PARTS LIST 113.174 Working Stirling-Motor Please Note The OPITEC range of projects is not intended as play toys for young children.they are teaching aids for young people learning the skills of Craft, Design and Technology.These projects should only be undertaken and tested with the guidance of a fully qualified adult. The finished projects are not suitable to give to children under 3 years old. Some parts can be swallowed. Danger of suffocation! Tools needed Ruler,pencil, Fretsaw,craft knife,scissors, bradawl, scriber Drill ø 1, ø 2,5, ø 4 + ø10mm Forstner bit ø 20 mm Pillar drill + Machine vice Sand paper, File Round nose pliers, Side cutters Try square + Centre finder Hacksaw Crosshead screwdriver Super glue and all purpose glue Part Size (mm) Description Part-Nr. MDF-Sheet 1 8x100x100 Base, Cylinder base 1 Plywood 1 3x160x160 Frame 2 Pres cover 2 ø110 Base, top 3 Metal axle 1 ø 3x70 Shaft 4 Screw 6 2,9x6,5 Fixing 5 Brass tube 1 ø 4x8 Bearing 6 Card tube 1 ø19,5 x 65 Cylinder 7 Wooden wheel 1 ø15 Piston 8 Gloves 1 Membrane 9 Spring steel wire 2 ø1 x 200 Crank 10 Beer mat 1 ø107 Displacement piston 11 Steel wool 1 Displacement cylinder (Regenerator) 12 Gear, Module 1, 58 teeth 1 ø60 Wheel, large 13 Rubber ring 1 ø40 Membrane 14 Gear, Module 0,5, 30/10 teeth 1 ø26 Wheel,small 15 Washer 2 2,9x9,5 Bearing 16 Silicon tube 1 ca. ø1,7/0,7x10 Drive shaft 17 Hard paper tube 1 ca. ø114x 43 Displacement cylinder 18 Tea light candle holder 2 Frame 19 1
INSTRUCTIONS Function description The following HOT AIR Motor works on the principal of an external heat source and heat flow. Principle: The air in the can is heated by the candles and expands. The membrane of the working piston moves upwards and pushes the working piston upwards out of the cylinder. This in turn pushes a connectng rod on the large flywheel which is moved to top dead centre. At the same time the small the small flywheel moves to bottom dead centre, and the warmed air is pushed to the top. Here it cools down and shrinks The membrane collapes and and brings the working piston with it. The displacement piston is in the meantime on the way up and drives the cooled air downwards.there it is rewarmed and the proccess starts all over again. To improve the working, the displacement piston is made partly from steel wool. This takes up a part of the energy and then gives it up the other direction. Constructing the parts made from wood MDF-Sheet Plywood sheet 1. The pattern shows two variations of the machine frame (1a) choose which one you want to make and trace it on to the MDF sheet. 1 Trace it so that the foot is against the edge of the board,this way the frame will stand properly Mark out the holes and centre them with a bradawl. Make sure all the holes are marked in this way, Frame (1a). Take the pattern for the plywood (2) mark it out. Cut out the marked parts from the plywood (2) again make sure that the feet line up with the edge of the plywood, this is to ensure that the feet are straight and at right angles for standing 1b Ø 20 1a 98 1a Ø 4 Ø 4 10 2b 2a 2a 1b Ø 20 10 98 2. Firstly drill the MDF parts ø2,5, ø4 + ø20 mm. 2a For the vertical ø2,5 mm holes in the MDF sheet use a pillar drill.also drill the fixing holes ca 10mm deep, spacing 85mm. 2a Once all the holes have been drilled, the MDF and plywood parts can be sawn out and sounded smooth 1a 2b 1b 1a 2 E113174#1
INSTRUCTIONS 3. Glue together the plywood base frame (2a+2b) Insert the tabs from the tea lights in the slots in the holding plate (2b) and bend them over 19 19 Making the lid 4. Cut out the pattern carefully ( Page 11) on the outer edge for the lid (3a) Fix it in place ( Hold it tight) and use a scriber or bradawl to mark out the the hole markings. Lay the lid on the wooden plate and drill the 1mm holes. Afterwards mark out the remaining holes (ø3 + ø10mm) Clean up any rough edges from the holes. 3a 5. Press the brass tube bearing (6) in the frame (1a) making sure that it is at right angles 6 6. Fit the mounting frame (1a) on to the lid(3a) using the two screws Also fit the cylinder base (1b) using 4 screws (5) in the holes in the lid (3a) 7. From the card tube (7) cut a 20mm piece (7a) use a craft knife or fretsaw Make sure that the cut is at right angles. 20 7 65 20 7a 8. From the ø3mm-rod (4) cut a 20 mm (4a) piece, carefully remove any sharp ends with a file 20 4 70 4a 20 9. Take the wooden wheel (8) drill a hole through the middle 1,0 mm diameter. Use a centre finder guage to mark the centre. Place the wheel in a machine vice and drill through carefully 8 3
