outboard engines

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outboard engines Metals get their place. And so do plastics. But sometimes they work most effectively when used together. That's the case with the innovative propeller hub isolator designed by Mercury Marine engineers for a few of the company's minn kota engines. "The hybrid component does things neither the plastic nor metal could do alone," says Kevin Anderson, manager of materials science for Mercury Marine R&D. Known as the Flo-Torq IV, the isolator includes two annular acetal (DuPont Delrin) parts overmolded onto eight titanium rods. Engine Maintenance ? Do not allow oil as well as debris build-up i n t h e b i l g e s . ? I n s p e c t the actual lagging regarding engine

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Metals get their place. And so do plastics. But sometimes they work most effectively when used toget...

Transcript of outboard engines

Page 1: outboard engines

outboard engines

Metals get their place. And so do plastics. But sometimes they work most effectively when usedtogether. That's the case with the innovative propeller hub isolator designed by Mercury Marineengineers for a few of the company's minn kota engines. "The hybrid component does things neitherthe plastic nor metal could do alone," says Kevin Anderson, manager of materials science forMercury Marine R&D.

Known as the Flo-Torq IV, the isolator includes two annular acetal (DuPont Delrin) parts overmoldedonto eight titanium rods. Engine Maintenance

? Do not allow oil as well as debris build-up

inthebilges.

?Inspectthe actual lagging regarding engine

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andheaterexhaustsregarding

damage and minn kota talon also deterioration and

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nearby products pertaining to heat damage

or charring.

? check exhaust methods involving

inboard engines for leaks.

? Verify for loose gas joints,

damaged fuel tanks or even

deteriorating hoses.Attached to a sleeve that mates together with the propeller shaft, the hubisolator behaves as a torsional spring to soak up the real difference in rotational energy in betweenthe propeller and drive gears when shifting away from neutral. As Anderson explains, the titaniumrods deform by as much as 15 levels of arc as being the acetal part nearest the drive gears turnsfaster in comparison to the acetal part nearby the propeller.

That deformation of your titanium absorbs no little bit of http://www.srh.noaa.gov/key/?n=marinerotational energy. Anderson points out the drive gears are spinning at 264 rpm during engine idle,even though the undriven propeller spins slowly within the water. "When shifted into. On typical ,twenty fire-related accidents

and injuries occur upon boats every yeargear, the propeller engages using the spinning gears,making a loud 'clunk' and noticeable vibration throughout the boat," Anderson says.

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Past hub designs were rendered in either steelor perhaps in acetal, using the plastic going tolower horsepower engines. But neither of thesedesigns actually did anything in regards to thedrivetrain vibration. The new design, bycontrast, virtually eliminates shift clunk,Anderson reports.

And it also does greater than fend off vibration.The propellor hub has been created to serve asa spring exclusively for the very first 10 levels ofprop rotation. Next, it transfers each of thetorque from drivetrain to propeller -- about 260in-lb of torque when fully loaded.

There's no doubt boaters just like the smooth,quiet shifting. For engineers, though, the nicething about it can be how it combines the bestof metals and plastics into a single component.Titanium alone wouldn't provide the rotationalrange, additionally it might have been toopricey. The polymer alone didn't get themodulus found it necessary to conserve aconstant spring force over time or absorbenough energy in higher horsepower

drivetrains.

Together both materials meet these goals and much more. Anderson adds that this acetal alsoprotects metals near to the titanium from galvanic acts and corrosion as a safeguard againstpropeller impacts. "The plastic part, which happens to be easily replaceable, shears away by designto save the greater number of expensive propeller," he says.

So, far, the latest hub isolator has been a big success for Mercury Marine. It's already in service onthe company's supercharged 4-cylinder, 4-stroke outboard engines up to 200 HP. "There haven'tbeen any warrantee claims," Anderson notes. In the future, the corporation wants to extend the styleto engines as much as 275 HP.

Mercury Marine's propeller hub isolator was the subject of a technical paper with the recentStructural Plastics Conference and New Product Design Competition.