Best prop for economy cruise

[pilote999]

I want to change my wood prop (A-D 68 X 74) on my RV-6 with a 160 HP (Good prop, but no good in rain).
I read a lot of post about propellers. More I read, more confused I am !!!

What is the best prop for economy cruise (Most of my flights are between 3000 to 7500 ft) at 55 to 65% (2300 to 2400 RPM)? In that range of power, is it the Catto or the metal Sensonich that is more efficient (in cruise and climb)? The Catto can deliver more power of the engine from 2600 to 2700 because the prop is not limited to 2600 but I will never use the engine at max power for long period of time.
Can we say that a light composite prop is better on the engine live (less centrifugal force and less vibration but not at idle)?
For long time period, it is appropriate to keep the prop outside without affecting the composite?
I want to fly in light rain and I used gravel runway.

Thanks for your inputs!

 

[Sam Buchanan]

I want to change my wood prop (A-D 68 X 74) on my RV-6 with a 160 HP (Good prop, but no good in rain).
I read a lot of post about propellers. More I read, more confused I am !!!

What is the best prop for economy cruise (Most of my flights are between 3000 to 7500 ft) at 55 to 65% (2300 to 2400 RPM)? In that range of power, is it the Catto or the metal Sensonich that is more efficient (in cruise and climb)? The Catto can deliver more power of the engine from 2600 to 2700 because the prop is not limited to 2600 but I will never use the engine at max power for long period of time.
Can we say that a light composite prop is better on the engine live (less centrifugal force and less vibration but not at idle)?
For long time period, it is appropriate to keep the prop outside without affecting the composite?
I want to fly in light rain and I used gravel runway.

Thanks for your inputs!

I can't compare the Sensenich to the Catto but can tell you I have been very pleased with how the Sensenich has performed on my 160hp RV-6 for twelve years. It has 80" pitch and I customarily see 150 kts TAS, 24 squared, 7.5 gal/hr. 80" is definitely a cruise prop for a 160 but climb is still satisfactory east of the Rockies.

 

[smokyray]

Prop me up, again...

Raynald,

During my two RV's (RV4/RV6X) 17 year "test period" (they are always being tested) I bolted no less than Nine different propellers to the nose. I ranked each according to their needs and more importantly, performance. I fly aerobatics, encounter light rain regularly and 70% of my landings are off-pavement. That said, here is how I personally rated the available props then, and now. Worst to first.

9. Sensenich Wood: Big "paddle" low static, low max cruise, poor in rain, 2nd worst cruise, cracked twice during ownership (3 months)

8. Sensenich 70CM Metal FP: Heavy, reduced ground clearance on short geared RV's (3,4, A models) noticeable flywheel effect for aerobatics, 2600 RPM factory restriction. OK for cross country, level flying. Very durable in rain.

7. Ed Sterba Wood: Excellent value, fragile in rain, needs torquing every 25 hours. Good for economy purchase and fair weather flyers.

6. Performance Propellers three blade. Excellent aerobatic prop, great climb, lowest cruise numbers but very smooth. Poor rain protection. Great for a Pitts, One design or low use RV.

5. Bernie Warnke "almost constant speed Wood/Composite. I met Bernie right before he passed away. His small shop in Tucson smelled like a cuckoo clock factory in the German Black Forest, a true craftsman. His razor thin laminates and carbon fiber backing that allowed prop "flexing" inflight were light years ahead of their time and current owners cling to them like a prop cult following. Excellent performance, amazing cruise/climb RPM ratio. Fragile for off pavement pilots like myself, erodes easily in rain. A real collectors item from a master craftsman and true gentleman.

4. Margie Warnke "Claw" Bernie's daughter worked very hard improving on and perfecting her Dad's amazing design. Sadly, she retired from prop making but a few examples remain out there. Best performance ever, period. Fragile, easily eroded by rain but simply gorgeous with multiple laminates and a unique "twist". Best Cruise/Climb to RPM ratio of any FP prop I tested. My last flight with it was the Wright Brothers 100th anniversary back in 2003' with a photo taken by DR riding in Danny's back seat of Beautiful Doll.. My wife retired the prop to static display on our mantle.

