Direct Drive Honda/B&S limits

Discussion in 'Firewall Forward / Props / Fuel system' started by LHH, Jan 13, 2020 at 2:30 AM.

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  1. Jan 14, 2020 at 2:12 PM #21

    LHH

    LHH

    LHH

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    Thanks all.
    Will start with Billski's advice and model in Solidworks and then model against propellers to see what happens.
    Honda price is almost identical to Kohler and B&S for same HP. All are around $2k.
     
  2. Jan 16, 2020 at 11:54 AM #22

    Armilite

    Armilite

    Armilite

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    ==============================================

    The fellow using the Honda GX200 Clone in Direct Drive on a Lazer was turning them at 4400rpm. Small 7/8" PTO Shaft (The Rotax 185UL when upgraded to 7/8" PTO used 5000rpm), the Honda/Clone GX390+ Singles uses a bigger 1.0" PTO Shaft. A Preditor 670 V Twin uses a 1.0" PTO. The Biggest I have seen used on V Twin is 1-1/8". The Stock Flywheels are good to 5500rpm Max, and 5000rpm is Max I would turn them for Plane use. Most of these Industrial Engines need to Save Weight, so People use the Billet Aluminum Flywheels which are good to 10,000+rpm which Saves a lot of weight over the Stock Cast Iron Flywheel. Use the Billet Aluminum Rod which is stronger than the Stock Rod. They usually take out the Balance Shaft to save 4-6 lbs of Weight and just have the Crank Balanced. The only thing you need to worry about is using the right Size Prop and Pitching it for the Engine's Max Hp. Like if you're turning it 5000rpm, you Pitch it -100rpm for 4900rpm. I personally would not use Direct Drive on these, I would use a Good Belt Drive like from ACE. I haven't seen anyone Adapt a Gear Drive to one of these Honda/Clones yet. Kawasaki FH680D-FS08S 675cc replacement engine with a horizontal PTO shaft measuring 1-1/8 in. x 3-15/16 in.

    5000rpm in Direct-Drive is going to regulate you to a Max 48" x 10 (2) Blade Prop making 355.83 lbs Static Thrust. Needs 45.080 hp.
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    5000rpm with 1.8 ACE Belt-Drive is going to give you 2,777.7rpm, Pitched for 2,677.7rpm, an Option to run a 72" x 10 (2) Blade Prop making 516.64 lbs Static Thrust. Needs 35.053 hp.

    5000rpm with 1.8 ACE Belt-Drive is going to give you 2,777.7rpm, Pitched for 2,677.7rpm, an Option to run a 68" x 12 (2) Blade Prop making 411.05 lbs Static Thrust. Needs 33.467 hp.

    So as you can see, using a Belt Drive allows you to make more Thrust running a Bigger Prop. You can play with the Numbers for whatever Engine you are thinking of using.

    An ACE Belt Drive for V Twins I consider Best for these Honda Clones shipped to the USA is $649 & $699.
    Freight to Mainland USA - - US $109
    So $758 & $808.

    For Singles: US $569
    Freight to Mainland USA - - -US $99
    $688



    Static Thrust Calc.
    http://godolloairport.hu/calc/strc_eng/index.htm
     
  3. Jan 16, 2020 at 12:07 PM #23

    Armilite

    Armilite

    Armilite

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    A Honda/Clone 460 Single Dynoed making 37.37hp@5000rpm. At 3600rpm was making 30.68hp. Used a 34mm Carb, 11.0cr, 307 CAM, 40mm/32mm Valves, K&N Type Air Filter, Tuned Header Exhaust.
    Clone 460 HP Graph.jpg
     

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