INSTRUCTIONS 10. Cut from the plastic gloves (9) the small finger or the ring finger (9a). Place it over a finger. Add a drop of instant glue (2min) on the end (9a) and insert it centrally in the piston(8) gluing it in place Hold it in place until the glue sets ( about 2minutes.) and then remove your finger 9 9a 9a 11. Bend an "S" shape on both ends at both ends of the spring steel (10) connecting rod The shape of this "S" must be as exact as possible otherwise it will not fit in the flywheel.trim it to shape with side cutters. Note : The length given is the length of the stroke! S-Form (enlarged!) 1,5 10a 1,5 The connecting rod (10c) is made from the remainder of the spring steel (11) Remove any rough edges from the ends 70 67,5 10b 32 10c 12. Check the length of part (10a) that it is staright ( Use a Try square to che ck,glue it in the piston with instant glue. Be careful not to puncture the membrane (9a) which was cut from the glove at an earlier stage 10a 13. The piston -conrod and menbrane are assembled as shown in the tube (7a) and the excess membrane (9) folded back over the tube. 11 14. Trace the pattern for the diaplacement cylinder ( see page 9) on the beer mat (11) ( The centre must be accurate to 0.5mm ). Make the middle hole 1mm dia with a hole maker. Cut the circles ø25 mm with a scapel or craft knife 4 E113174#1
INSTRUCTIONS 15. Axle part (10c) must be glued at right angles in the middle ( check with a try square) in the dispacement piston (Beer mat, 11) 10c 11 16. Take the steel wool (12)pull it apart and evenly spread it out over the displacent cylinder. From the steel wool should be a maximum of ca. 11mm on the beer mat Use scissors to adjust None of the steel wool should protrude over the edge of mat, otherwise it will rub (18) on the side of the cylinder and effect the action of the engine. 12 17. Take the large gear (13) and drill a 10.00mm hole on each side of the centre boss. Drill slowly to the middle only the remove the rest with a sharp knife. The drilling pattern (Page 11) cut out and the middle point (ø 3mm) cross form cut. Insert the axle (20 mm) in the gear so that it protrudes out the side with the boss removed so that about ca. 5 mm stands proud.place the pattern over the front and fix with sellotape. Drill the 3 x ø1mm holes. Remove the pattern Insert the axle (4a) lmaking sure that it is at right angles 18. Insert the end of the conrod (10a) in one of the holes around the centre of the gear (13) the next is (7mm. Pattern on page 11). By using another hole (8 + 9 mm) the speed ( revolutions per minute, rpm) can be altered at a later stage Finished drilled gear (13) Front ( centre boss removed ) back 13 4a 10a 19. Try the piston and membrane unit in the cylider base (1b) the conrod musn#t be turned 1b 20. Place a washer (16) on the shaft (4a) and insert it through the brass bearing (Brass tube 6) in the frame. When the flywheel is turned, the membrane should should tighten in the bottom dead centre. This membrane must stretch properly not just a little (see diagram A on page 11) 16 Sketch A A 5
INSTRUCTIONS 21. Cut a rubber band (14) and tie it with a knot around the top of the tube. Do not overtighten so that the card tube will be crushed. 14 22. If the membrane is fitted properly fix the tube in the cylinder base (7a) with an instant glue or all purpose glue. Be careful that none of the glue gets on to the membrane. 23. From the other side add a washer (16) and then place the small gear (15) on the axle so that it turns without any play. 16 15 24. On the straight end of the conrod (11b) slide the piece of tubing(17) half way on Finally insert the connecting rod in one of the holes in the small gear 11b 17 General : The fit between the lid (3) and the cardboard tube (18) has been especially chosen so that after assembly, and after taking it apart a few times it will not leak. Because so many are made it is possible that the lid fits so tightly that it is not possible to remove without damaging the tube 25. Press the second lid (3) in the card tube (18) and check it for tightness. If you can remove it easily you do not have to carry out the next stage. If the lid is tight try the following: Go round the lid with the point of a pair of scissors. Repeat this carefully 3-4 times until the lid becomes loose. The bottom lid (3b) must not be done in this way, because once the lid has been damaged it cannot be repaired 3 18 6 E113174#1
