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  1. #16
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    they say ''intelligence is the immense curiosity and desire to learn from what surounds us.. Albert Einstein.
    Glastron GT 150 W OMC 140
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    I know two things that are infinite, the Universe and Human's Stupidity, although I am not sure about the first one.

  2. #17
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    Quote Originally Posted by Chris Carson's Marine View Post
    The flywheel rotating acts like a gyroscope,and fights changes in angle,just as a side grinder fights changes in angle when it's spinning.Try it,then realize the fighting force(of directional change) of the spinning object is in direct proportion to the weight of the object.So,when the boat tips from side to side the upper crank bearing has hundred of pounds of side stress applied to it holding the flywheel at the same angle as the boat,the flywheel weighing many times more than the 4 ounce grinding disk. Not as much of an issue on a tunnel boat...more stable,so less stresses,Chris

    Yep.!!!
    Glad you said that because nobody ever listens to me.

    Dago.

  3. #18
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    It isn't just the weight but the diameter that creates the gyro.
    second patches, no measurable performance gain. Add the the best drag boats in the country for the most part use heavy pistons and big rods. Retaining shape is a lot more important. As for dynos, I know 3 merc guys with dedicated dynos, the best being accurate to less than 1/2 of a percent.
    There are three good flywheels. Stock, diamond and PPE. The rest explode.... Or will

    their is my gallon of gas for the fire.
    2023 TUFF 25

  4. #19
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    I happen to have been around long enough to remember an old screen name. Firestarter was it?
    Erik Kiser

  5. #20
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    Didnt think about the gyro effect. Thanks Chris.
    13' Biel tunnel AKA "Flight Risk"
    13" Modified Yamaha V4 - 101 mph

    21' Paramount
    Mercury 300 Promax

  6. #21
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    So a heavy flywheel would actually improve the high-speed (high rpm) stability, especially on a light boat... interesting idea.

  7. #22
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    Cruise ships have a flywheel under deck to stabilize the ship in rough seas...

  8. #23
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    Quote Originally Posted by David - WI View Post
    So a heavy flywheel would actually improve the high-speed (high rpm) stability, especially on a light boat... interesting idea.
    at the expense of your crank and top bearing...

  9. #24
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    Quote Originally Posted by Chris Carson's Marine View Post
    Cruise ships have a flywheel under deck to stabilize the ship in rough seas...

    The actually make gyro systems for smaller vessels like sportfish boats. There is probably an online calculator thats you could use to see the difference in gyroscopic effects. Would be interesting to see what the differences in rather small applications like a flywheel.
    13' Biel tunnel AKA "Flight Risk"
    13" Modified Yamaha V4 - 101 mph

    21' Paramount
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  10. #25
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    Quote Originally Posted by RBT View Post
    As for dynos, I know 3 merc guys with dedicated dynos, the best being accurate to less than 1/2 of a percent.
    .
    Have to agree with that. If your 2-4% accuracy you need a new data acquisition system.

  11. #26
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    Ive have often heard circle racers saying a light flywheel will help them get out of the gas later before a turn. Less "Freight Training" into a corner.

    If you can stay in the gas just a bit longer and have your RPM fall off quicker it can be an advantage I guess.

    Just what Ive heard over the years reading what others have posted.

    C
    L6fan57-88

  12. #27
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    Quote Originally Posted by milkdud View Post
    Ive have often heard circle racers saying a light flywheel will help them get out of the gas later before a turn. Less "Freight Training" into a corner.

    If you can stay in the gas just a bit longer and have your RPM fall off quicker it can be an advantage I guess.

    Just what Ive heard over the years reading what others have posted.

    C

    "Slowin' down" was tha reason for it "showin' up" way back when!.........

  13. #28
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    And folks really don't think "speeding up" has anything to do with it? Really.A light flywheel might help decelerate for cornering,but it seems it should likewise accelerate more quickly as power is applied.I feel like i'm at a Flat Earth Society convention again.Matter has weight,matter requires energy to put it into motion...the heavier the object the more energy required.If the same amount of energy is spent moving two objects of different weights,the lighter of the two will accelerate faster and attain a higher speed than the heavier one.Equal forces of friction will also slow the lighter object faster.This is simple science,and not having noticed is no excuse to deny the existence of basic properties of physics.
    The earlier reference to the accuracy of dyno repeatability was simply to note that there are many more less controlled variables encountered on a boat with water conditions,propeller,driver input,etc than in a more controlled environment with a powerhead mounted on a dyno,so I'm not surprised a small change might go unnoticed.
    Anyway,I feel as though I've made the point as well as I care to...Chris
    Last edited by ChrisCarsonMarine; 09-27-2014 at 07:28 AM.

  14. #29
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    Well said Chris......

    PS. My white reeds are still holding up well 3 yrs later ! Thanks
    1990 22' Activator Yami HPDI 300-sold-86.4
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  15. #30
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    And folks really don't think "speeding up" has anything to do with it? Really.A light flywheel might help decelerate for cornering,but it seems it should likewise accelerate more quickly as power is applied.I feel like i'm at a Flat Earth Society convention again
    Chris,
    I am assuming your directing this at me since I am the only one that brought up the deceleration benefit.

    I was nearly stating something that nobody had said yet in this thred, I did not discredit acceleration did I ? dang...

    I believe the acceleration can benefit as well, never said it didn't. Any time you give a motor less "work" to do there is a result, even if its small.

    When accelerating a big flywheel on lets say 300 HP the benefit can be extremely small because the energy required to spool it up is very easily overcome by 300 ponies. Its a very small part of the frictional/load package going up in RPM on a drag launch.

    2oz is less in the flywheel is a mole hill on top of the mountain of other things going on with the boat when accelerating. Water friction, moving the mass of the boat overshadow it by so much that its probably hard to even notice. It may be like taking 2 lbs out of the boat when the boat weighs 1000 Thats like a 2/1000th of an advantage. Its an advantage, but hardly measurable considering water drag is never 100% constant from launch to launch. And you should not see more HP. Its not there to make more HP. Just spool up quicker, and decal down quicker.

    An good test of this flywheel theory is put the motor on a dyno that can give it a constant load. Then time the time it takes to spool up from 2000 RPM to 9000 RPM. Under NO load the lighter flywheel will show OBVIOUS benefit. But under a larger and larger constant load the benefit will not show up as much. The benefit is still there, but it overshadowed by much bigger things to deal with.

    Now that big flywheel under decel is has no "power assist" to bring it down in RPM for the most part. And when at WOT the the flywheel is storing LOTS of kinetic energy that the motor has no control over in a "power assist" deceleration. The motor does not retard advance to power assist the deceleration of the boat, nor does it have a jake brake. The motor has internal friction that brings it down, but its a lot less friction than lets say 300 HP going up.


    In recap. Under acceleration the benefit is overshadowed by much bigger work to be done. (accelerating the entire weight of the boat) (larger water friction on launch)

    Under deceleration much the frictional work has been done (water to hull) and the flywheel is "loaded" with energy and is much harder to bring down in RPM due to less friction in the system to help it down.

    You have to remember the flywheel is a part of a whole package of work being done. Its not an isolated event, its tied to the entire job being done when the boat accelerates. The rest of the job is so overshadowing its hard to pick up any noticeable gains.

    If your the guy that likes to snap his throttle in Neutral in his driveway then the lighter flywheel will defiantly make you feel all warm and fuzzy inside.



    Conrad
    Last edited by milkdud; 09-27-2014 at 11:07 AM.
    L6fan57-88

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