Talking about blade numbers in general. Would two a bladed deck work better than a three bladed deck? Let's say a 36" to 42" deck range and this would be a do all mower, weekly mows, by weekly with the occasional over grown clean up.
Two blades vs three blades?
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playersc
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Talking about blade numbers in general. Would two a bladed deck work better than a three bladed deck? Let's say a 36" to 42" deck range and this would be a do all mower, weekly mows, by weekly with the occasional over grown clean up.
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Longer blades will have faster speed at the tips if they are spinning at the same RPMs as a shorter blade. I don't know if this is the reason why but in my experience our machines with 24" blades are the best mulchers.
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That is true about BTS all else being equal, but in the last decade or so, all mowers of commercial quality have their deck and pto pulleys designed to spin the blade tips at the same 18-18.5K FPM, so that would be awash there now. IME, 3 blades hitting the clippings on their way out makes for smaller clippings and also a cleaner finish left behind. How well a deck cuts has more to do with the deck's design than the number of blades IME.
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I looked into this a lot when I was shopping around for a new ztr. I was looking at 36/42. Almost everyone who makes 36/42 decks are 2 blade. The only one I found that was different was gravely that had a 3 blade 42. After 42, 48-72 it's 3 blades. but I agree with ridin green on the deck making more of a difference then how many blades and how fast they are spinning.
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Is anyone familiar enough with the maths on this topic to tell me if the difference in RPMs to maintain the same blade tip speed is proportional to the difference in blade length?
Like does a 24" blade need to spin 33% slower than a 16" blade to match blade tip speed?
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That's a good question and beyond my pay grade payup:laugh:
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Figure the circumference c=pi • diameter
So 24•3.14=75.4
And 16•3.14=50.26
The 24 inch blade tip travels 75.4 inches per revolution while the 16 inch only goes 50.26. The 16 inch blade has to spin 1.5 revolutions to match the 24 inch.
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Longer Blades definitely Mulch better w/a cutoff point of about 24".
18" units Mulch better than 16". More space for grass to process
18" units Mulch better than 16". More space for grass to process
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