INSTRUCTIONS 26. Insert the displacement cylinder in the tube from underneath so that the shaft ptotrudes through the 1nm hole in the top (3a) 10c 3a 11 27. Insert the 2nd lid (3b) in the non. stretched side of the tube(18) 3b 18 28. Carefully assemble the top part of the lid (widenened end Press in place. Make sure that the steel wool does not rub on the walls of the tube or is trapped in any way. 29. Let the connecting rod (10c) go loose The displacement piston is now at bottom dead centre. The connecting rod (10b) and the small flywheel (15) can be turned to Bottom dead centre At this point position the plastic tube (17) and join it to the part (10b) Raise the stroke (10c) of about (max. 2 mm) with pliers so that the piston is not at the bottom of the tube (3b) when at bottom dead centre of the stroke is reached Remove the top part carefully from the cardboard ( do not damage the displacement cylinder) NOTE When pulling the top lid out of the tube (18) do not use the fame as a lever Always lever from the edge of the tube. 15 10b 17 10c 30. Once you have taken it apart move the small flywheel to the top dead centre position. in this point the displacement cylinder should only lightly touch the screws. If the braking effect is too much,the motor will not start. In this case press the steel wool down a bit or remove a little making sure to do it evenly. 7
31. Once the motor has been reassembled it time for the first trial run: INSTRUCTIONS The angle between the two pistons should be between 80-90 degrees see sketch b Turn the small gear to bottom dead centre and hold it in place. Now turn the large wheel also to the bottom dead centre on the cycle. So that it can move when heated. Set the large flywheel and the small flywheel to 80-90 degrees as shown (see diagram and sketch B page 11) The flywheels can be simply turned against each other in opposite directions to achieve this angle Trial run: Firstly check that all the parts work freely. Place and light the candles. Set the displacement centre with the small flywheel so that it is on top dead centre. After a heating time of ca. 20-30 Seconds give the large flywheel a turn. The direction of rotation depends on which the large flwheel is turned The motor does no have much power, so you have to ensuse that all the parts rotate with as little friction as possible 15 Front view(15) Back view (13) 80 90 13 Important. Never leave the candle to burn unattended. When candles burning, the diplacement cylinder must not be at bottom dead centre when the engine is in the stopped position. The beer mat can burn in this position If the motor will not run check the following points: - Is the displacent piston hitting against the bottom of the cylinder? - Is the displacement piston hitting against the top of the cylinder? - Is the displacement piston rubbing against the wall of cylinder - Is the shaft running freely in the brass bearing? if necessary add a drop of oil. - Is the "S" shape of the connecting rod rubbing on the frame? - Is the working cylinder running properly in its cylinder (Card tube 7a)? - Ist the connecting rod the correct way around ( Is it catching in the hole of the large flywheel)? - Is the connecting rod catching on the small flywheel? - Does therod run freely through the hole in the lid? - Is the membrane whithout any holes - Are the flywheels set up at ca. 80-90 degrees when the machine is started? 8 E113174#1
Pattern for the displacement cylinder (Beer mat, 11) E 1:1 Pattern for the plywood sheets (2) E 1:1 9
Pattern Kurbelrad (Zahnrad,13) E 1:1 Steuerzeiten (Skizze B) E 1:1 Ø 18 Ø 1 Ø 52 Ø 16 Ø 14 Ø 3 80 90 10 E113174#1
Sketch A Membrane fitting (9a) A Ø 3 Ø 10 Pattern Deckel (3a) E 1:1 Ø 1 11
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Pattern MDF-Sheet 1 M 1:1 Ø 20 Ø 4 Ø 4 Ø 20 10 10 98 98 13
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Section through the Stirling-Motor 15 16 1a 6 13 4a 10b 10a 8 9a 17 14 3 10c 7a 1b 12 5 18 11 19 2 15