Blade Tip Speed Question

Discussion in 'Hustler Turf Equip (Archived)' started by lawnspecialties, May 20, 2006.

  1. lawnspecialties

    lawnspecialties LawnSite Silver Member
    Posts: 2,513

    Hey Pj, just wondering.

    Why hasn't blade tip speed really increased in the past several years? It seems horsepower keeps going up as well as ground speed. One would think blade tip speed would also increase proportionately as well.

    It appears the industry standard is around the mid-18,000's. That is obviously "smokin" but as our ground speeds increase, blade tip speed needs to increase to keep up. Is it the spindle capacity or PTO abilities? I don't have a clue.

    Hustler has obviously set the bar for ztr ground speed. This appears to be the next step. :)
     
  2. mowerconsultant

    mowerconsultant LawnSite Fanatic
    Male, from Syracuse, NY
    Posts: 9,761

    Its not a component reason.
    It is ANSI and CPSC regulated.
    These are the 2 regulating bodies for safety standards in our industry.
     
  3. lawnspecialties

    lawnspecialties LawnSite Silver Member
    Posts: 2,513

    Duh! I should have known. More government involvement to tell me how to be safe. Although, it takes about 30 seconds on this internet to find a story on some bonehead hurting himself over something stupid. :)

    Thanks for the response.
     
  4. gps_jetskier

    gps_jetskier LawnSite Senior Member
    Posts: 303

    Keep up?!??

    18,000rpms is roughly 300 times a second.
    Even cutting grass at 30mph would still let you cut each foot nearly 7 times over. I don't think tip speed is a problem.

    gpshemi
     
  5. mowerconsultant

    mowerconsultant LawnSite Fanatic
    Male, from Syracuse, NY
    Posts: 9,761

    It is not RPM's
    It is measured my FPM, feet per minute.
     
  6. gps_jetskier

    gps_jetskier LawnSite Senior Member
    Posts: 303

    Ah...good catch. DUH.
    Well let's figure it out then since I stuck my foot into it.

    18,400ft/min for the 54" & 60"
    18,900ft/min for the 66" & 72"

    gives :dizzy:

    3800 rpm for the 54"
    3430 rpm for the 60"
    3210 rpm for the 66"
    2948 rpm for the 72"

    since I'm cranking numbers....;)

    The Super Z moving full tilt @ 15 mph:
    54" 2.88 revs per foot
    60" 2.59 revs per foot
    66" 2.43 revs per foot
    72" 2.23 revs per foot

    The Z moving full tilt @ 9mph:
    54" 4.80 revs per foot
    60" 4.33 revs per foot
    66" 4.05 revs per foot
    72" 3.72 revs per foot

    That sounds better....still fast.
     
  7. lawnspecialties

    lawnspecialties LawnSite Silver Member
    Posts: 2,513

    You obviously don't try to cut at 15 mph.:weightlifter:
     
  8. gps_jetskier

    gps_jetskier LawnSite Senior Member
    Posts: 303

    Why not? :laugh: j/k I know.

    No the Super's recommended cutting speed is only 1 mph faster then the Standard Z. Makes me wonder how you are suppose to justify the price difference for 1mph. I mean how much "transport" time do you do really where you need that extra 6mph. Obviously you really can't for just the 1mph. There's more to it....

    It's just interesting numbers is all.

    gps_jetskier
     
  9. Accu-cut Lawn Care

    Accu-cut Lawn Care LawnSite Bronze Member
    Posts: 1,206

    If you want to see what really high tip speeds will do, put a set of 52" blade pulleys on a 66. You'll see why code calls for a 18,900 ceiling. Grass gets laid down and reverberations almost make riding the machine impossible.
     
  10. gps_jetskier

    gps_jetskier LawnSite Senior Member
    Posts: 303

    That's an interesting thought. Wonder what 52" pulleys would do on a 60".
    Was that with stock blades?
     

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