Originally Posted by Blackdog_kt

The short version is that it's not a bug, we just have early model Spits in the sim. The early Spits had a propeller with only two positions and no ability to precisely fine tune the blade angle. In essence, it's like flying with a fixed pitch prop but you get two available pitch settings instead of one.

What this means is that you can't precisely fine tune it like you can do in the 109 (where you directly influence pitch over its entire range of motion) or the Rotol Hurri (where you influence the governor and it keeps the RPM where you want within its limits of motion): you get only two available angles to set the prop to and any single given pitch angle is very limited in terms of how much of your available speed range it is efficient at.

If i was to describe it in a single sentence, i'd say we have correct modeling of the wrong variants.

These Spits flew like that during the battle of France (and Hurricanes too) so i'm not in favor of them getting changed altogether to constant speed prop models, since we have a map that can do BoF as well. What needs to be done is just alter the Ia to a constant speed prop model since it already has the CSP spinner modeled in terms of graphics. Then we could use the Spit Mk.I and the Hurri with the DH prop with their two-pitch props for BoF, while still having the Mk.Ia and Mk.II Spits along with the Rotol prop Hurricane for BoB scenarios.