Posts Tagged ‘engines’

Back to Front Design

Not sure if I have a weird way of approaching the design of a new model engine or just like the idea of starting with perhaps the most artistic part and then developing the idea from there…..

100mm or 4″ diameter flywheel

This flywheel is 100mm diameter and 25mm think and made from a solid disc of cast iron.

The engine? Well my thought is that this will form the basis for a new horizontal steam engine – single double acting cylinder or maybe a compound – not sure yet…..will add the description and images to the model engineering gallery as it progresses.

Ignition System from Just Engines

Just Engines have an ignition system for converting glow engines to spark ignition – may be just the thing to use if you are building a model spark ignition engine as this comes as a complete conversion kit.

Just Engines Online Ltd Ignition Systems for Glow Engines.

ModelEngines.info

ModelEngines.info

Just had to write a quick post about John Bentley’s website as I have spent over an hour today browsing through the different models – they are just stunning and inspirational.

I included an image here from the front page of the website – wow….

Model Engine Kits and Ready to Run

I was looking around for model engines that you can buy ready built or as kits and came up with the following.

Part Machined kits:

• Bengs Modellbau – stirling, steam and flame eaters, very beautiful designs

Machined kits:

• Stuart Models – steam engines
• Bohm – stirling engines, these models come as machined kits and ready to run

Ready to run:

• Stuart Models – ready to run versions of the famous engines
• Kontax – stirling engines, low temperature, high temperature, acoustic engines and stove engines
• Bohm – stirling engines, ready to run

We wrote a page dedicated to Hit and Miss Engines.

Piston Rings

I started listing the different cylinder liner and piston material combinations, but the piston rings are a significant factor in friction losses and wear.

Piston rings should be as thin as possible to reduce contact area.

I have made cast iron piston rings, but not for a long time. I made them by firstly turning a cast iron ring to size. The ring is then split and filled to give a small clearance on the ends so that the ring can be squeezed into the liner. The ring is then held in a fixture to keep it flat at the same time being expanded with a small piece of steel between the ends. I then coated the ring in a brazing flux to stop it oxidising whilst being heated to cherry red.

This is where my memory goes as I cannot quote remember how hot and for hope long – can anybody help here?

This link describes using the Trimble method: Feeney Construction

Cylinder Liner – Piston Materials

The basic options are:

• Cast iron liner – cast iron piston
  • Modelenginenews.org – much favoured of yore by the likes of ET Westbury.
  • glue-it.com – Mick Cherry’s hit and miss engine – “The engine does not have piston rings, it has a cast iron lapped bore and piston, they never wear out.”
• Cast iron liner – steel piston
• Cast iron liner – aluminium piston with cast iron rings
• Phosphor Bronze liner – steel piston
  • glue-it.com – lamp post engine – this is a steam engine that has to date just been run on compressed air. Not the easiest materials.

• Steel liners
  • model-engineer.co.uk – forum discussion on the use of steel liners
• Steel liner – steel piston
  • Modelenginenews.org – A steel piston is fitted with clearance at TDC and will always have an oil film, and a better and extended life–without the “run-in, peak, and run-out” cycle exhibited by a CI piston.
• Steel liner – aluminium piston
• Steel liner – aluminium piston with cast iron rings
  • Modelenginenews.org – In summary, not a combination for the absolute, raw beginner, but not that difficult either. Best suited to larger engines–say with a bore 5/8″ and upwards.
• Steel liner – Cast iron piston
  • Modelenginenews.org – This combination gives the first time constructor the highest possibility of producing a runable engine that will have a reasonable working life.

I’ve added a page to glue-it.com listing the different materials and showing some examples: Pistons and Liners

Hit and Miss Engines

Hit and Miss castings and engines.

• Engineers Emporium – engine kits
• Antique Engines – a page of hit and miss engines
• Harold Depenbusch – hit and miss engine plans
• David Kerzel – images, plans and build notes – includes a plan for making the spark plug.