The rocket diaries
The team
Jonathan Hare's diary about the challenge for the Rocket programme, from the BBC/OU series Rough Science 4
Day One
Kathy, Mike and I are have to make three different rockets, but the only fuel we’ve got is water. Ellen and Iain have to make parachutes that can bring our rockets and their payload – a raw egg – safely back to Earth.
Spend a happy day fiddling around with various bits and pieces trying to design something that might work for a steam rocket. A slow start to day one with some nice pieces to camera with us all up on the hill by the disused electricity pylons. An end of series feeling …
Manage to find a threaded tube and adapters so that we can make up a sealed system. Also play around with various end sealing flanges. One of these I try to drill on the lathe so that there is a small hole in it for the steam to come out. This was hard work as it was a toughened bolt and very hard to cut (ruined three of the cheap drills!). I took the bolt that was about five centimetres long and sawed off the head so that I had a piece of threaded bar about three centimetres long. This was put into the lathe and then the centre drilled out.
By the end of the day we have a basic rocket made out of a steel tube about 30 centimetres long with a steel screw top cap and adapters on the bottom (the engine) end drilled with a one to one and half millimetre hole. Added fins made out of the thick tin.
Day Two
Today I have fun learning to braze the metal parts together to get a good seal. Unfortunately there weren't any cleaning brushes so I didn’t do a good job in cleaning up the parts before brazing and so it didn’t go well. But I had a lot of fun with the oxy-acetylene torch and managed to get the hang of it all okay.
The seal at the end of the rocket is crucial for the success of the thing taking off. Ideally it would be good to have a lead seal which would melt at a high temperature and then release the pent up pressure – and launch. However I could not get the lead to stick in properly and it leaked water anyway! So for a first try we used epoxy resin to seal the hole.
Tried out the first steam rocket experiments. Made up a launching system to hold the rocket upright while it is being heated. Unfortunately I found that the thing leaked and so had to go back to the drawing board. It didn’t leak at the epoxy hole though so it seems that the welding / brazing weren’t good enough.
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Content last updated: 19/07/2006
