Second Chamber Pipe Effect - Analysed and Quantified

[yachtexplorer]

David at TobaccoDays has published his study on the effectiveness of various RC designs. This is not simply a subjective comparison but rather he used equipment to measure smoke temperature at various points in the smoke stream, doing his best to make the pipe the variable. I contributed the use of one of my pipes for this study. Interesting stuff, at least to me.

http://tobaccodays.com/articles/100-pro ... ler-smoke/

[The Smoking Yeti]

Very interesting for sure. I'm curious though, is there a point when the expansion chamber results in a loss of flavor? A well engineered pipe(no Calabash) can easily deliver cool flavorful smoke in the hands of an adept pipe-man. Does the chamber add more flavor? Or does it just make smoking cooly easier?

[yachtexplorer]

Very interesting for sure. I'm curious though, is there a point when the expansion chamber results in a loss of flavor? A well engineered pipe(no Calabash) can easily deliver cool flavorful smoke in the hands of an adept pipe-man. Does the chamber add more flavor? Or does it just make smoking cooly easier?

More the latter than the former, I am sure. I good pipe properly smoked will deliver the goods. An RC is more forgiving of an enthusiastic puffer. One thing is certain though and that is the cooler smoke by physics 101 will carry less moisture. This is born out by the need to swab these pipes out after finishing the bowl. By most accounts cooler and dryer are better. I have had people claim to notice nuances of flavor from their favorite tobaccos that they had not noticed before. Whether this was because they were paying more attention or that cooler, dryer smoke reveals more subtlety is clearly an open question.

From personal experience, the best smoking pipe I own is a briar Calabash by Tonni Nielsen. I do like the way my 2nd chamber pipes smoke more than just about any of my conventionally drilled pipes (and I have a well represented assortment of pipes by the most respected carvers). This is not to say that I only smoke 2nd chamber pipes or that I do not derive immense pleasure smoking my Larsens, Ilsteds, Dunhills, etc. or newer Davidsons, Howells, Negoitas, etc.

[andrew]

Interesting.

andrew

[Yak]

His "With Rear Chamber" illustration squares with my long time experience with old Britwood that had their shanks drilled out oversized for "fitaments" long since discarded. Very cool-smoking and tasty pipes, as a rule.

[oklahoma red]

The "why" it works as far as cooling is concerned is straightforward. Bernoulli's equation/principle comes into play. Smoke is pulled from a large chamber (tobacco bowl) thru a small orifice (the airway between the two chambers) and into a second, larger chamber. The sudden volume change upon entering the expansion chamber causes a drop in pressure and temperature. Think about the "real" calabash pipes made from gourds. Little hole in bottom of tobacco cup opens up to a very large space below it.
I'll stand by my earlier statements that in the RCs that I have made and kept I CAN detect a cooler and dryer smoke. BUT, as I have stated before, it is NOT a dramatic difference and I would mostly attribute that to the scale of the whole system. Is the extra work worth the effort? In my case yes. Engineering them is fun for me. Perhaps not for someone else. I'm an engineer by trade. This shit is in my blood.
What might be an interesting exercise would be to play with the size and length of the airway between the chambers.
Lastly, can anyone explain where the term "reverse" calabash came from? I see nothing working in reverse of what a normal calabash does. Big chamber, small orifice, big chamber. That's it in both cases.
Chas.

[d.huber]

Seems legit. Cool article.