I can't resist

[Peter Nevai]

Talk about over anaylisis. A grade school law of physics. Every Action has an Equal and opposite Reaction.

This applies just as much to propellors and engines as it does to rockets. P factors, Torque reactions  does contra rotation work or not. Sheeesh.

Everyone who does not believe in evolution raise your hand.

[Phil Bare]

Talk about over anaylisis. A grade school law of physics. Every Action has an Equal and opposite Reaction.

This applies just as much to propellors and engines as it does to rockets. P factors, Torque reactions  does contra rotation work or not. Sheeesh.

Everyone who does not believe in evolution raise your hand.

Of course contra rotation works, very well, matter of fact......and evolutionary speciation never happened, according to ALL the evidence...

[Jim Thomerson]

I do not believe in evolution.  I have studied the matter and I am convinced of evolution. 

[Wayne Collier]

I think Peter meant the point on evolution humorously and rhetorically; even so, I've had an interest in the topic for about three decades.  Granted, I haven't taken as in depth a look as some folks, but I know of no real evidence (conjecture based on fossil fragments and similarity of organisms is still conjecture) for evolutionary speciation.  Plenty of evidence for mutation and adaptation and change within species, but that is not evidence for speciation. Come to think of it, this probably isn't the place for this discussion. 

Back to the real topic here.  By cotnra rotation do you mean a pair of propellers or rotors on the same shaft, so to speak, spinning opposite directions?  In terms of spinning mass in opposite directions to help counter torque, it would seem effective. There is still the spinning and reciprocating mass inside the engine to consider.  I guess I've never understood the aerodynamics of this sort of situation.  The more I think about it, the more uncertain I become.  I see these little cheap RC helicopters flying about, but I don't completely know how they work.