Van's Air Force
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Power Settings for 0-320 with Catto Prop
- Thread starter ksouthar
- Start date
Kevin Horton
Well Known Member
Do you have a manifold pressure gauge? If so, you could create your own power chart from the info in the Lycoming O-320 Operator's Manual. I think the best sort of chart would be one that had tables for different altitudes, with the table listing MP along one axis, and rpm along the other axis, with the percent power for each rpm and MP combination. You would set a MP value with the throttle, let the aircraft stabilize, see what the rpm was, then look in the table to see what percent power resulted from that rpm, MP and altitude.ksouthar said:
If you don't have a MP guage, then you'll need to work from the fuel flow, assuming you have a calibrated fuel flow indicator. If you lean to best economy, the specific fuel consumption should be somewhere around 0.45 lb/hp/hr. Assuming 6 lb/USG, and a 150 hp engine:
55% power = 6.2 USG/hr
65% power = 7.3 USG/hr
75% power = 8.4 USG/hr
Note - those fuel flow values are only valid if you lean to best economy. If you lean to best power, then the fuel flow will be more.
If you don't have either a MP or fuel flow gauge, then we can't help you. Sorry.
Catto Propeller
I haven't flown yet - I'm complete and awaiting final inspection.
The economics of the Catto prop are decent but not that different from a Sensenich. You can save a few hundred bucks. I installed a SJ Cowling that requires a 4" prop extension so any savings in the prop got eaten up in the Sabre prop extension.
The prop is significantly lighter. I haven't put it on the scales but it feels about half the weight of the prop on my 150 hp 150.
The Catto prop is a thing of beauty. If it flies as good as it looks, it will be sweet. Craig will also do the spinner work for a nominal fee. You get the prop with the spinner cut out for the blades and spinner/back plate drilled and ready for nutplates. No muss or fuss. It is ready to finish and mount.
Unfortunately on the HP chart question - sparse panel. No MP or Fuel Flow gauge...... I guess I can estimate from my 150/150 charts - same engine 0-320 E3D...!
I haven't flown yet - I'm complete and awaiting final inspection.
The economics of the Catto prop are decent but not that different from a Sensenich. You can save a few hundred bucks. I installed a SJ Cowling that requires a 4" prop extension so any savings in the prop got eaten up in the Sabre prop extension.
The prop is significantly lighter. I haven't put it on the scales but it feels about half the weight of the prop on my 150 hp 150.
The Catto prop is a thing of beauty. If it flies as good as it looks, it will be sweet. Craig will also do the spinner work for a nominal fee. You get the prop with the spinner cut out for the blades and spinner/back plate drilled and ready for nutplates. No muss or fuss. It is ready to finish and mount.
Unfortunately on the HP chart question - sparse panel. No MP or Fuel Flow gauge...... I guess I can estimate from my 150/150 charts - same engine 0-320 E3D...!
pierre smith
Well Known Member
Power settings
Mornin' y'all. It doesn't matter that you have a Catto prop........we do too. Just find a Skyhawk with a 150 HP engine and use those numbers. We have a 180 HP Lyc with three blade Catto and 75% at 7500 ft is 2700 RPM and get 198 MPH Gps speed on a four way run in our 6A. The prop is sooooooooo smooth and Craig pitched it for max cruise. Although we only get 2250RPM on initial takeoff, we climb at 1900 ft/min solo at 135 MPH! We usually see 180 + at 2500 RPM at most any altitude as well,
Pierre
Mornin' y'all. It doesn't matter that you have a Catto prop........we do too. Just find a Skyhawk with a 150 HP engine and use those numbers. We have a 180 HP Lyc with three blade Catto and 75% at 7500 ft is 2700 RPM and get 198 MPH Gps speed on a four way run in our 6A. The prop is sooooooooo smooth and Craig pitched it for max cruise. Although we only get 2250RPM on initial takeoff, we climb at 1900 ft/min solo at 135 MPH! We usually see 180 + at 2500 RPM at most any altitude as well,
Pierre
rv8bldr
Well Known Member
I second Pierre's analysis. I have a 3 blade Catto on my -8 with an IO-360-A3B6D and I get 1800'/min at 1650 lbs. I have seen as high as 2200'/min on a cold day, and as little as 1400'/min on a hot and steamy day.pierre smith said:
At 2200 RPM I tool along at 155 kts, and have seen 190 kts WOT at 4000' (actually had to throttle back a tiny bit as I was turning 2750 RPM). I asked Craig to pitch the prop as a compromise between take-off and cruise. It is 66"x78".
Cheers
Catto vs. Sensenich
Here's what I'd like to know . . .
On a 160 h.p. O-320 powered RV9A, what's faster, a 79" Sensenich at 2600 rpm or the Catto at 2700 rpm? It would also be interesting to know which one climbs better.
Has anybody done a side-by-side comparison?
Mark
Here's what I'd like to know . . .
On a 160 h.p. O-320 powered RV9A, what's faster, a 79" Sensenich at 2600 rpm or the Catto at 2700 rpm? It would also be interesting to know which one climbs better.
Has anybody done a side-by-side comparison?
Mark
LifeofReiley
Well Known Member
Any new information on the prop comparison? I'm looking for the same info...rv9builder said:
