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Catto 3-Blade vs Sensenich Wood

RV8R999

Well Known Member
When I built my -8 a year and half ago I installed a wood sensenich 2-blade prope 71" dia pitched to 83. I really liked the look of the wood prop and was very happy with the performance but happy is a relative term and often elusive so....

Today I installed a new Catto 3-blade 68" dia, pitched 75. I entered myself back into a 5 hour phase 1 test period and am not notifying the FSDO.

Here is a pic:
fmkl05.jpg


Several flights were conducted with both props at a Weight/Delta of 1800lbs. The OAT and fuel burn were noted for each data point and the altitude adjusted to account for decrease in weight as the flight progressed - altitude increases with decreasing weight to remain at the same Weight/delta of 1800lbs.

Once the Catto was installed I flew several flights at two differenct Gross Weights with (400lb delta) to highlight the advantage of this test technique. The plots below show an average of 3 runs with the Sensenich, and averages of 3 runs each for the Catto at 1700lbs and 1300lbs. - note the data for the two averaged Catto runs line up nicely. I'll refly this profile at 3 different Weight/Delta Values (2000, 2200, 1500). This will provide a family of 4 level flight curves. Linear regression will allow building actual performance charts at any gross weight and DA from those...

2enn9zr.png


I'll let you guys chew on the data above for awhile...

Other info:

1 - Catto Prop climb rate was 200 FPM greater than the Sensenich through a 1000ft altitude band, WOT at Vy (110mph), 4000-5000ft AP at 62 deg F at a Gross weight of 1546lbs and was 1306FPM
2 - Sound dramatically decreased (almost eerie)
3 - Vibrations through entire speed sweep were noticeably lower
4 - T/O distance was improved by 200 ft
5 - CHT in climb were significantly cooler (I'm still crunching data on this so no numbers yet)
6 - Cost: Sensenich $1600 + Spinner Kit, Catto - $3000 w/ Spinner Kit
7 - Delivery time: Sensenich: 6wks, Catto almost 12 weeks
8 - The Prop Disk is invisible in flight at RPM above 1400. The sensenich was always visible and distracting.
9 - Installation/Removal of Cowl is much more difficult but doable. I have slightly less than 1/8" gap between cowl and spinner so this is part of it.
9 - My GF says "The plane looks much sexier now!" this is the most important data point of all!!
 
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Ken,

Is that white tips? If so, Craig sent you my prop!:rolleyes:

I ordered the exact prop 2 weeks ago...

Looks great!
 
Whats the current wait time between date of order and date of delivery for Catto?

Seems to vary quite a bit. Craig says typically 4-6 weeks, but I've been waiting on mine for 13 weeks. Should be any day now. I think he runs them in batches that are similar, so lead times vary. I've heard of folks waiting a lot longer. But I also have a friend who got his in 2 weeks because he had an urgent need. Can't wait for mine.
 
My Catto 3 blade should be here today

I just checked the fedex tracking and it is due today. I am switching from a metal sensenich to a catto 3 blade, the sensy being a cruise prop, the catto a climb cruise combo, should be interesting.

Randy
8A
 
Nope - yellow tips!

I ordered mine last November and just received it yesterday! Nearly 4 months!!

Ewww, Not good news for me!

Couldn't see the color well with the camera angle... yellow tips look great.

Congrats on the new prop,

Scott
 
Flight Test Data

When I built my -8 a year and half ago I installed a wood sensenich 2-blade prope 71" dia pitched to 83. I really liked the look of the wood prop and was very happy with the performance but happy is a relative term and often elusive so....

Today I installed a new Catto 3-blade 68" dia, pitched 75. I entered myself back into a 5 hour phase 1 test period and am not notifying the FSDO.

Here is a pic:

ixuy9u.jpg


Several flights were conducted with both props at a Weight/Delta of 1800lbs. The OAT and fuel burn were noted for each data point and the altitude adjusted to account for decrease in weight as the flight progressed - altitude increases with decreasing weight to remain at the same Weight/delta of 1800lbs.

