My -9a 0-320 150 hp will show about 152 kts below 8000' on the GPS. that's close to full throttle, maybe 2450 rpm, which is all she will do.
I am curious about the Sensenich ground adjust....have you tried the 'fine' limit, where you spin up 2700 rpm plus?
...or the coarse pitch that gives decent cruise, but won't pull full power at 2300 or so?
Is this 152 kts TRUE AIRPSEED or GROUND SPEED? Others are discussing TRUE AIRSPEED. I have not seen a GPS that shows TRUE AIRPSEED so any clarification would be appreciated.My -9a 0-320 150 hp will show about 152 kts below 8000' on the GPS. . .
My -9a 0-320 150 hp will show about 152 kts below 8000' on the GPS. that's close to full throttle, maybe 2450 rpm, which is all she will do.
I am curious about the Sensenich ground adjust....have you tried the 'fine' limit, where you spin up 2700 rpm plus?
...or the coarse pitch that gives decent cruise, but won't pull full power at 2300 or so?
I do understand this concept. I have made the same speed tests for calculating my true airspeed using the GPS ground speeds to derive an average true air speed. However, I was inquiring as to what was meant when flyboy1963 stated . . . will show about 152 kts below 8000' on the GPS. This statement is implying the GPS reading showed 152 kts. He did not mention anything about a derived true airspeed he calculated from a GPS speed test. Thus my request for clarification on what speed he was referring to when stating the 152 kts -- TRUE or GROUND SPEED?I calculate true airspeed by averaging my groundspeeds going all 4 directions. I have heard that some do 3 directions, but haven't heard that actual procedure.
Is this 152 kts TRUE AIRPSEED or GROUND SPEED? Others are discussing TRUE AIRSPEED. I have not seen a GPS that shows TRUE AIRPSEED so any clarification would be appreciated.
Incidentally, the engine/prop combination offers 2700RPM at any altitude up to ~6000', much to my surprise.
Thanks for the clarification.yeah, sorry Steve, I just threw that in to the mix. Let's say it was a day close enough to 'standard' with light winds, that I thought the groundspeed would be meaningful to someone.
perhaps not. I wish I had all the data to project some meaningful numbers like Ted.
Paul, I am not Terry but this is what I have; I have an ECi IO-340 with a Catto 3-blade 68x72 prop. I have been in discussions with Craig for a year now concerning my pitch. I have done several GPS speed tests at 8000' DA WOT and have easily maintained 2800 RPM - 24.7 MP in straight and level flight. At those settings my best GPS speed tests revealed a True Airspeed of 192 MPH (167 kts).Terry,
I'm interested in the pitch of your Catto. Mine on my 9A with an O320 will spin over 2700 quite a little past 6000'. I'm assuming you're talking about MSL? I'd have to look at my numbers when I get home but I think mine will turn 2700 to almost 8000 msl.
I've been thinking about having Craig re-pitch it a little but am undecided.