Optimax Lightened & Balanced FW gives Rapid Acceleration!!!!

[beyondhelp]

Except that physics dictates something else must be going on if he has found extra speed. As its nothing to do with the flywheel being lighter.

[Andy B]

Oh how I just chuckled....lol

Originally Posted by beyondhelp

Except that physics dictates something else must be going on if he has found extra speed. As its nothing to do with the flywheel being lighter.

Originally Posted by Banana Shark Dave

.
So here's the deal we go to the fuel station, which is on the way out of the harbour and fill to the top. We go out and test the set up as is, we both take a turn driving.

We return to the marina, where there is electric and the boat stays in the water and we swap the FW over for the stock FW.

I am so confident ( I've done hundreds of test runs with different props at different levels of modification) I am happy to run the stock test without refuelling, so the boat will be lighter. Or We can refuel, testers choice.

Again we return to the same test area ( I have an area I use that has bouys to run between and also can follow same track on gps), we both drive and the results are compared.

Ed you really need to accept that life isn't just about numbers on a chart.
If you had to calculate every veriable factor in life then you'd just end up going mad and missing all the fun

[Toffy]

I cannot believe this story of "using the hp more efficiently because of a lighter flywheel to obtain higher top speed" keeps coming back. It is just so impossible and so wrong.

Why is it so hard for people to understand that the power needed for keeping a light flywheel and a heavy flywheel at a constant rpm is exactly the same ?? This is just basic flywheel physics.

Enjoy, I'm out.
T.

[Banana Shark Dave]

Hi Gents

Would now be a good time to tell you about my lightened propellers???

Ok a stock Bravo 1 26 weighs around 6.8kg

After I have fully lightened it it weighs around 4.75-4.80 kg

The difference in weight again lightens the load on the engine.

There is a certain amount of work the engine has to do before it can do its job of pushing the boat along.

I believe by making the work load lighter the engine is able to rev a little higher.

I am not claiming lightening the FW or the lightened prop increases HP, but it is a more efficient use of the available HP.

So with the lightest FW 4516grams (approx 1/2 stock weight) and a lightened prop 4810 grams (1989grams lighter) I have lightened the load by approx 6kg

Through extensive testing during the last few months it has become apparent that a lightened prop also revs higher as long as it was over pitched to start with.

I have several props that I have only lightened the hub and the blades have been untouched, in like for like tests the average gain is around 100/120 rpm with faster acceleration as well. Infact it's pretty much on a par for the effects of working the blades.

I have also lightened the compressor wheel however there isn't much of a weight saving and as such I shan't be conducting extensive testing into the results, but I will try on 1 possibly 2 props. In the coming weeks, weather permitting. If anyone would like to join me, just ask.

[beyondhelp]

Originally Posted by Andy B

Ed you really need to accept that life isn't just about numbers on a chart.
If you had to calculate every variable factor in life then you'd just end up going mad and missing all the fun

In my line of work, understanding cause/effect/forces/(thermo)dynamics/energy/power is what I get paid for. I don't get paid to make guesses, or to assume things I don't fully understand.

People who don't understand this always seem to have a problem with it, especially when I try to explain why they don't quite have it right. Now matter how much I carefully try to explain.

[OCRDA]

[QUOTE=Banana Shark Dave;251387]Hi Gents

Would now be a good time to tell you about my lightened propellers???

Probably not !

If anyone has a spare V6 Yamaha Flywheel and you can lighten it for next weekend I will try a controlled test at Records Week !
I am struggling to find one.

[2jz]

Originally Posted by Toffy

I cannot believe this story of "using the hp more efficiently because of a lighter flywheel to obtain higher top speed" keeps coming back. It is just so impossible and so wrong.

Why is it so hard for people to understand that the power needed for keeping a light flywheel and a heavy flywheel at a constant rpm is exactly the same ?? This is just basic flywheel physics.

