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  #1  
Old 01-11-2019, 07:48 PM
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Default Centuri Viking reproduction build (and a bunch of research)

Early last October a thread called “Centuri Viking decal ”, originally started in 2016, resurfaced. Towards the end of that thread Gordon from Excelsior, who was the source of the decals being discussed, offered his last one (and two Star Trooper decals) for free to anyone willing to do a Viking build thread. I stuck my virtual hand up and not too long afterward, the decals arrived.

But.... which version of the Viking to build? I knew of the Akela-1 connection to the Centuri version of the Viking and I knew Estes was and is selling a similar (but NOT the same - more on that in a bit) model - but I didn’t know how it all fit together. Being the slightly crazed researcher/history buff I am, I embarked on a research project.

It started with searching right here on YORF, where I found a number of Viking- and Akela-1-related threads. I also started looking at online versions of Centuri and Estes catalogs and gathering example kits - some from eBay and some from Gordon himself.

The closest I was able to come to an actual Centuri Viking kit I was able to get was supplied by scigs30 when he sent me the scans of the instructions he’d made when he built a Centuri Viking kit in 2014. In one of those lovely circular bits, it was his redrawing of the decal and sending that to Gordon that led to Excelsior being able to print Centuri Viking decals in the first place, the last of which I now have in my possession. (http://www.oldrocketforum.com/showthread.php?t=14550).

I do, however, have two examples of Akela-1 kits. One - an almost complete kit from a Cub Scout 8-pack - was gifted to me by Earl as part of this thread: http://www.oldrocketforum.com/showthread.php?t=12060. The other - an example of the single kit - I acquired from a fellow who was selling a bunch of vintage stuff out of his truck in the parking lot at the field during NARAM-60. So I know what is in those kits.

With those kits in hand, and examples of four different versions of the Estes Viking and one example of a Black Diamond also in hand, I have a pretty good idea of how the model has evolved if I assume (as seems reasonable) that the Centuri Viking is pretty much the same as the Akela-1 single kit.

I also had in hand a set of original Centuri Akela-1/Viking/Vector-V fins - probably from a lot of donated-to-my-club rockets and parts, as well as five sets of Semroc FV-44 fins that I bought in my parts-buying binge when Sheryl was shutting down the company. And I had some ST-7 tubing, so it seemed like getting as close as I could to the Centuri Viking (without building one of the Akela-1 kits) was the thing to do.

The Akela-1 package here http://www.oldrocketplans.com/centu...654/cen1654.pdf was also of help.

So, with the resulting model being shot with primer today (amazingly we have weather warm enough to spray paint outside in the Seattle area today, and for the weekend to come), it’s high time I make good on my promise for a build thread.

....but first I have to tell the story of the Centuri and Estes Viking as I now understand it. So that’s the next two posts.
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Last edited by BEC : 01-11-2019 at 11:47 PM.
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Old 01-11-2019, 07:55 PM
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Default Centuri Vector-V to Akela-1 to Viking

Here is a chronology I’ve written that goes from the Centuri Vector-V to the current Estes Viking. Thanks to blackshire for the pointer to the Boy’s Life magazine where the Akela-1 was introduced.


Centuri Engineering introduced the catalog number KB-2 Vector-V in their 1972 catalog. It was an unusual model in that it had five die-cut fiberboard fins which, since they had no discernible grain direction, could be installed using any edge as the root. Consequently the builder had a number of configuration choices when building the model. (See http://www.spacemodeling.org/jimz/kb-2.htm)

The Akela-1 - a simple crepe-paper streamer recovery model for 18mm motors based on a 9-inch ST-7 body tube and a plastic nose cone, is first mentioned in the September 1973 Boy’s Life magazine, pages 58-59 (https://books.google.com/books?id=S...page&q&f=false). It is shown being flown by Ricky Piester as a Cub Scout. (Ricky is the son of Centuri Engineering’s founders Lee and Betty Piester). The Akela-1 used the same fiberboard fins from the Vector-V and expanded the options to include using three to five fins as well as using even the narrowest side of the fin as the root. This meant the model could have dozens of different configurations.

The kits were made available through BSA in boxes of eight kits and also singly. The single kit was labeled “Model Rocket Derby single kit”, catalog number 1654. According to the Boy’s Life article the single kits initially sold for 69 cents and a box of 8 (catalog #1655) was $4.70 (!)

Centuri Viking - Beginning with the 1980 Centuri catalog the same model, save for the decal supplied and the recommended shock cord mounting method, appeared as the Viking (pages 34-35). Instead of a motor block spacer made from an empty engine casing as in the Akela-1, a folded cardstock spacer is used. A small portion of this is also used as a shock cord mount, with the shock cord looped and tied around this piece.

