Performance comparison

ghrasko

During my learning curve of a simulated aircraft, I used to check the performance against the tables provided in the documentation. In case of PA-28R Arrow III, these are the real aircraft's tables - I guess. I know it is impossible to replicate the exact real performace, so I only want to know, how the simulated plane compares to it, so that I could safely plan my trips (speed, range etc.).

I made only a few test flights, but it seems for me that the aircraft is about 8-10% faster in various performance settings. I used to set configuration based on the Power setting tables (best economy or best power) and then check stabilized TAS based on pressure altitude and OAT. I check TAS of the aircraft based on ASI (by setting pressure altitude and OAT) and also check it using Little Navmap GS and wind data.

Example 1:

Power setting table (best power)
ALT: 8000 ft
OAT: 0 deg
Mixture: 100F rich of peak EGT
Prop: 2500 RPM
Power: 65% (21.5 In.Hg)

Best power cruise table (65% power)
Pressure alt: 8000ft
OAT: 0 deg
TAS: 129.5 kn

Meanwhile the simulated aircraft stabilises at around IAS/TAS=125/143 kn.

Example 2:

Power setting table (best economy)
ALT: 8000 ft
OAT: 0 deg
Mixture: Peak EGT
Prop: 2200 RPM
Power: 55% (21.8 In.Hg)

Economy cruise table (55% power)
Pressure alt: 8000ft
OAT: 0 deg
TAS: 122 kn

Meanwhile the simulated aircraft stabilises at around IAS/TAS=119/134 kn.

The difference is a larger at low altitude (2000 ft) economy test flights.

Example 3:

Power setting table (best economy)
ALT: 2000 ft
OAT: 10 deg
Mixture: Peak EGT
Prop: 2500 RPM
Power: 55% (21.8 In.Hg)

Economy cruise table (55% power)
Pressure alt: 2000ft
OAT: 10 deg
TAS: 113 kn

Meanwhile the simulated aircraft stabilises at around IAS/TAS=130/135 kn.

I would like to know if others could akcnowledge this difference. Or I might mess up something in the tests or in the interpretation of the performance tables.

Gábor

JH147

@ghrasko
I am also experiencing the same discrepancies when comparing against the published performance tables.

Can anyone let us know if there are any plans in tweaking the performances to match as close as possible the ones found on the POH?

It does have a big impact when working on the Navlog...

Many thanks for any feedback.
Julian