Doc Savage 006 - The Red Skull - by Lester Dent

The Red Skull
Doc Savage 006
August 1933
By Lester Dent

Doc flies out to Arizona to help build a dam that's being sabotaged.  That's about it.  There's an attack dog with teeth of hypodermic needles filled with poison but it doesn't really do anything.  A couple twists that make no damn sense.  There's prominent use of an autogyro, which I guess was exotic at the time.