By Benjamin Wilkosz
Part 1, 20 April, 2008
Disclaimer: all liability waved! The contents of this page is presented for informational purposes only. Do not try to recreate any experiments presented in this page. The NAVRO and the author of this article cannot assume responsibility for any use readers make of this information. In The Netherlands it is forbidden by law to own this type of propellant if you do not have an exemption of the "Wet Explosieven Civiel Gebruik" (WECG).
The Kinetics project is a part of the newly founded cooperative project of the NAVRO. This new project involves quite a large part of the club with the goal of building a two stage rocket, capable of reaching heights in the range of approximately 5km. Many challenges are to overcome. The high altitude recovery plays a major role and certain conditions have to be guaranteed when igniting the second stage. This requires a reliable awareness system. To cut a long story short, this "cooperative project" will be a long term project. Early in the development stage of the rocket, we decided to build the rocket in a modular way. So each project member or project group could develop a specified part of the rocket, which makes the planning and fabrication more flexible. To ensure enough structural stiffness, an easy access to the electronics and a well defined/tolerated fuselage for the project the 3.9 inch Phenol tube from Public Missile serves as a base. This way all the coupler elements and flanges can be made independent from other groups or members of the project. My (first) job was to develop the booster of the second stage. The second stage will be propelled by an Avalon 8 solid rocket motor (3000Ns, 900N). It will be developed and tested as a subproject called Kinetics. The Kinetics is a very simple rocket, as can be seen in this preliminary design.
The Kinetics is nothing more than the booster of the second stage and a nosecone with some electronics in order to recover the rocket. Although the design is very simple, the structure must be very rugged to withstand the first test flight. The high speed reached during flight (approx. Mach 1) and the little space for the parachute due to the maximum flight time and altitude at 't Harde demands a "hard" recovery. The parachute will be deployed during the accent at a speed of approx. 200km/h. The under dimensioned parachute will cause a rough way back to earth ending in a hard landing. The aluminium coupler not only serves as a connection between the first and second stage, it also protects the nozzle of the Avalon 8 during the landing. The fuselage is reinforced with four layers of glass fibre. Glass fibre also serves as a base for the fins, which will be fitted in slots, milled in the aluminium flanges supporting the backend of the Avalon motor. The whole fin structure will be reinforced with two layers of carbon fibre. The Avalon motor will be centred and fixed in the fuselage using the aluminium flanges at the end of the motor. On top a small parachute will be installed which will be deployed by the electronics in the nosecone, a R-DAS with a Trax-Art as a backup.
The new Avalon 8 motor is modified by using a nozzle with a smaller throat and a larger expansion ratio. The different parts and the grains of the new Avalon 8 motor are displayed in the picture to the right. Next to it the reinforced body of the Kinetics can be seen. The static test was planned for 26 April, 2008. When the motor successfully completes the next test run, nothing will stand in the way of the production of the Kinetics booster.
Next part: Kinetics, part 2, 6 May, 2008