Posted 2006
Air Engine One Movie
WMV Format 2.3MB
This is
my first attempt at a compressed air engine. The air control
valve is made from 15mm plumbers copper pipe and has a resin
piston, (see my first
Stirling
Engine for how to make a resin piston),
(fig 1),
(fig 1a),
(fig 1b),
(fig 1c),
(fig 1d).
A power
cylinder was constructed from 20mm plumbers copper pipe and is
fitted with a three pence piston, (see
How to Make a power
piston for three pence),
(fig 2),
(fig 2a),
(fig 2b),
More 15mm
plumbers copper pipe was used for the arm that holds the
flywheel, and the flywheel was made from a scrap of hardboard
cut to the size of a CD and then a CD was glued on to it to
make it a bit heavier,
(fig 3),
(fig 3a),
(fig 3b).
The crank
assembly was made from two pence pieces, along with nuts and
bolts,
(fig 4).
At this
stage a wooden twin deck frame was built and the various parts
were assembled onto it,
(fig 5),
(fig 5a),
(fig 5b),
(fig 5c),
(fig 5d),
(fig 5e),
(fig 5f). Note that the air control valve is 90
degrees out of phase with the power piston.
When it
came to testing, I was disappointed with the results. Although
the engine ran, it was very sensitive to air pressure, and
worked best on low air pressure. The reason being, when the
power piston was at top dead centre and the air valve shot off
the air. Air was trying to push the air valve piston up and
thus the air valve piston and the power piston where fighting
each other.
I fitted
a spring to the air valve piston to try and compensate of
this,
(fig 5d), and this helped a bit. I conclude that the air
valve was not of a good design and that I would improve on
this on my next engine.
This engines work by allowing compressed
air to enter the cylinder when the piston is at top dead
centre, thus pushing the piston down and turning the flywheel.
When the piston reaches bottom dead centre, the control valve
shuts off the compressed air and vent the air in the cylinder.
Due to inertia the flywheel continues to turn pushing the
piston back up the cylinder. Once the piton reaches top dead
centre, the control valve closes the vent, and allows compressed
air to enter the cylinder once more. This process continues
until the compressed air is shut off.
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Posted 2006
Air Engine Two Movie
WMV Format 2.6MB
This is
my second compressed air engine and it differs from the first,
in two ways. Firstly the power piston is mounted on top of the
top deck,
(fig 1),
(fig 1a).
Secondly,
the air control valve is made from 4mm
copper pipe, which came
from a telescopic radio aerial, and was assembled into a block
of wood,
(fig 2) and is mounted under the top deck, doing away with
the double crank arrangement,
(fig 3),
(fig 3a). The air control valve piston was made from a
ground down bolt,
(fig 4).
The rest
of the machine was made in a similar way to my first engine,
(fig 5),
(fig 5a),
(fig 5b),
(fig 5c),
(fig 5d),
(fig 5e),
(fig 5f). The completed engine is shown in,
(fig 6),
(fig 6a),
(fig 6b),
(fig 6c),
(fig 6d). The bend in the air valve piston connecting rod,
is for fine adjustment,
(fig 6c).
This
machine runs 100% better than me first effort, and doesn’t
suffer from the two pistons fighting each other, as they did
in my first engine. This engine runs smoothly and slowly on
low air pressure and as the air pressure increases so dose the
speed of the engine.
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Posted 2006
Air Engine Three Movie
WMV Format 2.6MB
With
this engine I’ve built the air control valve into the power
piston’s cylinder,
(fig 1),
(fig 1a),
(fig 1b),
(fig c1),
(fig 1d). The air valve piston was made from a ground
down masonry drill,
(fig 2),
(fig 2a). The air valve piston is operated with a rocker
arm that sits in a aluminium tube,
(fig 3),
(fig 3a),
(fig 3b).
See
here for how I
made the power piston. The power piston connecting rod, is
made from a cut down junior hack saw blade,
(fig 4),
(fig 4a),
(fig 4b). Most of the parts are shown in
(fig 5).
I
decided this engine would have it’s own air pump, to save on
lung power or having to connect the engine up to a
compressor. An air tight box was constructed, with an air
pump, (bought from a local pound shop), sealed in,
(fig 6),
(fig 6a),
(fig 6b),
(fig 6c).
The
engine was then assembled onto the base board, and then
sealed on top of the air tight box with bathroom sealer and
screws. A pipe goes from the engine into the air tight box,
(fig 7),
(fig 7a),
(fig 7b),
(fig 7c),
(fig 7d),
(fig 7e).
The
idea being, when the pump is operated enough air would be
compressed in the air tight box to drive the engine – it
worked!
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Posted June 2007
Scotch Yoke Air Engine Movie
WMV Format 4.2MB
This single-acting twin cylinder
engine works with a single Scotch Yoke piston rod.
Here is the completed engine. I may
replace the plastic piping for copper so that the engine
can be run on steam. As it is, the engine runs well on
compressed air. The engine is quite powerful and drives a
small generator which lights up a wheat bulb. I think that
an engine similar to this one, could be built into the
frame of a model boat, and power it, using steam.
