In addition to designing and manufacturing our own hot air engine models, we are always looking for older engines to buy.
| Stock code | Description | Price |
4179 |
Twin cylinder hot air engine | £250 |
The original "Super Vee" engine was designed in a mad bout of AutoCAD late one Friday night, made over the weekend from the scrap box and presented to Samuel (my chief test engineer) for his 5th birthday on the Monday morning. It first ran at 5.30am and had cooled down sufficiently to wrap up for breakfast time!
Having responded to requests for more engines from neighbours,
relatives and passing costermongers, I set to and produced a rather more
professional design for batch production. The current Super Vee is, like it's
birthday present ancestor, designed to give many years of service. It's
constructed entirely in steel, brass and aluminium, finished in a durable powder
coat and anodising.
|
The Super Vee A table-top engine which will run for several
minutes on a filling of its miniature spirit burner, the Super Vee has
power and displacer cylinders set at right angles, causing the connecting
rods to describe the eponymous "V". The displacer cylinder is turned from stainless steel for rapid heat exchange and long life. The displacer cap is turned from aluminium billet and anodised. All other parts are in brass, copper or powder-coated steel to produce a durable, good-looking engine. Fun to run, hypnotic to watch and attractive on your desk when it's doing nothing else - the Super Vee is an ideal introduction to the world of hot air engines.
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Apply a few drops of thin oil to the displacer clevis pin, displacer and connecting rods at the crankpin and to the top of the piston. Turn the engine over by hand to distribute the oil - this is particularly important in the cylinder, where the oil both lubricates and forms a gas seal as it fills the piston grooves. Fill the burner with a small quantity of methylated spirits and replace the top - allow a minute or two for the meths to soak into the wick before lighting and placing under the hot end of the displacer cylinder. Wait a few moments for the temperature to rise, then start the engine by flicking the flywheel counter-clockwise viewed from the connecting rod side. The engine performance and length of running time will increase over several runs as the components run in. After use, empty any remaining spirit from the burner, wipe any oil residue from the engine and store it somewhere prominent! |
A fixed volume of air is heated. As it gets warmer, its pressure increases. By allowing
the air to act on the underside of a piston, the engine can do work. Having pushed the
piston to the top of its stroke, the air is then cooled, reducing its pressure and
allowing atmospheric pressure to push the piston back down. Repeat rapidly and you have a
hot air engine!
Turning the idea into reality has involved many engineers over a long period of time. The
Frenchman Carnot proposed the first theoretical work, which was developed into a practical
machine by the Englishman Thomas Mead and, in Scotland, Dr Robert Stirling. Such was
Stirling's contribution that "hot air engine" and "Stirling cycle
engine" now get used almost interchangeably.
There are several design considerations. Firstly, the air must be heated from an external
source (yes - this is an external combustion engine!). Having heated the air, it must then
be cooled effectively and some way found of preventing heat "leaking" from one
end of the engine to the other. Finally, some mechanical means must be contrived to make
the preceding things happen in an appropriate order.
Taking the Super Vee as an example:
The engine starts with the displacer at the hot end of its cylinder - conversely, the air
is displaced to the cold end. As the air cools, the pressure drops. This in turn acts on
the piston.
The piston descends, moving the displacer piston back along its cylinder.
The cool air is forced to the hot end of the displacer cylinder by the displacer. The air
pressure increases rapidly, forcing the piston back up its bore.
This is turn starts to moves the displacer piston back to the hot end, the air is
displaced to the cold end, its pressure drops and - we start again!
mike@stationroadsteam.com
Telephone
01526 328772
International +44 1526 328772
Web site copyright © Station Road Steam 2001-2011
