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.

Vehicle 22 Redux

The evolved version of the original Vehicle 22 payload model rocket, Vehicle 22 B, while being prepared for launch from my metal theodolite launcher at Allmend Frauenfeld, Switzerland, on Saturday, April 26, 1986.

Vehicle 22 B flew with a Flight Systems Inc. 21 mm black powder D or E motor. And while my flight data sheet of that day indicates a very good deployment of the parachute and a perfect post-flight condition of the rocket, the flight itself is described by means of a brief, wry remark: "stability deficiencies".

Photography by Martin Kyburz.

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.]

Rocket Fleet, 1989

Scans of two regrettably very deficient analog photos taken at my former home in Nürensdorf, Switzerland, in autumn of 1989, depicting part of what was then my rocket fleet as well as some designs under construction at the time.

Top photo shows, from left: Vehicle 59, built from Flight Systems and Centuri parts and designed to fly with Flight Systems E black powder motors. Vehicle 59 measured 886 mm in length (including a payload section of 456 mm length). The rocket in the center is my scratch-built Honest John semi scale model (still lacking any finer details), while the model on the right is Vehicle 51 B Enigma II, a development of the earlier Vehicle 39 A Enigma. Vehicle 51 B was constructed using Estes, Centuri, and CMR components and intended to be flown with Flight Systems E and F motors. It measured 896 mm in length and featured a payload section of 158 mm usable space. The lower and upper sections of the rocket were recovered by means of two separate parachutes.

Lower photo, from left: Vehicle 32, a cluster design utilizing three 18 mm motors and featuring a payload section. Next to it are Vehicle 23, a 24 mm experimental design with ultra thin, high aspect-ratio plywood fins, and Vehicle 22 B, also using three high aspect-ratio plywood fins that were strengthened with an epoxy coating. The rocket line-up is completed by Vehicle 48 A Heracles (designed for 21 mm and 24 mm D motors), Vehicle 39 A Enigma, and Vehicle 44 A Rhea (a sport model with payload section, built specifically for Flight Systems D18 motors).

Rocket Fleet, 1986

Part of my active fleet, photographed on the occasion of our morning to afternoon launch at Allmend Frauenfeld, Switzerland, on Saturday, April 26, 1986. It was a beautiful, clear day with only low wind and a temperature of 20 degrees Celsius. Incidentally, this was also the day the Chernobyl nuclear disaster took place.

Lower photo shows, from left: the black Vehicle 31 (featuring self adhesive Mylar foil on payload section), the white and black Vehicle 39 A Enigma, (flown for the first time during this launch), and the black Vehicle 28 A (with white fin and nose cone), a rocket built specifically to fly with Flight Systems E and F black powder motors. The flights of Vehicle 28 A revealed stability deficiencies which subsequently led to a redesign.

Next are the two prototypes of Vehicle 30; #8230 B is on top and #8230 A at bottom. I was about to lose the latter that day. Then the silver/black/red Vehicle 44 Rhea, a payload carrier built from CMR components. To the right of Vehicle 44 are my Estes Bandit (repaired from its previous motor failure) and my trusty Centuri Starfire. Then, the newly completed silver/white/black Vehicle 48 A Heracles (bottom) and the red/white Vehicle 36 B sport model, built from Centuri parts (top).

This is followed by the silver/white/black Vehicle 22 B payload model with its high aspect-ratio fins, my Centuri Excalibur 2, and my Estes Titan II ICBM. The line-up is completed by Vehicle 33, a delta-wing boost glider loosely inspired by Estes' legendary Astron Skydart. Vehicle 33 was scratch-built in 1981, using Flight Systems and Estes components.

In addition to all of these rockets, the top photo also shows one of my Estes Astron Alphas (far right), frequently used to open a launch and determine the wind conditions.

Photography by Martin Kyburz.

[Entry amended October 17, 2016.]

Vehicle 31

Vehicle 31, at the time one of my most advanced model rockets, seen on my metal theodolite launcher. I built Vehicle 31 in 1982, using CMR components; it measured 770 mm in length and 29.5 mm in diameter and was specifically designed for Flight Systems Inc. E and F black powder motors. It further featured a payload section with a length of 230 mm, plywood fins, and a Mylar parachute.

The photo was taken at Allmend Frauenfeld, Switzerland, on April 26, 1986. Vehicle 31 was flown extensively that day on various FSI motors. It was a very graceful and stable design, and it survived the launch in very good condition, if my contemporary notes are to believed.

