Fly by Wire Rocket
The rocket is projected along a guide cable using Rocket Fuel (meths)
â€¢ A dry 2-litre PET carbonated drinks bottle, with lid. (The bottle will either say PET or have a â€˜1â€™ inside the recycling triangle)
â€¢ 2 screw-in hooks or eyes (if there are no suitable fi xings already).
â€¢ A length of string or wire (we have been using nylon fishing line).
â€¢ A couple of â€˜runnersâ€™ (lengths of straw will do though the best we have found are a couple of short lengths of glass tubing).
â€¢ A cork borer/glass rod/drill to make the hole on the bottom of the bottle.
â€¢ A small bung to fit the hole you make.
â€¢ Tape (SellotapeÂ®, masking tape etc.);
â€¢ Methylated Spirits or Ethanol (caution - flammable)
â€¢ If there are no fixing points in place, screw the hooks/eyes into somewhere appropriate. A door frame is good for this. We do this outside in a tennis court using the fence to fix the line)
â€¢ To make the runners, either cut two sections of straw or break two pieces of glass tubing, roughly 3-4 cm in length, heating the ends to smooth them.
â€¢ Slip the runners over one end of the string/wire before fixing.
â€¢ Tie the two ends of the string/ wire to the hooks/eyes, making sure it is tight. This is especially important if using fishing line as the nylon is elastic and will stretch.
â€¢ Make a hole (a heated cork borer is an ideal tool for this) in the base of a 2 litre drinks bottle ca. 5-6 mm is a good size.
â€¢ Ensure the bottle is dry. Water in the bottle will affect the combustion, leading to disappointing effects.
â€¢ Put 0.5 to 1.0 cmÂ³ of Methylated Spirits into the bottle, insert the bung (or put the lid on depending on which hole you put the fuel in) and shake the bottle to evaporate the Methylated Spirits.
â€¢ Use the tape to fix the bottle securely to the two runners.
â€¢ Make sure everyone is standing well clear of the flight path, behind the rocket.
â€¢ Wearing eye protection, remove the bung from the bottom of the bottle and apply a flame to the opening, using a splint or a Bunsen lighter at armâ€™s length.
The rocket will shoot along the string/wire with a dramatic hiss.
If you only use 1 cmÂ³ (or less) there should be no significant Methylated Spirits to dispose of. If you use more, any spare Methylated Spirits can disposed of down the sink, followed by plenty of water, before firing the rocket.
Re-use of bottles - if the bottle is showing signs of cracking (or more likely warping from the heat), replace it with a new one (they are not expensive).
If you are short of bottles and want to do a repeat fairly soon after the first rocket, make sure it is cool and blow fresh air through the bottle to remove the accumulated CO2 that would otherwise interfere with the combustion.
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