If one runs the mixture properly to keep the peak ICP out of the choke
area, having choke in the barrel is a good thing.  If one operates the
mixture in such a manner so as to place the thetaPP too close to TDC,
then not having choke could be a way to overcome the error slightly. 
Having no choke is one way of covering up poor technique.  It is a
sub-optimal way to do things IMO.

Walter

Interesting conclusions Walter.

 

Seems to me that operating with theta PP closer to TDC would increase the need for choke.

 

Essentially, the fluid temperature varies directly with the pressure and the heat transfer rate per unit area varies directly with the temperature. Thus, moving theta PP closer to TDC would result in additional heat transfer to the upper combustion chamber and less heat transfer to the lower chamber. This results in increased differential thermal expansion of the barrel and a flaring effect at the top of the cylinder. 

 

I could be mistaken, but I am of the understanding that countering this flaring effect is the whole point of cylinder choke.

 

As for the claim of an unchoked barrel being better, if the cooling fins were better optimized to the operating heat transfer rates, then the cylinder would remain straight at operating temperature without the need for choke. Also, when a choked barrel is started from cold, it generates additional ring movement until it reaches its design temperature. This results in additional wear to the ring lands. I have no knowledge whether Chuck Ney has altered the cooling fins, found through experience that choke is unnecessary or if he is simply B.S. promoting a cheaper manufacturing process.

 

Rob