Originally posted by weargle:
Mr. Bernoulli explains it well; the speed of the gas on the outside of a bend necessarily travels faster than that on the inside of a bend, and there is friction as a result. When you have turbulence on the inside of a bend, as a result of crushing pipe, the friction is increased, and the gas moves slower as a result.

I know speed of the gas on the outside of the bend goes faster then the inside of bend and it gets to the pont of creating a vortex which is not good a chush at the right place and right size will reduce the vortex and make for a better flow so mandrel or chush? Stills applies the best for reducing vortex is call (Cobra Neck) bend.

SVT 99 #526 of 2760