[SEL] Did they ever make?

[Rob Skinner]

>Now, here's the big question,
>the 30 and 50 both have a counter balanced crank, the 20
>doesn't.  This looks like it would be just the opposite of
>what it should be.  If there is a reasoning for this,
>maybe this is one of the reason's JD did it the way they
>did, to prevent from having to do additional counter
>weighting of the crank. 

The 30 and 50 Hagans, as described, would have even power output, but would not
be inherently smoother running engines.  (Titan drivers say this is better in
the slow race, but the proof is in the ribbon)

720 degrees of crankshaft rotation are required in our standard four-cycle
engines.  Divide by 2 cylinders and we have a cylinder firing every 360 degrees.
That will mean that BOTH crankshaft throws will be lined up and the pistons will
be moving up and down at the same time.  That's a LOT of mass flying around, and
even with crankshaft counterweights, there will be vibration.  

Take a look at the early Rumelys.  They had crankshafts that were lined up.  You
hear the evenly spaced exhaust... thump... thump... thump... and see the whole
tractor rocking because of an engine that isn't well balanced.  

In 1917 Rumely changed it's crankshaft throws to 180 degrees apart, like the the
Hagan 20 horse or a John Deere.  The cylinders now fired at 180 degree and 540
degree spacing... thump thump... thump thump... thump thump... 

The result is that they built smoother running engines.  



=-=-=-=-=-=
Rob Skinner
La Habra, California
mailto:rskinner at rustyiron.com
http://www.rustyiron.com