I hope I am not opening up another Pandora’s box but the issue of the difference in prop blades continous to be unanswered. About nine out of ten planes are coming off the line with a 3 blade prop.Questions: 1) What is the REAL difference in performance with the 2 vs 3? 2) Are folks ordering the 3 blade just because it looks nicer or are there real advantages? 3) The 3 blade weighs more and is more expensive to maintain so why not the 2 blade?
I hope folks have some factual answers out there on this as there are a lot of misleading information on 3 blade props.
Thanks for your help.
Brian
The official word is that there is no significant performance difference between the two- and three-blade props.
The only significant difference (other than the cool looks and the extra weight) is that the blades are two inches shorter on the three-blade, resulting in a bit less blade erosion when operating on the ground, and quieter operation due to reduced tip velocity.
Maintenance is more costly, but not 50% more.
I hope I am not opening up another Pandora’s box but the issue of the difference in prop blades continous to be unanswered. About nine out of ten planes are coming off the line with a 3 blade prop.Questions: 1) What is the REAL difference in performance with the 2 vs 3? 2) Are folks ordering the 3 blade just because it looks nicer or are there real advantages? 3) The 3 blade weighs more and is more expensive to maintain so why not the 2 blade?
I hope folks have some factual answers out there on this as there are a lot of misleading information on 3 blade props.
Thanks for your help.
Brian
Brian,
I was told that the 3-blade prop results in significantly less vibration, with resulting longer life in landing light (and presumably long-term better environment for engine accessories, etc.)
That said, I personally am leaning toward the 2-blade for the reasons you mentioned – the 3 doesn’t seem worth it.
Maybe some folks with experience in the 2 vs. 3 blade cirri can confirm or deny the vibration issue?
Steve
The only significant difference (other than the cool looks and the extra weight) is that the blades are two inches shorter on the three-blade, resulting in a bit less blade erosion when operating on the ground, and quieter operation due to reduced tip velocity.
FWIW: This was a tough decision for me, but in the end I opted for the 3-Blade. The decision was based on what I heard about landing-light-life in the 2- vs. in the 3-blade configuration. I’m concerned about vibration levels, not the cost of the landing light; but it seems like a reasonable barometer. Less vibration means an easier life for gyros in particular, but also for connections, couplings, avionics, occupants, etc.
All the 2-blade owners I spoke to or emailed reported a need to change landing lights every 40-50 hours, almost regardless of how much they used it. On the other hand, most (but not all) 3-blade owners said that the landing light lasted much longer. Walt told me that he has yet to replace his - I believe he has over 400 hours so far.
Another factor is the frequency of the cabin noise. When I visited the factory, someone (don’t remember who) told me that the 3-blade installation results in a frequency which is closer to the design-point for the Lightspeed headsets, so the noise cancelling should be more effective. I don’t know whether other manufacturers design around the same frequency, but I use Lightspeeds.
In the end, though, there’s not much in it; especially considering the $$ and the extra weight. Be careful about the prop weight - the sample W&B schedules I requested showed a 23 lb difference over an otherwise identical 2-blade installation.
I’m still not sure I made the right choice, but at least I feel like I did my “due diligence”.
I hope I am not opening up another Pandora’s box but the issue of the difference in prop blades continous to be unanswered. About nine out of ten planes are coming off the line with a 3 blade prop.Questions: 1) What is the REAL difference in performance with the 2 vs 3? 2) Are folks ordering the 3 blade just because it looks nicer or are there real advantages? 3) The 3 blade weighs more and is more expensive to maintain so why not the 2 blade?
I hope folks have some factual answers out there on this as there are a lot of misleading information on 3 blade props.
Thanks for your help.
Brian and Steve, As an owner of a two blade prop for the very reasons you indicated. The two blade is 1" closer to the ground, a little faster in cruise, lighter, cheeper, lower maintence, a slight bit noiser. I put my $ into 2 new pair of lightspeed (20xL,and 15xL) Very little difference there either! I also have been in other 3 blade airplanes (Walt’s) and he has been in mine, and we both saw little difference, vibration or noise. We both used our old ears to make the test. Save your $ unless you like the look.
Sam Johnson
Brian
Brian,
I was told that the 3-blade prop results in significantly less vibration, with resulting longer life in landing light (and presumably long-term better environment for engine accessories, etc.)
