Looking at the stats breakdown on Wikipedia here for the Merlin 61 series reciprocating engines used in Spitfire planes, I noticed that maximum horsepower is given at approximately 3000 RPM. But AirPages has what looks like a manual here that lists the maximum RPM as 3000.
Are they simply stating that the same thing: that torque starts to fall off at 3000 RPM? Or are they saying that the engine is just physically incapably of spinning faster than 3000 RPM (seems unlikely)?
In the case of the first one, what is the (approximate) redline for one of these engines?