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Could this solve blowout once and for all!

Discussion in 'Lawn Mowing' started by CharlieBingo, Oct 13, 2004.

  1. CharlieBingo

    CharlieBingo LawnSite Senior Member
    Posts: 400

    O.K., This may seem too simple but the concept makes sense. Blowout of clippings,dust, leaves etc occurs because the turbulence (wind) caused by the blades has no were to go, except out of the front of the deck. So why not cut the distcharge chute bigger to relieve the turbulenc under the deck? I think this may help; any opinions?
  2. riches139

    riches139 LawnSite Senior Member
    Posts: 369

    It would probably only help on the right side of the deck. The left and center would remain the same.
  3. Richard Martin

    Richard Martin LawnSite Fanatic
    Posts: 14,700

    The discharge on a Dixie Chopper is over 19" wide and blowout is still a problem.
  4. Runner

    Runner LawnSite Fanatic
    Posts: 13,496

    That would throw your vacuum and all the dynamics of flow off in youyr deck. These decks are carefully designed, not just thrown together with a rough hole cut in the side.
  5. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Posts: 11,062

    The dynamics of blowout are simply mis-understood.
    And that's all I have to say about that....
  6. tiedeman

    tiedeman LawnSite Fanatic
    from earth
    Posts: 8,745

    just get yourself a blowout baffle
  7. Sam-Ohio

    Sam-Ohio LawnSite Senior Member
    from Ohio
    Posts: 304

    Gravely has a 24 inch wide discharge on their 60 inch deck !
    and this still doesn't stop the blow out.

    There is an area of ROLLING super air turbulance under all multi blade mower decks. This occurs right in the notch where the blade tips pass each other. On a right side discharge mower, all 3 blades are going in a clockwise circle as seen from above. As the left hand blade turns and blows its air to the center blade , the blade tips are actually moving in opposite directions at this overlaping point. This happens again as the center blade swings around and its tip passes by the right side blade tip. So, all the air isn't blowing straight across the deck front and out the chute. Some of the air is getting whirled sideways, almost like a tornado that is laying on its side would look like. It's this Rolling air turbulance that you see escaping under the front skirt of the mower - what we all call front blowout.

    A front baffle plate with a turned under "ledge" about an inch wide is what several companies have tried to control this blow out air. The problem is that this ledge shaped baffle can push over tall grass and keep the blades from cutting it all cleanly.

    The most effective design for an anti blow out baffle I have seen is on the newest Scag decks. Their "ledge baffle" is only about 8 or 10 inches long and its only in the 2 overlaping points of the blade circles. These two narrow baffles don't seem to cover the blades leading edge and so don't impede the cutting of taller grass at all, but they do combat the blow out that occurs at the blade overlap point.

    The only mowers that don't have any problem with this rolling air blow out are units like the Walkers, or Bobcats that have 2 blades that turn in opposite directions and blow all the grass or leaves to a rear pick up tube. Since the blades tips are both going in the same direction right at the point that they overlap there isn't all this turbulance under their mower decks.
  8. Gilla Gorilla

    Gilla Gorilla LawnSite Senior Member
    Posts: 923

    Sam that was a great post. I deffinately learned a couple things about blowout.

    Thanks alot
  9. CharlieBingo

    CharlieBingo LawnSite Senior Member
    Posts: 400

    If anyone has made a leaf box with a leaf-vac blowing air (turbulence) in the box; then you grasp the concept that this turbulence needs an outlet it's this I am basing my notion. I am very aware these decks are not thrown together with a rough hole cut out. I'd be suprised if more than a handful of people on this site have spent more time than me working (fabricating) decks, airflows, baffles etc.

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