That said, I personally am leaning toward the 2-blade for the reasons you mentioned – the 3 doesn’t seem worth it.
Maybe some folks with experience in the 2 vs. 3 blade cirri can confirm or deny the vibration issue?
Steve
I hope I am not opening up another Pandora’s box but the issue of the difference in prop blades continous to be unanswered. About nine out of ten planes are coming off the line with a 3 blade prop.Questions: 1) What is the REAL difference in performance with the 2 vs 3? 2) Are folks ordering the 3 blade just because it looks nicer or are there real advantages? 3) The 3 blade weighs more and is more expensive to maintain so why not the 2 blade?
I hope folks have some factual answers out there on this as there are a lot of misleading information on 3 blade props.
Thanks for your help.
Brian and Steve, As an owner of a two blade prop for the very reasons you indicated. The two blade is 1" closer to the ground, a little faster in cruise, lighter, cheeper, lower maintence, a slight bit noiser. I put my $ into 2 new pair of lightspeed (20xL,and 15xL) Very little difference there either! I also have been in other 3 blade airplanes (Walt’s) and he has been in mine, and we both saw little difference, vibration or noise. We both used our old ears to make the test. Save your $ unless you like the look.
Sam Johnson
I chose the 2-blade for all the reasons
Sam mentions. I have flown in both 2 and 3-bladers and cannot tell the difference in noise or vibration. I would be curious to see some data on landing light life; at 60 hours mine is still alive. Regarding the Lightspeed ANR setup, I spoke to the guy at Lightspeed who did the work. He told me that he aimed the noise cancelling between the 1 and 1-blade frequencies. Also, as Sam points out the 2" difference in prop length only gives you 1" more off the deck. Just keep your tires inflated. You will have nearly the same prop clearance with one less blade to nick. You will cruise comfortably past the 3-bladers while also enjoying greater range. Remember to keep your prop turning and you won’t look uncool. 
Bill Graham
Brian,
I was told that the 3-blade prop results in significantly less vibration, with resulting longer life in landing light (and presumably long-term better environment for engine accessories, etc.)
That said, I personally am leaning toward the 2-blade for the reasons you mentioned – the 3 doesn’t seem worth it.
Maybe some folks with experience in the 2 vs. 3 blade cirri can confirm or deny the vibration issue?
Steve
I hope I am not opening up another Pandora’s box but the issue of the difference in prop blades continous to be unanswered. About nine out of ten planes are coming off the line with a 3 blade prop.Questions: 1) What is the REAL difference in performance with the 2 vs 3? 2) Are folks ordering the 3 blade just because it looks nicer or are there real advantages? 3) The 3 blade weighs more and is more expensive to maintain so why not the 2 blade?
I hope folks have some factual answers out there on this as there are a lot of misleading information on 3 blade props.
Thanks for your help.
Brian and Steve, As an owner of a two blade prop for the very reasons you indicated. The two blade is 1" closer to the ground, a little faster in cruise, lighter, cheeper, lower maintence, a slight bit noiser. I put my $ into 2 new pair of lightspeed (20xL,and 15xL) Very little difference there either! I also have been in other 3 blade airplanes (Walt’s) and he has been in mine, and we both saw little difference, vibration or noise. We both used our old ears to make the test. Save your $ unless you like the look.
Sam Johnson
I chose the 2-blade for all the reasons
Sam mentions. I have flown in both 2 and 3-bladers and cannot tell the difference in noise or vibration. I would be curious to see some data on landing light life; at 60 hours mine is still alive. Regarding the Lightspeed ANR setup, I spoke to the guy at Lightspeed who did the work. He told me that he aimed the noise cancelling between the 1 and 1-blade frequencies. Also, as Sam points out the 2" difference in prop length only gives you 1" more off the deck. Just keep your tires inflated. You will have nearly the same prop clearance with one less blade to nick. You will cruise comfortably past the 3-bladers while also enjoying greater range. Remember to keep your prop turning and you won’t look uncool.
Bill Graham
Sorry, he aimed between the 2 and 3-blade frequencies.
Bill Graham>>>
Brian,
I was told that the 3-blade prop results in significantly less vibration, with resulting longer life in landing light (and presumably long-term better environment for engine accessories, etc.)
