checking doubles and single blde rpm

[awm]

this by that great master mechanic aw.
checked max rpm with doubles
high lift gator comb. max at 3860.
blades engaged . same check w high lifts only 3860.. surprised me a bit.
by the way im talkin a 20 kohler command.
another surprise max rpm without bldes engaged 3750. ???
also checked 141/2 briggs max rpm 3650 turned all the way up. engaged bld
3250. turned it back to 3350 which is what i started with unengaged.
engaged 3250.
now this leaves me knowing one thing for sure . that i dont understand all i know about these things:)
guess the main result is that doubles
didnt slow the rpm. of course it would have more affect in cut ,as u have a lot more blade contact with the grass.
hope somebody finds this info worth while.

[FrankenScagMachines]

Interesting results....
It's all in the governor's on the engine. The Kohler over compensates for the load (thats why they're so much better than a Briggs, Tecumseh etc.) so that it is actually faster under load (more power) so it won't bog down as easy. The Briggs has a crappy guv'ner on it so it doesn't take as much, proportionally, to bog it down.
The governor in a Kohler is much quicker and picky-er than a Briggs.
Eric

[yardboyltd]

The double blade rpm sounds about right because two blade have twice as much intertia as one. Meaning it takes more power to get the blades up to speed, but not much more to keep them running.

[vipermanz]

Originally posted by yardboyltd
The double blade rpm sounds about right because two blade have twice as much intertia as one. Meaning it takes more power to get the blades up to speed, but not much more to keep them running.

exactly , if i wanted to, some physics and math might make it look more technically orientated:)

[scott's turf]

You will need more power to spin doubles do to the friction with the air. The higher lift bleades the higher the resistance. Most of the enigines that we currently have enough hp to over come this.