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KS90 Black LTD

Price including UK & worldwide postage: £86.00

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This engine is available ready assembled and in self-assembly kit form, 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 assembled engine 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: Reid from Miami

The KS90 kit which I bought from Kontax several months ago has provided much joy here. The kit assembled like the proverbial Swiss watch, albeit much more simply! All the hard work has been done by the makers. The assembly was simply a pleasure, and provided me with a more intimate understanding of the construction and operation of these amazing bits of precision engineering. The engine is absolutely as sensitive as promised. It has run now for many hours from various power sources, including chemical hand warmer packets. Happen to have a stainless steel "brick" found in the bits bucket of my hobby shop; a slab of that metal the size of a common brick (but heavier, of course). If I warm that brick in hot water, it absorbs enough heat to run the model for a few hours to come; offering a convenient and portable source of energy. The kit includes a CD-ROM of amazingly clear photographs of the simple stages of the kit's assembly. The presentation of text and pictures of that disk are of the same sterling quality as the KS90. Summary: Entirely satisfactory in every detail, this kit, this engine, this firm's productions and presentation and customer services.

Reviewer: Mike Richardson from Pudsey, Leeds, West Yorkshire

After placing an order with Kontax for the KS-90 Hand Held kit (Black), a small package arrived the next day. Upon opening the sealed package it was apparent straight away of the quality, each individual meticulously engineered part was placed into a dense foam sandwich which had been machined out to give an exact tight fit to ensure that no damage to the very delicate parts would occur. The kit came with a very concise instruction manuel on a CD which could be printed off for convenience, the actual CD manuel on screen was very clear with large highly detailed photographs. All parts of the kit fitted together perfectly and each piece was machined with incredible accuracy, the kit from start to finish took about 1.5 hours to complete. The engine was placed on a hot cup of tea and with a little turn of the flywheel began to work approaching what must have been about 100 RPM and made a great "very quiet" sound. I have made a number of Sterling engines in the past both low and high temperature types but never of the quality associated with this kit, I would strongly recommend this to anybody interested in Sterling engines or to those who just like constructing things. It may sound as though I work for the company which I do not but credit should be given where credit is due. 10/10.

Reviewer: Philip from Farnham, Surrey UK

This engine is a piece of precision engineering excellence. The kit went together faultlessly.Works really well. Well packed and next day delivery. Great value for money. Well done Kontax.

Reviewer: Rob from Queensland Australia

I'm absolutely impressed with so many aspects of the self build kit. The quality of the parts is uncompromising and utterly without fault. The workmanship is that of a person who undoubtedly has a passion for their work. And the most impressive bit of all? The packaging. Whoever designed this kit and made made the packaging double as a simple fixture aiding assembly is nothing short of a genius. From one Engineer to another, I am UTTERLY impressed. I thought this level of engineering skill and attention to detail was dead in the UK. This kit is world class - I can guarantee whoever buys one will be impressed. With my kindest regards, Rob

Reviewer: Brian from Austin, TX

Precision crafted, runs smoothly. I love the subtle sounds it makes as it runs, like a softly ticking clock in the distance.

Reviewer: Andrew from Singapore

The KS90 Black was very easy to assemble, with excellent CD-ROM instructions and fabulous part quality. Here in the tropics it won't run on the heat of your hand but that's not the engine's fault, it's because ambient air temperature is almost exactly the same temperature as my hand. It runs very well with a halogen desk lamp shining on the black top plate and of course spins particularly fast when resting on a hot cup of tea.