That said, I personally am leaning toward the 2-blade for the reasons you mentioned – the 3 doesn’t seem worth it.
Maybe some folks with experience in the 2 vs. 3 blade cirri can confirm or deny the vibration issue?
Steve
Jim
what are the squawks you heard about the rate of climb?
Placido
As you can tell by my position # I have no experience with 2 VS 3 blades on the Cirrus yet, but I can add this. I now own a PA-32-260. I had flown it for 450 hours with a 2 blade prop and then this summer replaced both the engine and a new 3 blade prop. I’m sure that some of the improvement was due to the fresh engine, but I now get significantly better climb, a shorter take off distance, and a much smoother and quieter ride.In my 6 I even got a few more knots in cruise, but I understand that is not typical in most instances.
With some of the squawks I have heard about the rate of climb in the Cirrus I would wonder if the 3 blade might help.
As you can tell by my position # I have no experience with 2 VS 3 blades on the Cirrus yet, but I can add this. I now own a PA-32-260. I had flown it for 450 hours with a 2 blade prop and then this summer replaced both the engine and a new 3 blade prop. I’m sure that some of the improvement was due to the fresh engine, but I now get significantly better climb, a shorter take off distance, and a much smoother and quieter ride.In my 6 I even got a few more knots in cruise, but I understand that is not typical in most instances.
With some of the squawks I have heard about the rate of climb in the Cirrus I would wonder if the 3 blade might help.
I guess that is the type of information I am looking for. Is there valid evidence that the 3 blade prop is better in cimb performance? Is the 3 blade prop slower in cruise or no change in speed? In other airplanes (Mooney in particular)this has been an issue but I am not sure the same applies to the Cirrus. Do you know for sure?
Brian
As you can tell by my position # I have no experience with 2 VS 3 blades on the Cirrus yet, but I can add this. I now own a PA-32-260. I had flown it for 450 hours with a 2 blade prop and then this summer replaced both the engine and a new 3 blade prop. I’m sure that some of the improvement was due to the fresh engine, but I now get significantly better climb, a shorter take off distance, and a much smoother and quieter ride.In my 6 I even got a few more knots in cruise, but I understand that is not typical in most instances.
Last March Tom Bergeron told me that the three-blade made no real difference. He added that a more powerful engine would be required to see a real climb enhancement. I think that he had the SR-22 in mind. To sum up: I think the 3-blade sells primarily because - like the rest of the SR20 - it looks cool.
With some of the squawks I have heard about the rate of climb in the Cirrus I would wonder if the 3 blade might help.
I guess that is the type of information I am looking for. Is there valid evidence that the 3 blade prop is better in cimb performance? Is the 3 blade prop slower in cruise or no change in speed? In other airplanes (Mooney in particular)this has been an issue but I am not sure the same applies to the Cirrus. Do you know for sure?
Brian
Thanks George:
Now what I would to know is whether anyone has ANY information that suggests the 3 blade prop DEGRADES performance (speed, climb etc.) or is the difference a wash and just a matter of extra weight and cost. The vibration issue may be difficult to evaluate as I understand that it may take many hundreds of hours on the engine before vibration differences become noticeable.
I think I would not want to consider a 3 blade prop if there was any data that suggested it made the plane run slower or have degraded climb performance. Anybody know out there?
Brian
3 blade prop cost you 20 lbs useful load and gives you better looks on the ramp. Otherwise its a wash.
As you can tell by my position # I have no experience with 2 VS 3 blades on the Cirrus yet, but I can add this. I now own a PA-32-260. I had flown it for 450 hours with a 2 blade prop and then this summer replaced both the engine and a new 3 blade prop. I’m sure that some of the improvement was due to the fresh engine, but I now get significantly better climb, a shorter take off distance, and a much smoother and quieter ride.In my 6 I even got a few more knots in cruise, but I understand that is not typical in most instances.
Last March Tom Bergeron told me that the three-blade made no real difference. He added that a more powerful engine would be required to see a real climb enhancement. I think that he had the SR-22 in mind. To sum up: I think the 3-blade sells primarily because - like the rest of the SR20 - it looks cool.
With some of the squawks I have heard about the rate of climb in the Cirrus I would wonder if the 3 blade might help.
