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Aymar Demuth to Catto 3 blade

Karbonkid

Member
Excited for my new prop so figured I'd post

Purchased RV4 with Aymar Demuth prop, swapping to catto 3 blade

Seems everyone is always interested in performance numbers so figure I would document before and after...

numbers of interest? Static, climb @100, full at 8000 ??

I rarely ever look so imput on what is of intrest welcome.....

first attempt at photos below:

Plane / prop in a box... was a little worried with cond of box / shiny new prop
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A/D to Catto

I recently, 1.5hrs ago, replaced my A/D 2 blade with a Catto 3 blade. I have been totally impressed. The pull on the runway is better, top end better, and when I pull the throttle to slow it down, the Catto seems to deaccelerate faster.
I am sold....

I have not been able to get real world numbers yet, maybe this weekend if the weather holds.

Phil

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I am replacing a 68 x 78 A/D

I was concerned with the spacer configuration so I ended up just ordering new extension and spacers for the catto from saber. went with a 20lb crush plate as well that I will put on when my brothers want a ride.

anyways, I got everything on the plane last week. will have to do the A/D numbers later though should be easy as I have all old spacer fwd setup I can just bolt on.

I went for 2 short flights in the pattern as it was a busy week....

First impressions:
on ground
- prop looks amazing
- Surprised that the prop felt no smoother than the old A/D
- seems like more vibration under ~1200 rpm
flying
- Prop pulls hard on run up 2200 static iirc
- no noticable difference on takeoff
- on climbout the noise was much different then the A/D sounded like a 185 more like it was cracking the air (not sure how else to discribe)
- Seemed to be more vibration in the downwind than the A/D though I may have been overly sensitive with new prop.
- final / landing I couldnt really tell a difference, possibly slowed faster.

I contacted catto and googled the potential vibration and noise
- catto thought the increase in noise may have actually been hearing more engine noise bc of quiter prop. I may believe this

- I have moved the prop 1 bolt hole clockwise to see about vibration

going to try this afternoon and see how it is

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I recently, 1.5hrs ago, replaced my A/D 2 blade with a Catto 3 blade. I have been totally impressed. The pull on the runway is better, top end better, and when I pull the throttle to slow it down, the Catto seems to deaccelerate faster.
I am sold....

I have not been able to get real world numbers yet, maybe this weekend if the weather holds.

Phil

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Wow, N621RT sure looks good with that 3-blade prop on it. I bet Tim will wish he never sold it after he sees this pic.
 
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Neal,

I miss the Christin Eagle sometimes, but the RV is such a relaxing and fun plane to fly, I am glad I made the trade. Tell Tim hello for me.

Phil
 
OK, slow progress on getting real numbers but I do have close ones that I will narrow down in the next week or so.

This weekend I flew from new orleans over to the thomasville, GA fly in. Fun time nice group and great food. I only stayed for sat but many were camping over the weekend.

so, on the way back
10,500
2400 rpm ~140mph ind /168 true
2500 rpm ~148mph ind / 177 true

The A/D was ~10mph faster

two things that come to mind, the three blade has a larger diameter nosecone and I am now running 20lb crushplate.

would you guys expect these to reduce speed by ~10mph?

just looking for similar experiences and thoughts.

I am very happy with the prop and it is smooth now that I rotated 1 bolt hole clockwise (why this did anything I have no idea)
 
OK, slow progress on getting real numbers but I do have close ones that I will narrow down in the next week or so.

so, on the way back
10,500
2400 rpm ~140mph ind /168 true
2500 rpm ~148mph ind / 177 true

The A/D was ~10mph faster

two things that come to mind, the three blade has a larger diameter nosecone and I am now running 20lb crushplate.

would you guys expect these to reduce speed by ~10mph?

just looking for similar experiences and thoughts.

I am very happy with the prop and it is smooth now that I rotated 1 bolt hole clockwise (why this did anything I have no idea)

Did you measure both props at full throttle?

A measure at WOT at the similar weather conditions and altitude. That would be your best static data point to start from. If you have accurate fuel flow and MAP measurement- use those also. Then you could measure similar power settings/conditions at what TAS. The RPM setting is a minor power data point with different prop comparisons since that will vary.
 
You know I never thought about it, I have no idea what my power setting is with my setup ... Just picking rpm at altitude. I will get wot at altitude so then approx power setting is known.
 
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