The Viking is shown in boxes of 12 models (catalog #5441) and as a single kit (catalog #5440). The single kit, priced at $1.75, is called “the hobby’s lowest priced rocket kit” in the catalog description. Boxes of 12 are priced at $17.95 and a bulk package of 12 A8-5s (a great motor for the model) are listed at $7.50.

There was also a “Viking Explorer” starter set in the 1982 Centuri catalog which included a Viking kit, Lightning Bolt launcher (one which used a rectangular 12V lantern battery as the base and was also in some Estes starter sets in the same time frame) and two motors. It was catalog number 5204 and listed for $9.95. The Viking 12-pack was still available with a price of $19.95. The single Viking kit was up to $2.25 in this catalog.

.....continued next post
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Last edited by BEC : 01-18-2019 at 07:27 PM. Reason: Found Viking Explorer set in 1982 catalog (inside front cover) - updating text to reflect
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Old 01-11-2019, 08:08 PM
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Default Estes Viking (and Black Diamond)

Estes Viking - The Viking first appeared in the 1986 Estes catalog (pages 27-27) as catalog #1949. It is pictured with a white with red nose cone livery similar to its last Centuri incarnation (though the world “Viking” is turned around to read towards the nose) and with a little cartoon Viking head added down towards the fins. (This Viking cartoon first appeared in the 1982 Centuri catalog with the Viking 12 pack on page 23.) This marking is a waterslide decal.

However, the Estes Viking shares no actual parts with its Centuri forbear. The body is BT-20 based (using a BT-20B - 8.65 inch long body tube). The Estes fins are not cut from the same dies and are slightly different shape with a little more sweep and slightly less chord and span. (See picture below)

The nose cone is also lighter and a little pointier (PNC-20N). In the initial Estes version the nose cone is molded in red plastic. This version has a white rubber shock cord that’s only a foot long and an orange plastic flagging streamer also only a foot long. Shock cord mounting is done via the standard Estes tri-fold mount. The motor block is much shorter than the Centuri TR-7 but common to many other Estes kits. Further the launch lug is shorter at only 1 1/4 inches long (the old LL-2A size). It is shown nestled into a fin/body joint as in the Centuri Viking/Akela-1 configuration.

In 1993 the Estes Viking received a new livery (as part of the Beta series) showing the model painted yellow with a green nose cone. It also has new markings which are now stickers rather than waterslide decals. This livery carries on to the this day. The 1993-2000 kit content is otherwise unchanged from the first Estes release except that the nose cone is now molded in white plastic, the motor block has a green outer layer (part of the color-coding of components that was introduced with the Beta series) and the shock cord material was changed to 1/8 inch wide elastic as was typical for Estes kits at this time.

When the kit’s production was moved China (~ early 2001) the parts remained unchanged (though I suspect that new tooling for the nose cone and fins were made in China), except that the shock cord returned to being made from 1/8 inch white rubber. The shock cord and the streamer remained only about 12 inches long.


In the 2005-2008 Estes catalogs there were a series of starter sets called “Launchables”. One such set, catalog #1452, includes an E2X kit called Outlaw (looks like the current Code Red) and a rebadged Viking called “Black Diamond”. This kit differs from a contemporary Viking only in the stickers provided.

As far as I know, the current Estes 1949 Viking and the kits in the 12-kit bulk box (#1755) as well as the kit included in the current “AVG” (Alpha/Viking/Generic #1753) bulk pack are the same configuration as the Estes version as made in China beginning in the early 2000’s. The one exception that I know of is that sometime between 2006 and 2016 the instructions were changed to have the launch lug mounted two inches from the aft end of the body tube and between two fins rather than at the aft end and nestled in a fin/body joint. When exactly that took place I do not yet know.


.... OK - now on to deciding what parts to use (well, what nose cone to use) and the build. But it’ll take me a little while to get ready because I need to go and resize all my pictures smaller before I can post them.....

The picture shows that original Vector-V/Akela-1/Viking fin sheet I mentioned in the first post, with a current Estes Viking fin (upper one) and a Semroc FV-44 fin (lower one) overlaid on top. This shows the Estes Viking fin shape is slightly different, and that Carl, as usual, nailed the geometry of his reproduction parts.
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Old 01-11-2019, 09:08 PM
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Default Parts choices.....