Photography by Martin Kyburz.

Estes Bandit Motor Failure

These are the last photos to show the only Estes Bandit I ever owned while it was still in pristine condition. They were taken in northeast Switzerland on April 16, 1986, during the same launch that saw an Estes D12-5 motor failure destroy my Centuri Nike Smoke.

When building the Bandit, I had converted it to fly on 24 mm motors, and this would turn out to be its ruin. The top photo shows pre-launch preparations; this flight was also going to use an Estes D12-5 motor, which can be seen already installed, with the Estes Solar Ignitor in place. Also of note are the Flight Systems Inc. E and F black powder motors in the range box.

The lower photo shows the Bandit on my converted theodolite metal tripod launcher, shortly before the launch button was pressed. Upon ignition, the motor disintegrated before the rocket lifted off. A single, burning motor fragment was ejected from the resulting fireball. The rocket suffered significant internal damage, but the main airframe was surprisingly still somewhat intact.

This was the second Estes D12-5 motor failure that day, and another one (a D11-9) was still to come. The damage to the Bandit was rather disappointing; its beautifully nostalgic design was among Estes' most attractive at the time, and its internal baffle system made it an intricate and unusual model.

Photography by Marco Schenker.

[Entry amended October 17, 2016.]

Centuri Starfire (Redux)

My Centuri Starfire, already discussed on this blog in mid-July, seen returning to earth after one of several fantastically stable and reliable fights at Allmend Frauenfeld, Switzerland, on April 26, 1986. It was a beautiful and only slightly windy day, and we flew our rockets next to the launch site chosen for a model rocket competition hosted on the same date by the Technorama science museum.

We conducted a total of 31 launches during the morning and afternoon, and without intending to do so at all, we ended up stealing the spotlight from the official competition. The competitors' rockets were required to be powered only by mini motors, while we flew anything from Estes B to Flight Systems E motors, including some rare D13-7 composite motors of eastern European manufacture - these were the days when the Iron Curtain still existed. Needless to say, we received a number of jealous glances from the organizers of the competition, as the spectators kept watching our flights rather than theirs. But such is life.

Vehicle 57

First flight of Vehicle 57 Mimas, powered by an Aerotech E30-4T composite motor. The rocket carried a Transolve Ultra-Beep sonic beacon.

After an initial misfire upon ignition, the ascent portion of the flight was perfect. But upon parachute ejection, the payload section separated due to an attachment point failure. The main section of the rocket was recovered intact, the payload section and payload were found with some damage, and the nose cone was lost. Vehicle 57 was later fully repaired and still exists to this day.

Vehicle 57 measured 1070 mm in length and 56 mm to 42 mm in diameter, at a weight (without motor) of 131 grams. It was built in April and May of 1986, from Centuri, Estes, and Flight Systems parts.

Photos by Erol Ünala (top) and Daniel Zingg (bottom), northeast Switzerland, June 17, 1999.

Flight Systems Motors

A selection of 1970s vintage Flight Systems Inc. black powder motors. The discovery of Flight Systems' more powerful motor range in the late 1970s enabled us, finally, to fulfil a burning desire to construct rockets capable of a noticeably superior performance.

As young teenagers in 1975 and 1976, we initially built self-made and utterly flawed aluminium tube rockets filled with any highly flammable material we could obtain. These efforts resulted in far more explosions than legitimate flights, and it is solely due to sheer luck that we came out of this period without any serious injuries. In late summer of 1976, we finally discovered professional 18 mm and 24 mm black powder motors of the A through D range, first those manufactured by Estes, and soon after those by Centuri. At this time, they were still somewhat difficult to acquire in Switzerland. Frequently driven by ambition and youthful enthusiasm, however, we were often dissatisfied by the speeds and altitudes attainable with these motors.

Through our subsequent NAR membership and the associated subscription to the Model Rocketeer magazine, we soon learned that there existed further companies that manufactured different motors. But it was only when German distributor ESE Electronics and Scientific Equipment started carrying the Flight Systems Inc. product line that we finally were able to actually purchase that company's E and F motors. They were a revelation to us at the time, and they enabled us to accomplish a brief revolution in our rocketry activities before certain harsh realities in our lives temporarily forced us to divert our attention to other issues.

