Piper Forum > General Discussion > General Piper Discussion > 2 blade vs 3 blade prop. Pros/cons


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Old 01-01-2014, 07:31 AM   #1
bgiles
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Default 2 blade vs 3 blade prop. Pros/cons

I am considering upgrading my 2 blade prop to a 3 blade prop on my 1977 Cherokee 235 Pathfinder. Anyone done this in the past? I have heard it will increase my rate of climb after takeoff? Any other benefits or negatives I should be aware of? I will be moving to Colorado late 2014 or mid 2015 and am wondering if it will increase my aircraft ceiling if I need to climb over a hill/mountain as well. Lastly, wondering if there will be an impact to my cruise/GPH consumption.



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Old 01-01-2014, 10:01 AM   #2
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Cruise will be very slightly slower, but not really enough to worry about.
Biggest benefit will be due to the 50% increase in the frequency of the sound generated by the prop combined with the reduction of tip speed mach effects on the front side of the prop. It will 'sound' much quieter due to the frequency shift, which becomes a significant benefit during a long trip. The 3 blade scimitar tips look very nice on the ground. A buddy made the change on his Six and doesn't regret it.



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Old 01-01-2014, 01:06 PM   #3
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I have a 3 blade on my Arrow. I have flown them with a 2 blade. Way smoother and quiet with the 3. Ramp presence is nice too as Jim pointed out.

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Old 01-01-2014, 02:08 PM   #4
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I had a three blade on my 180 Arrow. Was nice. Went for overhaul and found two blades bad. Did lots of research. Went back to a newer two blade from Professional Pilots, propilotsinc.com. Brian Sutton was very helpfull. He explained that a three bladed prop is not really efficient with less than 300 HP. My prop shop backed that up. Also if you have a two bladed prop now and convert to a three bladed prop there might be a vibration issue if the engine has lots of hours. Something about internal wear and balance. I had a slight vibration change going to the three blade. Very slight. Did not notice any change in noise, too noisy to begin eith. Happy with my two blade, faster. But does not look as nice, but who notices that while flying.

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Old 01-01-2014, 02:27 PM   #5
Ed Dartford
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As has been stated above the 3-blade prop is "nice" although performance change is trivial. Our club 235 got the 3-bladed prop at no cost to us through a prop strike and insurance. At no cost I would go for it. But I doubt I would pay for it.

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Old 01-01-2014, 02:44 PM   #6
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I flew my Arrow for many hundreds of hours with a two blade till a prop strike incident resulted in my insurance company providing a three blade since it was cheaper than a new two blade one. The two blade was smooth and this one is too though I think that it might be slightly quieter during takeoff run, otherwise nothing noticeable. I think it's cost me a knot or two in cruise but not certain about that as it's so little. Can't say I've noticed any measureable change in takeoff run or climb. I guess it looks better on the ramp but is kind of inconvenient in the hangar. I sure wouldn't change if I were paying for it as the only real advantage is a bit better ground clearance which should reduce gravel damage.

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Old 01-01-2014, 04:27 PM   #7
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Wondering how the heck a 3 blade prop gets crated for shipping?

When I need to ship a 2 blade prop, Sensenich Prop Service (on the same field as Sensenich Propeller, Lancaster Airport) ships me an empty cardboard prop box. The boxes are well engineered and I've never had a problem. I always ship FedEx.

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Old 01-01-2014, 04:32 PM   #8
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The advantages of a three blade prop are grossly over stated.

Three blades are heavier, cost more to buy, cost more to maintain, slower in cruise, often vibrate if coming from a two blade, sometimes louder, and make the airplane difficult to tow.

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Old 01-01-2014, 06:05 PM   #9
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Default This feedback is outstanding

Thank you all for giving me your perspectives. The current prop has 800 hours SOH so I have some time to ponder this. I agree, I love the look @ the Ramp of 2 blade but not sure that is enough for my needs. We only have 235 HP so we are not at the 300 HP RAFLA suggested. I will however be replacing my prop shortly after putting a zero time Lycoming Engine (currently being installed on my plane) so it sounds as though it may run smooth during the first thousand hours and then get rougher as hours build up. Something to consider.. Also I had not thought about ground clearance benefits, or towing and hanger space issues with tri-blade. This is all great stuff. So much to consider. Thank you all for this input in a timely fashion..

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Old 01-01-2014, 07:32 PM   #10
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I test flew two Dakota 236's back to back four years ago, one with a two blade prop and one with the scimitar 3 blade. I was worrying that the 3 blade would be a bit slower but I could not tell any difference in speed. But the 3 blade is much quieter. Friends on the ground have commented that take off climb is steep but the noise is low. I bought the 3 blade Dakota and have been very happy with it. I suspect that any differences to top speed between a 3 blade and 2 blade is due to trim. With Gap seals, wing fillets, wing tips and wheel pants, it tops at 146 knots at 10,500 feet with full fuel, two adults, 2 suitcases and a 95 lb Labrador Retriver. (200 lbs under gross)



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