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.

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.

1972 Enerjet Catalogue

Sample pages from the unique and intriguing 1972 Enerjet advanced rocketry model products catalogue (no. 721).

As deeply curious and utterly determined teenagers building model rockets in remote (from a consumer point of view) Switzerland in the mid to late 1970s, we were continuously driven towards increasingly advanced rocket concepts and the quest for rocket motors more powerful than the commonly available A, B, C, and D-class motors. Mind you, it was far from granted to find even such "regular" motors in Switzerland at the time. Our ambitions were satisfied to some extent when a German distributor brought the product line of Flight Systems Inc. to our hemisphere and we were finally able to obtain their range of D, E, and F black powder motors.

In our minds, however, Enerjet represented the holy grail of advanced model rocketry, and it therefore served as the underlying inspiration for many of our own projects. This was of course long before readily available information by means of the internet, and even though Enerjet was no longer trading as an active company by that time, the company, for us, was thus an entity equally shrouded in mystery and emitting a limitless fascination. The few things we knew about Enerjet had been glanced from pictures in books (the Handbook Of Model Rocketry) and Centuri brochures, or from the remnants of Enerjet's existence as evident in Centuri's catalogues.

I would have given anything to own the 1972 Enerjet catalogue at the time (or to even be granted to have a brief look at it), but any such publications remained unobtainably elusive for us two rocket obsessed adolescents in Switzerland. Only much later in my life was I finally able to obtain a pristine original edition. The infinite waiting period mattered little; Enerjet's very existence and iconic designs still represent the same captivating inspiration to me to this very day.

The above excerpts from the 24-page catalogue show, for example, Enerjet's revolutionary "port burning" composite motors with glass fibre casing, or the fantastic (and operable) Nike Smoke semi scale rocket (vaguely similar to the Centuri kit) and Nike Ram high altitude payload rocket.

1972 Enerjet catalogue sample pages © by Enerjet Inc., Phoenix/AZ, USA, 1972, scanned from my personal copy of the catalogue.

[Entry amended October 31, 2016; with thanks to Chris Michielssen.]

Vehicle 77 Redux

A clear personal favourite in my fleet, the Enerjet Nike Ram-inspired Vehicle 77, photographed in northeast Switzerland on July 30, 1999, on the occasion of a flight powered by a 24 mm Aerotech E28-7T RMS composite motor. This flight took place in the early afternoon of a beautifully clear day, with low winds, and a temperature of around 30 degrees Celsius.

Launched off an Aerotech Mantis pad, Vehicle 77 carried a 6 volt piezo sonic locator. The rocket flew fast, very stable, and out of sight, to a computed altitude of slightly over 800 meters. The parachute deployed perfectly, but the rocket's payload section and parachute became entangled in a barn drain pipe upon landing. The tallest member of our little launch group was just able to pull it free, but the piezo sonic locator was lost during the retrieval, and the plastic parachute was damaged. Vehicle 77 itself survived in perfect condition.

A few weeks later, I replaced damaged parachute (it had likely been the wrong choice for such a rocket at any rate) with a nylon parachute by Rogue Aerospace.

Astro Dynamics Corporation Catalogue, Early 1980s

Sample pages from a rare six page fold-out "specialized rocket kits" brochure by Astro Dynamics Corporation, published during the early 1980s.

In the bygone days of actual written letters and postal money orders, I acquired this brochure of this then newly emerging company from Everett/WA, USA. Astro Dynamics Corporation's somewhat Enerjet-inspired rocket kits were clearly aimed at the advanced rocket builder. The rocket kits offered (Models 1500, 1750, 2000, 2500, and 2800) were all designed for 29 mm motors (with Models 1500 and 1750 also available with 24 mm motor mounts) and payload sections intended to hold "telemetry equipment, remote cameras, altitude pollution monitoring equipment, cloud seeding devices, signal flares, and other applications".

Model 1500 measured 42" in length while Model 2800 came in at 74". The kits featured custom made fabric parachutes but no decals. According to the brochure, Astro Dynamics Corporation also offered an "Electrical Firing System" as well as an "Electrical Staging System", but no further information on either of these systems was provided.

The final page of the brochure (bottom scan) showed yet another four (cluster) rockets, apparently part of a selection of rocket kits not offered to the general public.

Unfortunately, I have no further information about the activities of this company nor its fate.

Astro Dynamics Corporation brochure pages © by Astro Dynamics Corporation, Everett/WA.