OK - so we’ve almost got everything. A 9-inch section of ST-7, a TR-7 thrust ring, FV-44 fins, a 2.25 inch long launch lug (to match what’s in the Akela-1 kits), about 32 inches of crepe paper for a streamer are all easy enough. But what about the nose cone. One can’t just buy one of those Centuri plastic nose cones. The Estes Viking cone is too pointy and will be sloppy loose in ST-7. Semroc/eRockets has a balsa rendition that’s the right shape, but....

Fortunately, in a prior similar discussion (http://www.oldrocketforum.com/showthread.php?p=150034), Chris Michelsson suggested a plastic nose cone that Apogee sells for BT-20 that actually fits ST-7 better and is similar in shape and in two sections so it could be ballasted to be the same mass as the original nose cone. (Remember that shreadvector occasionally warns us that the Estes Viking is unstable with C motors and some fin configurations).

So a complete set of parts, after selecting the nose cone.
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Old 01-11-2019, 10:16 PM
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Default Start gluing stuff....

From this point it’s pretty straightforward, so I’ll only hit spots where things are kind of unusual or where I departed from the instructions.

Of course the first thing one has to do is decide how many fins (so to know how to mark the body tube) and in what orientation. Since a number of the prior builds have been five fins, I opted for three, but in the wide orientation often seen, with the second narrowest edge as the root.

So, after treating both ends of the tube on the inside with thin CA to toughen things up, I marked the body for three fins using the Estes tools for such things. In particular I’m a fan of John Boren’s “portable door jamb” tool...the Ultimate Tube Marking Guide.

Next comes gluing on the fins (nothing special here - I used Titebond). Once they were on I put the model on a Qualman rocketry stand to let the fins dry. These Semroc fiber fins are a bit thicker than the current Estes ones and between that and the Titebond I wound up with much more solid feeling fin attachments than on an Estes Viking I built last spring.

Then the instructions have you glue the nose cone parts together. I packed 1.5g of clay into the tip of the Apogee cone before gluing it up so as to make this one have the same mass as the Akela-1 cone I have.
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Last edited by BEC : 01-11-2019 at 11:01 PM.
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Old 01-11-2019, 11:09 PM
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Default That shock cord mount....

The most unusual aspect of the build (at least to me) is the shock cord mount. I’ve never seen it done this way anywhere else....and after having seen the finished product I’m not entirely surprised.

The instructions have you remove a section from what will become the tool for installing the thrust ring, which appears to be folded from cardstock, to act as the shock cord retainer. Just eyballing the artwork I took a guess at the size of this part at about 1/2 inch by 1 inch. For material I cut a bit off the back of a cheap notepad (one of those one gets in the mail with donation solicitations). Then, with that part I followed the instructions to roughly shape it to fit inside the body tube, then tied a loop of shock cord around it, followed by gluing that assembly in about an inch down in the tube.

Once it’s in there, the knot holding the loop in the shock cord is really going to be in the way. It makes putting an Estes tri-fold in this size tube look like a good idea.


(and no, I don’t know why the pictures suddenly reversed order after I made a minor text edit above)
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Last edited by BEC : 01-11-2019 at 11:35 PM.
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Old 01-11-2019, 11:18 PM
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Default It’s easy from here....

Then, tape the end of the streamer to the middle of the shock cord and tie the other end to the nose cone (actually the instructions have this done before putting in the shock cord retainer).

After the shock cord and streamer are done the instructions have you put in the thrust ring. Since I didn’t have the folded cardstock “tool” I just did it with a yellow spacer tube that was laying around from some Estes kit or other.

After that, the launch lug, nestled in a fin-to-body joint with the lower end flush with the aft end of the body tube.

As you can see from the nose cone-on-body picture, that yellow Apogee nose cone really does fit ST-7 well. The shoulder is a little loose but that’s easy to deal with.

And....it’s structurally done.

As I said above, it was warm enough to spray paint outdoors so there is now a coat of Rusto 2x white primer on the model. I plan to paint it gloss white with an Apple red nose cone and let that cure well before I put on that last-of-its-kind Excelsior decal. So depending on weather.....it may be awhile before the finished product pictures appear here.
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Old 01-12-2019, 01:59 PM
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Default

Thank you Bernard for posting this. I had thought the Estes version of the Viking just used Estes parts, but as you clearly pointed out, the fin shape is slightly different. I recently picked up an Estes Viking from my local HL with coupon, and would like to finish it in the original Centuri scheme of red and white.
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Old 01-12-2019, 05:23 PM
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Check it out, the Viking is standing on the Rainbow Bridge to Asgard...maybe on his way to Valhalla?
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Old 01-12-2019, 07:32 PM
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Default

I always found the Estes version to be a bit of a ViQUEEN.
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