3. Gary Hertzler "Silver Bullet" Wood/composite. Gary won the CAFE Triaviathon back in 89' with his amazing Vari-EZ and his own design prop. I was fortunate enough to have him build two for my RV4, one of which I shared with a friend in CA, the other adorns DR's mechanic friend "Monkey's" RV6. Best cruise/climb ratio ever. Best efficiency, period. Rain however is it's nemesis. In the SE USA, light rain during sunshine in the summer is a way of life. Other than that, it's the best efficiency I have ever seen for FP props. Gary might build you one if you ask nicely...

2. MT Fixed Pitch Wood/Composite prop. Excellent performance, excellent climb/cruise ratio, factory backing and warranty, excellent rain protection, light weight and utility. Slightly lower performance than Catto and Hertzler, just.

1. "New" Catto design 2 blade. Craig's latest prop design with optional Nickel leading edges. I met Craig Catto in 98' and began a long term friendship that would span 3 airplanes, six propellers and over 2500 Hours of flight time. The improved blade/airfoil design, better top end performance and rain protection produce a true home run prop. Excellent value, light weight and smoothness. I like getting rated power(2700RPM) at 13,500'. To do this requires higher max RPM in lower altitudes. Craig's props address this well, hard to beat.

For your application I would recommend the Catto 2-Blade or MT FP over the Sensy metal.

V/R
Smokey

 

[Neal@F14]

I've got the same Aymar-Demuth 68x74 prop on my 160hp RV-6.

The economy cruise capability of this prop is downright amazing. I've only owned the plane for 3 months, but on the Texas-to-Oshkosh and back flights just a couple weeks ago, I got about 195-200 mph (169-173 knots) true airspeed at 7500/8500MSL and 8.9GPH running wide open throttle and leaned to peak rpm (I was told that's running it at "full rental power" ). I did have to throttle back to 2000 rpm when I ran into some light rain.

When I fly around locally, I throttle back a lot (e.g. 2200-2300 rpm and still can easily hit 160+ mph and burn very little fuel.

Like you, I'd really like to have better leading edge protection for flying in rain.

My climb performance with this prop stinks though. With two persons aboard, on a hot, high density altitude Texas summer day, the takeoff and climb performance almost makes me feel like I'm back in my old Cherokee 140

Also on takeoffs, the p-factor produced by this prop is incredible for such a small airplane, I have to add a bunch of extra right rudder immediately after the wheels leave the ground or the plane will make a big abrupt sidestep to the left as soon as it gets airborne. I can't add that much right rudder before liftoff, or it'll run off the right side of the runway. It's been a bit of a learning curve to get it just right.

Someday when I can afford to change the prop, I'm probably going for a clone of SmokyRay's newest Catto 2-blade, maybe pitched just a little bit higher. A Hartzell Blended Airfoil CS prop would sure be nice to have too... my engine is a -D1A which is capable of accepting a CS prop and governor, but unfortunately my bank account is not capable

 

[springer]

Raynald,

5. Bernie Warnke "almost constant speed Wood/Composite. I met Bernie right before he passed away. His small shop in Tucson smelled like a cuckoo clock factory in the German Black Forest, a true craftsman. His razor thin laminates and carbon fiber backing that allowed prop "flexing" inflight were light years ahead of their time and current owners cling to them like a prop cult following. Excellent performance, amazing cruise/climb RPM ratio. Fragile for off pavement pilots like myself, erodes easily in rain. A real collectors item from a master craftsman and true gentleman.

4. Margie Warnke "Claw" Bernie's daughter worked very hard improving on and perfecting her Dad's amazing design. Sadly, she retired from prop making but a few examples remain out there. Best perforrmance ever, period. Fragile, easily eroded by rain but simply gorgeous with multiple laminates and a unique "twist". Best Cruise/Climb to RPM ratio of any FP prop I tested. My last flight with it was the Wright Brothers 100th anniversary back in 2003' with a photo taken by DR riding in Danny's back seat of Beautiful Doll.. My wife retired the prop to static display on our mantle.
Smokey

I tested various Bernie's new designs for many years on my '88 RV-4. Always enjoyed his ear to ear grin when I taxied back in with a 'thumbs up.' Margie's ex continued the business with similar designs in Patagonia, AZ. He sold it several years ago to someone in Texas.

Everything you said about his props were true although I never experienced erosion in light rain. Bernie was a great guy and a true friend. He flew his RV-3 to the end. I miss him.