I didn't get that from reading the article. If the Hiroshima bomb was 15 kilotons and the expected maximum yield from a drone-carried bomb is .1 kiloton:
Realistic yield range: Roughly 10–100 tons of TNT equivalent (0.01–0.1 kilotons), possibly up to a few kilotons in an optimized design.
So 15 compared to .1 kiloton. 1/150th of the yield, if my early morning math is correct.
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.
It’s not, because the yield isn’t linear. There’s critical mass to start with. You cant get an event without reaching critical mass. Just a radioactive mess - dirty bombs.
Assuming you achieve critical mass, with a well designed device, yield goes up quadratically with mass, as long as your design remains efficient. At some point it’s not possible to efficiently compress the entire mass if it’s too large and the yield curve starts dropping off.
So, assuming it’s roughly as efficient as the Horoshima device and assuming it reaches critical mass, it’s more than two orders of magnitude weaker.
Using those assumptions.