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whifof100ll

Well Known Member
Does the orientation of the 3 blade catto prop, and/or saber spacer matter. If so, how should it be oriented.

Also, anybody know the proper torque specs for the saber spacer.
 
Catto & Saber

On the Catto prop - make sure the round end of the blades are facing forward and the thin, sharp ends are facing rearward. ;)

From Saber's web site:

Q. What is the procedure to torque my new SABER Prop Extension?
A. Torque the bolts in a crossing pattern (1,4,6,3,5,2). The torque values for the engine flange to the Prop Extension are as follows:

3/8" bolts: 30-35 ft-lbs
7/16" bolts: 35-45 ft-lbs
1/2" bolts: 40-50 ft-lbs

The torque should be applied in three equal steps (for example 10,20,30 ft-lbs for 3/8") and at least one final pass at full torque. The torque value for the propeller comes from the propeller manufacturer. When requesting the torque value from the prop manufacturer, be sure to let them know whether the prop side of your Prop Extension is 6" in diameter or 7" in diameter. The crush plate and Prop Extension flange should be the same diameter.


Al Thomas
N880AT
RV-8A QB
IO-360 with Catto 3 blade
Never ending wiring!
 
Catto allignment

There are six lugs on a Lycoming flange and 3 blades on a Catto prop, therefore there are only two choices with respect to prop installation.

You may find, as I did, that switching from one way to the other makes a difference in prop vibration and smoothness. Only trial and error will tell. I think this is something which is unique to each individual engine/ prop combo.
 
Clocking of 3 blade

Jeff, how is you prop clocked when #1 is TDC compression? Do you know?

With power pulses coming at 180 deg on 4cyl, I can believe there is some smoothness difference . . .

Rick
 
Don't know about Jeff's, but mine is at 6 O'clock, straight down. It makes finding TDC a bit easier and it is smooth.

Bob Kelly
 
I recently changed out a Sensenich 2-blade for a Catto 3-blade on my -4 w/O-360.

The first flight produced rather heavy vibration (compared to the Sensenich) in two rpm ranges.. 1100rpm, and 2200rpm.
I switched the prop one bolt to left-- counter-clockwise facing the prop. Results were awful with much heavier vibration in almost all ranges.:eek:
Next, I did another one-bolt rotation same direction and was rewarded with smoothness better than the 2-blade and, of course, much better T.O and climb performance.

The residual vibrations are higher frequency and lesser amplitude than what I started with.
 
Thread CPR

Hey guys,
Sorry to ask this, but I'm not following you with regards to orientation. If I have my crank flange setup so it's pointed up at TDC, I would think the prop could go on in any of the 6 bolt patterns...therefore, 6 combinations to try. Am I missing something? Or does it not matter which blade is pointed up or down? From one of the posts above, it seems that there are at least 3 different combinations to try.

Also, do you need to use the crush plate for the Catto 3-blade?

I guess I should also ask about torquing the prop bolts...I didn't get an installation sheet or paperwork of any kind from Catto. I've read that most people torque to 45 ft. lbs. Is that right?
 
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On the prop hub.

Sonny. my Catto has a sticker on the center that specifies torque and RPM restrictions. Yours doesn't?

Regards,
 
Hi Pierre,
I didn't see it at first, but it sure does...I wasn't looking in the right place I guess! It says 40 ft/lbs. with a 7 inch crush plate.

I guess I'm a bit confused at the assembly order then...because I have a 2-1/4" prop spacer and a 1/2" crush plate. The 2-1/4" spacer goes directly on the crank flange, right? Then the prop, then the 1/2" crush plate?
 
lostpilot28 said:
Hey guys,
Sorry to ask this, but I'm not following you with regards to orientation. If I have my crank flange setup so it's pointed up at TDC, I would think the prop could go on in any of the 6 bolt patterns...therefore, 6 combinations to try. Am I missing something? Or does it not matter which blade is pointed up or down? From one of the posts above, it seems that there are at least 3 different combinations to try.

Also, do you need to use the crush plate for the Catto 3-blade?

I guess I should also ask about torquing the prop bolts...I didn't get an installation sheet or paperwork of any kind from Catto. I've read that most people torque to 45 ft. lbs. Is that right?
Click to expand...

In speaking with Craig Catto, I was informed 1) Yes, the crush plate was required, and 2) The torque he recommended was 42 ft/lbs. done in increments which for me involved three successive settings and torquings until the 42 ft/lbs were accomplished.

Jim
 
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