Completed Enerjet 1340/20 & 1340 Replicas

This is the result of having come to terms with the realization that I couldn't bear living my life without ever having owned the iconic Enerjet 1340 and, particularly, 1340/20 rockets we so admired as teenage model rocket enthusiasts. After finally being able to track down all of the necessary components from overseas, and after investing a few weeks of work, these are the finished Enerjet 1340/20 (left) and 1340 replicas.

The young teenage me would have loved this sight. As, indeed, the current me does as well. What beautiful, clean, and functional designs these are; very vintage 1970s and yet - in my view - not detrimentally dated at all. As mentioned previously, I closely adhered to Enerjet's original specifications in building these rockets. Among the very minor amendments to the original designs are, for example, pressure equalization openings in the nose cones, in order to make it feasible to carry altimeters.

It is currently somewhat difficult to mentally grasp that this brings to a conclusion a personal ambition that has existed for over four decades.

Enerjet 1340 and 1340/20 flyer images © by Enerjet Inc., Phoenix/AZ, USA.

Enerjet 1340/20, Part 3

Due to the nature of the components and construction of the Enerjet 1340/20 replica, I pre-painted the sub-sections of the rocket before assembling them and applying glue. I have rarely done this before - if ever - but it made attaining the original 1970s Enerjet paint scheme far easier. I also applied the same procedure to my Enerjet 1340 replica, conceived and begun slightly ahead of the 1340/20.

After the final step of installing the 29 mm motor mount, which was left protruding from the rear end of the airframe as per the original design, both rockets were ready for a gloss coat and decaling. As stated in an earlier post, my stock of original Enerjet waterslide decals had dwindled to a mere few logos, and I therefore ordered a few sheets of custom made replica decals. As it happened, however, one of the remaining original decals fit the 1340/20 replica perfectly, matching the size of the decal seen on the rocket in Enerjet's 1970s photos. I thus used the new decals only on the 1340 replica, again striving to make it look as visually authentic as possible. Decal setting solution was needed to achieve a good sit of the delicate decals.

Enerjet 1340/20, Part 2

In building my Enerjet 1340/20 replica, I largely followed the original design as shown in Enerjet's 1340/20 Sounding Rocket flyer of the 1970s. For example, I installed a 29 mm motor mount but concurrently also constructed a dedicated, removable 24 mm adapter for use with this rocket. A small deviation was made with regard to the parachute material; instead of the original two 12" silk parachutes, I used a hexagonal Rogue Aerospace PP-45 (45 cm diameter) nylon parachute and chose a combined recovery of airframe and payload section.

The most significant difference to the original 1340/20 rocket is the launch lug. Enerjet had fitted the rocket with wire loops for guidance during launch. While this likely made sense aerodynamically, I always felt unsatisfied when looking at the iconic 1970s photos prominently showing the #13 plastic fin unit's integrally moulded launch lug left without any purpose on the front side of the rocket. This was a design decision I didn't quite comprehend. I thus modified the top section of the moulded launch lug to hold a plywood stand-off, on which I later glued the lower of two conventional launch lugs. This worked flawlessly and left the front aspect of the rocket pleasantly uncluttered.

Epoxy adhesive was used throughout the construction of the rocket.

Astron Alpha Recovery

The fourteen year old me holding my freshly recovered Estes Astron Alpha after the launch seen elsewhere on this blog. This particular model was an early-style Alpha, featuring balsa wood fins and nose cone.

As noted in the aforementioned earlier post, this rocket was likely a self-made clone, as evidenced by what seems to be a Centuri parachute. I built a number of Astron Alphas of all incarnations, both from official Estes kits and as self-made replicas. It soon became a tradition to initiate launches with an Alpha, in order to determine wind conditions before switching to larger models.

Photographed by Hans Hofer in northeast Switzerland, in July 1978.

Handbook Of Model Rocketry

Another quest that proved a slightly more challenging than anticipated was my aspiration to find those editions of G. Harry Stine's Handbook Of Model Rocketry that my enthusiastically completist mind perceived as still dreadfully missing.

I first purchased the Handbook in its fourth edition in 1976 or 1977, and the latest, seventh edition is still readily available at the time I am writing this. We were utterly excited - rightly so! - about the Handbook when we first received it, and I thus also purchased any subsequent editions throughout the years. But obtaining the earlier and therefore historically rather fascinating editions was near impossible from Switzerland before the advent of the internet. And, as I found out, it can at times be somewhat difficult even today.

