Andy Ross
>
> Vivian Meazza wrote:
> > However, eng-power should be the un-supercharged max power, so I
> > reduced eng-power value,
>
> No no, I was wrong. Use the superchared value, the eng-power
> gets corrected before solving to assume "max" sea level
> manifold density (i.e. with boost and wastegate applied).
>
> > Is it possible that "reduction gearing" reduces engine revs for a
> > given propeller rpm? I thought it was the other way around.
>
> You are correct. The gear-ratio value is multiplied by the
> engine RPM to get the propeller RPM. Typical PSRUs will have
> a value less than 1.0.
>
> Andy
>
This converges (1):
eng-power="1140" eng-rpm="2850"
turbo-mul="2" wastegate-mp="48"
cruise-alt="17500" cruise-power="1140"
cruise-speed="308" cruise-rpm="5975"
takeoff-power="900" takeoff-rpm="5000"
manual-pitch="true"
gear-ratio = "0.477"
As does this (2):
eng-power="1140" eng-rpm="2850"
turbo-mul="2" wastegate-mp="48"
cruise-alt="17500" cruise-power="1140"
cruise-speed="308" cruise-rpm="2850"
takeoff-power="900" takeoff-rpm="2000"
manual-pitch="true"
gear-ratio = "0.477"
This does not (3):
eng-power="1140" eng-rpm="2850"
turbo-mul="2" wastegate-mp="48"
cruise-alt="17500" cruise-power="1140"
cruise-speed="308" cruise-rpm="1360"
takeoff-power="900" takeoff-rpm="1200"
manual-pitch="true"
gear-ratio = "0.477"
I ran FGFS using (2). From the property browser, at throttle = 1 engine rpm
= 6779. I note that 6779 * 0.477 = 3233.6
This also converges nicely (4):
eng-power="1140" eng-rpm="2850"
turbo-mul="2" wastegate-mp="48"
cruise-alt="17500" cruise-power="1140"
cruise-speed="308" cruise-rpm="2850"
takeoff-power="900" takeoff-rpm="2650"
manual-pitch="true"
gear-ratio = "1"
I now ran FGFS using (4). At throttle = 1 from property browser engine rpm =
3233.8
I conclude from the foregoing that the gear ratio is being applied
incorrectly by YASim.
I think that the correct input data is at (3) above.
Sign wrong somewhere?
Vivian
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