The Modders might be interested in what I have put my poor brain through to understand this drive system.
To explain, I need a compact cam drive system for my compressed air V8 engine see:-http://www.homemodelenginemachinist.com/index.php?topic=14530.0
I had seen this system in a review of a NSU Prinz car years ago and
filed it away to look at later, because I didn't understand how it
worked. The journalists that reviewed it didn't understand either so
just described it as "Two eccentric rods" http://cybermotorcycle.com/gallery/nsu/NSU_Ultramax_Camshaft_Drive.htm
This is an animated version :-http://www.nsu4.nl/english/e1ultramaxcamshaftsystem.html
The third rod nearest the engine just maintains the centre distance.
So, this how I have managed to explain it to myself, if it helps
anyone else, that would be a bonus.
Firstly, locomotve wheels are phased 90 degrees on each side, it is
called quartering and allows the double acting cylinders to be self
starting. ( Pretty useful, wouldn't want to push a steam train!)
Lego model so that both sides can be seen, not easy with a full
Note that only the left side is driven. The right hand side is
made to rotate by the coupling rods.
Now I have transferred one of the rods to the other side :-
Another view :-
Again only the left side is driven.
If I can manage to machine the two 90 degree cams, I should have
a slick way of joining the crankshaft to the overhead cam without
the use of gears,belts or chains.