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Old 03-17-2012, 03:05 PM
gasman gasman is offline
Join Date: Mar 2007
Location: Sonoma County
Posts: 4,335

Originally Posted by N208ET View Post
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.

8A 0-360 dual bendix mags
That's why you have a manifold gauge.................
VAF #897 Warren Moretti
2021 =VAF= Dues PAID
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Old 03-17-2012, 03:49 PM
Join Date: Mar 2008
Location: Seattle
Posts: 1,412

What is your engine, and configuration?
Do you have fairings and wheel pants? Any draggy antennae?
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...
Scott Emery
EAA 668340, chapter 326 & IAC chapter 67
RV-8 N89SE first flight 12/26/2013
Yak55M, and the wife has an RV-4
There is nothing-absolute nothing-half so much worth doing as simply messing around with Aeroplanes
(with apologies to Ratty)
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Old 03-17-2012, 07:46 PM
dealfair dealfair is offline
Join Date: Feb 2006
Location: George West, TX
Posts: 567
Default Ha Ha!!

Originally Posted by RV8R999 View Post
Other info:

9 - My GF says "The plane looks much sexier now!" this is the most important data point of all!!
THAT, is the exact reason I bought a Catto 3 blade prop!!! No regrets.
Deal Fair
RV-4 (N34CB)
George West, TX (8T6)
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Old 03-17-2012, 09:18 PM's Avatar is offline
Join Date: Aug 2006
Posts: 167
Default Weight differences

Ken nice prop, what was the difference in weight between the two props?
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Old 03-17-2012, 10:48 PM
RV8R999 RV8R999 is offline
Join Date: Dec 2008
Location: na
Posts: 1,457

Originally Posted by View Post
Ken nice prop, what was the difference in weight between the two props?
about 1 lbs
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Old 03-18-2012, 10:00 AM
RV8R999 RV8R999 is offline
Join Date: Dec 2008
Location: na
Posts: 1,457
Default 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:

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

Last edited by RV8R999 : 03-18-2012 at 10:03 AM.
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Old 03-18-2012, 10:12 AM
RV8R999 RV8R999 is offline
Join Date: Dec 2008
Location: na
Posts: 1,457
Default Catto Static RPM

Forgot to add this:

Catto 3-blade 68" dia / 75 pitch


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!
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Old 03-19-2012, 01:21 PM
mlw450802's Avatar
mlw450802 mlw450802 is offline
Join Date: Jan 2005
Location: Payson, AZ
Posts: 436
Default 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 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!

Michael L Wilson
Resuming building after a 4ish year hiatus! (life got in the way)
N194MW (reserved) RV9A SB
VAF# 148
Payson, AZ

Last edited by mlw450802 : 03-19-2012 at 03:28 PM. Reason: new data
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Old 03-19-2012, 02:50 PM
Paul Tuttle's Avatar
Paul Tuttle Paul Tuttle is offline
Join Date: Apr 2006
Location: Lantz,Nova Scotia ,Canada
Posts: 556
Default This Catto address worked for me.

PM me for address if you like.
Paul Tuttle
RV 8

Last edited by Paul Tuttle : 03-19-2012 at 03:00 PM. Reason: Not sure if I was breaking rules by including address
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