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Old 08-12-13, 01:59 PM   #21
wideguy
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Default Re: USD forks? Been there done that - try USD engine.

A well designed crankcase is strong enough to handle the loads imposed on it by the engine and transmission, but no stronger. Using the crankcase for a stressed frame member requires that it be made stronger. Hopefully the designers made their crankcase strong enough to handle both duties, and if they did, they made the crankcase heavier than it would have been if it was not being used as a part of the frame.
The heaviest parts of an engine assy. are the crankshaft and transmission. Turning an engine upside down puts the heavier parts higher up. Moving the oil from the crankcase to the top of the bike adds to this. Most bike designers seem to agree, the CG should be low, not high. Could be they've been wrong about this for many years, but I doubt it. Honda has tried various weight distribution schemes for their GP bikes over the years, and it didn't result in them moving the CG upwards.
I think the builders of this bike did a fantastic job. It's light, powerful and visually striking. I can see that without having any hard numbers.
What it isn't is innovative, other than perhaps the idea that a high CG will improve handling.
200 hp from a 2 liter engine isn't difficult, even from an air cooled bike, and I could be wrong about the cooling. As you say, time will tell.
I simply suspect that there are good reasons why they didn't provide dyno numbers or lap times, or let independent testers ride it in city traffic, or anywhere else.
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Old 08-12-13, 05:12 PM   #22
Sid Squid
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Default Re: USD forks? Been there done that - try USD engine.

Is it a good bike? Hmmm... I don't know and I doubt I'll ever find out, I can see the arguments used to provoke the thinking that inspired it, but that's not to say I agree. There are several things about it, primarily the higher CofG that are bound to cause disagreement. Taking that first, it has been shown that a raised CofG can improve traction, both acceleration and braking, under certain circumstances, in this I am recalling the experimentation done in - as I remember, the early eighties - by some independent chassis builders, (Peckett and McNab comes to mind, but I'd have to check a book for confirmation), who constructed a mechanical anti dive front brake/suspension system, and also the anti squat linkage used by Honda, and possibly others, that mounted the rear caliper freely on the wheel spindle, and applied brake torque via a linkage into the frame such as to extend the rear suspension. Both of these raised the CofG, even if only slightly, but with demonstrable improvements in traction under test circumstances.
The principle is simple and easily demonstrated, on a grippy surface place a box, push on the box at the very bottom and it will move across the surface, then push at the top, the box will tip up pushing the front edge downward - it grips better.
Clearly in any given experiment the box's smoothness and that of the surface will play their part in the results, but the principle is sound - whether any such advantage in the areas that it may give outweigh any disadvantages it may saddle one with in other areas is the question. A question I don't have an answer for - but I suspect you guessed that already.

Does any of this suggest the bike in question is 'better'? I doubt it, but as with all dynamic devices every part of the construction is a compromise between the varying demands of it's foreseeable use, as such the - potentially - improved degree of frame stiffness and the, again - potentially - improved cooling airflow, may shift those compromises for the better or for the worse. Frame stiffness is a double edged sword, clearly a certain amount of stiffness is a necessity, but as Ducati have found too much may be problematic as well, and tuning the strengths of the frame in the varying axes is a science of terrifying complexity. Add to this that modern beam framed road bikes are hardly suffering from a deficiency in this area, so this machine may simply be addressing in this respect a problem we don't have to any significant degree.

Personally I think it's an interesting curio, but ultimately a developmental cul-de-sac, I rather suspect, in engineering terms at least, that Wideguy is correct, but, for the reasons previously stated, I don't think that's necessarily the major factor, I heartily applaud those who constructed it though, and hope that they and others continue to try and push us all on to better things with their efforts, even if some of their ideas do not bear fruit, but that's an inevitability of design and redesign.
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Old 08-12-13, 07:16 PM   #23
orose
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Default Re: USD forks? Been there done that - try USD engine.

I must admit, one of the most interesting things from where I'm sitting (as a non-mechanical engineer) is the reversal of the cylinders. In my head, it always seemed strange that the inward bound air is drawn from the rear rather than the front, and the reverse with the exhaust where the airflow could assist in clearing the gases.
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Old 09-12-13, 10:14 PM   #24
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Default Re: USD forks? Been there done that - try USD engine.

Modern practice to get the most air through an engine is to use velocity stacks on the throttle bodies and feed them with a tuned air box/intake system. It would be hard to find a way to make it work in the front of a bike, as far as location goes. Probably if you moved the radiator... but it might look less than cool.
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