Do 18 vs. Bv 138

[Pasoleati]

Common sources claim that the Do 18 was supposed "obsolete" and that the Bv 138 replaced it because of that. However, why is the Do 18 supposedly more "obsolete" than the Bv 138?the references I have indicate that the Bv 138 wasn't much faster and had actually considerably shorter range. And if for example Eric Brown's comments are reliable, the Do 18 was much more pleasant to fly and handle.

 

[Avimimus]

190km/h -> 235km/h cruise speed
200kg->600kg bombload
7.92mm->13mm+20mm defensive armament

Not sure about range or ergonomics...

 

[Pasoleati]

Didn't some Do 18s have 20 mm rear gun? What is interesting is that the bomb loan in both is so meagre compared to the Catalina (comparable in power to the 138): 4000 lbs.