Lil' Hercules rocket kit build
The Thrifty Rocketeer blog continues...
It's been a long while since we've done a build thread.... or posted anything in this blog, for that matter.
A recent photo on Facebook showed a short, small rocket with what appears to be washers on the lower tips of each fin. A closer inspection reveals that it's a "Lil' Hercules" reproduction rocket by Semroc.
Now, Semroc has been acquired some years ago by eRockets.biz who have reissued many of the classic kits. This is part of a reissued repro rocket line. As some parts and motors have been discontinued, there have been some slight alterations in the kit, but they were made available to the buying public.
After a number of years, all that appear to remain are a few sheets of laser cut fins, a file of the reissued instructions, and a parts list. Fortunately, all the parts listed (all 12 of them) are still available. Note that the washers are for weight purposes, as the length of the motor has changed, throwing the CG off and needing to be adjusted, I presume. Also, note that the listing for WW-5 is for a single washer... NOT a package of 8 like you might find at Lowes or your local hardware store. So if you order them, you must specify that you need 8 of the WW-5 washers, or you might be shorted.
A thank you to Randy Boadway who noticed this and corrected it for my order. Thanks, Randy!
The instruction sheet can be printed off in color from a reference file that eRockets.biz maintains on their website. It was easy to find. Though there are 17 individual steps listed on the instructions, They can be reduced down to about a dozen, in my estimation.
Still, my very first kit was a Semroc, and I remember the hesitation and trepidation with which I approached this new field of rocketry. I was SO cautious and careful that a one evening build took me two days, as I waited for the glue to dry completely before moving onto the next step. I had no idea how this was all going to go together, the scale or the structure of a model rocket...so I was slow and the instructions held my hand... every step of the way.
I have to say that I LOVE Semroc instructions. They are very well illustrated, with close up diagrams and parts clearly labeled. There are check boxes along each step, so any kid who can read, can follow along.
So let's begin...
First, I always unpack the kit and count the parts against the parts list so that I know and recognize them. This is a given, in case of any damage in shipping or delivery.
Most all kits begin with a suggestion to sand off the sheet of balsa wood supplied with the kit. There apparently was a time when these sheets arrived somewhat rough, and had splinters or uneven surfaces. More recently, my experience is that every sheet is smooth and the laser burn is exact and clean, with only the slightest of hold tabs keeping the parts intact in the sheet. They are easily flexed or cut free, leaving the minimal amount of tab left to be sanded off. Therefore, My first step is almost always to stack the fins and holding them as a block, to slide them over a flat piece of sand paper, and make all edges even and smooth. The slight tab stubble is gone within one or two strokes across the sandpaper, so it doesn't take much.
Next, I always identify the root edge and after sanding the slightest amount of burned wood off, I leave it alone. But identifying the leading edge and trailing edge of the fins, it has become my practice to always feather those edges to either an knife's edge or a rounded feather edge, depending on the thickness of the sheet and the sturdiness of the fin. (Well get to methods to improve the sturdiness of a weak fin in a few moments.)
Second, I have fallen in the habit of always pre-treating all my balsa wood parts with a slurry of wood glue and drops of water, to produce my own sealer. Not only does this seal the wood pours, but it stiffens the fins and produces a firm, sand-able surface to paint later one. I absolutely love the diagram Semroc includes in every kit, showing how a filler/sealer fills the pours, scratches and indentations on the surface, as well as the need to sand between coats to make for a smooth, even surface. Never has the concept been shown so clearly as here!
Of course, the obvious alignment of the wood grain down the length of the fin is important, but with a laser cut fin, that choice has already been made for you. Back in the day, it was necessary for the rocketeer to lay out patterns for the fin in alignment with the wood grain.
By careful juggling of the pattern and arranging them carefully, it was sometimes possible to save half the balsa wood sheet, or compromise slightly to create the fins, stand offs, or various pieces and still have the wood grain running the correct direction. (*For those who don't know, the root edge almost always has the wood grain running perpendicular, out of the root edge and down the length of the fin. If your wood grain is parallel to root edge, you are almost certain to snap a fin or two off on the first flight or the first time any strain is put upon your fin.)
My choice in marking a fin line on the body tube has changed over the years. I have learned that most door frames are not necessarily square. And so, I have picked up a piece of angle iron or lightweight aluminum piece either from house siding, left-over window framing or drop ceiling rails. I use that to help mark the lines that the fins become aligned to.
The diagram looking down the body tube, showing the angular positioning of 3 or 4 or 5 fins always seems to be excessive to me. However, it was a necessary step for the beginner builder. And I have always found it makes the point clearly, to see how the fins will attach.
Now, it has become my practice to always sand most of that thin pencil line off of the body tube, once it has been marked... to roughen up the body tube and give the glue something to bite on, or to penetrate. This is critically true for glassine coated body tubes, that some Chinese manufacturers insist upon using. I hate them. But virtually every body tube or other craft tube from eRockets has always been plain white or gray, with NO problems at all.
To help position and glue the fins onto the body tube, I used a Styrofoam egg cartoon laying upside down, so that the multiple bumps and domes of the carton cradle and hold the smaller low power rocket just so while the wood glue dries. Yes, I prefer yellow wood glue to most any other adhesive, though I know options vary. My brand of choice is Elmer's Carpentry glue, and Titebond II at times. You may prefer CA or Superglue, especially on smaller light low power rockets, but let's stick with the instructions for now.
