The question was a natural one: Could a Titan Master Headmaster fit on Generations Brainstorm, or vice-versa? And the answer seems to consistently be an immediate "no", typically declaring Titan Masters to be smaller than Generations Arcana. Brainstorm's Headmaster already seemed to be rather on the small side, so the idea that a line would come out with even smaller ones was intriguing, and I wondered if I could find enough information in the stacks of photos to figure out just how big or small they were. The answer I got was quite a surprise. Keep reading!
So, the first step was the most difficult of the entire process, as I needed a fixed reference point to start constructing a scale. Without something in reasonable proximity to a Titan Master whose size I could know to begin with, I would have no way to even begin on this. Thankfully, Ben Yee provided that necessary launch point with the following photo (full photo gallery can be seen here), which had exactly what I needed: A 5mm weapon handle right next to a Titan Master. In this case Blaster's friend Twincast. They were close enough together that I could reasonably determine that the square outline of Twincast's head was roughly the same width as the diameter of the 5mm post, give or take a fraction of a millimeter. We've got our start point.
To move to the next step, I needed a good straight-on shot of head and body. This got to be a little difficult as I couldn't turn up suitable photos of Twincast to carry on with. But one simple fact saved the project: Hasbro's people said that all the Titan Masters are intercompatible, which means that the square part of the head must be the same width on everybody. And it just happened that good photos of Nucleon, Galvatron's Titan Master, were available. With the head width determined, the next move was to measure across the shoulders. To keep things as accurate as possible, I copied the 5mm measure line and precisely aligned the edges. It's not a perfect process, but it's definitely good enough for this exercise. The width across Nucleon's shoulders was about 16.5mm, again, give or take a sliver. Thanks go out to diecast from RFC for getting this great photo of Nucleon. Oh, and the individual millimeter measures at the end? Measured with pixel counting and a calculator. Tedium like no other!
Okay, we've got the shoulder width - which by the way roughly gives us a general sense of the width of any given head mode. There might be tiny variances, but since everyone has to work everywhere, and the bigger toys have helmets the heads need to fit inside, it's unlikely any head would go past 17 or maybe 18mm at the very upper end. Anyway, we have a shoulder width, which for the sake of expedience, we can use as our basic unit for measuring the height. It took just slightly over two and a half shoulder widths to make the line from head to toe, working out to a distance of approximately 42mm. Okay, so we have the numbers figured out as close as we can from the yardsticks we derived from the photos. So where's the surprising part?
These measurements have only the tiniest variance from Generations Arcana's humanoid mode, about 0.5mm on average. That's a close enough difference to simply come down to a rounding error. Even Arcana in head mode is 16mm wide - fully consistent with the findings. While I will stress that all of this is on the rough side based on the best reference points available in photos, the indications right now are that Titan Masters are almost exactly the same in overall size as Generations Brainstorm's head! Here I've used one of my photos of Arcana (and its Fansproject equivalent) overlaid with the CG stock image of Nucleon to help illustrate the result I found.
So, does it mean that the new heads will be backward compatible, or that Arcana can migrate to a new body? I'm thinking no. The body connectors on the Titans Return figures look pretty different, a bit more simple. Plus while I worked out width and height, I didn't study the depth of the heads. There's a chance that a Titan Master might be able to fit and ride Brainstorm's body, but I doubt the opposite would be true. The best outcome would probably be seeing Generations Brainstorm get retooled to have a compatible neck joint and a Titan Master to replace the existing Arcana - not that this helps existing Brainstorm owners like you or I particularly. In any case though, if you do own Generations Brainstorm, congratulations, as you would seem to have an early preview at the general size of next year's line-wide accessory gimmick item!