Do you use the 'Cruise Power Settings' tables in the Pilot's Operating Handbook to plan your flights? If so, how do you adjust the calculated fuel consumption and true air speed for FSX?p.s. This is one of the best add-ons planes I have ever seen.

On climb I usually set 35 manifold pressure and 2750 RPM and leave them there for cruise.The problem is that the default FSX mixture programming leads to increased, not decreased fuel flow with leaning.Robert

Do you use the 'Cruise Power Settings' tables in the Pilot's Operating Handbook to plan your flights? If so, how do you adjust the calculated fuel consumption and true air speed for FSX?p.s. This is one of the best add-ons planes I have ever seen.

FSX fuel-flow is weird..It doesn't really increase with leaning.. It does increase when going from too rich to optimum, and then starts decreasing again. It's obviously how they tied a loss of power to improper mixture. FSX (and FS9) is modeled so that fuel-flow is tied directly to power. In it's own, odd way, it's kinda like EGT. .. in that it will climb, peak, and then decrease as you lean.The upside is that it's like a good mixture setting gauge.. just keep power peaked as you climb.. AND at least it DOES force you to use mixture.The other downside, is that it doesn't mate realistically with turbo-charged (or super-charged) engines. They do not need to be leaned much, until MP starts falling off.. but in MSFS, engines need to be leaned with altitude as though they were not turbo-charged.

To further complicate things.. It isn't about mixture being related to manifold pressure.. It's about WHEN the the fuel and air are mixed.With turbo-charging, 99.9 % of the time the mixture happens AFTER the turbine. With mechanical SUPER-charging, there are some setups (especially older radials) where the mixture happens BEFORE the compressor (i.e.. after the carb.. picture an old muscle car with a super-charger and carbs sitting atop it).With turbo-charged airplanes (like the Duke) where fuel is introduced after MP is increased, you DO set mixture by MP (except in FSX..lol).When fuel is introduced before pressurization, mixture is altitude dependent (so FSX is realistic for some, older super-charged engines "kinda" ..lol)Visualize it like this. As air get less dense, it requires less fuel per cubic foot. Turbo/super-charging increases the air density. If fuel is added before that density is increased, the mixture needs to be adjusted by ATMOSPHERIC pressure. If the fuel is introduced after the density is increased, the mixture needs to be adjusted by THAT pressure (MP)

Thank you for the very interesting responses. RealAir's manual did say that FSX's behavior was hard coded but I had no idea of the extent of the problem they had to deal with. Since I got the RealAir Duke a couple of weeks ago I've been getting acquainted by flying from Provincetown to Oakland in legs of about 90 minutes. If I'm flying at a pressure altitude of 4000 feet with an outside air temperature of 27