On 6/2/2019 12:39 PM, AMuzi wrote:
On 6/2/2019 11:18 AM, Frank Krygowski wrote:
On 6/2/2019 5:48 AM, John B. Slocomb wrote:

See https://www.youtube.com/watch?v=-9gQ1KRhesM

In the narration he mentions that a 24 speed gear set, or
even more,
would be perfectly feasible. No wires, no cables, either.

I estimate that a New! Innovative! Revolutionary! Better!
bicycle transmission has been invented every two years or so.


I would expect a hypoid gear set in an oil bath to be relatively
efficient compared to a chain. Any ME comments on an open crown & pinion
set?

I'm pretty sure a chain is the most efficient mechanical transmission by
far. It can get over 98% efficiency under good conditions.

Going entirely by memory, I think one pair of spur gears are typically
90 - 95% (depending on manufacturing accuracy), and hypoids, etc. are
less. You can think of hypoids as a sort of semi-worm gear, and the more
sliding contact, the more friction.

Somewhere around here I may have typical numbers - unless they were
donated to my successors when I retired.


--
- Frank Krygowski