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Old 10-21-2015, 01:38 PM   #1
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Yanmar re-enters 50hp Diesel outboard market with Neander!!!!

Wow, at last a replacement for the old Yanmar 28hp diesel OB.

Yanmar takes on global diesel outboard distribution from NEANDER - Yanmar Marine

NEANDER Outboard Engine : Neander Shark

What do you think..?
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Old 10-21-2015, 02:10 PM   #2
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I wish we could purchase a NEANDER Shark Turbo Diesel outboard engine in the US.
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Old 10-21-2015, 02:34 PM   #3
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I wish we could purchase a NEANDER Shark Turbo Diesel outboard engine in the US.
Ah, I didn't realise it doesn't comply with US regs; are you sure you can't import it from Europe?

I've sent off an email to get the price.

What do you think: 2x as much as a gasoline 50hp?
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Old 10-21-2015, 02:40 PM   #4
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Have a look at the engineering: wtf!!!

Technology : Neander Shark

The key enabler for a dual crankshaft engine with a constrained piston movement by two con-rods with theoretically no piston side forces is provision for forgiveness towards tolerances, which can lead to off-design positions of the piston in its cylinder bore and unfavorable mechanical effects like scuffing, sticking or simply higher friction as the least bad of effethis

PS: I had to look at the photos to understand this....lol.
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Old 10-21-2015, 04:15 PM   #5
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Neat stuff!!!
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Old 10-21-2015, 04:21 PM   #6
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Neat stuff!!!
Sounds like a complicated solution to a simple problem: vibration .

What's wrong with a counter weigh/damper on the crank/flywheel?
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Old 10-21-2015, 05:02 PM   #7
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Sounds like a complicated solution to a simple problem: vibration .

What's wrong with a counter weigh/damper on the crank/flywheel?
Increase weight??
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Old 10-21-2015, 05:16 PM   #8
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Increase weight??
I think a standard 50hp gas outboard would be about 100-110kg, so 175kg for the diesel is pushing the limits on the transom of a planing hull designed for half the load.

I'm thinking you would need a redesigned hull to take the extra weight.

Maybe its designed for displ. Speeds?
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Old 10-21-2015, 05:28 PM   #9
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Sounds like a complicated solution to a simple problem: vibration .

What's wrong with a counter weigh/damper on the crank/flywheel?
A two cylinder four stroke is an infernal machine. With two pistons moving together, firing is 360deg, but dynamic balance is HORRIBLE. Counterweights on the fw or crank can help, but they provide a rotating force, the piston force is linear along bore axis. Only way to cancel is to have a counter rotating balance shaft. Which these guys basically get with the two cranks.

Only thing with worse vibes is a single cyl, and not by much!!

Better balance can be had by a 180deg crank, with pistons moving opposite. But then firing order is 180deg/540deg which provides it's very own special flavor of shake at low rpm. Also sounds horrible. Sounds like a misfiring three cyl. And balance of the 180deg crank is better, but still sucks.

The Neander design looks like it has or nearly has perfect mechanical balance. Weights added to the CR cranks will act linear like the piston forces and should be able to nearly cancel.

I think also the low rpm shake from firing impulses is canceled too.

Maybe they could use this design for the snotty running four stroke two cyl gassers.

Only downside I see is cost. Low volume Euro stuff is expensive.
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Old 10-21-2015, 05:47 PM   #10
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A two cylinder four stroke is an infernal machine. With two pistons moving together, firing is 360deg, but dynamic balance is HORRIBLE. Counterweights on the fw or crank can help, but they provide a rotating force, the piston force is linear along bore axis. Only way to cancel is to have a counter rotating balance shaft. Which these guys basically get with the two cranks.

Only thing with worse vibes is a single cyl, and not by much!!

Better balance can be had by a 180deg crank, with pistons moving opposite. But then firing order is 180deg/540deg which provides it's very own special flavor of shake at low rpm. Also sounds horrible. Sounds like a misfiring three cyl. And balance of the 180deg crank is better, but still sucks.

