COZY: Input on props, please - 2 or 3 blade?


Keith Spreuer
 

I've come to have a strong opinion about 2 vs 3 blade.Been in this game for 35 yrs and find the performance difference of a well made 2 is every bit as good as a well made 3. So then the 2 wins easily the question of weight, cost, shipping hassle, and soot accumulation. Cosmetics.. well no opinion there
Keith

On Thu, Aug 11, 2022, 12:58 PM James Russell <fshort@...> wrote:
Hi all:

 I'm to the point of ordering my prop from Catto. My Cozy Mk IV will have a 180 hp O-360, eventually.

I need you flyers to please give feedback on props - 2 or 3 blade?

Nicole from Catto said:

1) Shipping: truck for 3 blade vs regular for 2 blade

2) 72 x 68 2 blade  vs 72 x 66 3 blade

3) 3 blade 2777 rpm @ 7500'   slightly slower @ 7500' 2 blade

4) 2 blade faster higher up

4) Accelerates & climbs slightly better - 3 blade

5) No nickel LEs - too much rework for pushers

6) Polyurethane LE tape - change 4-5 yrs for $90/kit

7) Much less noise 3 blade inside

My airplane will be a crusier, extra RoC never hurts, my main driver is noise inside: she said "3 blade is like putting on NC headphones"

Comments & feedback welcomed!

I have researched this topic...

Regards,
James

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gary stull
 

I had a 2 blade prop. Man was it noisy inside. Even with ANR headset it drove me crazy from the noise


On Aug 11, 2022, at 5:28 PM, Keith Spreuer <kspreuer@...> wrote:


I've come to have a strong opinion about 2 vs 3 blade.Been in this game for 35 yrs and find the performance difference of a well made 2 is every bit as good as a well made 3. So then the 2 wins easily the question of weight, cost, shipping hassle, and soot accumulation. Cosmetics.. well no opinion there
Keith

On Thu, Aug 11, 2022, 12:58 PM James Russell <fshort@...> wrote:
Hi all:

 I'm to the point of ordering my prop from Catto. My Cozy Mk IV will have a 180 hp O-360, eventually.

I need you flyers to please give feedback on props - 2 or 3 blade?

Nicole from Catto said:

1) Shipping: truck for 3 blade vs regular for 2 blade

2) 72 x 68 2 blade  vs 72 x 66 3 blade

3) 3 blade 2777 rpm @ 7500'   slightly slower @ 7500' 2 blade

4) 2 blade faster higher up

4) Accelerates & climbs slightly better - 3 blade

5) No nickel LEs - too much rework for pushers

6) Polyurethane LE tape - change 4-5 yrs for $90/kit

7) Much less noise 3 blade inside

My airplane will be a crusier, extra RoC never hurts, my main driver is noise inside: she said "3 blade is like putting on NC headphones"

Comments & feedback welcomed!

I have researched this topic...

Regards,
James

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Tim Andres
 

I once had a 3 blade Catto from Jon Dembs MK IV to test against my 2 blade Silver bullet on my MK IV. I don’t have numbers in front of me but there wasn’t much difference in the 2. Takeoff performance, cruise and top speed were all probably within the limits of my test pilot skills but the info was taken from the EFIS data and I think fairly accurate.  Top speed was 2~3 knots faster on the 3 blade.
The 3 blade “seemed to have more takeoff thrust, but the data didn’t support it when takeoff distance was measured. This was a pre CNC Catto prop. The new ones easily could be better. 
Subjectively the 3 blade sounded much “busy’er” than the 2 blade, like the engine was spinning faster, and it was slightly higher in rpm during top speed tests, but it always sounded like it was spinning faster. 
The 3 blade will be hard to clock where one blade won’t be in the exhaust stream as well as the other drawbacks mentioned already. For me it’s a no brainer, 2 blade unless looks is the main consideration.
Tim Andres

On Aug 11, 2022, at 6:56 PM, gary stull via groups.io <garyvel55@...> wrote:

I had a 2 blade prop. Man was it noisy inside. Even with ANR headset it drove me crazy from the noise


On Aug 11, 2022, at 5:28 PM, Keith Spreuer <kspreuer@...> wrote:


I've come to have a strong opinion about 2 vs 3 blade.Been in this game for 35 yrs and find the performance difference of a well made 2 is every bit as good as a well made 3. So then the 2 wins easily the question of weight, cost, shipping hassle, and soot accumulation. Cosmetics.. well no opinion there
Keith

On Thu, Aug 11, 2022, 12:58 PM James Russell <fshort@...> wrote:
Hi all:

 I'm to the point of ordering my prop from Catto. My Cozy Mk IV will have a 180 hp O-360, eventually.

I need you flyers to please give feedback on props - 2 or 3 blade?

Nicole from Catto said:

1) Shipping: truck for 3 blade vs regular for 2 blade

2) 72 x 68 2 blade  vs 72 x 66 3 blade

3) 3 blade 2777 rpm @ 7500'   slightly slower @ 7500' 2 blade

4) 2 blade faster higher up

4) Accelerates & climbs slightly better - 3 blade

5) No nickel LEs - too much rework for pushers

6) Polyurethane LE tape - change 4-5 yrs for $90/kit

7) Much less noise 3 blade inside

My airplane will be a crusier, extra RoC never hurts, my main driver is noise inside: she said "3 blade is like putting on NC headphones"

Comments & feedback welcomed!

