What am I doing wrong? 2-stage prop spitfires.

[Blackdog_kt]

The two-stage prop operation is essentially like exchanging one fixed pitch prop for another in mid flight.

What is the most tell-tale characteristic of such props? The fact that RPM is not constant for the exact same pitch value.

If you go faster the RPM will go up, if you go slower it will go down and all this while you're not even touching the pitch controls.

Why am i mentioning all this? Because even though setting the pitch to coarse might drop your RPM too much, you can still make it reach the 2700 RPM sweet spot by speeding up a bit

Give it a bit of a shallow dive and trim level as you pick up speed and it wants to pull the nose up, you'll see she picks up speed and keeps it in a much better way.
Hope it helps