The Neander design looks like it has or nearly has perfect mechanical balance. Weights added to the CR cranks will act linear like the piston forces and should be able to nearly cancel.

I think also the low rpm shake from firing impulses is canceled too.

Maybe they could use this design for the snotty running four stroke two cyl gassers.

Only downside I see is cost. Low volume Euro stuff is expensive.
Thanks for your explanation; very interesting..

Here's a video showing the setup:
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Old 10-21-2015, 06:59 PM   #11
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Counter weights on a single or 360 twin if heavy enough can counter Ballance for up and down but when the counter weights are thrown sideways (as in 90 or 270 degrees) there's nothing to the side to counter weight wise so most engineers compromise by giving the counter weight about 1/3 of a total up and down Ballance. Old Brittish twin cyl motorcycles were all (almost) w 360 cranks and were quite smooth to about 50% rpm max but terrible above that.

For a smooth engine I've thought a 90degree V3 w the single cyl side having a cyl about twice the size as the twin cyl side would be good. No counterweights required ... I think.

But this Yanmar twin connecting rod engine will be very widespread soon .. I think. The Pistons coming almost straight down on the crank pins is a wonderful new design. If they have it heavily patented they should make millions with it.
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Old 10-21-2015, 07:44 PM   #12
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This would also work on a single cyl.
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Old 10-21-2015, 07:46 PM   #13
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I'll bet these engines will show up on the new pocket trawler Ken Fickett is designing at Great Harbour.
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Old 10-21-2015, 08:17 PM   #14
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Quote:
The key enabler for a dual crankshaft engine with a constrained piston movement by two con-rods with theoretically no piston side forces is provision for forgiveness towards tolerances,
Does this mean it will be built with hand tools in a country with the cheapest labor?
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Old 10-21-2015, 08:37 PM   #15
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The big question is do we really need a expensive heavy hard to maintain 50hp diesel when we have so many cheap light 4 stroke petrol outboards that have a proven history ?

And as my late father would say DON'T mention the WAR
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Old 10-21-2015, 09:17 PM   #16
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This would also work on a single cyl.
Ski,
What about torsional vibration?
This would be an engine w more crankshafts than cylinders?
gaston,
"Light 4 stroke gas ... " never heard that one before.
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Old 10-21-2015, 09:32 PM   #17
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Ski,
What about torsional vibration?
This would be an engine w more crankshafts than cylinders?
gaston,
"Light 4 stroke gas ... " never heard that one before.
The Honda 50 is within a few kg of the Yamaha 50 2 stroke so yes light 4 stroke
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Old 10-21-2015, 10:48 PM   #18
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gaston,
Yamaha is offering a 50hp 2 stroke?
Must be like the Evinrude E-tec. And they aren't light.
Only light OB is an old one.
I'll look up the Yamaha though.

Went to the Yamaha site and the only 50hp engine was SOHC and 249lbs or 113kg. The Yanmar diesel OB is 175kg.
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Old 10-21-2015, 11:33 PM   #19
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Ski,
What about torsional vibration?
This would be an engine w more crankshafts than cylinders?
gaston,
"Light 4 stroke gas ... " never heard that one before.
Torsional vibes are an issue with long multi cylinder crankshafts. Crank flexes in the twisting sense, and has a natural frequency that can get excited by firing pulses. Not really an issue with few cylinders, the cranks are relatively stiff in the twisting sense.

But I do wonder about gear lash between the cranks, and how ever they extract the output. Guess one crank is driving output shaft, other is geared to the main, so a prime candidate for gear lash rattle.

Proof is in the pudding!! I'd love to see the details and fiddle with one. Some elegance seen in the casual glance!!
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Old 10-22-2015, 06:44 AM   #20
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WHY a Diesel?

With many new fancy gas engines creating 14hp per gal/hr and diesel 15%+ more costly than gas why bother?

Surely you wont be up in the 1,000 - 2,000 hours of operation per year that might justify a diesel?
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