I guess that is the type of information I am looking for. Is there valid evidence that the 3 blade prop is better in cimb performance? Is the 3 blade prop slower in cruise or no change in speed? In other airplanes (Mooney in particular)this has been an issue but I am not sure the same applies to the Cirrus. Do you know for sure?
Brian
Thanks George:
Now what I would to know is whether anyone has ANY information that suggests the 3 blade prop DEGRADES performance (speed, climb etc.) or is the difference a wash and just a matter of extra weight and cost. The vibration issue may be difficult to evaluate as I understand that it may take many hundreds of hours on the engine before vibration differences become noticeable.
I think I would not want to consider a 3 blade prop if there was any data that suggested it made the plane run slower or have degraded climb performance. Anybody know out there?
Brian
3 blade prop cost you 20 lbs useful load and gives you better looks on the ramp. Otherwise its a wash.
As you can tell by my position # I have no experience with 2 VS 3 blades on the Cirrus yet, but I can add this. I now own a PA-32-260. I had flown it for 450 hours with a 2 blade prop and then this summer replaced both the engine and a new 3 blade prop. I’m sure that some of the improvement was due to the fresh engine, but I now get significantly better climb, a shorter take off distance, and a much smoother and quieter ride.In my 6 I even got a few more knots in cruise, but I understand that is not typical in most instances.
Last March Tom Bergeron told me that the three-blade made no real difference. He added that a more powerful engine would be required to see a real climb enhancement. I think that he had the SR-22 in mind. To sum up: I think the 3-blade sells primarily because - like the rest of the SR20 - it looks cool.
With some of the squawks I have heard about the rate of climb in the Cirrus I would wonder if the 3 blade might help.
I guess that is the type of information I am looking for. Is there valid evidence that the 3 blade prop is better in cimb performance? Is the 3 blade prop slower in cruise or no change in speed? In other airplanes (Mooney in particular)this has been an issue but I am not sure the same applies to the Cirrus. Do you know for sure?
Brian
Thanks George:
Now what I would to know is whether anyone has ANY information that suggests the 3 blade prop DEGRADES performance (speed, climb etc.) or is the difference a wash and just a matter of extra weight and cost. The vibration issue may be difficult to evaluate as I understand that it may take many hundreds of hours on the engine before vibration differences become noticeable.
I think I would not want to consider a 3 blade prop if there was any data that suggested it made the plane run slower or have degraded climb performance. Anybody know out there?
Brian
Warren:
Do you know that for a fact or is this just something you heard. I am looking for concrete evidence that the 3 blade does not DEGRADE performance. Thanks for your input.
Brian
I am looking for concrete evidence that the 3 blade does not DEGRADE performance.
I don’t think you’re going to find it, actually. The official CD position is that the performance is the same, and the unofficial position appears to no different. I have talked to a number of people at CD informally, and all have said that there is no measurable difference between the performance, but to determine this for sure, you would need to take a plane and run the necessary tests.
If you are concerned about performance, then the safest choice would be the 2-blade. This is because if there is any difference, however slight, it is likely to favor the 2-blade, and in any case, the extra weight of the 3-blade is a handicap, even if it makes no difference to cruise speed. Then you could spend the money saved on regular cleaning, which will definitely boost performance. It does not take too many bugs on the wings to drop cruise speed noticeably.
3 blade prop cost you 20 lbs useful load and gives you better looks on the ramp. Otherwise its a wash.
As you can tell by my position # I have no experience with 2 VS 3 blades on the Cirrus yet, but I can add this. I now own a PA-32-260. I had flown it for 450 hours with a 2 blade prop and then this summer replaced both the engine and a new 3 blade prop. I’m sure that some of the improvement was due to the fresh engine, but I now get significantly better climb, a shorter take off distance, and a much smoother and quieter ride.In my 6 I even got a few more knots in cruise, but I understand that is not typical in most instances.
Last March Tom Bergeron told me that the three-blade made no real difference. He added that a more powerful engine would be required to see a real climb enhancement. I think that he had the SR-22 in mind. To sum up: I think the 3-blade sells primarily because - like the rest of the SR20 - it looks cool.
With some of the squawks I have heard about the rate of climb in the Cirrus I would wonder if the 3 blade might help.
