Given that getting information out of Ducati is about the equivalent of extracting pennies from Scrooge’s purse, what we have so far is not to go on. However, a couple of track outings, some pictures and a heavily-doctored video still can’t disguise the fact that some opinions can already be formed about the team’s contender for the new formula next year.
Despite generally looking like the current GP11, there are several key differences between the 800cc machines used at Jerez for the race a week or so ago and the 1000cc prototypes tested a few days later.
1: Engine. We might not be able to actually see the new V4 in the Desmosedici GP12, but there is one clue to the fact it fits the new 2012 regulations – the exhaust pipes are far longer.
While we can’t see the additional length in the under-seat pipe from the rear cylinders, the side-mounted exhaust that the front pair breathe out of extends about a foot backwards – more like a road bike system than the usual truncated stub that sits flush with the side panel on the GP11.
That gives a clue to the three biggest changes of the 2012 MotoGP regulations; the additional engine capacity, the introduction of an 81mm limit for the cylinder bore and the fact engines designed for the new formula must last far longer. Those three rule changes add up to one thing – much lower rev limits.
The ideal length of an exhaust will be longer for lower-revving engines than for higher-revving ones, so the fact the GP12 has several inches more pipe suggests the motor isn’t reaching anything like the peak revs of the current machine.
While Ducati has experience of higher capacity V4s with the 990cc motor in the original Desmosedici, that bike used a far bigger bore and shorter stroke than would be allowed under the new rules – reducing peak piston speed and allowing the engine to rev higher. The road going Desmosedici RR that’s derived from the older 990 machine uses a huge 86mm bore, way bigger than the 2012 regulations allow.
The firm’s trademark desmo valve system helped the old engine achieve high revs even while other firms started resorting to pneumatic valves. Under the new rules, desmo won’t be such a benefit, as piston speed and the need for longevity will limit peak revs long before valve float becomes an issue. The long exhausts of the new bike show Ducati hasn’t (yet) found a way to restore those lost revs.
2: Swingarm. The GP12 prototype tested by Hayden and Rossi features a new swingarm design and linkage, with the bracing for the arm moved from the top to underneath.
Although it’s hard to be certain from pictures alone, it appears that the new swingarm, like the frame, is made of carbon fibre. This change is interesting, as it is something that could well appear on the GP11 well before the end of this season as Ducati battles to improve its handling and lap times. Indeed, some have speculated that Ducati’s decision to test the GP12 so publicly this early in the season is something of a smokescreen – with testing of current GP machines strictly limited, the ability to run the GP12 (which doesn’t fall under the testing ban, as it’s not legal to race under the current regulations) means Ducati can also get more miles on parts that could be just as useful on the 800cc bike as on the future 1000cc machine. (my emphasis)
3: Bodywork. One thing that we’ve seen a lot of this year is Ducati riders chopping and changing between different sets of bodywork. While the GP11 sported distinctive new styling at its pre-season launch – with “shark gill” air vents, side-mounted winglets, a heavily sculpted belly pan, a lower nose and a different seat unit to the GP10 – so far both Hayden and Rossi have ended up racing with bodywork that’s far more like that of last year’s bike, suggesting there’s still work to be done to perfect the aerodynamic behaviour of the new design.
The GP12’s bodywork is much more clearly derived from the styling that the GP11 was launched with, including the new seat, nose, belly and side panels, albeit without the winglets. Again, since it’s clear Ducati originally intended to race with this type of bodywork during 2011, the GP12 test will surely have given information that will be useful long before the 1000cc engine is actually needed.
thanks to visordown for this story