I have researched this topic...

Regards,
James

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So I am firmly in the 2 Blade camp.  Noise is so much lower than tractor airplanes it is a moot point.  I like the in cowl exhaust, and the extra efficiency that comes with it, so the extra 10 kts + lower cost of the prop..... easy choice for me.
If your plane is offensively noisy with a 2 blade, I would measure/compare blade pitch or Balance.  My Hartzel C/S prop on My Glastar is deafening compared to my canard 
My 2 cents
Ross

On Thu, Aug 11, 2022 at 2:28 PM Keith Spreuer <kspreuer@...> wrote:
I've come to have a strong opinion about 2 vs 3 blade.Been in this game for 35 yrs and find the performance difference of a well made 2 is every bit as good as a well made 3. So then the 2 wins easily the question of weight, cost, shipping hassle, and soot accumulation. Cosmetics.. well no opinion there
Keith

On Thu, Aug 11, 2022, 12:58 PM James Russell <fshort@...> wrote:
Hi all:

 I'm to the point of ordering my prop from Catto. My Cozy Mk IV will have a 180 hp O-360, eventually.

I need you flyers to please give feedback on props - 2 or 3 blade?

Nicole from Catto said:

1) Shipping: truck for 3 blade vs regular for 2 blade

2) 72 x 68 2 blade  vs 72 x 66 3 blade

3) 3 blade 2777 rpm @ 7500'   slightly slower @ 7500' 2 blade

4) 2 blade faster higher up

4) Accelerates & climbs slightly better - 3 blade

5) No nickel LEs - too much rework for pushers

6) Polyurethane LE tape - change 4-5 yrs for $90/kit

7) Much less noise 3 blade inside

My airplane will be a crusier, extra RoC never hurts, my main driver is noise inside: she said "3 blade is like putting on NC headphones"

Comments & feedback welcomed!

I have researched this topic...

Regards,
James

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--
Thank You!
Ross Burk
307-277-4642 cell


Tony Rothwell
 

I had an MT three blade constant speed prop with Woodward governor for many years on my Mk III.
Now have one of Gary Hertzler's two blade fixed pitch silver bullets.
Lighter, faster, smoother..... and a whole bunch of dollars cheaper both to buy and maintain... 1200 Hr 5 yr TBO vs nil limits.


On Fri, 12 Aug 2022 at 13:49, Ross Burk <apogee.design@...> wrote:
So I am firmly in the 2 Blade camp.  Noise is so much lower than tractor airplanes it is a moot point.  I like the in cowl exhaust, and the extra efficiency that comes with it, so the extra 10 kts + lower cost of the prop..... easy choice for me.
If your plane is offensively noisy with a 2 blade, I would measure/compare blade pitch or Balance.  My Hartzel C/S prop on My Glastar is deafening compared to my canard 
My 2 cents
Ross

On Thu, Aug 11, 2022 at 2:28 PM Keith Spreuer <kspreuer@...> wrote:
I've come to have a strong opinion about 2 vs 3 blade.Been in this game for 35 yrs and find the performance difference of a well made 2 is every bit as good as a well made 3. So then the 2 wins easily the question of weight, cost, shipping hassle, and soot accumulation. Cosmetics.. well no opinion there
Keith

On Thu, Aug 11, 2022, 12:58 PM James Russell <fshort@...> wrote:
Hi all:

 I'm to the point of ordering my prop from Catto. My Cozy Mk IV will have a 180 hp O-360, eventually.

I need you flyers to please give feedback on props - 2 or 3 blade?

Nicole from Catto said:

1) Shipping: truck for 3 blade vs regular for 2 blade

2) 72 x 68 2 blade  vs 72 x 66 3 blade

3) 3 blade 2777 rpm @ 7500'   slightly slower @ 7500' 2 blade

4) 2 blade faster higher up

4) Accelerates & climbs slightly better - 3 blade

5) No nickel LEs - too much rework for pushers

6) Polyurethane LE tape - change 4-5 yrs for $90/kit

7) Much less noise 3 blade inside

My airplane will be a crusier, extra RoC never hurts, my main driver is noise inside: she said "3 blade is like putting on NC headphones"

Comments & feedback welcomed!

I have researched this topic...

Regards,
James

--
You received this message because you are subscribed to the Google Groups "COZY Builders Mailing List" group.
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--
Thank You!
Ross Burk
307-277-4642 cell


Ryszard Zadow
 

Tony, how did takeoff and climb performance differ? 

On Sep 9, 2022, at 21:37, Tony Rothwell <tony13rothwell@...> wrote:


I had an MT three blade constant speed prop with Woodward governor for many years on my Mk III.
Now have one of Gary Hertzler's two blade fixed pitch silver bullets.
Lighter, faster, smoother..... and a whole bunch of dollars cheaper both to buy and maintain... 1200 Hr 5 yr TBO vs nil limits.

