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PROP CHOICE...2 BLADE vs 3 BLADE?

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Old 05-18-2010, 09:53 AM
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RPool
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Default PROP CHOICE...2 BLADE vs 3 BLADE?

I've got a 73" Sbach on the way; it's a 30cc plane. Engine choice has not been made. Was looking at Syssa and DLE 30 sized engines. I like the looks of a 3 bladed prop and have seen them used in aerobatic applications. I know it takes more power to spin a 3 blade prop. I see that YDA has a 38cc and 42cc engine coming out that are only 2 or 3 ounces heavier than the other engines. Is there a benefit with going to the larger engine, and does a 3 blade prop make a better choice for aerobatics in this case. What are advantages and disadvantages? Thanks for your input!
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Old 05-18-2010, 10:04 AM
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Default RE: PROP CHOICE...2 BLADE vs 3 BLADE?

Blade choice is a personal thing. All I can do is give you my thoughts and experiences

For me and for flying IMAC, a three blade works well. You do lose vertical on a 3-blade in most cases but on my planes, I gain smoothness in throttle response and slower down lines. All my planes are seriously over-powered so I can get away with a three blade.

If you are concerned with sound, a 2-blade blade can be quieter but also what the prop is made from also makes a difference. I've seen two blade props quieter than three blades made form the same materials. I run a 2-blade 30x13 on my DA170 when it's a really windy day but run a 29x12 3-blade at all other times. I can just about rip the three blade, especially if it's cool outside and that is why in wind I use the two blade, but I cannot get the 30x13 even close to ripping. I run canisters and I am actually a bit short on the header length so my engine is not breathing like it should.

It's a matter of load on the engine. Now if you are running stock mufflers, then noise is not going to get much better no matter what prop you use unless you are really really good at throttle management
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Old 05-18-2010, 11:32 AM
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Default RE: PROP CHOICE...2 BLADE vs 3 BLADE?

Bill what are you referring to when you say that your ripping? I'm not familiar with that term. Thanks
Terry
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Old 05-18-2010, 11:45 AM
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Default RE: PROP CHOICE...2 BLADE vs 3 BLADE?

Prop tips making lots of noise. You could almost say the tips are going supersonic. It mainly comes from the prop losing bite. To small a prop, certain wooden props and a number of other factors cause it. Once you hear it, you know'll exactly what it is
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