"Flag of the Sultanate of Rum", modified version of a design by Akib Özbek (1969) [In the original design, the bow is arranged so that the arrow lies horizontally]
Flags of the World:

"The alleged flag of the Great Seljuk Empire is blue with a white winged and double-headed silhouette and a black bow and arrow." (Ivan Sache &amp; Thomas Robinson, 4 July 2004)
Own work
Demircan Yiğit Öney