I got this pipe (a Ukrainian product by the way) for my birthday. Nice long thing I didn't notice the smoke being cooler, is it a legend or truth? Came with a pouch of Danish tobacco, really nice.
I remember in a thread someone broke it down using the laws of thermodynamics showing that the stem would have to be much longer than any pipe to actually cool the smoke
Myth. Most stem materials have good insulating properties making them ineffective at cooling over the distance especially considering how quickly the smoke travels through the stem.
The conductivity of rubber (vulcanite) or plastic is not sufficient to diffuse or dissipate a significant amount of heat before it reaches the mouth, especially because of the moisture content of the smoke. Maybe one could try a 30-100 foot stem and see if that's enough.