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1/4 Scale Pavati R/C Power Boats!!!

Discussion in 'Power Boats' started by Golden Child, Feb 3, 2014.

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  1. Golden Child

    Golden Child Moderator Staff Member

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    The jet drive unit will be for the sprint boat hull to come later. As for beveled gears, the reason isn't to reduce the inherent whine, but to accommodate the different degrees on the input and output shafts of the v-drive itself. So, not beveled like a car gear-drive, but slightly beveled on edge. see Below...

    V-Drive Gearbox.JPG
    This is a HALLCRAFT-MENKENS V-Drive unit typical for drag racers. You can see the handle on the back side that is a F-N setup to disengage the drive while idling. To engage the drive you actually need to shut the engine off, put the v-drive box in gear, and fire up the motor (in gear!), to begin your run.

    V-Drive Gears.jpg
    These are the gears inside that drive unit. This pic shows the back side of the gearset. Notice the lower gear shaft is angled down. This is done by beveling the gears on edge (conical). This can be accomplished also with straight gears, and U-joints attached to the input and output shafts, but that robs power and adds more spinning parts. More parts=more potential for failure. Milling-out a case to hold this setup is quick and easy. However, making beveled gears isn't. And since I need to do this after-hours when the machines are is less use, time is of the essence. So if I can't find the gears I need, I'll have to go with straight and the u-joint setup.
    Golden Child, Feb 17, 2014
    #41
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  2. l8rg8r

    l8rg8r Registered

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    l8rg8r, Feb 17, 2014
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  3. GPS

    GPS Registered

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    That mini flat Ferrari-style 12 cylinder sure sounds sweet! Thanks for posting.
    GPS, Feb 18, 2014
    #43
  4. l8rg8r

    l8rg8r Registered

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    I agree if I hit the loto I'm gonna find me one and build a 1/4 scale cracker box with that in it might pirate one of golden child's ideas and go with a v drive
    l8rg8r, Feb 18, 2014
    #44
  5. GPS

    GPS Registered

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    It seems to me that it sounds quite like a actual Ferrari engine.
    GPS, Feb 18, 2014
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  6. l8rg8r

    l8rg8r Registered

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    I agree put that in a cracker box with a set of Bassett headers that would be sweet
    l8rg8r, Feb 18, 2014
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  7. GPS

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    Now if the guy who made that engine would just make a mini Ferrari car chassis... :)
    GPS, Feb 18, 2014
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  8. Golden Child

    Golden Child Moderator Staff Member

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    OOOOHHH! Bassett Headers! Yeah. Gotta TIG up a set of those, wet of course, when I design the sprint hull :D
    Golden Child, Feb 18, 2014
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  9. l8rg8r

    l8rg8r Registered

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    A 1/4 scale sprint with 1/4 scale super charged v8 and Bassett headers that would be grate if I don't hit the loto might have to hit a liquor store lol that would be awesome though now I got to go find my ski mask

    l8rg8r, Feb 18, 2014
    #49
  10. Golden Child

    Golden Child Moderator Staff Member

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    LMAO!!!
    Golden Child, Feb 19, 2014
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  11. l8rg8r

    l8rg8r Registered

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    here is another engine option for ya
    l8rg8r, Feb 21, 2014
    #51
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  12. GPS

    GPS Registered

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    That's a nice motor, good find. You know what I noticed? All the engines are longitudinally mounted instead of transverse mounted. I'm sure that this is to make the already complicated drive system simpler, but a transversely mounted motor would improve the torque steer which you can see when the guys revs the motor on the stand.
    Are there any boats with transverse mounted motors?
    GPS, Feb 21, 2014
    #52
  13. GPS

    GPS Registered

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    GPS, Feb 21, 2014
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  14. l8rg8r

    l8rg8r Registered

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    l8rg8r, Feb 21, 2014
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  15. GPS

    GPS Registered

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    Ah, good idea. Counter rotating motors should help with the torque. You will have to make sure they are in sync though won't you?
    GPS, Feb 21, 2014
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  16. l8rg8r

    l8rg8r Registered

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    Oh yeah synced and tuned and I would prefer to run them into twin props if your gonna run duel engine might as well address the prop walk issue while your at it
    l8rg8r, Feb 21, 2014
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  17. GPS

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    What is prop walk?
    GPS, Feb 23, 2014
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  18. l8rg8r

    l8rg8r Registered

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    Under hard acceleration the stern of the boat runs out to the side because the prop is walking sideways it becomes more of a issue as the hp and prop size go up
    l8rg8r, Feb 23, 2014
    #58
  19. GPS

    GPS Registered

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    Ah. So dual counter-rotating props would help, or completely eliminate that.
    GPS, Feb 23, 2014
    #59
  20. l8rg8r

    l8rg8r Registered

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    If it doesn't eliminate it it damn near does
    l8rg8r, Feb 23, 2014
    #60
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