While I eventually found a copy of the second edition in decent condition, it was due to the extremely generous efforts by American collector Steve Kristal that I was able to complete the long-coveted line-up of books by adding the first and third editions. Needless to say, I am deeply grateful for such kindness.

For somebody who has been fascinated by model rocketry for most of my life, this means a lot. G. Harry Stine's Handbooks are not mere collector's items to me; it is still quite fascinating to read them, and the information therein has aged quite well. These books are like a time machine to an era when model rocketry lived through a golden age.

The photo above thus shows all the editions in chronological order. Top row, from left: Handbook Of Model Rocketry, original edition, Follett Publishing Company, Chicago, 1965; second edition, Follett Publishing Company, Chicago, 1967; third edition, Follett Publishing Company, Chicago, 1970; my original copy of the fourth edition as purchased when I was a teenager, Follett Publishing Company, Chicago, 1976.

Bottom row, from left: fifth edition, Prentice Hall Press, New York, 1987; sixth edition, John Wiley & Sons, Inc., New York, 1994; seventh edition (with Bill Stine), John Wiley & Sons, Inc., New Jersey, 2004.

Enerjet 1340/20

In my posts on this blog, I frequently alluded to how mythical Enerjet and that company's products appeared to us teenagers in mid-1970s Switzerland. At the same time, it was often difficult for us to find sufficient and reliable information about developments in our field of interest. We had to rely on issues of Model Rocketeer magazine, sporadic glimpses offered in company periodicals such as the Rocket Times or Model Rocket News. Or we deducted as much as we could from photos and text published in G. Harry Stine's Handbook Of Model Rocketry or Centuri's Model Rocket Design Manual, among others.

Congruent with our increasing skill in building and flying model rockets, we coveted any possibility to accomplish more advanced concepts and obtain motors with increased power. In the second half of the 1970s, when we became increasingly immersed in rocketry, Enerjet no longer existed, and it is very doubtful if any of Enerjet's products ever even made it to Switzerland while the company traded. We eventually found some solace when it became possible to obtain Flight Systems' products through a distributor in Germany, and we duly moved up a notch, both in motor power and materials.

But one of the rockets that always exerted an iconic radiance on me was Enerjet's 1340/20 payload rocket, first seen by us on page 231 of the fourth edition of the Handbook Of Model Rocketry, in 1976. Although I knew next to nothing about this rocket at the time, it became one of those designs that has never ceased to fascinate me in the 41 years since.

After Enerjet's demise, parent company Centuri continued to offer a number of components that were part of some of the former's most notable rockets. Among them were the #13 plastic fin unit (prod. no. F-413L), used by Enerjet's 1340 and 1340/20 designs and later part of Centuri's Phoenix Bird and Argos "Kwik Kits". Or the transition section and nose cone of the payload section of Enerjet's 1340/20, later offered in the guise of an egg capsule (prod. no. PNC-13E/ST-202), for example in Centuri's Rocket Times in fall of 1975 (a supplement to Centuri catalogue no. 761). And following the merger of Centuri and Estes, these parts occasionally reappeared as part of Estes kits, such as the Eliminator (the fin unit) or Eggspress (payload section).

Nonetheless, obtaining these parts to construct an Enerjet 1340/20 replica in the present day proved somewhat challenging, in spite of their sporadic availability and modern procurement tools such as the internet and eBay. Another surprise was the material used for the 1340/20's transition section and nose cone in their most recent guise as the egg capsule of the Eggspress. Instead of the more common, glueable high-impact styrene used for most nose cones, the plastic used for these parts is reminiscent of cheap garden toys for children, as usually imported from Asia, i.e., polyethylene. This flexible plastic is difficult to sand (and sanding is unavoidable due to the age of the original moulds), glue, and paint. I suppose this material was chosen due to its ability to absorb impacts without cracking.

The styrene plastic fin unit, on the other hand, appears to be entirely unchanged from the one I owned as part of my Centuri Phoenix Bird in 1978. The only difference is the colour in which it is moulded. As I was beginning to run low on original Enerjet waterslide decals, I had Wessex Transfers in Australia print me some replica decals.

Enerjet logo and Enerjet 1340/20 brochure sample page © by Enerjet Inc., Phoenix/AZ, USA.