Once the Catto was installed I flew several flights at two differenct Gross Weights with (400lb delta) to highlight the advantage of this test technique. The plots below show an average of 3 runs with the Sensenich, and averages of 3 runs each for the Catto at 1700lbs and 1300lbs. - note the data for the two averaged Catto runs line up nicely. I'll refly this profile at 3 different Weight/Delta Values (2000, 2200, 1500). This will provide a family of 4 level flight curves. Linear regression will allow building actual performance charts at any gross weight and DA from those...

2enn9zr.png


I'll let you guys chew on the data above for awhile...

Other info:

1 - Catto Prop climb rate was 200 FPM greater than the Sensenich through a 1000ft altitude band, WOT at Vy (110mph), 4000-5000ft AP at 62 deg F at a Gross weight of 1546lbs and was 1306FPM
2 - Sound dramatically decreased (almost eerie)
3 - Vibrations through entire speed sweep were noticeably lower
4 - T/O distance was improved by 200 ft
5 - CHT in climb were significantly cooler (I'm still crunching data on this so no numbers yet)
6 - Cost: Sensenich $1600 + Spinner Kit, Catto - $3000 w/ Spinner Kit
7 - Delivery time: Sensenich: 6wks, Catto almost 12 weeks
8 - The Prop Disk is invisible in flight at RPM above 1400. The sensenich was always visible and distracting.
9 - Installation/Removal of Cowl is much more difficult but doable. I have slightly less than 1/8" gap between cowl and spinner so this is part of it.
9 - My GF says "The plane looks much sexier now!" this is the most important data point of all!!
__________________
 
All I can say is WOW!

Twenty additional mph at the same rpm (2700) on +1 gph in ff----that is a major improvement. You must have a really big grin on your face!!

Congratulations and of course,

Cheers,

db

ps. Craig better brace for a surge in orders.
 
what did you have

for a static rpm. I just put my catto 3 blade on 68 by 74 pitch, static was 2040, upwind at 115 mph was 2100 rpm, 1500 lbs, top speed was 200 mph at 2550 at 1000' My engine is either not making full power, which I don't think is the case, or my prop is way overpitched.

Randy
8A 0-360 dual bendix mags
 
for a static rpm. I just put my catto 3 blade on 68 by 74 pitch, static was 2040, upwind at 115 mph was 2100 rpm, 1500 lbs, top speed was 200 mph at 2550 at 1000' My engine is either not making full power, which I don't think is the case, or my prop is way overpitched.

Randy
8A 0-360 dual bendix mags

That's why you have a manifold gauge.................:D
 
Gasman;
What is your engine, and configuration?
Do you have fairings and wheel pants? Any draggy antennae?
Etc.?
I have a CATTO 2 blade, and have been planning to upgrade to a CATTO 3 blade after I start flying and get some data.
I'm not using a Lycoming, so I can't compare, except to observe the performance of known Lycoming, airframe, and prop combinations to get a relative idea of my own power output.
Call it a comparative dyno...;)
 
Climb CHT Comparisons between props

This data might interest you:

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:
2r2pr88.png


It would be interesting to collect CHT data for those with 2 blade props versus those with 3 blade props.
 
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Catto Static RPM

Forgot to add this:

Catto 3-blade 68" dia / 75 pitch

Xp-O360-carb

Averaged Static RPM at brake release (4 runs, DA 1100-1400ft) WOT, Full Rich

was 2120 RPM.

at 10,000FT DA, WOT, leaned to best power of 10.5 g/hr, RPM was 2700 resulting in MTAS of 210 @ GW of 1540lbs, CG 80.1"

Craig nailed my requested specs perfectly!
 
did catto change web address?

I'm finally nearing completion of my plane and I decided to go online to order my prop and got indication that cattoprops.com had expired and was available for purchase. Anyone with inside knowledge here?


update: Must have been a weird internet glitch.

His site is coming up perfectly now!

-Mike
 
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