Ken K had a great thread regarding comparison testing his new Catto vs. a Sensenich wood prop. But I've searched the archives and cannot find any data regarding comparison tests between the Catto and a FP metal prop. Lots of you seem to be running Cattos now, and I'm curious about any numbers or impressions you have between the two. I recently installed a 3-blade Catto on my 180hp Pitts S-1S. I know this is not RV-related, but I'm just curious what others' experience is moving to a Catto from a Sensenich. I'm well aware of the vastly different drag/speed profile of the RV compared to the Pitts. Based on the numbers I got, I'm wondering if it's even possible to match the efficiency of a metal blade with any wood core composite blade. I have been running a Sensenich 76x59 and replaced with a Catto 72x56 3-blade.
I flew both props back-to-back last weekend in an attempt to maximize the consistency of the Wx conditions. My main reason for buying the Catto was to get rid of most of the stress on my light crank flange when doing acro. I was not expecting additional performance, but was hoping not to lose any. Even if performance ends up very slightly less than the Sensenich, there's enough positive about the prop to keep it for my purposes. But as far as performance goes, the RV platform may be totally different, and the Catto pitch/diameter for the RV airframe may compare better than the results I saw for the Pitts.
Test runs were done with the same fuel load and from the same altitudes. I tested the Catto first. Density altitude at the start of the first test was 1,348' (247', 72 deg, 50 deg. dewpoint, 29.86"Hg) At the start of the Sensenich test, DA was 1,485' (73 deg. 52 deg. dewpoint, 29.85"Hg). Here are the numbers:
Rate of Climb @ 100mph IAS from 1000'-2000' MSL:
1,818 fpm @ 2,350 rpm (Catto)
1,935 fpm @ 2,525 rpm (Sensenich)
Level flight, full-throttle IAS (1000' MSL):
160 mph @ 2,850 rpm (Catto)
162 mph @ 3,000 rpm (Sensenich)
Cruise IAS @ 2500 rpm (1000' MSL):
139 mph @ 10.5 gph (Catto)
130 mph @ 9 gph (Sensenich)
Cruise IAS @ 9 gph full rich:
130 mph @ 2400 rpm (Catto)
130 mph @ 2500 rpm (Sensenich)
IAS @ 3,000 rpm, full-throttle (WOT):
180 mph (Catto)
162 mph (Sensenich)
Max altitude gain, 45 degree pitch up from level flight, WOT:
1,200' (Catto)
1,300' (Sensenich)
Max altitude gain, 4.5G pull to vertical from level flight, WOT:
900' (Catto)
1,020' (Sensenich)
I'm going to send the prop back to Craig for repitch to get the RPM up. Aside from the performance numbers, these are the positives to the prop, as expected simply due to the construction (laminated maple w/ CF and glass outer layups). The Catto is much smoother in flight through all RPM ranges than the Sensenich. Much less vibration, and no red arc. It weighs about 20 lbs. less than the Sensenich. There is no prop bark at 3,000 rpm (noise friendly). There is MUCH less gyroscopic/torque effect. Hammerheads require much less forward stick, and don't have a tendency to torque nearly as bad. Can fly over the top of a humpty much slower without uncontrollable torque rolling. Spins are much cleaner...no hesitations in the spin rate while under 2-turns, and the nose doesn't oscillate up and down before the spin fully develops. Snaps and spins seem to stop more quickly and crisply. Elevator stick force is lighter due to less gyroscopic resistance. Oh yeah, and it looks pretty cool.
I flew both props back-to-back last weekend in an attempt to maximize the consistency of the Wx conditions. My main reason for buying the Catto was to get rid of most of the stress on my light crank flange when doing acro. I was not expecting additional performance, but was hoping not to lose any. Even if performance ends up very slightly less than the Sensenich, there's enough positive about the prop to keep it for my purposes. But as far as performance goes, the RV platform may be totally different, and the Catto pitch/diameter for the RV airframe may compare better than the results I saw for the Pitts.
Test runs were done with the same fuel load and from the same altitudes. I tested the Catto first. Density altitude at the start of the first test was 1,348' (247', 72 deg, 50 deg. dewpoint, 29.86"Hg) At the start of the Sensenich test, DA was 1,485' (73 deg. 52 deg. dewpoint, 29.85"Hg). Here are the numbers:
Rate of Climb @ 100mph IAS from 1000'-2000' MSL:
1,818 fpm @ 2,350 rpm (Catto)
1,935 fpm @ 2,525 rpm (Sensenich)
Level flight, full-throttle IAS (1000' MSL):
160 mph @ 2,850 rpm (Catto)
162 mph @ 3,000 rpm (Sensenich)
Cruise IAS @ 2500 rpm (1000' MSL):
139 mph @ 10.5 gph (Catto)
130 mph @ 9 gph (Sensenich)
Cruise IAS @ 9 gph full rich:
130 mph @ 2400 rpm (Catto)
130 mph @ 2500 rpm (Sensenich)
IAS @ 3,000 rpm, full-throttle (WOT):
180 mph (Catto)
162 mph (Sensenich)
Max altitude gain, 45 degree pitch up from level flight, WOT:
1,200' (Catto)
1,300' (Sensenich)
Max altitude gain, 4.5G pull to vertical from level flight, WOT:
900' (Catto)
1,020' (Sensenich)
I'm going to send the prop back to Craig for repitch to get the RPM up. Aside from the performance numbers, these are the positives to the prop, as expected simply due to the construction (laminated maple w/ CF and glass outer layups). The Catto is much smoother in flight through all RPM ranges than the Sensenich. Much less vibration, and no red arc. It weighs about 20 lbs. less than the Sensenich. There is no prop bark at 3,000 rpm (noise friendly). There is MUCH less gyroscopic/torque effect. Hammerheads require much less forward stick, and don't have a tendency to torque nearly as bad. Can fly over the top of a humpty much slower without uncontrollable torque rolling. Spins are much cleaner...no hesitations in the spin rate while under 2-turns, and the nose doesn't oscillate up and down before the spin fully develops. Snaps and spins seem to stop more quickly and crisply. Elevator stick force is lighter due to less gyroscopic resistance. Oh yeah, and it looks pretty cool.
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