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KS90 blue LTD

Price including UK & worldwide postage: £86.00

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This engine is available ready assembled (full price) and in self-assembly kit form (10% discount), select option above when adding to cart.
The kit is supplied with a CD containing nearly 50 photos showing the full assembly process along with detailed written instructions.

The Kontax Low Temperature Differential Stirling Engine is an excellent demonstration of a heat engine, showing with one spin of the flywheel a clean and simple way of converting thermal energy into motion. This engine will operate from many heat sources, including hot water, computer monitor, TV and the human hand. As long as there is a small difference in temperature between the upper and lower plates this engine will run.

Every one of these engines has been tested to run off the heat of a hand.

This engine has been meticulously engineered. As any Stirling Engine enthusiast knows, friction is your enemy in LTD models. With this in mind, all potential sources of friction in this engine have been eliminated. Another common problem with LTD Stirlings is heat transfer between the plates. Again, all possible routes for heat to transfer directly between the plates have been eliminated.

Based on the pioneering work done by Dr Senft at the University of Wisconsin, this model has been engineered in England, manufactured in England using hi-tech CNC equipment, and is sold from England.

A large number of schools and universities have bought our engines for educational use, the transparent chamber and cylinder make it very easy to explain the Stirling cycle to students. Many of our engines have been kept running for years on top of coffee machines, computers, fax machines, etc. in shops, kitchens and offices all over the world. Many customers take great delight in running our engines on a bowl of ice or snow, where the engine happily runs, but backwards.

Engine features:-

Low-profile heat insulating chamber pillars, giving good surface contact with heat source
Aluminium main pillar, hub & spokes
All airtight seals are made with high strength precision screw threads and nitrile O rings
Both connecting rods are positively located using low friction PET and stainless screws
Micron precision Borosilicate glass cylinder and Graphite power piston, the best combination
Ultra low friction demagnetised and de-greased bearings, NO lubrication required
Fully CNC machined, ensuring crisp, clean tidy edges all over
Engine parts ultrasonically cleaned before hand assembly
Precision engineered and hand built in England
Engraved it with the KONTAX name

Major dimensions:-

Base plates - 92mm diameter, 2mm thick
Flywheel - 82mm diameter, 4mm thick
Power piston - 9.5mm tube diameter
Displacer - 70mm diameter, 8mm thick
Overall height - 120mm

For more information please download our pdf files:

Operation instructions.pdf
Stirling engine how it works.pdf
Stirling engine history.pdf

Customer Reviews
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Reviewer: Gavin from England

Excellent, ran first time on my hand straight from the box!

Reviewer: Steve from England

Amazing Stirling engine, a wonderful gift. Thank you.

Reviewer: Mark Turner from London

Thanks Kontax for your very swift turnaround…. I ordered a KS90 Sterling engine late one Saturday night. The engine was delivered Tuesday morning… Outstanding! The engine is beautiful. Extremely well engineered – it ran from my hand straight out of the box…. The engine will even run off a glass of ice cold water in my centrally heated living room!!!! (but backwards) Thanks again. Mark Turner - London

Reviewer: Clive from Suffolk, UK.

Kontax choice of materials, components and design make the KS90 an aesthetically pleasing small object of desire which is also attractive to watch in operation. I particularly like the see-through cylinders, the rimmed flywheel, and the odd symmetry of the 5 curved spokes and 7 insulating pillars. The KS90 is remarkably free running. On my windowsill it runs for well over 3 hours on the heat retained after the sun has gone down. As it continues to turn reliably well below 25 revolutions per minute, slow motion becomes apparent as one of its charms. The attention to detail evident in manufacture is also given to the packaging and dispatch.

Reviewer: Paul Lawler from Honolulu, Hawaii

This engine is truly a thing of beauty. It will indeed run on the heat from your hand, but for some real excitement put it on a cube of ice or a steaming cup of tea. Perhaps the most fun is pulling it out at a pub and watching the crowd gather around you to try and understand why and how it works!

Reviewer: P Lock from Farnham, Surrey UK

Over Christmas I order the KS90 kit, it arrived the next day!. Super fast service. The engine went together with no problems at all. I had it running on the heat of my hand, it will run with just a temperature difference of just 5 degrees centigrade. This engine is perfectly engineered and I just love it. Well done Kontax.