The atomic bomb “Little Boy,” dropped on Hiroshima on August 6, 1945, contained 64 kilograms (approximately 141 pounds) of highly enriched uranium.
A quick estimation, not exact, is that 40kgs would be about half a Hiroshima.
You’re comparing weight of the fissionable material. I thought you were referring to explosive yield. At any rate, you must take into account the weight of the complete bomb, not just the radioactive material. The drone carries a bomb, not simply enriched uranium.
Otherwise you could give a false impression of the power of such a drone nuclear explosive.
See post 28.