The Coupe

I would love to identify the actual car used by the Black Bat and his companions. To the extent that I've read his adventures, and as far as I can remember, we are only told that it is a beat up coupé that has been augmented without modifying its appearance so as to not draw undesired attention.

It was a popular priced model on the surface, but several times the original cost of the car had been placed beneath the modest hood. A motor that would drive it over a hundred miles an hour purred smoothly under Silk's foot. The rest of the car had been weighted down so cleverly that not a sign of this work could be seen from outside. -- The Voice Of Doom (Nov. 1941)

Initially, we didn't even get that much. It was just mentioned that a cheap, nondescript coupé was ready and available for use at all times. One book said it was registered to Bat heavyweight assistant Jack "Butch" O'Leary.

Then in Black Bat And The Trojan Horse, the ninth book in the series (Nov. 1940)...

This car was something like a Q-Boat, for though it looked like a wreck, there was plenty of speed in her smoothly running motor. Recently, the Black Bat had installed cleverly hidden compartments which held a rifle with telescopic sights and a sub-machine gun with plenty of ammunition.

That compartment (or perhaps a separate one) also helped to conceal the Black Bat's uniform on a number of occasions. We know it has bulletproof glass and there are references to a foot board. In Shadow of Evil (May, 1942), at the touch of button, the windshield rise by a couple of inches to enable Butch to fire a gun while driving.  

I visualize the car something like this. 

That is a 1933 Chevrolet Coupe and I came across it on Barn Finds. Being from 1933, it would have had some time to get that "beat up" up appearance before becoming a staple of the Black Bat stories starting in 1939 or 1940 or so.

I'll add details about the Black Bat's coupé as I come across them from reading his various adventures.