Lkinser
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- Sep 18, 2019
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I'm soon to be the proud owner of a 1977 PA-28-181 and I'm just curious what cruise settings are common.
I'm a low time / newly minted PPL with most of my time in a Diamond DA-40. The flight school had specific CHT numbers they wanted the aircraft ran at during cruise, along with specific MP and RPM speeds. It made the decision pretty easy... just do what that guy says. Now I've got to figure out those reference numbers for myself.
Luckily the Archer has an EDM-730, so getting CHT and EGT will be just as easy as the DA-40. Based on what I've seen in the Lean of Peak thread, I guess the right process there is basically to go lean of peak EGT slowly until roughness and then add a bit of mixture back in and get a feeling for how many degrees LOP that is, then shoot for that going forward. Am I way off base there? And that being said, are there general rule of thumb numbers for what to keep EGT and/or CHT under while figuring that out? Basically a "hey stupid, you went too far" line?
Beyond mixtures, what about engine RPM settings for cruise? What are the general guidelines there for best performance and best economy? Example POH docs online (don't have the one for the S/N I'm purchasing yet) show 2440 RPM for 65% power and numbers closer to 2550 RPM for 75%... what is everyone seeing/using in real world applications therein?
Thanks for any advice or tips!
I'm a low time / newly minted PPL with most of my time in a Diamond DA-40. The flight school had specific CHT numbers they wanted the aircraft ran at during cruise, along with specific MP and RPM speeds. It made the decision pretty easy... just do what that guy says. Now I've got to figure out those reference numbers for myself.
Luckily the Archer has an EDM-730, so getting CHT and EGT will be just as easy as the DA-40. Based on what I've seen in the Lean of Peak thread, I guess the right process there is basically to go lean of peak EGT slowly until roughness and then add a bit of mixture back in and get a feeling for how many degrees LOP that is, then shoot for that going forward. Am I way off base there? And that being said, are there general rule of thumb numbers for what to keep EGT and/or CHT under while figuring that out? Basically a "hey stupid, you went too far" line?
Beyond mixtures, what about engine RPM settings for cruise? What are the general guidelines there for best performance and best economy? Example POH docs online (don't have the one for the S/N I'm purchasing yet) show 2440 RPM for 65% power and numbers closer to 2550 RPM for 75%... what is everyone seeing/using in real world applications therein?
Thanks for any advice or tips!