Shown in the image above are Flight Systems Inc. 21 mm E5-6 motors produced in May 1978 (top left, yellow header), 21 mm D20-7 motors produced in June 1979 (top right, blue header), a 27 mm F7-4 motor produced in June 1979 (second from bottom, green print) and a 27 mm F100-8 motor produced in July 1979 (bottom, purple print). The small plastic bag at bottom right holds the electric ignitors. The photo was taken in Zurich, Switzerland, on May 18, 2016.

Flight Systems RX-1 Thruster System

The components of the Flight Systems Inc. RX-1 Thruster System booster, intended to be used with the same company's Dart model rocket. Flight Systems' 1979 catalogue featured the combination of Dart rocket and Thruster System booster under the title "The Mach 1 System" and noted that this model rocket system had "the ability to break the sound barrier". Moreover, the Dart's instructions boldly announced "supersonic potential". Whether attaining transonic or even supersonic speeds was actually possible with the design and motors in question is debatable. At any rate, such claims certainly captured our attention at the time.

The Thruster System consisted of a slightly modified Flight Systems F100-0 motor (far right in the photo) to power the booster, and a Flight Systems D20-12 motor (second from right) for the Dart upper stage. It also contained launch lugs and plywood fins which were to be permanently attached to the F100-0 motor with epoxy, making the booster a single-use item. An electric match igniter (contained in the folded instructions, top centre) completed the package.

In 1979, Flight Systems sold the Dart upper stage for $ 3.25 and RX-1 Thruster System for $ 7.95.

Rocket Vision Mach Buster

In the late 1970s, we were deeply captivated by the possibility of building - with the limited means then available to a rocket builder in Switzerland - model rockets capable of attaining transonic speeds. It was not least the purchase of Flight Systems' remarkable Dart rocket kit (intended to fly with the separately available RX-1 Thruster System booster) that inspired our imagination and ambitions.

There were some other concepts we considered at the time, some of them rather adventurous. Various changes and occurrences in our private lives at the time prevented us from realizing them, however.

Of three minimum-diameter, G motor-powered transonic rockets I eventually built in the late 1990s, one was a kit: the Rocket Vision Mach Buster. I acquired it out of sheer inquisitiveness. It consisted of a fibre phenolic tube, G10 glass epoxy laminate fins, and a heavy-duty polystyrene nose cone; and it featured a kevlar shock cord/nylon parachute recovery system. The Mach Buster was designed to fly with motors in the D12 to G55 range.

I didn't use the kit-supplied launch lug and instead built the rocket to utilize my own tower launcher which could be fitted to my Impulse Aerospace/Rocket Vision Quad-Pod launch pad.

The photos were taken in Zurich, Switzerland, on May 14, 2016.

Vehicle 22 Evolution

Evolution of a design. Vehicle 22 was created in autumn of 1980 to fly with minimum thickness, high aspect-ratio fins; its 41.4 mm diameter payload compartment was originally intended to carry a CMR Foxmitter transmitter. The rocket was first flown on April 16, 1986, powered by a Flight Systems D18-3 black powder motor (top photo, taken by Marco Schenker). The flight revealed design deficiencies, however, and the recovery system became detached at ejection.

The design was thus revised later that same month, increasing airframe length from 582 mm to 686 mm and using slightly stronger fins. The resulting Vehicle 22 B was photographed three years later, in summer of 1989, in the backyard of what was then my home in Nürensdorf, Switzerland (lower photo).

Having made its maiden flight on April 26, 1986, at a launch at Allmend Frauenfeld, Switzerland, Vehicle 22 B's flight characteristics still proved dissatisfying. Unfortunately, the rocket suffered irreparable damage during a subsequent relocation.

[Entry amended June 3, 2016.]

First Flight Of Enigma

Vehicle 39 A Enigma launching from customized theodolite metal tripod on a Flight Systems E60-8 mid-power black powder motor. This was the rocket's first flight. 

Vehicle 39 was built during March and April of 1986, loosely based on a design for a smaller rocket constructed by my best friend Dave Sharma in 1978. Utilizing CMR and Estes parts, Vehicle 39 measured 835 mm in length and 41.5 and 29.5 mm in diameter. It was originally intended to be flown with Flight Systems E and F motors and later converted for use with Aerotech motors.
 
Photographed by Martin Kyburz at Allmend Frauenfeld, Switzerland, on Saturday, April 26, 1986.