[Shop-talk] Mower blade orientaaion relative to piston

[Karl Vacek]

They reason I thought of it is that aircraft propellers are supposed to be 
phased in a certain way.

My Stearman has a 7 cylinder radial engine and when it has the Macaulay 
hollow steel prop on it the prop goes in line with the master rod of the 
engine (vertical) when cylinder 1 (top) is at TDC, but a wood prop is 
installed 90 degrees from that, or horizontally when 1 is at TDC.

The wood prop and it's steel hub are maybe 30 pounds lighter than Macauley. 
 It's not lore, it's in the Type Certificate.  And people have put props on 
wrong and it's smoother once they remount then properly.

On May 18, 2021 4:56:44 PM Jim Franklin <jamesf at groupwbench.org> wrote:
> I can't think of a reason it would matter. Also, I think if it did, they'd 
> have keyed it.
>
> jim
>
>
>> On May 18, 2021, at 5:52 PM, Karl Vacek <stearman809 at gmail.com> wrote:
>>
>> Last time I sharpened my 21” walk-behind mower blade I thought of something 
>> that’s never occurred to me, after using the same brand of mower for 25 years..
>>
>> On a Snapper, the blade can actually go on any way onto the square adapter 
>> keyed to the crankshaft.  The mounting point is square, no pins, no longer 
>> side, nothing.
>>
>> One way would be aligned with the cylinder at TDC/BDC, and the other way 
>> would be across.  It’s been off many times and there’s no way to tell how 
>> it was mounted originally.  The manual is silent on this.
>>
>> Power stroke shouldn’t matter, but maybe some dynamic issue one way or the 
>> other?
>>
>> Thanks!
>> Karl
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