Swapping stock 2 Blade Prop for a 3 Blade One?

2 blade Hartzell Scimitar and a Skytech starter dropped 20+ pounds out of the nose of my Arrow. That and a couple of cheep speed mods (gap seals) gets my Arrow to 140 Knots on 180HP at cruise...Could not be happier with the prop and the noise level has diminished as well. I would consider it if there is that option.
 
txflyer said:
Have you checked if MT has one for your plane? I'm happy with mine.

It's a two blade, but it dropped 10lbs. off the very front c.g. station in our nose heavy skywagon.

The lighter composite MT spins up faster, and spins down faster acting like an air brake.
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This is exactly what you don't want happening. All that braking force is translated to stretch on your rod bolts, and extra vacuum slapping on your rings.
 
netsurfr said:
I'm seriously considering replacing my Dakota's 2 blade prop with Hartzel's 3 Blade Scimitar. My 2 bladed has 1000 hrs since it's last overhaul 13 years ago and it's been spilling grease on one blade so rather than OH I'm leaning w/ paying more and going with a 3 blade.

Would love to hear from those of you who have swapped out your 2 blade prop for a 3 blade in terms of how happy (or not) you are with the change.
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Why do you want a 3 blade Scimitar over a 2 blade Scimitar? I would suggest that if your prop is due that you do the upgrade, modern designs have performance benefits. Three blade gives up some benefits and adds others. If you are in a noise sensitive situation, the three blade will probably win the debate. If you are looking to maximize performance and efficiency, you will stay with a two blade.
 
Ted DuPuis said:
The considerations when making a prop change are:

1) Weight
2) Takeoff/climb
3) Cruise
4) Noise

Typically more blades will increase weight and hurt cruise speed, but improve takeoff/climb and reduce noise. This equation can vary some, as the Hartzell Schimitar blades are better than the old style ones that you'd likely be replacing, so you need to look at the specifics. I do know of one Dakota that went with a 3-bladed Hartzell following a prop strike, and it was definitely quieter, and the owner was happy with it.

For me, reduced weight and improved cruise speed are the two key metrics, but I'm picky so I'd want to get reduced weight, improved cruise speed, and reduced noise all together. :)
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And that is where the Scimitar design comes in. You gain blade length without increasing diameter, and diameter is where noise comes from while blade length is where performance and efficiency come from.
 
StinkBug said:
That's sometimes the case, but you have to look at the prop and the particular plane. For some planes the 3 blade is the same diameter as the 2 blade.
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:yesnod:

I've seen that discussion on the mooney site, and IIRC the blade lengths are often the same for us.
 
Thanks everyone. I think I'm going with the 3 bladed scimitar vs the 2 bladed scimitar or vs. OH. First this is the original prop so it's 36 years old and although it only has 3000 hours since new & 1000 since OH (only 1 OH since new btw) my expectations is that OH will uncover some issues that will drive up the cost of the OH and start reducing the spread between an OH and a new prop. So now that leaves me w/ 3 or 2 blade scimitar... I would certainly appreciate less noise and smoother ride so my understanding is 3 blade wins here. Also better climb is welcome as I fly out of dense city airports so the faster I get to 1000+ AGL the better. The 3 bladed kit is also 2" smaller diameter so it gives me a bit extra ground clearance so that's good. Of course the 3 blade design also looks better. Now the downside could be a loss of a bit of cruise speed compared to the stock 2 blade but considering I'm moving from a 35 year old prop last OH 13 years ago I don't think I'll see a loss here since the scimitar prop will be new & with better design. Now I could go for the 2 bladed scimitar but that STC is not held by Hartzell and I would loose some of the other pluses of the 3 (ground clearance, noise, optimal climb). The price of the 3 vs 2 is the same and I would keep my existing prop/hub/spinner and list it for sale in the event I can get some $ out of it. So that's where I'm at now. About ready to put in the order...
 
Sounds like you worked it out. All in all you will be happy with it. Remember to always park it with a blade down so the water can drain.
 
Yeah looking forward to it. Park w/ blade down really???

Henning said:
Sounds like you worked it out. All in all you will be happy with it. Remember to always park it with a blade down so the water can drain.
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netsurfr said:
Yeah looking forward to it. Park w/ blade down really???
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Yeah, that way rain doesn't puddle in your spinner, the lowest point will have open airflow. It's really telling in coastal planes because the rain and such carries salts in it and you can see the results of electrolysis and corrosion on the spinner and plate more distinctly on planes where they park them with the prop sideways. In winter it can also lead to an ice cube shake.
 
Ok now I see it! Placed the order today & prop should ship out next week.

Henning said:
Yeah, that way rain doesn't puddle in your spinner, the lowest point will have open airflow. It's really telling in coastal planes because the rain and such carries salts in it and you can see the results of electrolysis and corrosion on the spinner and plate more distinctly on planes where they park them with the prop sideways. In winter it can also lead to an ice cube shake.
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netsurfr said:
Ok now I see it! Placed the order today & prop should ship out next week.
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Cool, hey, do a few quick experiments for us with your phone if you have a smart phone. Get a dB app and get some base line noise readings with the current setup at various power/speed settings and then get some comparatives with the new prop to get some real world data.
 
Henning said:
Yeah, that way rain doesn't puddle in your spinner, the lowest point will have open airflow. It's really telling in coastal planes because the rain and such carries salts in it and you can see the results of electrolysis and corrosion on the spinner and plate more distinctly on planes where they park them with the prop sideways. In winter it can also lead to an ice cube shake.
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And when the birds land on your prop and take a ****, it ends up on the ground rather than the spinner.
 
I was thinking of setting up my camera to record cabin noise to compare before and after but this is even better. I'll check to see if an iPhone app can do this...

Henning said:
Cool, hey, do a few quick experiments for us with your phone if you have a smart phone. Get a dB app and get some base line noise readings with the current setup at various power/speed settings and then get some comparatives with the new prop to get some real world data.
Click to expand...
 
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