On Fri, 12 Aug 2022 at 13:49, Ross Burk <apogee.design@...> wrote:
So I am firmly in the 2 Blade camp.  Noise is so much lower than tractor airplanes it is a moot point.  I like the in cowl exhaust, and the extra efficiency that comes with it, so the extra 10 kts + lower cost of the prop..... easy choice for me.
If your plane is offensively noisy with a 2 blade, I would measure/compare blade pitch or Balance.  My Hartzel C/S prop on My Glastar is deafening compared to my canard 
My 2 cents
Ross

On Thu, Aug 11, 2022 at 2:28 PM Keith Spreuer <kspreuer@...> wrote:
I've come to have a strong opinion about 2 vs 3 blade.Been in this game for 35 yrs and find the performance difference of a well made 2 is every bit as good as a well made 3. So then the 2 wins easily the question of weight, cost, shipping hassle, and soot accumulation. Cosmetics.. well no opinion there
Keith

On Thu, Aug 11, 2022, 12:58 PM James Russell <fshort@...> wrote:
Hi all:

 I'm to the point of ordering my prop from Catto. My Cozy Mk IV will have a 180 hp O-360, eventually.

I need you flyers to please give feedback on props - 2 or 3 blade?

Nicole from Catto said:

1) Shipping: truck for 3 blade vs regular for 2 blade

2) 72 x 68 2 blade  vs 72 x 66 3 blade

3) 3 blade 2777 rpm @ 7500'   slightly slower @ 7500' 2 blade

4) 2 blade faster higher up

4) Accelerates & climbs slightly better - 3 blade

5) No nickel LEs - too much rework for pushers

6) Polyurethane LE tape - change 4-5 yrs for $90/kit

7) Much less noise 3 blade inside

My airplane will be a crusier, extra RoC never hurts, my main driver is noise inside: she said "3 blade is like putting on NC headphones"

Comments & feedback welcomed!

I have researched this topic...

Regards,
James

--
You received this message because you are subscribed to the Google Groups "COZY Builders Mailing List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cozy_builders+unsubscribe@....
To view this discussion on the web visit https://groups.google.com/d/msgid/cozy_builders/68834414.394633.1660247910224%40mail.yahoo.com.



--
Thank You!
Ross Burk
307-277-4642 cell


Tony Rothwell
 

Hi Ryz,  still have a tacho problem so can not do accurate numbers yet but I am not noticing anything significantly different.


On Sat, 10 Sept 2022 at 12:54, Ryszard Zadow <ryszardzadow@...> wrote:
Tony, how did takeoff and climb performance differ? 

On Sep 9, 2022, at 21:37, Tony Rothwell <tony13rothwell@...> wrote:


I had an MT three blade constant speed prop with Woodward governor for many years on my Mk III.
Now have one of Gary Hertzler's two blade fixed pitch silver bullets.
Lighter, faster, smoother..... and a whole bunch of dollars cheaper both to buy and maintain... 1200 Hr 5 yr TBO vs nil limits.

On Fri, 12 Aug 2022 at 13:49, Ross Burk <apogee.design@...> wrote:
So I am firmly in the 2 Blade camp.  Noise is so much lower than tractor airplanes it is a moot point.  I like the in cowl exhaust, and the extra efficiency that comes with it, so the extra 10 kts + lower cost of the prop..... easy choice for me.
If your plane is offensively noisy with a 2 blade, I would measure/compare blade pitch or Balance.  My Hartzel C/S prop on My Glastar is deafening compared to my canard 
My 2 cents
Ross

On Thu, Aug 11, 2022 at 2:28 PM Keith Spreuer <kspreuer@...> wrote:
I've come to have a strong opinion about 2 vs 3 blade.Been in this game for 35 yrs and find the performance difference of a well made 2 is every bit as good as a well made 3. So then the 2 wins easily the question of weight, cost, shipping hassle, and soot accumulation. Cosmetics.. well no opinion there
Keith

On Thu, Aug 11, 2022, 12:58 PM James Russell <fshort@...> wrote:
Hi all:

 I'm to the point of ordering my prop from Catto. My Cozy Mk IV will have a 180 hp O-360, eventually.

I need you flyers to please give feedback on props - 2 or 3 blade?

Nicole from Catto said:

1) Shipping: truck for 3 blade vs regular for 2 blade

2) 72 x 68 2 blade  vs 72 x 66 3 blade

3) 3 blade 2777 rpm @ 7500'   slightly slower @ 7500' 2 blade

4) 2 blade faster higher up

4) Accelerates & climbs slightly better - 3 blade

5) No nickel LEs - too much rework for pushers

6) Polyurethane LE tape - change 4-5 yrs for $90/kit

7) Much less noise 3 blade inside

My airplane will be a crusier, extra RoC never hurts, my main driver is noise inside: she said "3 blade is like putting on NC headphones"

Comments & feedback welcomed!

I have researched this topic...

Regards,
James

--
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--
Thank You!
Ross Burk
307-277-4642 cell