Flywheel:
The flywheel came from an old tape
recorder, (fig 1). A crank arm was fitted to take the
Scotch Yoke, (fig 1a). Two brass pipes that slide into
each other where used for the flywheel bearing, (fig 1b),
(fig 1c), (fig 1d).
Cylinders:
The cylinders were made from 22mm
plumbers copper pipes, and are 40mm long. 8mm copper pipes
where fitted to the back of the cylinders for the
steam/air to enter. A nut and bolt was also fitted to the
end of the cylinders to enable the cylinders to be
attached to the frame, (fig 2) and (fig 2a).
Scotch Yoke and Pistons:
The Scotch Yoke assembly is made from
threaded bars, electrical block connectors and copper
pipes, (fig 3) and (fig 3a)
shows how it was assembled and
soldered together. The pistons were made from one pence
pieces, they where turned down a little so that they
fitted the cylinders and then bolted to the Scotch Yoke,
(fig 3c). The excess thread was cut off later when I was
sure the pistons where in the right position.
Steam/Air Inlet and Outlet Valves:
Another Scotch Yoke assembly was
used to control the steam/air inlet and outlet. A disk
with a crank arm to take the Scotch Yoke, was fitted to
the flywheel shaft, with the crank arm being 90 degrees
out of phase with the crank arm on the flywheel, (fig 4)
and (fig 4a).
The steam/air inlet and outlet valves
where made from 7mm and 6mm brass pipes, they where drilled
and soldered as shown in (fig 4b) and
(fig 4c). Bicycle
spoke wires, electrical block connectors and two pop
rivets, where used to make up the Scotch Yoke. It was
soldered together as shown in (fig 4d), (fig 4e) and (fig 4f).
Assembling:
(Fig 5) shows many for the parts for
the engine. The engine was assembled on to a 180mm x 120mm
MDF cut down floor tile, which was drilled to take the
engine parts, (fig 5a). The frame of the engine was cut
from 15m block of wood, these where sprayed red, (fig 5b)
and (fig 5c).
The engine was assembled as shown in
(fig 5d), (fig 5e), (fig 5f), (fig 5g), (fig 5h), (fig 5i)
and (fig 5j).
A base was made for the engine and
the plumbing was sorted, (fig 5k). The engine was then
tested and adjusted for best performance. The generator,
was the drive motor from the old tape recorder that the
flywheel came out of. It was screwed to the top of the
engine frame, and is driven from the flywheel with the tape
recorders drive belt, (fig 6), (fig 6a), (fig 6b), (fig 6c), (fig 6d) and (fig 6e).
The size of the engine is: 180m x
120m x 150m.
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Posted June
2007
Liam's Air Engine Movie
WMV Format 4MB
I made this air engine for my grandson; he’s only six, so I
couldn’t build him an engine where you have to light a fire
under it!
It has its own, bicycle air pump, (fig
1), (fig
1a). Pressing the pump down once, turns the engine four
times.
I used a 50mm length of 10mm aluminium pipe for the cylinder,
(fig
2). The piston was made from an old car socket, (fig
2a), (fig
2b).
The air control valve was soldered into a length
of 15mm copper pipe and then the aluminium cylinder was wedged
into the copper pipe, (you can't solder aluminium), (fig
3), (fig
3a).
This engine works in much the same way as the other air
engines.
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Posted August 2008
Beam Air Engine Movie
WMV Format 2MB
This beam engine runs on
compressed air. It has two decks, the top deck holds the
flywheel, the beam, and the top of the cylinder, (fig 1).
The bottom deck houses the
bottom of the cylinder and the air inlet and outlet valve, (fig 2).
The air inlet and outlet valve
is operated with a lever that is attached to the crank pin.
It works a bit like a Scotch Yoke, (fig 3).
The cylinder is made from 10mm
aluminium pipe from B&Q, (fig 4).
The cylinder sits on top of the air control valve, (fig 5).
The piston was made from
plumber's micro copper pipe, (fig 6).
It was a tight fit in the cylinder and had to be turned down
in the drill press so that it just slid down the cylinder. A
bolt was fitted in the top of the piston to take the
connecting rod and then the piston was filled with 151
epoxy adhesive, (fig 6a),
(fig 6b)
and (fig 6c).
The beam ,(fig 7),
came from an old hard drive; as did the flywheel, (fig 8)
and (fig 8a).
The air control valve allows
compressed air to enter the cylinder when the piston is at
bottom dead centre, thus pushing the piston up and turning
the flywheel. When the piston reaches top dead centre, the
control valve shuts off the compressed air and vents the air
in the cylinder. Due to inertia the flywheel continues to
turn pushing the piston back down the cylinder. Once the
piston reaches bottom dead centre, the control valve closes
the vent, and allows compressed air to enter the cylinder
once more. This process continues until the compressed air
is shut off.
To run the engine, a small
bicycle pump was connected to the back of a plastic pop
bottle, (which acts as an air reservoir), the top of the
bottle was connected to the engine, (fig 9).
This engine runs well, with very little air pressed.
(Fig 10),
(fig 10a),
(fig 10b)
and (fig 10c) are a few more close-ups of the build.