Enjoy, I'm out.
T.

its more harder for you and some other members to understand because you guys are fixed on rpm been the same. I really really hope this helps clears up things.
A mercury 200hp spinning 26 prop @5000 70mph with heavy flywheel
A mercury 200hp spinning 26 prop @5500 77mph with lightweight flywheel.
A mercury 200hp spinning 28 prop @5000 76mph with lightweight flywheel. FEEL free to use any prop calculator this basic
This very basic to understand if you reduce rotating mass

[Banana Shark Dave]

I will need it by Friday idealy but Saturday would be ok, in order to get it done in time. Because my mates business is so busy at the moment I can currently only use the machines on Friday late afternoons, Saturday mornings or if a complete emergency on Sunday's.

I am in the process of buying my own Computer controlled Mill at the moment so this will change in the next few weeks.

Your not going to notice a massive difference with the yam FW's though as I can't remove a huge amount of metal from them.

The Optimax FW's I can get upto 4100grams out of them, so the gains are huge.

You will see a difference though.

What about if I lend you some lightened props, what pitch do you use???

[kitten]

Originally Posted by Toffy

Why is it so hard for people to understand that the power needed for keeping a light flywheel and a heavy flywheel at a constant rpm is exactly the same ?? This is just basic flywheel physics.

Enjoy, I'm out.
T.

If this statement is true, you must be well on your way to developing perpetual motion and powering the planet for free!

[still no worries]

OK why are the stock FW's not lighter to start with ????????
(this should keep the thread going for a while)

[RossM]

Back to the basics:

It's impossible to create energy as it is impossible to destroy it, all you can do is change its state.

Explain how a flywheel converts any energy and if so what does it convert it to?

Something light will take less time to react to a change in force, something heavy takes longer, you will accelerate quicker, but your top speed will be exactly the same, minus the flywheels one way of loosing energy: drag of it spinning through the air, which lets face it, is **** all.

If you're being picky, the crank which its bolted to has bearings, and the more weight that there subjected to the more friction you have and the bigger the loss of energy though heat is, again absolutely **** all.


The process of lightening a flywheel doesn't 'free up' any hp, it doesn't allow any more power at the propshaft, because other than the loss of air friction, the flywheel doesn't consume ANY power AT ALL.


So how on this planet to you expect to gain any power from lightening a part which doesn't consume or convert any energy to heat, or sound, vibration or any other form, other than a negligible amount of friction????

[RossM]

Originally Posted by still no worries

OK why are the stock FW's not lighter to start with ????????
(this should keep the thread going for a while)

and why aren't ports higher, and matched, ignition timing bumped up, throttle body's enlarged, hell-why don't all engines come out of the factory F1 spec!?

[racefan]

Originally Posted by 2jz

its more harder for you and some other members to understand because you guys are fixed on rpm been the same. I really really hope this helps clears up things.
A mercury 200hp spinning 26 prop @5000 70mph with heavy flywheel
A mercury 200hp spinning 26 prop @5500 77mph with lightweight flywheel.
A mercury 200hp spinning 28 prop @5000 76mph with lightweight flywheel. FEEL free to use any prop calculator this basic
This very basic to understand if you reduce rotating mass

You've lost me there, are you saying this is what you've found with your boat/engine combination, or are you just picking figures out of the air and trying to baffle us with bullshit?

If these are true speeds, then I'd be interested to know engine and boat make.

[still no worries]

Originally Posted by RossM

and why aren't ports higher, and matched, ignition timing bumped up, throttle body's enlarged, hell-why don't all engines come out of the factory F1 spec!?

so true why bother building stock motors at all just high spec race engines, we would all love that.

[Banana Shark Dave]

An engine has to be made with a wide variety of uses, the manufacturer has no idea what you will bolt it to, or use it for.

Ross I have coming on for 30 props now and at least 20 totally stock, also I have several stock Optimax FW's and several in various stages of lightening.

I have done hundreds of test runs and I can catorgotally state that lightened FW's and props (as long as the prop is over pitched from the start) gain revs and go faster.

