Twin tails of the B-24

[spicmart]

The twin tail should be kept right behind the inner engines in the propeller's airstream and thus enhance rudder responsiveness and flight stability.
But the B-24 was not particular known for good stability or light controls. On the contrary.
With the B-24N a large single tail was to be implemented and test results were more than promising to improve ease of flight.
Though the N would not be produced in the end the tail would become a distinct feature of the PB4Y-2 Privateer.

Now can someone explain why the (logical) assumption of the engineers fell short as for the twin tail arrangement and the large single tail proved a success despite it not being in the propeller airstream?

 

[OldParts]

I found the following on WIKI and it would indicate that the twin tail design just happened to be available. WIKI also indicates that it was recognized by 1942 that a single vertical stabilizer and rudder were more effective. Like putting a larger velocity gun on the "Sherman" it was not expedient. I would also guess that air tunnel tests were insufficient or misinterpreted. I don't know but WIKI points the reader to an archive of Consolidated various products and project. The development of the "Davis" wing is an example of how some testing was conducted in the late 30's.

The new Model 32 combined designer David R. Davis's wing, a high-efficiency airfoil design created by unorthodox means,[6]​ with the twin tail design from the Consolidated Model 31 flying boat, together on a new fuselage. This new fuselage was intentionally designed around twin bomb bays, each one being the same size and capacity of the B-17 bomb bays.

 

[OldParts]

I wanted to mention this book. I am afraid I may have misplaced my copy. It has a chapter on the Davis wing which is very interesting.

What Engineers Know and How They Know It - Wikipedia

en.wikipedia.org