Here's a scannergraph of the old Wellington not long after I brought it back from the brink of oblivion. It was part of an eBay lot and I immediately decided it was a keeper, because I had no other pipe like it.
The Wellington is the WDC copy of the Peterson System pipe. Here's a cutaway diagram that I snagged from Pipe & Pouch to help explain this pipe's design.
The bit, rather than connecting directly to the bowl via the shank, fits into a sort of pocket or reservoir where the air sort of swirls around as it goes into the bowl. The upper air passage goes on into the bowl, and the bottom reservoir collects moisture. This looks like another odd gimmick, but in my opinion, this one works very well. Of course, it requires additional attention when cleaning. I use a cotton swab to clean out the reservoir, and pipe cleaners as usual to clean the air passage.
Another thing about the Wellington (and other Peterson copies) is the military bit. Rather than the traditional tenon/mortise arrangement, the bit simply tapers down slightly and wedges into the shank, remaining in place from the pressure of insertion. This design makes it safe to remove the bit while the pipe is still warm--something that is not a good thing with a tenon/mortise design.
A third thing that sets the Wellington/Peterson pipes apart is the button on the bit. Go back and look at the first photo as well as the cutaway graphic and pay attention to the end of the bit. This is a bit design created by Peterson and is called the P-lip. The hole is on top of the button rather than in the very end, and is angled upward to direct smoke toward the roof of the mouth rather than straight into the tongue. Also, the curved underside of the bottom helps to prevent the tongue from touching the opening of the air passage. The upward-pointing opening is supposed to help prevent tongue-bite, and the curved "tongue shield" helps keep saliva from getting into the stem by being touched with the tongue (something that is a troublesome unconscious reflex for some pipe smokers).
Some people hate the P-lip because it feels different. I have no special preference nor objection to it, at all. To me it's just another bit. The P-lip bit does have a more rounded shape than most bits, and it does feel somewhat different, but it's nothing that anyone shouldn't be able to get used to.
This old Wellington has become one of my favorite pipes. It's size and deep bend gives it an impressive appearance and a comfortably low center of gravity. As you can see in the second photo, I have managed to wear off some of the finish since it came into my hands, and I will eventually be refinishing this one. Meanwhile, this is one of my regular truck pipes and I often smoke it on the long commute home in the afternoon. If I manage to come across any more of these pipes in my eBay adventures, I will probably keep them all--at least until I build up a good week's worth of pipes for rotation.
FYI, Kaywoodie also had a copy of the Peterson System pipe, called the Chesterfield. Unfortunately, I haven't been able to acquire one of those yet.