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Old 10-22-2015, 08:19 AM   #21
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The really long head bolts which go right down to the casing are unique as well.

I'll have to read the spaceballs thing a few more times through.
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Old 10-22-2015, 08:25 AM   #22
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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?
At wot, there is no outboard that produces 14 hp per gph. The best I have seen is 12 and a lot of them are less than 11. The Yanmar diesel should do 20 as it is a small displacement (for 50 hp), turbo charged, common rail. That is a 67% improvement over the best gas outboard.

I agree that it will take a lot of hours to justify it based on fuel usage. It all depends on price, but as Ski said low volume high tech manufacturing is expensive.

David
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Old 10-22-2015, 08:51 AM   #23
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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?
Why buy a diesel car? Same reasons.

Spy the long bolts could stretch.

Ski (re your #19) you mean one cyl engines have no torsional vibration? I would think one cyl engines would have max torsional vibration. Looks like I may not know what it is.
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Old 10-22-2015, 12:40 PM   #24
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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?
Handy not to have to carry gasoline onboard for an outboard.

Could make a standby engine for a trawler: bolt a jack plate onto the transom and drop on the diesel OB....
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Old 10-22-2015, 12:59 PM   #25
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Spy the long bolts could stretch.
I would imagine they are torque to yield fasteners with a hard head gasket to get maximum sealing.
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Old 10-22-2015, 05:06 PM   #26
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Handy not to have to carry gasoline onboard for an outboard.

Could make a standby engine for a trawler: bolt a jack plate onto the transom and drop on the diesel OB....
Yep, no longer have to carry gas that goes boom on the boat and you have a common fuel for the trawler and outboard. With the common fuel you now have a workable, sorta, backup engine.

Later,
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Old 10-22-2015, 05:57 PM   #27
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Why buy a diesel car? Same reasons.

Spy the long bolts could stretch.

Ski (re your #19) you mean one cyl engines have no torsional vibration? I would think one cyl engines would have max torsional vibration. Looks like I may not know what it is.
Long bolts and short bolts stretch to get the clamping force. Long bolts actually easier to deal with as clamping force as clamped parts heat and cool. Bolts are really just stiff springs.

Torsional vibration usually refers to a shaft like a crankshaft twisting and acting like a spring doing it. That's why straight sixes have the "torsional damper" on the nose. Absorbs energy from the twisting vibration. Short cranks have no such issue.

But low cylinder count engines have another issue that is not really "torsional vibration". I'm not sure what is the best term, but "unsteady rotational speed" seems to fit. The engine speeds up and slows down with firing and compression, and this applies shake to the engine structure, rattles the boat, and rattles whatever is being driven.

Looks like the Neander will still have unsteady rotational speed, but the CR cranks will prevent the engine itself from shaking. Whether 1, 2, or more cyl. But not 100% on how it will behave. A big part is if there is one or two flywheels and what their inertia is. If different, engine will still shake.
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Old 10-22-2015, 08:07 PM   #28
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Thanks Ski,
So that's why they call the "torsional"vibration dampener "torsional". And then there's torsion bar suspension .. think Crysler products (50s).
I thought the jerking unsteady rotational movements of rotational parts connected to the crankshaft and the crankshaft itself was torsional vibration. The effects can be clearly seen on gravel or a beach where a motorcycle rear wheel "scratches" or looses traction when the abrupt torque of a single cylinder fires. I'll be looking for a word or perhaps a pair of words to express that.

I once had an inline 3 cyl motorcycle (4 stroke) that had a gear driven flywheel that rotated opposite of the crankshaft. There was none of the sideways or torque rotational movement of a normal motorcycle w an inline (w the wheels) crankshaft .. think BMW or Goldwing. Flywheels rotating opposite the crankshaft has a profound effect on vibration .. or lack of it. With this 3cyl motorcycle I could go 70mph or more for miles not being in top gear. Sometimes I'd be cruising down the highway .. Look down at the gear position indicator and see that I was in 4th and not 5th.

But the big plus w this Yanmar twin is the near vertical thrust direction from piston pin to crankpin. That should bring about large increases in efficiency and even larger life to pistons. And perhaps less need for high viscosity in the lube oil.
Some engines in the past have had cylinder bores slightly offset to reduce side thrust and have a better mechanical advantage but nothing like this Yanmar. I'm in awe of Yanmar for developing such a monumental breakthrough. Off the top that's what it seems to be. Does anyone know any different?
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Old 03-23-2016, 04:33 PM   #29
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Ski, the term I think you are looking for is "torque ripple." All motors have torque ripple, some configurations more than others, depending on RPMs and throttle position/load.

This is different from the torsional vibration as you likely know, that depends on the inertia and stiffness of the drivetrain and the excitation from power stroke events.

For example, a Harley big twin (45 degree Vtwin) can generate a torque ripple of 600 ft-lbs (or more) at the crank, hence the need for primary end torque devices. Diesels have relatively large fluctuations in torque as well, but that is designed for and is part of why all the rotational and up/down stuff is heavy.

I think this new motor is pretty cool for boats up to a certain size. I recall seeing some Devlin Design boats with OB's in this HP range that were spacious for their length and got good range/milage too.

Edit: OK, after reading closer, I think what they are referring to here is that the twin crank/rod design allows them to design out the forces that cause an outboard to try to rotate around its steering axis, which would be really nice to have and would really smooth out the power delivery and forces/vibration applied to the transom.
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Old 03-23-2016, 08:33 PM   #30
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The proof is in the pudding!!!

They should send me one and I will test it and report back!!
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Old 03-23-2016, 09:01 PM   #31
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In some things I've read Neander is specifically aiming at the commercial users of outboards, or for tenders to mega yachts. Kinda leaves the likes of us out of the loop...however, the amount of torque this outboard has at low speeds makes it interesting;

Quote:
The force of a Neander diesel engine is shown in its excellent torque, which is available even at very low speeds. The power advantage in comparison with gasoline-driven outboard motors can be felt from the very first seconds of operation.Because of its high torque, the 55 hp Neander diesel can directly compete with a 70 hp petrol-driven outboard.
M A R X - Technik entdecken
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Old 03-23-2016, 11:17 PM   #32
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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.
That is going to take some time to digest...
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Old 03-24-2016, 05:14 AM   #33
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That is going to take some time to digest...
I still haven't recovered from the shock of ' cutting and pasting' that quote. Lol!
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