Vehicle 89

Top: Vehicle 89, a vaguely Enerjet-inspired sport model rocket with a 130 mm payload section. Vehicle 89 is based on the earlier Vehicle 69, originally designed to carry the then state-of-the-art Estes AstroCam aerial camera. Vehicle 89 measures 611 mm in length and 34 mm in diameter. It was built with Estes parts, and it was intended to be flown with 24 mm D or E motors.

Bottom: Vehicle 89 and Vehicle 77, an approximate hommage to the fantastic Enerjet Nike Ram advanced model rocket of the early 1970s. Both photos were taken in Zurich, Switzerland, in June of 2016.

Classic Centuri Publications

As much as I of course also loved Estes' extraordinary product range, I will likely forever lament the unfortunare demise of Centuri as an active manufacturer. There was just something about Centuri (and Enerjet) that connected seamlessly with my own frame of mind. With such confession out of the way, these are some of the truly extraordinary booklets and brochures published by Centuri in the 1970s. It was sometimes challenging for us, who were based in Switzerland, to obtain these publications at the time (as related in various posts in this blog). Moreover, when spending whatever pocket money was available to us, our priority was of course to obtain model rocket kits and motors.

Needless to say, every single one of these releases by Centuri was thus a veritable treasure to us. Not just because of the information contained therein, but also because of the wealth of deeply inspiring photos they presented. This was long before the internet, after all, and the nearly limitless amounts of reference material it offers to today's model rocket enthusiasts.

American Rocketeer was Centuri's house magazine, providing a mixture of company and product news, educational material, and advertising. Volume 4/Number 1 (1970, top row, left) was a prime example, its pages filled with beautiful black & white period photos of real and model rockets. Of note is the announcement, in a small article on page 11, that Centuri Engineering had acquired an 80% interest in a new subsidiary company called Enerjet. The magazine also proudly declares that Centuri's impressive Saturn V model rocket had one advantage over the original: it could be flown repeatedly.

American Rocketeer Volume 5/Number 1 (1971, top row, right) provided more of the same. Most prominent was an article about the Apollo 16 moon mission, followed by an extremely detailed two-page article on scratch-building the large and unusual Uni-Bird model rocket (also shown on the cover). But for us fanatics in Switzerland, starved for anything model rocket related, even just seeing the photo featured as part of the Centuri ad on the back cover amplified our enthusiasm.

Centuri's original Model Rocket Designers Manual (1971, top row, centre left) was one of the publications we frequently saw advertised but never managed to obtain until many years later. It is a small-format guide to all things model rocketry, beautifully illustrated and very comprehensive.

The petite Model Rocket Mini-Manual (1975, top row, centre right) was just a folded flyer included with some of Centuri's kits. It contained only the most important information about model rocketry, but we loved it as an addition to our collections of rocketry items.

The Model Rocket Design Manual (1975, bottom row, left), authored by Grant Boyd, was a large-format, expanded version of the above mentioned Model Rocket Designers Manual. Now printed as a substantial softcover booklet, it served us countless times as a source for new ideas. It contained chapters on techniques, staging, gliding, clusters, scale, displays, odd designs, and much more. Its layout, articles, and photo content also had the (thoroughly intended) effect to make us even more eager to obtain Centuri products.

The fantastic Power-System Handbook Operating Manual (1977, bottom row, centre) recycled some of the Design Manual's material, but it was truly unique in leading the modeller through a cohesive and educational building project involving the X-7 and X-16 modular rockets. And once again, the countless drawings and photos serve make this booklet a joy to browse through, even decades later.

Centuri's Model Rocket Club Guide (bottom row, right) was exactly that, a primer on establishing a model rocket club. Dave Sharma and me preferred to refrain from joining any club at the time (not that there would have been many options), and so the actual value of the Club Guide, to us, was again to be found in the inspiring photographic content.

Photo taken in Zurich, Switzerland, on July 1, 2016.

Enerjet Nike Ram Copy

Vehicle 77, a sport model rocket with payload section, loosely based on Enerjet's iconic Nike Ram advanced model rocket of 1972. Vehicle 77 measured 643 mm in length (versus the Nike Ram's 590 mm) and 34 mm in diameter (as per the original). It was designed to be powered by D or E-type composite motors and was constructed slightly more robustly than the original.

Vehicle 77 is shown here on an Aerotech Mantis launch pad. The photo was taken in Thalwil, Switzerland, in May 1999, the month of its completion. Vehicle 77 first flew on June 17, 1999, with an Aerotech E15-7W motor.