That's what I call them, anyway.
If you're wondering what the hell I'm talking about, it's a set of four voyager class TFs: Energon Bulkhead, Universe Springer, HftD Highbrow, and T30 Springer.
Why these four? I guess it all goes back to Energon Bulkhead. When this guy came out, back in the fall of 2004 (!), it was part of the very G1 homage-heavy Energon line and in the midst of the franchise's 20th anniversary. As such, people assumed that Bulkhead (who came before the now-famous bulky autobot bruiser of Animated and Prime) was an homage to G1 Springer. It made sense - Energon also saw characters like Rodimus get homage toys, and Bulkhead was a green autobot helicopter, that, while it lacked a true third mode, could have a ground mode thanks to its ability to combine with its walker-mech "accessory."
Anyhow, one year later, Hasbro releases the orange rescue copter Evac as part of the Cybertron toy line, who then got repainted into an official Springer toy as part of the Universe 2.0 line during the franchise's 25th anniversary. Seeing that I never use UT molds as G1 characters as the repaint was intended, that meant that this Springer would be my UT Springer. This also meant that Bulkhead, also being a UT character, definitely couldn't be the UT version of Springer, despite the design similarities. Now, granted, I had never really been sold on the E. Bulkhead = Springer idea, for a few reasons, but now I had to decide for sure on a separate personality for him. Whoever he would be, in my mind he'd function as UT Springer's mentor and partner/friend (the mustache and his characterization in the show indicated that he was an older 'bot).
Enter 2010's Hunt for the Decepticons Highbrow. Like most of the HftD toy, it was designed to be part of the movie universe (basically a "latter-day" RotF toy), but it was also the first new Highbrow toy, by name, since G1. While he did have blue and gray in his color scheme, it was more dominated by the dark WWII green of his P-38-ish alt mode and therefore the guy didn't look much like G1 Highbrow at all. In fact, they only thing they really have in common is the fact that both of them have twin propellers in alt mode and a head gimmick (G1 = headmaster; HftD = sliding visor).
However, HftD Highbrow sure did have a lot in common with Energon Bulkhead. Both were intended to be older characters in-fiction; both had spinning propeller weapon gimmicks, both had wings on the hips armed with rockets, both had really long lower legs, both had visors covering their eyes, both had alt modes whose noses tilted up when landing gear were deployed, both were predominately green, both had transformable weapon-hands...etc. So, all the similarities, in addition to the toyless Animated Highbrow also being an older, mustachioed Autobot, lead me to conclude that I should rename E. Bulkhead as Highbrow. And thus he has remained. He and his buddy UT Springer have had a few adventures with HftD Highbrow in the past few years, and the three looked great together. What they really lacked was another good Springer to allow UT Springer to have a multiversal counterpart to join in on the fun. I owned Botcon Springer (a CDF Hotshot repaint) for a while, but he didn't quite cut it. RotF Springer was only a legends-class toy, so that wouldn't fly (they really need to remold TFM Incinerator into Springer for TF4). And last fall, they remolded HftD Tomahawk into another pseudo-G1 version of Springer, which I was not going to fall for.
Good thing I didn't, as hasbro just put out Thrilling 30 Springer as part of the Generations line this summer. Who I now own, so he has taken his place as part of the Green Propeller task force. Now, I'd still like a good, deluxe-class G1 Springer (triple-changing not necessary), but thanks to the China Generations remold, I don't think we'll see that anytime soon. Oh well.