Fillets are easy with wood glue, as a damp or wet finger running down the fillet of glue makes for a nice radius. This is also the point where one adds the launch lug (straw) down the side of one of the fins. No stand-offs here.
When it comes to the balsa wood nose cone, I always prefer them to the blown plastic style parts, and prefer to treat and paint them red for ease of recovery. But this kit is not a detachable nose cone as it is tumble recovery. That means, the nose cone gets glued into the body tube. This is a rarity, as in almost all other low power rockets kits, the nose cone is attached by a shock cord and parachute or streamer instead of tumble recovery.
My very first rocket had a bright red nosecone and a rubber shock cord. I failed to seal and treat the wood before painting. The result was "an Estes smile" when the nosecone impacted the body tube after being blown off. It took two of these repairs before I got smart and began the slurry/seal process to protect my nosecones. It has worked well, even as the number of balsa wood plugs and nosecones have shrunk. (...those damn blown plastic nosecones again...)
I decided to experiment with the assembly of this rocket in several different ways.
First, I find it easier to paint the individual parts (body tube, fins, nosecone) separately before gluing them in place, especially if they are different colors. Now, you can mask off whatever part you want once assembled, and do it that way, but this time, I thought I'd pay attention to each part.
The downside is that once you sprayed paint (or primer) on your wooden or paper part, the paint can act as a barrier to proper adhesion. That is, perhaps it is better to rough up the wood or paper slightly to allow the wood glue to penetrate and bite.
Third, I've never glued washers onto fins before, and so, thought that I might try half BEFORE I spray paint the fins....and half AFTER spraying. The difference is once again, whether the glue bites the wood, or if a layer of paint gets under it. Also, do I want the silver washer not as obvious or to be an accent piece?
Now, before I go any farther, let me point out an inconsistency in the instructions. The cover color illustration of the rocket shows a red nosecone, blue body tube (with two thin black stripes) and blue fins, along with a long yellow jet of fire out the back end. However the instructions caution you to consider painting your rocket bright yellow or orange to make it more visible. Remember, this is a tumble recovery rocket, meaning no brightly colored parachute or streamer to aid in spotting it.
So the blue fins and body tube seem to be at odds with the written instructions near the end of the build.
I compromised once again, and chose to alternate colors on the fins... darker blue on two fins that face each other, alternated with bright yellow on the next two fin faces. This way, every fin has a blue and a yellow side. I specifically chose to glue half of the washers under the paint, and the other half on top of the paint to see which survived longer. And I used wood glue to adhere them.
Now, I could of used super glue, but I had already sealed the balsa fins with a slurry of wood glue and water drops, giving them three coats with sanding of raised spots in between. So I already had a base of wood glue to glue half the washers upon.
I'll make another confession here. While it had been my intent to feather the leading edge of the balsa fins down to a knifes edge...I forgot. I sealed both sides of the fins with my wood glue slurry before realizing that I had not done this. That makes them MUCH harder to sand down. So I have resolved to let the short stubby fins go "au Naturel", without shaping, as I don't expect this to be a high flier.
The finished fins are glued aligned over the pencil marks on the body tube. As you spin the rocket around, there is a blue pair of faces, a yellow pair, a blue pair and a final yellow pair. As you look at each colored pair, one has the washer under the paint, and the next is on top of the paint and bright silver.
Before I forget: Yes, I used wood glue to adhere the nosecone into the top of the body tube and let it dry. It's easy to overlook your launch lug, especially when you start taking steps out of turn. I had a spare 2.5" straw in my jump kit, so I glued the whole thing in place along side a fin that I thought needed a little more glue to strength it. And, I added fillets down either side of each fin over-top of the paint, for structural sturdiness.
My experience has been that Rustoleum paint ALWAYS takes longer to dry...as much as 2 or 3 days in some cases... so my red nosecone above the robin egg blue body tube had to dry a long time. Ditto, my dark blue paint had to dry a long time also.
If I were doing this again, I think I might have just glued it all together, and then shot the entire body tube and all fins with bright yellow. Then, I might have glued the washers atop of the paint, as I think the silver looks snazzy. But, it would be easier to glue those on before painting the rocket as well.
In any case, the gluing of the nosecone has to be the last step after all painting is done, to preserve the last of my red paint and to keep it separated from the body tube paint.
So, my assembly of this rocket was extended due to paint on parts before gluing... and my experience of having assembled rockets before allowing me to experiment and try a few new things.
While my go-to first rocket for teaching is the My-Boid (a smaller motor and motor mount construction), This Lil'Hercules could be just about the simplest rocket I have seen. It might be a good one to teach, except there are only two more sets of fins languishing in the Semroc clearance bin right now. All the parts can be had for under $10 total. As it has no motor mount, shock cord, chute or streamer, and minimal parts, it would have been a good candidate for teaching basic assembly to a rocket club or scout troop. Perhaps there are others out there that are just as good?
I'd love to hear what you think. Any suggestions (even if you disagree with my choices to build this one) I want to hear them.
This has been the Thrifty Rocketeer saying, "Don't overlook those clearance items. You can find bargains and revisit the early days for pennies on the dollar!"
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