A Sophisticated Marine Steam Engine Without Cranks

This model in the Science Museum London shows a sophisticated conversion of translation into rotation with the help of cam rollers sliding along sine shaped grooves in cylindrical cams. The valve gear works in the same way. This principle saves space like an electric motor, but there is probably excessive friction and side thrust on the cam rollers - you can see the lots of grease. It was a proposal of British engineer George Shott and his sons. This engine would have been expected to develop about 520 hp at 120 rpm. Only this 1:12 model was built about 1870 to show the function and it is doubtful, whether it had worked successfully in full scale . I've found this model incidentally in the naval department of the Science Museum, but had some difficulties, when I looked for it two years later - it's rather small and hidden.
A second video, taken at that time in HD, (see video answers) shows more details.




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Category:

Science & Technology

Tags:

• steam
• engine;
• ship;
• sine
• curve;
• cam
• rollers;
• Science
• Museum
• London;
• Dampfmaschine;
• Schiffsantrieb;
• crank;
• Kurbelwelle;
• ship

[timextwo]

It almost resembles a helix drive engine.

[harryolynx]

@timextwo

Well, maybe, but with a helix drive you cannot transform continiously up and down translation into rotation of one direction. The helix principle was used by Coffman starters (e.g. Spifire fighters) which had to do only a few revolutions while the piston was going down. Thanks for your interest and sorry for my late answer.

[harry4468]

that must take a bit of precision to get right

[harryolynx]

Hallo Harry, I think the same. Unfortunately I dont know, whether it ever has been built as a ship's engine.