vlittle
Well Known Member
I've spent quite a bit of time going through the Lycoming power curves.
If I had a constant speed prop, I could work out HP directly from MAP, RPM and altitude.
Unfortunately, I have a FP prop, and I'm finding it difficult to come up with a simple horsepower table...
Basically, what RPM setting for a particular density altitude will give me 75% power (or 65 or 55)? Engine is a 160 HP O-320, standard Sensenich prop (RV-9A).
I did manage to determine HP from RPM and fuel flow for two mixture points, but that's an indirect measure. [As a note, my engine monitor also uses fuel flow to determine %HP, which is only accurate at best power mixture and not LOP or above 75% HP].
I know this is not a simple question, but has any develop a horsepower table, or a formula for my engine/prop combination? I can spend hours flight testing, or just borrow the work of someone else who is smarter than me. I could 'borrow' one from an existing aircraft (Piper), but that's quite a bit different than an RV.
Vern Little
9A
If I had a constant speed prop, I could work out HP directly from MAP, RPM and altitude.
Unfortunately, I have a FP prop, and I'm finding it difficult to come up with a simple horsepower table...
Basically, what RPM setting for a particular density altitude will give me 75% power (or 65 or 55)? Engine is a 160 HP O-320, standard Sensenich prop (RV-9A).
I did manage to determine HP from RPM and fuel flow for two mixture points, but that's an indirect measure. [As a note, my engine monitor also uses fuel flow to determine %HP, which is only accurate at best power mixture and not LOP or above 75% HP].
I know this is not a simple question, but has any develop a horsepower table, or a formula for my engine/prop combination? I can spend hours flight testing, or just borrow the work of someone else who is smarter than me. I could 'borrow' one from an existing aircraft (Piper), but that's quite a bit different than an RV.
Vern Little
9A