Google English Electric and Deltic. They got it right. Three opposed
piston
cylinders in a triangle shape with a crank at each point (3 cranks) The
US
Navy used them in patrol boats. Used in trains and boats.
I have already seen that type.
Fancy, but not very volumetrically efficient.
The large space in the cylinder triad is totally useless.
"The Fairbanks Morse Opposed Piston (OP) engine has been designed and
developed for a wide array of electrical power generation and heavy
industrial applications."
It is a static engine, so can have heavy cranks. The TS3 was for road use
and only 3.5 litres, less than most US cars in cc's. Yet could pull
amazingly heavy loads - it was a truck. Hence the lighter knuckles.
Take the time actually to look at the engine you are talking about.
You have a 6 lobe crank that is connected to 6 rocker rods.
You have 6 rocker rods that is connected to 6 piston rockers.
You have 6 piston rockers that is connected to 6 primary piston rods.
Which in turn, connects to 6 pistons.
The space taken up by the piston rockers easily equals
the space taken up by a crankshaft.
So you could just have two cranks at each end of the cylinder,
and do away with the lower crank case section.
That will save a boat load of weight.
Probably equal to the weight of one of the three lobe cranks in and off it's
self.
You have to have a 6 lobe crank instead of two three lob cranks.
I don't know if you have rebuilt or worked with engines before,
But the basic required geometry of the crankshaft means that
A three lob crank is far lighter than a six lob crank.
The two three lob cranks will probably be close to
one and a half times the size of one six lob crank.
The entire mass of the six piston rockers and rocker connecting rods
Will not be negligible.
They will be solid steel.
The mass of them will easily equal the weight of a three lobe crank.
And the majority of the weight that crank lobs has to bear
is a result of the constant acceleration and deceleration of reciprocating
parts.
The weight that the actual compression pressure puts on the connecting rods
Is orders of magnitude less than the force it take to move a piston back and
forth
60 times a second.
So all that added acceleration weight from the added piston rockers put on
the crank
in addition to the piston weight will require bigger crank journals, and a
far more
substantial crank to tolerate the added force without fracturing..
The oversized crank will easily equal or exceed the weight of two cranks
that
is directly connected to the pistons with one piston rod.
The main crank journals will have to tolerate far more load.
The rocker pins will have to take 2X the load that the crank takes.
All those parts that are taking close to an order of magnitude more weight
than a normal crank will create a lot more frictional losses, no mater what
type of oil you put in it.
And those frictional losses will pretty much counter any gains in efficiency
you
get from the opposed piston design.
That is why they stated that the things would run great if you keep regular
maintenance on them.
That is because even a slightly substandard oil will cause catastrophic
effects with that much
moving mass.
So, in the end...........
You are adding about the same as 3 (three lobe) crankshaft weights to the
engine by
using that design, as compared to the dual crank design.
You are almost doubling the engine size.
You are reducing the total free running efficiency.
Yes, they used them in pre war planes.
But if you will read the literature,
You will see that FM designed the opposed piston engine in the 1930's
It even says it on that PDF that I linked to.
But they never started full scale production at that time.
They started full scale production in the 1940's for submarines for the war.
But it is safe to say that the word of design concept made it's way around.
And there was a lot of people that tried to put that type of engine in many
things.
Which they did.
If you believe someone else actually invented it, please link to some
literature that proves it?
I would be very interested.