloss surface and then let the paint dry too long before removing the masking tape. As a result, the paint lifted along the edges with the tape, leaving behind a ragged looking paint line. So I had to strip off all of the paint and start over. I had considered using a decal for the stripe at that point but thought I would give it one more try using some tips I got from a friend at our local club meeting.

1.) Mask such that your paint line is on the top layer of masking and can be removed first while the paint is still wet.
2.) Rough the surface of the gloss white base coat.
3.) When removing the masking tape pull it back on itself so that the edge of the tape will "cut" the paint as it is removed.

The results were much better the 2nd time!

Here is another view of the completed kit...

Centuri Micron Build

While waiting to get replacement parts for the Little Joe II, I decided to work on getting a couple of skill level 1 rockets completed. The first one I wanted to work on is very special to me in that it was the very first rocket I ever bought.

When my friend Jeff Brewer and I were in the 5th grade we read everything we could get our hands on about the U.S. Manned Space Program. Jeff's older brother Jimmy had been into model rocketry when he was younger and had a few rockets he had kept and shown to Jeff. I remember going over to Jeff's house one day after school and Jeff showing me a box with some of Jimmy's old rockets in it. Specifically I remember seeing a small Honest John, a Mars Lander, and one of his own designs he called the "Feces" (go figure). Anyway, it was enough to get us both hooked. Soon after Jeff showed me the first kit he bought which was a Centuri Lil' Hercules. I don't recall exactly how long it took, but I eventually talked my Mom into driving to the local hobby shop (an awesome place called "Mini City" in La Mesa, CA) where I purchased my very first Model Rocket - The Centurin Micron...

This is the identical kit to the one I bought back in 1975. I didn't want to open this kit since it is still sealed so I purchased a SEMROC clone kit. SEMROC kits are speced to be nearly identical in every way to the original kit.

The first step was to fill the spiral seems in the body tube. I used Elmer's wood filler for this and worked quite well.

After filling the body tube, the fins were next. SEMROC typically gives you laser-cut fins so there was no cutting necessary. Just sand and fill. In the above picture, the fins have been filled and are ready to be glued on.

From it's introduction in the mid 1960s most Micron kits came with a balsa nose cone. At some point in the mid 1970s, Centuri substituted a plastic nose cone. The SEMROC clone kit came with the original balsa nose and so this must be filled just like the fins.

After attaching the fins, a thick sandable primer coat was applied. This will be sanded and fine sanded and will end up being the base for the color coat

Here is the rocket after the the body has recieved it's gloss white color coat. The nose will be painted gloss black.

Finally, here is the completed Micron with paint and decals applied. I did this kit in the scheme presented on the kit panel above. Gordy at Excelsior decals was kind enough to work up a special roll pattern decal with the orange strips in between the black (thanks Gordy!). The original Micron decal didn't have those.

All in all, this was a fun quick and easy kit to complete and it fills a significant spot in my collection as the rocket that started it all for me...