The Stamboul is the sultan's airyacht. It has propellers and a brightly colored silk airbag covered in tassels, and is about one-fourth the length of the Leviathan. The Stamboul's prow looks like a falcon. It appears in Behemoth and carries Deryn and Dr. Barlow to see the sultan.
In the series[]
Deryn and Dr. Barlow board the Stamboul with one of Dr. Barlow's eggs to deliver it to the sultan. They are introduced to the Kizlar Agha, who is in charge of bringing them to the sultan, once on board. Deryn is reminded of her father's ballooning accident when she gets on a Clanker airship that uses fire, and The Kizlar Agha tries to reassure her that the airyacht is as safe as a Darwinist airship. Deryn and Dr. Barlow discuss the missing egg and Alek during the trip. The sultan has a garden in his palace where the airship can land, and Deryn notices that it lands there smoothly.
The Kizlar Agha later uses the Stamboul to take the sultan to safety after the revolution. Presumably, the sultan keeps the airyacht after he looses his empire.