I posted this in another thread a few days ago and don't think anyone really saw it. Thought this was revealing info you might find useful - if not disregard.
Previously I've conducted many, many hours of CHT testing with various cowl configurations including my current exit nozzle/variable exit configuration so I have solid repeatable data.
I have 7 hours on my new Catto prop and have collected 10 runs worth of CHT data during full rich, WOT, Vy (110 mph) climb from SL to 8000 ft in the same conditions as was conducted with the Sensenich prop (OAT within 3 degrees at SL and 1 deg at altitude) under similar GW (within 50 lbs).
I averaged all 4 CHTs at 2000ft, 4000ft, 6000ft and 8000ft and plotted vs Pressure altitude for both prop configurations with variable exit full open (my normal climb configuration).
The Sensenich prop cord varies from 6" to 6.25" for the length of the cowl inlets, while the Catto varies from 3.5" to 5" over the same inlet location.
The sensenich prop completely covers the both inlets for a short duration twice each revolution (a function of being a two blade and wide cord). While the Catto prop never completely blocks an inlet (narrower cord) and only 1 inlet is ever partially covered at a time (3 blades @ 120 deg phase).
The blade thickness of the sensenich throughout the inlet span location is almost twice as thick as the Catto.
Here are the results:
It would be interesting to collect CHT data for those with 2 blade props versus those with 3 blade props.
Previously I've conducted many, many hours of CHT testing with various cowl configurations including my current exit nozzle/variable exit configuration so I have solid repeatable data.
I have 7 hours on my new Catto prop and have collected 10 runs worth of CHT data during full rich, WOT, Vy (110 mph) climb from SL to 8000 ft in the same conditions as was conducted with the Sensenich prop (OAT within 3 degrees at SL and 1 deg at altitude) under similar GW (within 50 lbs).
I averaged all 4 CHTs at 2000ft, 4000ft, 6000ft and 8000ft and plotted vs Pressure altitude for both prop configurations with variable exit full open (my normal climb configuration).
The Sensenich prop cord varies from 6" to 6.25" for the length of the cowl inlets, while the Catto varies from 3.5" to 5" over the same inlet location.
The sensenich prop completely covers the both inlets for a short duration twice each revolution (a function of being a two blade and wide cord). While the Catto prop never completely blocks an inlet (narrower cord) and only 1 inlet is ever partially covered at a time (3 blades @ 120 deg phase).
The blade thickness of the sensenich throughout the inlet span location is almost twice as thick as the Catto.
Here are the results:
It would be interesting to collect CHT data for those with 2 blade props versus those with 3 blade props.