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New French made motorcycle

The model stands out in particular for its low level of longitudinal inertia...

Is that another way of saying it's slow? 🙂

I'm just amazed at how these guys get enough cash/financing to build the things. How many do they really expect to sell?
 
XabanakFanatik said:
I'm pretty sure there's a reason I've never seen another motorized vehicle with a cylinder pointed downward....
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Airplanes did it very often when they had piston engines. There's no mechanical reason an engine can't have its cylinders pointed downwards.

Usually the crankshaft is low on wheeled vehicles to facilitate better packaging. Having the crankshaft at the bottom of the engine makes it easier to mount a transmission to the wheels.

The inverted engine was common on airplanes because having the crankshaft high helped keep the propeller well above the ground for takeoff and landing. The Messerschmitt 109 and the de Havilland Tiger Moth, two very famous and reliable aircraft, both had inverted engines with the cylinders pointing down.

ZV
 
Zenmervolt said:
Airplanes did it very often when they had piston engines. There's no mechanical reason an engine can't have its cylinders pointed downwards.

Usually the crankshaft is low on wheeled vehicles to facilitate better packaging. Having the crankshaft at the bottom of the engine makes it easier to mount a transmission to the wheels.

The inverted engine was common on airplanes because having the crankshaft high helped keep the propeller well above the ground for takeoff and landing. The Messerschmitt 109 and the de Havilland Tiger Moth, two very famous and reliable aircraft, both had inverted engines with the cylinders pointing down.

ZV
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Maybe I am mistaken but I thought that even with multiple piston rings, there was still some amount of oil leakage into the cylinder? Wouldn't a cylinder pointed downward allow the (very slow) leakage to occur over time which happens frequently with motorcycles?

Edit: I understand Yahoo Questions isn't necessarily a reliable source, but... Link.
 
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Zenmervolt said:
Airplanes did it very often when they had piston engines. There's no mechanical reason an engine can't have its cylinders pointed downwards.

Usually the crankshaft is low on wheeled vehicles to facilitate better packaging. Having the crankshaft at the bottom of the engine makes it easier to mount a transmission to the wheels.

The inverted engine was common on airplanes because having the crankshaft high helped keep the propeller well above the ground for takeoff and landing. The Messerschmitt 109 and the de Havilland Tiger Moth, two very famous and reliable aircraft, both had inverted engines with the cylinders pointing down.

ZV
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Yes, and if they sat for a while, you would see them being turned over by hand to clear oil from the lower cylinders, because if you tried to start them, they would lock up.

And you'd see them smoke like hell on startup after they were rotated by hand. 😀
 
XabanakFanatik said:
Maybe I am mistaken but I thought that even with multiple piston rings, there was still some amount of oil leakage into the cylinder? Wouldn't a cylinder pointed downward allow the (very slow) leakage to occur over time which happens frequently with motorcycles?

Edit: I understand Yahoo Questions isn't necessarily a reliable source, but... Link.
Click to expand...

Piston ring technology and engine clearances have come a very long way since those engines were designed in the 1940s.

With a dry sump oiling system and an auxiliary electric scavenge pump you could avoid having anything more than a nominal amount of oil in the lower cylinder even after extended periods of non-operation.

It probably adds a degree of complexity, but it's far from insurmountable.

ZV
 
Zenmervolt said:
Piston ring technology and engine clearances have come a very long way since those engines were designed in the 1940s.

With a dry sump oiling system and an auxiliary electric scavenge pump you could avoid having anything more than a nominal amount of oil in the lower cylinder even after extended periods of non-operation.

It probably adds a degree of complexity, but it's far from insurmountable.

ZV
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Which begs the question, why do it on a bike?
 
Greenman said:
Which begs the question, why do it on a bike?
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Same reason you'd make a $186,000 bike. 😛

Also, IIRC all Harleys (Sportsters and Big Twins for certain) are dry sump, so dry sump alone can't cost that much. The addition of an electric scavenge pump shouldn't be absurdly expensive.

Honestly though, the angle isn't that severe and it's probably possible to prevent most seepage simply though the casting design of the sump.

ZV
 
Zenmervolt said:
Same reason you'd make a $186,000 bike. 😛

Also, IIRC all Harleys (Sportsters and Big Twins for certain) are dry sump, so dry sump alone can't cost that much. The addition of an electric scavenge pump shouldn't be absurdly expensive.

Honestly though, the angle isn't that severe and it's probably possible to prevent most seepage simply though the casting design of the sump.

ZV
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I don't think any Harley is a dry sump. I don't recall ever seeing an external oil tank.

Back on topic. I don't see the point of creating something different just because it's different. For my $186k bike, every single detail had better have been thought out, and every part manufactured to the highest possible standards from the finest material. I still wouldn't buy it, but I might approve of it. And lets face it, doesn't everyone want my approval?
 
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Greenman said:
I don't think any Harley is a dry sump. I don't recall ever seeing an external oil tank.
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All the Big Twins and Sportster models are dry sump since the 1930s. The oil tank on some modern (mid-1980s and newer) models (Sportster and Softail) sits under the seat on the right hand side of the bike. The Dyna and Touring models have the oil reservoir behind the engine and primary and it looks as though it's in the same case, but it's still a separate reservoir from the sump and is still a dry sump system (basically, on the Dyna and Touring bikes the remote reservoir is cast into the engine/transmission case behind/beneath the transmission).

In the photograph on this page you can see the Softail's oil tank clearly behind the rear cylinder, above the rear exhaust, and below the seat. If you look closely, you can see the two hard oil lines going to the tank (chrome) and the filler cap (also chrome).

Greenman said:
Back on topic. I don't see the point of creating something different just because it's different. For my $186k bike, every single detail had better have been thought out, and every part manufactured to the highest possible standards from the finest material. I still wouldn't buy it, but I might approve of it. And lets face it, doesn't everyone want my approval?
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Given the mediocre power level, I'd argue that different for the sake of being different is the only way to justify the bike's price. The manufacturer isn't selling the bike per-se, it's selling the exclusivity of owning something that is one of 35. The bike needs to look obviously different or there's not much point to it.

ZV
 
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