There are ever also people on this thread who have them fitted and will tell you the same thing, I will happily take you out to demo, so you can see for yourself.

I don't need to make up increased speed figures to sell these FW's, I simply cannot buy enough of them to met the demand!!!

You wil also notice not one person who has bought one of mine has complained!!!

On the Optimax Lightened Fly Wheels I offer a 28 day money back if your not happy!!!

[2jz]

[If you Don't understand how prop calculator works your on the wrong forum. Every boat manufactur and high performance boat owner uses to determine setup for speed. So you're new to high performance boating I will explain you. Lightened flywheel increased wot rpm and was able to turn larger prop both factors use in prop calculator. Fyi prop calculator doesn't care about boat or engine combination. It's basic can your boat spin prop n what rpm. If lightened flywheel helps Dave, me or anyone else to achieve anyone of those simple basic factors rpm or larger pitch you will gain speed

UOTE=racefan;251400]You've lost me there, are you saying this is what you've found with your boat/engine combination, or are you just picking figures out of the air and trying to baffle us with bullshit?

If these are true speeds, then I'd be interested to know engine and boat make.[/QUOTE]

[Paul E]

Prop slip calcs have NOTHING to do with lightening flywheels.

Can we please separate lightened props and lightened flywheels!

The way modern engines make their horsepower (torque instead of rpm) make the way you prop boats change. I can ping small props off the limiter easily and go nowhere, I can also add pitch and keep adding pitch and still attain similar rpm simply by propping to where the engine produces the most power and torque. As the pitch increases the speed increases to a point. Adding a lighter flywheel to my 'over pitched' prop of choice will improve acceleration, not top speed. Lightening the propeller and making it more efficient will make it easier to spin (in water), in theory adding more speed and rpm.

I can also see 3-4mph difference in peak speeds on any given day simply by changing direction, or by bumping the trim slightly, making any actual increases or decreases pretty subjective.

[motorvator]

I think Paul there seems to be a general misunderstanding here between power, torque and energy.

A flywheel becomes a store of energy from it's increase in inertial momentum. It takes energy to spin it up but once it is there the energy utilised hasn't disappeared (ignoring frictional losses). Energy in this instance is provided by the application of torque over a time period.

Newton tells us that a flywheel can supply an infinite amount of power, just that it is for zero seconds.

That power has nothing to do with the continuing duty power output of the motor itself. That power output is created from a different energy store, the fuel.

Going back to that physics it is possible to spin a heavier flywheel to exactly the same speed as a lighter one with a miniscule amount of applied torque, it is just that it takes a long time. Hence the beneficial acceleration from a lighter flywheel.

Once there it requires no additional application of torque for it to maintain it's inertial momentum.

So in round terms Dave, if you are seeing higher speeds over a set course perhaps you need to increase your run in?

[Paul E]

Originally Posted by motorvator

I think Paul there seems to be a general misunderstanding here between power, torque and energy.

I think there's many misunderstandings mate!

I still don't know where 2jz has plucked his figures from... 70mph at 5000rpm with a 26p prop is 0% slip even with being generous and assuming a 1.75:1 gearbox! The 500 rpm gain on his imaginary figures to reach 77mph must be from fantasy land too, as they sure as hell didn't come from a lighter flywheel!

[racefan]

Originally Posted by Paul E

I think there's many misunderstandings mate!

I still don't know where 2jz has plucked his figures from... 70mph at 5000rpm with a 26p prop is 0% slip even with being generous and assuming a 1.75:1 gearbox! The 500 rpm gain on his imaginary figures to reach 77mph must be from fantasy land too, as they sure as hell didn't come from a lighter flywheel!

exactly. I couldn't be bothered to reply, as having looked at some of his previous posts, I saw that he's an American, so probably thinks the world is flat!

A search on here for "flywheels" showed some other interesting facts.

suffice to say a lot seems to have happened in a year