I started writing this before Scott posted the last message. I'll post it anyway even though it was partially
answered already. The partial throttle power output difference is still an unanswered question.
Scott - A2A wrote:
Nice find. You are correct, if you start and then shut the engine down, some pressure continues to feed into the system. This has been fixed and will be in the next core update we'll get out in the next few weeks.
Good to know it's now solved and waiting for the next bundled update. Just don't release it too quick to get in all sorts of bug fixes that are likely to pop-up with all the changes made.For example, power output on partial throttle has increased noticeably (both Spit and P-40): I can notice it on taxi, during engine run-up tests, low-power take-off from longer runways, cruise at low altitude and approach - whenever I'm using reduced throttle.
20 inches is enough to launch P-40 into air as if it was strapped into a rocket booster. MP required to obtain textbook rpm for mag checks is much lower than before. It might be intentional (especially if the old performance figures were off), I don't know.
And that odd [carb temp / carb temp gauge / carb heat ] thing with P-40. Since the temperature is less than ambient when idling on the ground, I presume the sensor for carb temp is between throttle plate and supercharger or at the venturi. Anyway, if temperature drop is in any way unintentional, it could also solve why the engine seems to produce more power at same manifold pressure (air being thicker).
Anyway, it all looks logical for the carb temp to drop below ambient on partial throttle but there's still the partial throttle power difference between Accusim versions. Maybe the system was calibrated to obtain natural values with inaccurate carb heat modeling, and when latter was fixed, the engine started to produce too much power. That... or the power on partial throttle was off before, and is now closer to reality.