Post by volkerboehme on Apr 11, 2010 10:34:38 GMT -5
The original problem is unsolved. CHT gauges misread in MSFS because MSFS calculates CHT using the wrong correlation, not just an inappropriate slope of the correct correlation. Therefore 'damage modules' or 'Notepads' which use the internal CHT value are bound to be broken if they rely on MSFS to calculate CHT.
Oil temperature is primarily a function of friction and friction heating correlates highly to RPM. MSFS probably calculates oil temperatures 'realistically'. However it seems to use the same algorithm for CHT, yet IRL the temperature of the cylinder head is mostly a function of energy flow = PPH (other things equal). IRL I would expect CHT (absolute) to be nearly linear to PPH. In a properly lubricated engine, it is almost entirely the calories from the burning fuel that heat the cylinder head above OAT. There would be an exponential rise once oil started to 'burn' allowing friction to be a significant factor only after that circumstance.
I believe RPM should only alter CHT to not much more than the extent it alters PPH until Oil temp goes above limit. MSFS makes CHT instead depend primarily on RPM (friction) even when the engine is properly lubricated.
Altering factors and scalars of the broken MSFS CHT algorithm will not stop MSFS CHT being dependent on the wrong pilot input (RPM). In MSFS we can impose the same PPH from higher MAP and lower RPM, retaining the same power output from the engine, but that fails as a CHT reduction strategy in real life, even though it works IRL for oil limits.
Running the furnace with the same fuel mass and same air mass flow through the furnace using a smaller or bigger shovel at inverse frequency of shoveling should not alter CHT (significantly). Using a gauge (or damage module or notepad) which encourages consumers to make the wrong inputs to control CHT, using a false CHT, is not 'useful'. It just encourages them to focus on very basic skills which are not the skills of pilotage. Nobody should buy a flight simulator to learn to twiddle knob A until gauge B reads x.
In the absence of a realistic CHT slope versus MAP and RPM and mixture and cowl opening and IAS no one has a right to tell consumers they are mishandling the engines and nobody should be adding engine drag based on false CHT values to avoid a fake CHT value reaching a real limit. I fear you are just pretending that MSFS is accurate enough to allow micro management of something very basic. False CHT just isn't a make or break issue in a flight simulator unless it is given wholly inappropriate priority and focus.
However it is obviously superior to create a gauge with more realistic non linearity for all RPM by making CHT (non) linearity a more nearly linear function of PPH (calorific flow through the furnace). RPM should still have some, but limited effect on CHT, at normal operating oil temperatures. Excess CHT would then prompt consumers to reduce power by reducing MAP, retaining the correct RPM for the current phase, (to maximise thrust efficiency regardless of power produced), with or without a damage module or notepad. Adding drag at high power is not the correct solution during max cruise which is when CHT compliance matters most and endures for longest.
FSAviator
Oil temperature is primarily a function of friction and friction heating correlates highly to RPM. MSFS probably calculates oil temperatures 'realistically'. However it seems to use the same algorithm for CHT, yet IRL the temperature of the cylinder head is mostly a function of energy flow = PPH (other things equal). IRL I would expect CHT (absolute) to be nearly linear to PPH. In a properly lubricated engine, it is almost entirely the calories from the burning fuel that heat the cylinder head above OAT. There would be an exponential rise once oil started to 'burn' allowing friction to be a significant factor only after that circumstance.
I believe RPM should only alter CHT to not much more than the extent it alters PPH until Oil temp goes above limit. MSFS makes CHT instead depend primarily on RPM (friction) even when the engine is properly lubricated.
Altering factors and scalars of the broken MSFS CHT algorithm will not stop MSFS CHT being dependent on the wrong pilot input (RPM). In MSFS we can impose the same PPH from higher MAP and lower RPM, retaining the same power output from the engine, but that fails as a CHT reduction strategy in real life, even though it works IRL for oil limits.
Running the furnace with the same fuel mass and same air mass flow through the furnace using a smaller or bigger shovel at inverse frequency of shoveling should not alter CHT (significantly). Using a gauge (or damage module or notepad) which encourages consumers to make the wrong inputs to control CHT, using a false CHT, is not 'useful'. It just encourages them to focus on very basic skills which are not the skills of pilotage. Nobody should buy a flight simulator to learn to twiddle knob A until gauge B reads x.
In the absence of a realistic CHT slope versus MAP and RPM and mixture and cowl opening and IAS no one has a right to tell consumers they are mishandling the engines and nobody should be adding engine drag based on false CHT values to avoid a fake CHT value reaching a real limit. I fear you are just pretending that MSFS is accurate enough to allow micro management of something very basic. False CHT just isn't a make or break issue in a flight simulator unless it is given wholly inappropriate priority and focus.
However it is obviously superior to create a gauge with more realistic non linearity for all RPM by making CHT (non) linearity a more nearly linear function of PPH (calorific flow through the furnace). RPM should still have some, but limited effect on CHT, at normal operating oil temperatures. Excess CHT would then prompt consumers to reduce power by reducing MAP, retaining the correct RPM for the current phase, (to maximise thrust efficiency regardless of power produced), with or without a damage module or notepad. Adding drag at high power is not the correct solution during max cruise which is when CHT compliance matters most and endures for longest.
FSAviator