I guess that is the type of information I am looking for. Is there valid evidence that the 3 blade prop is better in cimb performance? Is the 3 blade prop slower in cruise or no change in speed? In other airplanes (Mooney in particular)this has been an issue but I am not sure the same applies to the Cirrus. Do you know for sure?
Brian
Thanks George:
Now what I would to know is whether anyone has ANY information that suggests the 3 blade prop DEGRADES performance (speed, climb etc.) or is the difference a wash and just a matter of extra weight and cost. The vibration issue may be difficult to evaluate as I understand that it may take many hundreds of hours on the engine before vibration differences become noticeable.
I think I would not want to consider a 3 blade prop if there was any data that suggested it made the plane run slower or have degraded climb performance. Anybody know out there?
Brian
Warren:
Do you know that for a fact or is this just something you heard. I am looking for concrete evidence that the 3 blade does not DEGRADE performance. Thanks for your input.
Brian
Brian-
I have no direct experience with the SR20, but on the Cessna 182, they went to a 3-blade prop in 1999 largely to cure vibration in the Lycoming 540 engine - not to gain performance (and it looks real cool sitting on the line that way, too.)
Best,
…Warren
I am looking for concrete evidence that the 3 blade does not DEGRADE performance.
I don’t think you’re going to find it, actually. The official CD position is that the performance is the same, and the unofficial position appears to no different. I have talked to a number of people at CD informally, and all have said that there is no measurable difference between the performance, but to determine this for sure, you would need to take a plane and run the necessary tests.
If you are concerned about performance, then the safest choice would be the 2-blade. This is because if there is any difference, however slight, it is likely to favor the 2-blade, and in any case, the extra weight of the 3-blade is a handicap, even if it makes no difference to cruise speed. Then you could spend the money saved on regular cleaning, which will definitely boost performance. It does not take too many bugs on the wings to drop cruise speed noticeably.
Thanks Clyde:
Some folks had suggested to me that the 3 blade prop actually had worst climb and cruise performance. I think this information was based on the experience with the Mooney, not Cirrus. But, to be sure, I was looking to see if Cirrus had any data to suggest a similar problem. The answer is “no” by your report and that helps. Just because a 3 blade prop produces given performace figures in one plane does not mean the same will be true in other models. I like the 3 blade but would be turned off if it meant degraded performance.
thanks again.
Brian
Just because a 3 blade prop produces given performace figures in one plane does not mean the same will be true in other models
This is absolutely true. The theory says that the fewer blades you have, the more efficient the prop will be (some control-line model planes use a 1-blade prop!) but there are many other variables that affect it.
In Mooney’s case, they did get performance gains by switching from a 3-blade to a 2-blade prop, but that was not just a matter of dropping off one blade - the new 2-blade prop is a completely new design, and propellor design seems to be as much art as science.
I actually think the SR20 has considerable scope for improvement in both the prop and in drag cleanup. It would be interesting to see what Roy LoPresti could do with it. The current performance seems to me to be mostly down to the high-aspect, laminar flow wing.
I actually think the SR20 has considerable scope for improvement in both the prop and in drag cleanup. It would be interesting to see what Roy LoPresti could do with it. The current performance seems to me to be mostly down to the high-aspect, laminar flow wing.
Clyde, funny you should mention that. In some airplane magazine article, they quoted Roy. If I recall correctly, he was impressed by the design, and said Cirrus didn’t miss much in the way of drag reduction. He did allow, though, that he wouldn’t mind taking a crack at it
-Mike
Just because a 3 blade prop produces given performace figures in one plane does not mean the same will be true in other models
This is absolutely true. The theory says that the fewer blades you have, the more efficient the prop will be (some control-line model planes use a 1-blade prop!) but there are many other variables that affect it.
In Mooney’s case, they did get performance gains by switching from a 3-blade to a 2-blade prop, but that was not just a matter of dropping off one blade - the new 2-blade prop is a completely new design, and propellor design seems to be as much art as science.
I actually think the SR20 has considerable scope for improvement in both the prop and in drag cleanup. It would be interesting to see what Roy LoPresti could do with it. The current performance seems to me to be mostly down to the high-aspect, laminar flow wing.
Sounds like Cirrus did a good job on drag cleanup which may explain the relative improvement with the 3 blade Vs the Mooney.
By the way: Did you get a 3 blade on your plane?
Brian