RE: Duct fan ?????????? OK MODEL TYPE II
The fan did come with OK Models DJ-1 and DJ-3 airplanes.
From their website DJ-1:
Lenght: 894mm
Wingspan: 1000mm
Wing area: 32 square decimeters
Weight: 1100 to 1200 grams
DJ-3
Lenght: 1310mm
Wingspan: 937mm
Wing area:28 square decimeters
Weight: 1500 to 1700 grams
The fan should then be able to fly somethting similar, I would opt for a model close to the light one.
Go to okmodel.co.jp and type DJ-1 in their search window.
(Hit and miss, it's mostly all japanese but the numbers and measurement are possible to comprehend for us that dont understand japanese, as is the pictures.)