Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Just wondering what the advantage was to having a 4 blade impeller vs a 3 blade... All the new Ariens model have 3 blade from the smallest to the largest (1336)...Some of last years models have the 4 and even 6 blade. How does this impact the performance of the machine??? DO they spin it faster with the 3 blades, or is the impeller redesigned so that the 3 blade works just as well as the 4 blade??

Good one Fred,

Well in my opinion, they tested 4 blades vs 3 blades and they probaly seen no difference but if you build 1000 unit a year and save 1000 piece of steel 2x4 inches, welding supply, time to assembling, companys saves a lot of money too. That's one story....

I  know they have gone back and forth over the years with number of impeller blades.

IIRC, there was really no differnce, since as long as the impeller is being fed the maximum amount of snow it can handle, it will move it at the same rate.

If the only variable is the number of blades then the 3 blade design should move a slight amount more snow since the volume taken up by the fourth blade is now filled with snow. The other argument is that each lump of snow in the impeller is smaller with a 4 blade design and therefore might go further or require a slightly smaller blade. Either way the engineering department will have tested this out three ways from Sunday and know exactly what the characteristics of each design is.

I have a hunch the performance difference is somewhere between none and negligible and that it comes down to manufacturing costs versus sales claims (  I.E. " now with the new 3/4 blade impeller for added performance" ).

Has anyone ever measured the thickness of the plate that the blades are welded to?  As Denis pointed out, there are production/material cost saving by using the three blade system vs. the four .  Unless, the four blade system provides better load distribution and stiffness to the mounting plate thus minimizing possible flexing and deflection.  The three blade system might require a thicker back plate.  Even if thicker plate was required, I cannot see that being more expensive than additional material for the fourth blade, plus cutting and welding.  Yeah, I'm with you guys....Can't see the reasons for the difference either.   

It will obviously depend on geometry and flow characteristics, but all things being equal there is little difference.  If anything, 3 blades may be slightly better. Some folks have opinions on slush versus fluffy snow and the effect of more blades, but most of this is baseless. Unless you have 2 identical units to compare, with different impellers, it is speculation.

Most of the 4 and even 6 blade impeller stuff is driven by customer perception. More blades = better to some customers. Exaggerate that slightly, say 25 blades, and you can see that is kind of silly. There is obviously a threshold where more blades does not help. 3 is it (for typical 10" to 14" snow impellers).

PK