Paddleducks

Paddler Modelling => Construction => Topic started by: Argonaut on February 20, 2016, 02:47:28 AM

Title: Rotary to reciprocal motion
Post by: Argonaut on February 20, 2016, 02:47:28 AM

In my quest to find a way to drive a stern wheeler I came across this interesting idea and think that I may attempt to use it.
https://www.youtube.com/watch?v=ScB6Wd4r9Jc

Title: Re: Rotary to reciprocal motion
Post by: steamboatmodel on February 20, 2016, 10:15:12 AM

Hi Jack,
Do a Google search for Scotch Yoke, and I think you will find what you want.
Regards,
Gerald.

Title: Re: Rotary to reciprocal motion
Post by: Bierjunge on February 21, 2016, 11:44:02 PM

Argonaut,

The reciprocating pinion/rack looks like an intersting mechanical toy to me, but in my opinion it would be totally unsuitable for driving a sternwheeler:
 
It leads to a discontiuous motion with constant speed between both dead centers, whereas the pitman drive of the sternwheel requires a sinusoidal motion:
(http://up.picr.de/24658215bd.jpg)

If you want, you can find a number of functioning pitman drives at http://www.paddleducks.co.uk/smf/index.php?topic=2838.0 (http://www.paddleducks.co.uk/smf/index.php?topic=2838.0) since the original scotch yoke mechanism isn't totally satifying either.

Moritz