N Project: 4" Glass Fibre/Carbon Fibre Rocket, Part 3

Top photo: Professor Eugene Trubowitz is examining one of the fresh arrived Rocketman parachutes at the machine shop of the Swiss Federal Institute of Technology in Zurich, Switzerland, in late summer of 2000. All three rockets of the N project used Rocketman main und drogue parachutes.

Second photo from top: the two custom threaded forward closures of the Dr. Rocket 98 mm aluminium motor cases used for the two 4" rockets of the project. We were very fortunate to be granted to use the tool machines of the Institute for any such special modifications required in the course of our project.

Lower two photos: first trail assembly of the electronics compartment for the 4" glass fibre/carbon fibre rocket. The design of the electronics compartments for both 4" rockets was identical. The mounting base for the electronics thus consisted of an aluminium ring/shoulder, screwed to the modified forward closure. This arrangement further provided a mounting point for the glass upper airframe section.

The circular white insulation foam disc was intended to shield the electronics from the head emitted by the subjacent N2000 composite motor. Again, four threaded steel rods served to hold four custom- made aluminium mounting bridges, to which the two BlackSky AltAcc dual deployment recording accelerometers would subsequently be attached.

N Project: 4" Aluminium/Glass Fibre/Carbon Fibre Rocket, Part 8

The final instalment in the series of photos depicting the various stages of the construction and launch of our 4" aluminium/glass fibre/carbon fibre N-motor rocket in autumn of 2000.

Top photo shows the smoke trail after launch on Saturday afternoon, September 30, 2000, photographed from the LCO's position. Propelled by the Aerotech N2000 motor, the vehicle literally leaped off the launch pad with astounding speed. The rocket ascended perfectly straight and stable, and the scattered smoke trail was thus caused by the range of winds at various altitudes over the Black Rock desert. Our team had previously calculated an approximate peak speed or Mach 2.2 and an approximate peak altitude of 10 kilometres.

A few moments after launch, however, two bangs could be heard from above, and observers further away saw the motor case fly through a cloud of debris and continue upward, still under power. At around two kilometres of altitude, as the rocket accelerated within the supersonic speed range, the glass fibre section of the airframe failed where it was connected to the motor case and electronics bay. The motor case with its welded aluminium fins subsequently continued a fairly stable flight to apogee.

The lower four photos show the recovered remnants of months of design, work, and financing. Almost all parts of the rocket were found, and we were thus able to reconstruct and confirm the sequence of events. As previously noted in this series, the electronics bay assembly was likely too delicate for the aerodynamic loads to be encountered.

The high-speed break-up shredded parts of the glass fibre airframe section and even sheared off a large section of the carbon fibre nose cone. It was difficult to determine how much of the damage at the top of the motor case was caused by the break-up and how much by the motor case's subsequent impact on the hard surface dry lake.

All electronics as well as the Rocketman drogue and main parachutes were damaged beyond repair. At least two of the aerodynamic fillets covering the aluminium welds were devoid of paint, indicating strong movement and stress, likely caused by the impact on the ground.

In spite of this dramatic result of the flight, I felt the entire effort was well worth it. Not only did it amount to a significant gain of theoretical and practical knowledge, it also was an experience to last a lifetime.

The next day, Sunday, October 1, 2000, would see our team launching the sister ship, the 4" glass fibre/carbon fibre rocket.

N Project: 6" Glass Fibre/Carbon Fibre Rocket, Part 4

Final construction activities on the 6" glass fibre/carbon fibre N-motor rocket at what was then the machine shop of the Swiss Federal Institute of Technology in Zurich, Switzerland, in September 2000.

Top photo shows the author of this blog (left) and Professor Eugene Trubowitz after the first full assembly of the still unpainted 6" (152 mm) rocket. The length of the rocket was 3000 mm. The design of the rocket provided for the integration of the Dr. Rocket N2000 98 mm aluminium motor case as a load-bearing structure. The release of the Rocketman drogue and main parachutes was to be guided by a BlackSky AltAcc recording accelerometer with dual deployment. The rocket was expected to exceed a speed of Mach 1.

Centre photo: the three rockets of the Balls 2000 N project assembled and displayed together for the first time. They were subsequently transported to an automotive paint shop we had contracted. Far left is the 4" glass fibre/carbon fibre/aluminium rocket, second is the 4" glass fibre/carbon fibre rocket, and far right is 6" glass fibre/carbon fibre rocket.

Bottom photo depicts concluding work on the freshly painted 6" rocket. Only the main body of the rocket was painted, the carbon fibre fins and carbon fibre/steel nose cone were deliberately left unpainted. In order to precisely drill the necessary mounting holes and access ports for the internal altimeter bay (to be installed last), the rocket has been temporarily wrapped with a large-scale, custom printed template.

All three rockets were shipped to the Black Rock Desert in late September of 2000. A number of circumstances during the preparation for the launch resulted in time constraints, however, limiting our team to only launching the two 4" vehicles of the project, while the 6" rocket remained unlaunched at the time.