Yet-to-be-named big water rocket
From YouWiki
The Yet-to-be-named big water rocket is a rocketeering project being undertaken by Willem. It began at the end of 2006 and shall most likely continue for quite a while, since exams and assignments will keep him occupied for the time being. See Gallery for pictures.
Contents |
Outline
The project is to construct a ~3L Water rocket from perspex tubing, which will safely return to ground using a vertical deployment timer similar to that of Robert Youens [1]. The aim of the project is to reach a height above 200 metres (which has been done on numerous occasions in other similar projects).
The Pressure Vessel
The pressure vessel is a ~200cm perspex tube weighing under one kilogram (including flight paraphernalia -- parachutes, fins, etc), excluding water 'fuel'. A total of three bottle neck bulkheads were glued into the pressure vessel: one at either end and a support bulkhead. This took a lot of careful planning and glueing in order to set them in there. Several pressure tests took place:
- The rocket only held till 20psi before the (poorly glued) bulkhead popped out
- Blow-out at 40psi
- Blow-out at 60psi
- Massive blow-out at 90psi, in which shards of broken bottle-neck flew dangerously close to the experimenters
- Finally held to over 100psi. Safe for preliminary launch.
The fins
The fins are made of double-airfoil sanded and sprayed balsa wood. The pieces are parallelogram-shaped. This fin shape was determine with information from this site as being the preferred fin shape for model rocketry.
The parachute
The parachute is made of garbage bag material and is well over one metre in diameter. Drag and flight-time simulators such as this one and this one were used to determine the required parachute size. Garbage bag material is preferred because it is light and very compressible.
The deployment mechanism
(Coming soon) For a description of a similar gravitational VDTT, go to Robert Youens' website.
Picture Gallery
The pressure vessel with drying support bulkhead (for internal launch tube support) |
The upper bulkhead setting |
The sanded and sprayed balsa fins |
Here, the double-airfoil profile of the fin can be seen. Took a long time to obtain this shape. |
The mechanical deployment system in open position. A very clever and resourceful device. Based on that of Robert Youens |
The mechanical deployment system in the cocked position. The fastening elastic bands can be seen. |
