Hi bmstrong and others,
I think I have provided some idea as to my thinking and plans in the recent thread that _JS_ started on the 3S VS PD lights. But I will add some more comments and opinion and observations specific to the PD and following comments made here in this thread.
For starters and to get something off my chest, Nitecore did contact me (actually it was 4Sevens) about the use of the piston drive in a light they planned and at the time they felt they were only going to do one run of lights and likely hit a target of 1000 units to be built. Instead of some form of royalty based on sales they offered and I accepted a one time payment in recognition of my design. To be candid, they didn't have to give me a dime as I have no legal claim to the PD design; no patent filed by me. A bit later I had some e-mail communication with a couple folks at Nitecore along the possibility of doing some design collaboration but nothing ever came of it. It seems later I read where Nitecore has a patented Smart PD of some such. I don't know what that is about nor do I really care. I assume if I ever decide to use the PD design again I will have clear sailing with it but it is an assumption. Just recently it has been brought to my attention that Nitecore has a switch that sure looks like an unimaginative direct copy of my McClickie switch. I've only seen pictures of it but did their specific needs and functionality dictate a design that happens to look like a direct copy of my McClickie or is is just that, a copy? :shrug:
Ironically I designed the McClickie specifically to the geometry and functionality of an "E" series lock out tail cap and retained the ability for lock out. In my present application that ability to lock out is not used and the design allowing for the feature is actually a shortcoming in the present application (read _JS_'s comment about the need to seriously snug down the McClickie switch in the McClickie pak to insure a good ground path). I understand that SF has of late pursued infringement on their IP of a LOTC. :green: I don't know if that includes a clickie version of tail cap as well but I would steer clear in any tail cap design I came up with these days....
But now on to the PD.
As some of you know there have been twisty, PD and clickie paks made to serve as host to the PD style heads and all have their pros and cons but it's cool that the options have been there. The "E" series geometry does not lend itself well (hell if at all!) to either a twisty or PD style pak and I think this is one if the real short comings of the "E" series but it is what it is. But just how important is a twisty or PD style pak, that is really the question I asked myself when I found myself at a fork in the road. In light of the 3S converter and its need for quick off cycling the clickie pak was the quite obvious choice. What may not be so obvious is the merit of a self contained if you will or modular Light Engine and what head to battery pak geometry is best suited for such a light engine. Well the larger diameter of a female thread in the head is the way to go, in my experience and this consideration coupled with a clickie pak choice is what led me to come back to the 'E" series platform when the 3S was in development and why I moved away from the PD platform. That I often get questions as to whether the PD and 3S lights are compatible tells me that some of you don't realize the fundamental differences between the two lights and I am not saying that you need to understand these differences. I sure as heck better though!
At this point I and many of you have investments in this modular system and it has become rather comprehensive over time. I attempt to maintain stock in three versions of McClickie paks (1x123, 2x123 & 2xAA) and I also have heads to keep in stock, namely Mule, SunDrop (original and XR-U), Haiku and Makai (which I will probably let run out). The Haiku was first offered with the XR-E LED and then later on with the XP-G and then even later, the XM-L and Nichia 119. It's nice to have a foundation that is capable of accommodating changes in LED developments. But I wander. I think my point is that the PD does not integrate with that I am now working with and invested in. That is not to say I don't think about it or have abandoned the design idea completely.
The subject question of whether the Classic Ti PD will ever be produced again is easy for me to answer; no. I can't imagine building more TiPD's with Seoul LED's epoxied to aluminum heat sinks behind a reflector and window retained by a threaded bezel ring. I think there are better solutions now. Will I ever come out with a light that uses a PD style battery pak is a question I can't answer beyond "I don't know".
I have only scratched on the surface here with my comments and yet it is still enough to put everybody to sleep I imagine. There is much more in full consideration than I have mentioned and frankly some ideas and thoughts I won't share publicly as it has been proven that there are those who will gladly take ideas of others as their own and with no benefit to the originator.