I've seen a fair number of Fan-dragon breeds before. The Texas Longhorn, of good nature and great size. The Virgina Orange Reaper, favorite of Washington and Lee. The Wendigo of northern Canada, a hell-monster of the tundra. A lighting breathing Aztec breed who's name I can't pronounce. Arrogant Prussian Bluejackets, including the partner of Manfried von Richtoven. The legendary Jotunmeister of the Baltic coast, who fights for it's own glory in battle, and are always very picky about their captains.

Your's are just as glorious as any of those. Is that mach 1.1 in a dive, or in level flight? And wouldn't feathers manifest elsewhere other than the wings, possibly along the crest and face? Smaller and finer feathers, to be sure, not the meter long blades of the wings.