Here’s an unproduced Cobra I don’t know anything about.
It’s worth noting now and again that as exciting as it is to see unproduced figure sketches and color schemes, no one at Hasbro was precious about this. Not the designers drawing the characters, and not the Marketing folks who would ultimately approve or nix them.
R&D drew hundreds of costumes and looks per year, if not thousands, and a figure could get a thumbs down for any number of reasons. Maybe it was too similar to something from a year earlier, or earlier in the day. Maybe it was the best design of the day, but it got shown last and everyone was tired. Or maybe it was a dud. I do like this one here, though, this Cobra Tech-ish Pilot, or whoever it may have been. Sometimes I look at something like this and think “If only THIS had made it to market!” But then I wonder how many keepers I’d draw if I drew 50 every other week for three years.
The art looks like Mark Pennington, but I could be wrong.
A Real American Book! 
If the drawing dates from before 1988, this guy looks like he could have evolved into the Frag-Viper. I like this design a lot better, though. The idea of a pilot is more realistic and appealing somehow.
I have from Bob Prupis that the Frag-Viper happened because he got the idea watching jai alai, so from that I assumed the first Frag-Viper appeared whole cloth with its cesta. But that doesn’t preclude this guy already being on the table and getting ported over, so you could be right.
I have a color sketch that is labeled “Frag Viper” from 86 or so, the uniform has a Heli-Viper kind of look, and he is throwing a grenade with no arm hardware.
Interesting…
An all silver Techno-viper… Gah !
The helmet seems to have similar shape and slope as the Nullifier’s helmet (without the visor.)
Yeah, my first thoughts were Nullifier. But a preproduction sketch of that character would be dated a year before the toy release, not the same year.